Category Archives: Emissions

Drought and heat together menace American West

Climate change really is a burning issue. Simultaneous drought and heat are increasingly likely for more of the American West.

LONDON, 13 October, 2020 − The American West is about to get hotter. It is also about to get drier. To make things worse, extremes of heat and of drought will happen more often at the same time.

And to compound the damage, such simultaneous assaults are likely to extend over larger areas and become more intense and more frequent, thanks to climate change driven by profligate use of fossil fuels and other human decisions.

This is not a prediction based on computer simulations of the future. It is already happening, and the story can be traced − according to the journal Science Advances − in the narrative of hot spells and dry weather over the entire contiguous United States for the last 122 years.

Not only have combined hot and dry episodes increased in frequency, they have also grown in size in geographic terms. Where once they happened in confined localities, they now extend over whole regions, such as the entire West Coast, and parts too of the Northeast and the Southeast.

Another Dust Bowl?

“Dry-hot events can cause large fires. Add wind and a source of ignition, and this results in ‘megafires’ like the 2020 fires across the west coast of the United States. Drought and record-breaking heatwaves, coupled with a storm that brought strong winds and 12,000 lightning events in a span of 72 hours, caused more than 500 wildfires,” said Mohammad Reza Alizadeh, of McGill University in Canada, who led the research.

Heat extremes can be damaging or even devastating. So can drought. When the two coincide, their compound impact can be tragic. The study also suggested that in some way such double jeopardy events could be self-propagating: they could spread downwind, seriously bad news for the American West and other areas at risk.

Long before any fears of the climate emergency, the US Midwest was scarred by drought, and in the 1930s Oklahoma and Kansas in particular became a “Dust Bowl” and inspired the classic novel The Grapes of Wrath by the American writer John Steinbeck.

“We observed that concurrent dry and hot events of similar intensity are becoming more frequent,” said Mojtaba Sadegh, an engineer at Boise State University in Idaho, and the senior author.

“Our results point to an urgent need to take action to enhance resilience to compound hot and dry events”

“The difference is that, in the 1930s, lack of precipitation led to the local atmosphere becoming hotter, whereas in recent decades increased temperatures are driving aridity. The triggering mechanism for compound dry-hot events is changing from lack of precipitation to excess heat.”

The warning of worse to come coincides with news that California’s fires have become so bad that they warrant a new classification: the “gigafire”, with so much smoke emitted from the combined fires of California and Oregon that fumes have been detected in New York, in northern Europe, and far into the Pacific.

Researchers have repeatedly warned of the double hazard of heat and drought and the combined impact on the US, as a consequence of climate change driven by greenhouse gas emissions from power station chimneys and automobile exhausts, as well as destruction of the natural wilderness.

“This research raises an alarm about increasing frequency and intensity of compound hot and dry events,” said Dr Sadegh. “Three such events between 2011-2013 in the US caused $60bn (£46bn) in damages. Our results point to an urgent need to take action to enhance resilience to compound hot and dry events.” − Climate News Network

Climate change really is a burning issue. Simultaneous drought and heat are increasingly likely for more of the American West.

LONDON, 13 October, 2020 − The American West is about to get hotter. It is also about to get drier. To make things worse, extremes of heat and of drought will happen more often at the same time.

And to compound the damage, such simultaneous assaults are likely to extend over larger areas and become more intense and more frequent, thanks to climate change driven by profligate use of fossil fuels and other human decisions.

This is not a prediction based on computer simulations of the future. It is already happening, and the story can be traced − according to the journal Science Advances − in the narrative of hot spells and dry weather over the entire contiguous United States for the last 122 years.

Not only have combined hot and dry episodes increased in frequency, they have also grown in size in geographic terms. Where once they happened in confined localities, they now extend over whole regions, such as the entire West Coast, and parts too of the Northeast and the Southeast.

Another Dust Bowl?

“Dry-hot events can cause large fires. Add wind and a source of ignition, and this results in ‘megafires’ like the 2020 fires across the west coast of the United States. Drought and record-breaking heatwaves, coupled with a storm that brought strong winds and 12,000 lightning events in a span of 72 hours, caused more than 500 wildfires,” said Mohammad Reza Alizadeh, of McGill University in Canada, who led the research.

Heat extremes can be damaging or even devastating. So can drought. When the two coincide, their compound impact can be tragic. The study also suggested that in some way such double jeopardy events could be self-propagating: they could spread downwind, seriously bad news for the American West and other areas at risk.

Long before any fears of the climate emergency, the US Midwest was scarred by drought, and in the 1930s Oklahoma and Kansas in particular became a “Dust Bowl” and inspired the classic novel The Grapes of Wrath by the American writer John Steinbeck.

“We observed that concurrent dry and hot events of similar intensity are becoming more frequent,” said Mojtaba Sadegh, an engineer at Boise State University in Idaho, and the senior author.

“Our results point to an urgent need to take action to enhance resilience to compound hot and dry events”

“The difference is that, in the 1930s, lack of precipitation led to the local atmosphere becoming hotter, whereas in recent decades increased temperatures are driving aridity. The triggering mechanism for compound dry-hot events is changing from lack of precipitation to excess heat.”

The warning of worse to come coincides with news that California’s fires have become so bad that they warrant a new classification: the “gigafire”, with so much smoke emitted from the combined fires of California and Oregon that fumes have been detected in New York, in northern Europe, and far into the Pacific.

Researchers have repeatedly warned of the double hazard of heat and drought and the combined impact on the US, as a consequence of climate change driven by greenhouse gas emissions from power station chimneys and automobile exhausts, as well as destruction of the natural wilderness.

“This research raises an alarm about increasing frequency and intensity of compound hot and dry events,” said Dr Sadegh. “Three such events between 2011-2013 in the US caused $60bn (£46bn) in damages. Our results point to an urgent need to take action to enhance resilience to compound hot and dry events.” − Climate News Network

Hotter seas imperil both human and marine life

Climate warming brings hotter seas. The waters mix less. And conditions for some creatures could grow increasingly stifling.

LONDON, 9 October, 2020 − Climate change has led to hotter seas across the world: in 2018 European water temperatures reached record levels, and a marine heatwave in the north-east Pacific devastated marine life.

Less predictably, global heating has made the oceans more stable, with discrete, stratified layers that resist mixing. And that could be very bad news, because it could make the blue water that covers 70% of the planet less effective at absorbing atmospheric heat and thus mitigating climate change.

And ever-warmer sea temperatures could have another unwelcome impact: as temperatures rise, levels of dissolved oxygen fall. And that could make it difficult for some sea creatures to breathe.

The oceans play a vital role in the water, energy and carbon cycles upon which all life depends. In 2010, demographers counted 1.9 billion people living within 100kms of the sea and less than 100 metres above sea level: that is 28% of all humanity. Many of them are crowded into 17 megacities with populations of more than 5 million people each. For many, the sea is the neighbourhood.

European researchers warn, in a new and detailed report on the state of the oceans from 1993 to 2010, that the rise in sea temperatures in the Mediterranean is without precedent, and the largest rise of all has been measured in the Arctic Ocean.

“Human society has always been dependent on the seas. Failure to reach good environmental status for our seas and oceans is not an option”

They also call as a matter of urgency for comprehensive and systematic monitoring of the ocean. “Human society has always been dependent on the seas,” they warn. “Failure to reach good environmental status for our seas and oceans is not an option.”

Chinese and US scientists report in the journal Nature Climate Change that − beyond reports of stronger winds and waves and ever more intense tropical cyclones − the rise in atmospheric temperatures has fundamentally altered oceanic temperatures and salinity, with a paradoxical effect: the seas have become more stable. Warm and therefore less dense surface water lies upon colder, more saline and denser waters at depth, to limit overall mixing.

Since 1960, the upper 2000 metres of the oceans have become 5% more stratified, and the top 150 metres 18% more stratified.

“The same process, global warming, is both making the atmosphere less stable and the oceans more stable. Water near the ocean’s surface is warming faster than the water below. That makes the oceans become more stable,” said Michael Mann of Penn State University in Pennsylvania, one of the team.

“The ability of the oceans to bury heat from the atmosphere and mitigate global warming is made more difficult when the ocean becomes more stratified and there is less mixing. Less downward mixing of warming waters means the ocean surface warms even faster, leading, for example, to more powerful hurricanes. Global climate models underestimate these trends.”

Struggle for survival

Warmer temperatures don’t just make the oceans more stable, they may make living conditions more uncomfortable or even impossible for some of the sea’s citizenry.

US researchers report in the journal Nature that they looked at the physiological challenge of oxygen and energy demands faced by 145 marine species − including shrimps, catsharks and sea squirts − to find that many are already under pressure.

“Organisms today are living right up to the warmest temperatures possible that will supply them with adequate oxygen for their activity level – so higher temperatures are immediately going to affect their ability to get enough oxygen,” said Curtis Deutsch of the University of Washington.

“In response to warming, their activity level is going to be restricted or their habitat is going to start shrinking. It’s not like they are going to be fine and carry on.” − Climate News Network

Climate warming brings hotter seas. The waters mix less. And conditions for some creatures could grow increasingly stifling.

LONDON, 9 October, 2020 − Climate change has led to hotter seas across the world: in 2018 European water temperatures reached record levels, and a marine heatwave in the north-east Pacific devastated marine life.

Less predictably, global heating has made the oceans more stable, with discrete, stratified layers that resist mixing. And that could be very bad news, because it could make the blue water that covers 70% of the planet less effective at absorbing atmospheric heat and thus mitigating climate change.

And ever-warmer sea temperatures could have another unwelcome impact: as temperatures rise, levels of dissolved oxygen fall. And that could make it difficult for some sea creatures to breathe.

The oceans play a vital role in the water, energy and carbon cycles upon which all life depends. In 2010, demographers counted 1.9 billion people living within 100kms of the sea and less than 100 metres above sea level: that is 28% of all humanity. Many of them are crowded into 17 megacities with populations of more than 5 million people each. For many, the sea is the neighbourhood.

European researchers warn, in a new and detailed report on the state of the oceans from 1993 to 2010, that the rise in sea temperatures in the Mediterranean is without precedent, and the largest rise of all has been measured in the Arctic Ocean.

“Human society has always been dependent on the seas. Failure to reach good environmental status for our seas and oceans is not an option”

They also call as a matter of urgency for comprehensive and systematic monitoring of the ocean. “Human society has always been dependent on the seas,” they warn. “Failure to reach good environmental status for our seas and oceans is not an option.”

Chinese and US scientists report in the journal Nature Climate Change that − beyond reports of stronger winds and waves and ever more intense tropical cyclones − the rise in atmospheric temperatures has fundamentally altered oceanic temperatures and salinity, with a paradoxical effect: the seas have become more stable. Warm and therefore less dense surface water lies upon colder, more saline and denser waters at depth, to limit overall mixing.

Since 1960, the upper 2000 metres of the oceans have become 5% more stratified, and the top 150 metres 18% more stratified.

“The same process, global warming, is both making the atmosphere less stable and the oceans more stable. Water near the ocean’s surface is warming faster than the water below. That makes the oceans become more stable,” said Michael Mann of Penn State University in Pennsylvania, one of the team.

“The ability of the oceans to bury heat from the atmosphere and mitigate global warming is made more difficult when the ocean becomes more stratified and there is less mixing. Less downward mixing of warming waters means the ocean surface warms even faster, leading, for example, to more powerful hurricanes. Global climate models underestimate these trends.”

Struggle for survival

Warmer temperatures don’t just make the oceans more stable, they may make living conditions more uncomfortable or even impossible for some of the sea’s citizenry.

US researchers report in the journal Nature that they looked at the physiological challenge of oxygen and energy demands faced by 145 marine species − including shrimps, catsharks and sea squirts − to find that many are already under pressure.

“Organisms today are living right up to the warmest temperatures possible that will supply them with adequate oxygen for their activity level – so higher temperatures are immediately going to affect their ability to get enough oxygen,” said Curtis Deutsch of the University of Washington.

“In response to warming, their activity level is going to be restricted or their habitat is going to start shrinking. It’s not like they are going to be fine and carry on.” − Climate News Network

River deltas become even riskier as climate warms

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

Antarctica’s ice loss could soon be irreversible

Global heating means the southern ice will melt. Antarctica’s ice loss could then be permanent, drowning many great cities.

LONDON, 2 October, 2020 – The greatest mass of ice on the planet is growing steadily more unstable, and that means Antarctica’s ice loss may before long be inexorable.

New studies show that right now, just one degree of warming must mean an eventual sea level rise of 1.3 metres, simply from the flow of melting ice from the continent of Antarctica.

If the annual average temperature of the planet goes beyond 2°C, then the Antarctic melting rate will double. And when global heating really steps up to 6°C or beyond, melting accelerates to the almost unimaginable level of 10 metres for every single degree rise in planetary average temperatures.

And, the researchers say, there is no way back. Even if the world’s nations stick to a promise made in Paris in 2015, to keep global heating to “well below” 2°C by the end of the century, the losses of the southern polar ice sheet cannot be restored: the process of melting, once triggered by global temperature rise, becomes inexorable.

European and US researchers report in the journal Nature that they worked through ice core records of long-ago change in Antarctica and employed a million hours of computer simulation time to build up a reliable picture of change on the Antarctic continent, in response to ever-higher planetary average temperatures, driven by ever more profligate use of fossil fuels to generate ever-higher atmospheric ratios of greenhouse gases.

Their word for the state they wanted to study is hysteresis: this can be interpreted as the way altered conditions might commit a state to further change.

“If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York”

The planet’s climate has oscillated many times over many millions of years. What this climate shift does to the polar regions can literally change the map of the planet. Antarctica is an enormous continent, the size of the US, Mexico and India together, and the ice it bears would, if it all were to melt, raise global sea levels by 58 metres.

“Antarctica holds more than half of Earth’s fresh water, frozen in a vast ice-sheet which is nearly five kilometres thick. As the surrounding ocean water and atmosphere warm due to human greenhouse gas emissions, the white cap on the South Pole loses mass and eventually becomes unstable,” said Ricarda Winkelmann, of the Potsdam Institute for Climate Impact Research.

“Because of its sheer magnitude, Antarctica’s potential for sea level contribution is enormous. We find that already at two degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 metres of global sea level rise just from Antarctica alone. At four degrees, it will be 6.5 metres and at six degrees almost 12 metres, if these temperature levels would be sustained long enough.”

That loss of ice would be slow – it would take many thousands of years – but the point the researchers make is that the continent may already be nearing a tipping point, after which the slide towards ever-higher sea levels would be unstoppable.

Since the great ice sheets of Greenland and Antarctica are part of the planetary cooling system – their whiteness reflects solar radiation back into space, so that the ice becomes its own insulation – their loss would inevitably trigger the process of further and faster warming.

Scientists from all nations have been warning for more than a decade that the continent is losing its protective screen of seaborne shelf ice, which in turn would make glacier flow towards the sea ever faster, and that the rate of loss of ice has begun to accelerate.

No going back

“In the end, it is our burning of coal and oil that determines ongoing and future greenhouse gas emissions and, therefore, if and when critical temperature thresholds in Antarctica are crossed.

“And even if the ice loss happens on long time scales, the respective carbon dioxide levels can already be reached in the near future,” said Professor Winkelmann.

“We decide now whether we manage to halt the warming. So Antarctica’s fate really lies in our hands – and with it that of our cities and cultural sites across the globe, from Rio de Janeiro’s Copacabana to Sydney’s Opera House. Thus this study really is another exclamation mark behind the importance of the Paris Climate Accord: Keep global warming below two degrees.”

And her Potsdam co-author Anders Levermann reinforced the argument. “Our simulations show that once it’s melted, it does not regrow to its initial state even if temperatures eventually sank again.

“Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery – a highly unlikely scenario. In other words: what we lose of Antarctica now is lost forever.”

And he warned: “If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York.” – Climate News Network

Global heating means the southern ice will melt. Antarctica’s ice loss could then be permanent, drowning many great cities.

LONDON, 2 October, 2020 – The greatest mass of ice on the planet is growing steadily more unstable, and that means Antarctica’s ice loss may before long be inexorable.

New studies show that right now, just one degree of warming must mean an eventual sea level rise of 1.3 metres, simply from the flow of melting ice from the continent of Antarctica.

If the annual average temperature of the planet goes beyond 2°C, then the Antarctic melting rate will double. And when global heating really steps up to 6°C or beyond, melting accelerates to the almost unimaginable level of 10 metres for every single degree rise in planetary average temperatures.

And, the researchers say, there is no way back. Even if the world’s nations stick to a promise made in Paris in 2015, to keep global heating to “well below” 2°C by the end of the century, the losses of the southern polar ice sheet cannot be restored: the process of melting, once triggered by global temperature rise, becomes inexorable.

European and US researchers report in the journal Nature that they worked through ice core records of long-ago change in Antarctica and employed a million hours of computer simulation time to build up a reliable picture of change on the Antarctic continent, in response to ever-higher planetary average temperatures, driven by ever more profligate use of fossil fuels to generate ever-higher atmospheric ratios of greenhouse gases.

Their word for the state they wanted to study is hysteresis: this can be interpreted as the way altered conditions might commit a state to further change.

“If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York”

The planet’s climate has oscillated many times over many millions of years. What this climate shift does to the polar regions can literally change the map of the planet. Antarctica is an enormous continent, the size of the US, Mexico and India together, and the ice it bears would, if it all were to melt, raise global sea levels by 58 metres.

“Antarctica holds more than half of Earth’s fresh water, frozen in a vast ice-sheet which is nearly five kilometres thick. As the surrounding ocean water and atmosphere warm due to human greenhouse gas emissions, the white cap on the South Pole loses mass and eventually becomes unstable,” said Ricarda Winkelmann, of the Potsdam Institute for Climate Impact Research.

“Because of its sheer magnitude, Antarctica’s potential for sea level contribution is enormous. We find that already at two degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 metres of global sea level rise just from Antarctica alone. At four degrees, it will be 6.5 metres and at six degrees almost 12 metres, if these temperature levels would be sustained long enough.”

That loss of ice would be slow – it would take many thousands of years – but the point the researchers make is that the continent may already be nearing a tipping point, after which the slide towards ever-higher sea levels would be unstoppable.

Since the great ice sheets of Greenland and Antarctica are part of the planetary cooling system – their whiteness reflects solar radiation back into space, so that the ice becomes its own insulation – their loss would inevitably trigger the process of further and faster warming.

Scientists from all nations have been warning for more than a decade that the continent is losing its protective screen of seaborne shelf ice, which in turn would make glacier flow towards the sea ever faster, and that the rate of loss of ice has begun to accelerate.

No going back

“In the end, it is our burning of coal and oil that determines ongoing and future greenhouse gas emissions and, therefore, if and when critical temperature thresholds in Antarctica are crossed.

“And even if the ice loss happens on long time scales, the respective carbon dioxide levels can already be reached in the near future,” said Professor Winkelmann.

“We decide now whether we manage to halt the warming. So Antarctica’s fate really lies in our hands – and with it that of our cities and cultural sites across the globe, from Rio de Janeiro’s Copacabana to Sydney’s Opera House. Thus this study really is another exclamation mark behind the importance of the Paris Climate Accord: Keep global warming below two degrees.”

And her Potsdam co-author Anders Levermann reinforced the argument. “Our simulations show that once it’s melted, it does not regrow to its initial state even if temperatures eventually sank again.

“Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery – a highly unlikely scenario. In other words: what we lose of Antarctica now is lost forever.”

And he warned: “If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York.” – Climate News Network

Supply chains generate massive carbon emissions

When it comes to cutting carbon emissions, think global. Think multinational. Think Coca-Cola, or Total. But don’t fly.

LONDON, 25 September, 2020 – Chinese and European researchers have identified the source of almost one-fifth of all the world’s carbon emissions. They come from the supply chains of giant multinational companies.

Not only does global business export investment, it exports carbon dioxide emissions as well. And the big players play it really big.

The US business Walmart, the world’s biggest retailer, with 11,500 stores in 28 countries, in 2016 generated more emissions abroad than the whole of Germany’s foreign-owned retail sector.

That year Coca-Cola’s global emissions matched those from the entire foreign food-and-drink industry in China. Total SA’s foreign affiliates generated more than a tenth of the total emissions of France. Altogether, the multinational giants accounted for 18.7% of global emissions.

By contrast, and to provide perspective, the entire global aviation industry contributes just 3.5% of the forces that drive climate change – and that includes the impact of condensation trails and soot and sulphur exhausts as well as carbon dioxide emissions.

“If the world’s leading companies exercised leadership on climate change they could have a transformative effect on global efforts to reduce emissions”

In fact, in eight decades, the aviation industry’s total carbon dioxide discharges add up to only 1.5% of all humankind’s total carbon emissions up to 2018, according to British researchers.

These two very different studies illuminate the great challenge of climate change: it’s not enough for a country to claim it has reduced its carbon footprint, if its big achievement has been to export the burden of emissions to a labour force somewhere else.

And it’s not enough to measure just carbon dioxide. Tomorrow’s planners, investors, economists, designers and engineers must also think about the whole package of anthropogenic change that has begun to raise the planetary temperature to dangerous levels. And in each case the message is the same: think of it as a transnational challenge.

“Multinational companies have enormous influence stretching far beyond national borders,” said Dabo Guan of University College London. “If the world’s leading companies exercised leadership on climate change – for instance by requiring energy efficiency in their supply chains – they could have a transformative effect on global efforts to reduce emissions.”

Outsourced responsibility

Professor Guan and colleagues from Beijing and Norway report in the journal Nature Climate Change that they looked for a new way to measure the impact of big business.

They followed the money. They found that when investment flowed from developed to developing countries, those businesses were also outsourcing the responsibility for carbon emissions. So a fair way of accounting carbon responsibility would be to return it to the investor nation.

For example in 2011, US investment in India resulted in emissions of more than 43 million tonnes. By 2016, this figure had passed more than 70 million tonnes. In 2011, emissions from multinational investment stood at 22% of all emissions worldwide. By 2016 this figure had fallen to 18.7% – partly because of improvements in energy efficiency, and partly because of a fall in foreign investment.

Although carbon dioxide emissions have become a standard measure for potential climate change, they are only part of the story. The climate damage from a jet flight is more than just the greenhouse gas from burning high-octane fuel.

New analysis in the journal Atmospheric Environment confirms that aviation’s biggest contribution to global warming is the effects on clouds: cirrus condensation trails formed by the almost-explosive growth in air traffic reflect and trap heat escaping from the atmosphere on a massive scale.

International flights exempted

The discharge of water vapour, soot and sulphate particles from the engines is also part of what the researchers call “effective radiative forcing,” or ERF.

And when these aspects are factored in, it seems that aviation on a global scale adds up to 3.5% of all human activities that drive climate change. The Paris Agreement on climate change – a global resolve to contain global heating by 2100 to “well below” 2°C above the norm for most of human history – includes domestic aviation within national targets to reduce emissions.

But it does not address international aviation, which adds up to 64% of all air traffic.

“The new study means that aviation’s impact on climate change can be compared with other sectors such as maritime shipping, ground transportation and energy generation, as it has a consistent set of ERF measurements,” said David Lee, of Manchester Metropolitan University, who led the research. – Climate News Network

When it comes to cutting carbon emissions, think global. Think multinational. Think Coca-Cola, or Total. But don’t fly.

LONDON, 25 September, 2020 – Chinese and European researchers have identified the source of almost one-fifth of all the world’s carbon emissions. They come from the supply chains of giant multinational companies.

Not only does global business export investment, it exports carbon dioxide emissions as well. And the big players play it really big.

The US business Walmart, the world’s biggest retailer, with 11,500 stores in 28 countries, in 2016 generated more emissions abroad than the whole of Germany’s foreign-owned retail sector.

That year Coca-Cola’s global emissions matched those from the entire foreign food-and-drink industry in China. Total SA’s foreign affiliates generated more than a tenth of the total emissions of France. Altogether, the multinational giants accounted for 18.7% of global emissions.

By contrast, and to provide perspective, the entire global aviation industry contributes just 3.5% of the forces that drive climate change – and that includes the impact of condensation trails and soot and sulphur exhausts as well as carbon dioxide emissions.

“If the world’s leading companies exercised leadership on climate change they could have a transformative effect on global efforts to reduce emissions”

In fact, in eight decades, the aviation industry’s total carbon dioxide discharges add up to only 1.5% of all humankind’s total carbon emissions up to 2018, according to British researchers.

These two very different studies illuminate the great challenge of climate change: it’s not enough for a country to claim it has reduced its carbon footprint, if its big achievement has been to export the burden of emissions to a labour force somewhere else.

And it’s not enough to measure just carbon dioxide. Tomorrow’s planners, investors, economists, designers and engineers must also think about the whole package of anthropogenic change that has begun to raise the planetary temperature to dangerous levels. And in each case the message is the same: think of it as a transnational challenge.

“Multinational companies have enormous influence stretching far beyond national borders,” said Dabo Guan of University College London. “If the world’s leading companies exercised leadership on climate change – for instance by requiring energy efficiency in their supply chains – they could have a transformative effect on global efforts to reduce emissions.”

Outsourced responsibility

Professor Guan and colleagues from Beijing and Norway report in the journal Nature Climate Change that they looked for a new way to measure the impact of big business.

They followed the money. They found that when investment flowed from developed to developing countries, those businesses were also outsourcing the responsibility for carbon emissions. So a fair way of accounting carbon responsibility would be to return it to the investor nation.

For example in 2011, US investment in India resulted in emissions of more than 43 million tonnes. By 2016, this figure had passed more than 70 million tonnes. In 2011, emissions from multinational investment stood at 22% of all emissions worldwide. By 2016 this figure had fallen to 18.7% – partly because of improvements in energy efficiency, and partly because of a fall in foreign investment.

Although carbon dioxide emissions have become a standard measure for potential climate change, they are only part of the story. The climate damage from a jet flight is more than just the greenhouse gas from burning high-octane fuel.

New analysis in the journal Atmospheric Environment confirms that aviation’s biggest contribution to global warming is the effects on clouds: cirrus condensation trails formed by the almost-explosive growth in air traffic reflect and trap heat escaping from the atmosphere on a massive scale.

International flights exempted

The discharge of water vapour, soot and sulphate particles from the engines is also part of what the researchers call “effective radiative forcing,” or ERF.

And when these aspects are factored in, it seems that aviation on a global scale adds up to 3.5% of all human activities that drive climate change. The Paris Agreement on climate change – a global resolve to contain global heating by 2100 to “well below” 2°C above the norm for most of human history – includes domestic aviation within national targets to reduce emissions.

But it does not address international aviation, which adds up to 64% of all air traffic.

“The new study means that aviation’s impact on climate change can be compared with other sectors such as maritime shipping, ground transportation and energy generation, as it has a consistent set of ERF measurements,” said David Lee, of Manchester Metropolitan University, who led the research. – Climate News Network

Melting Arctic needs new name to match reality

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

Mass migration set to increase as world warms

Climate change is now driving mass migration, which will only worsen unless governments take global heating seriously.

LONDON, 15 September, 2020 −There is strong evidence that deteriorating environments caused by climate change are driving millions of people to resort to mass migration in their search for a better life, both within countries and across borders.

As temperatures rise these migrations will only increase, particularly in Latin America and India, which is predicted to overtake China as the country with the largest population by 2025.

An analysis of environment and migration, published in Nature Climate Change, of 30 studies of individual countries across the world shows that there is no one single factor that drives migration.

But most research has found that environmental hazards have a major influence. Rising temperature levels, changes in rainfall and single sudden events like hurricanes are all triggers.

Policies for improvement

The analysis, by the International Institute for Applied Systems Analysis (IIASA) in Austria and research partners across Europe, was undertaken to try to inform policy makers about how to avert mass human migration.

It points out that two of the most high-profile mass migration episodes in recent times – the Syrian refugee crisis in 2015 and the “migrant caravan” from Central America to the United States in 2018 – have been partly attributed to severe droughts in the countries concerned.

While some studies conclude that environmental factors were not the main driver of migration, most thought it was one of the primary causes. The analysis says governments should expect significantly higher migration flows in the future.

Perhaps surprisingly, given the publicity surrounding the issue, migrations were not centred on poor people trying to enter rich nations in Europe or North America. Instead, most movements were from the countryside to urban areas in the same country, particularly in agriculturally dependent countries, or from one middle-income country to another.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels”

People with particularly low incomes normally stayed where they were,  despite environmental pressures, because they had no way of financing a move, while richer people had the means to adapt to new circumstances and so they also stayed put.

“Environmental factors can drive migration, but the size of the effects depends on the particular economic and socio-political conditions in the countries,” explains the lead author Roman Hoffmann, from Germany’s Potsdam Institute for Climate Impact Research (PIK).

“In both low and high income countries, environmental impacts on migration are weaker – presumably because either people are too poor to leave and therefore essentially become trapped or, in wealthy countries, they have enough financial means to absorb the consequences. It is mainly in middle-income regions and those with a dependency on agriculture that we see strong effects.”

IIASA predicts future higher levels of environmental migration for countries in Central America, the Caribbean, Brazil and Argentina. In Africa it is the Sahel region south of the Sahara that is already drying out, and East Africa that has the highest potential for people migrating because of climate change.

Eyes on India

Perhaps the most disturbing prediction is that India, with 1.3 billion people and soon to be the most populous country in the world, is likely to see large migrations. The heat and floods in the country are already killing hundreds of people a year, and many millions who are still dependent on subsistence agriculture are struggling with changing climate conditions.

“Our research suggests that populations in Latin America and the Caribbean, several countries in sub-Saharan Africa – especially in the Sahel region and East Africa – as well as western, southern and south-east Asia, are particularly at risk,” says co-author Anna Dimitrova from the Vienna Institute of Demography of the Austrian Academy of Sciences.

While the report is aimed at preparing governments for migrations that will inevitably happen in the future, with difficult consequences for both the migrants and the host country, the research suggests the best way of averting the coming crisis is to tackle climate change and reduce further rises in temperatures.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels as well as simultaneously to enhance adaptive capacity, such as through improving human capital,” says Jesus Crespo Cuaresma, a researcher with the IIASA World Population Program and professor of economics at the Vienna University of Economics and Business. − Climate News Network

Climate change is now driving mass migration, which will only worsen unless governments take global heating seriously.

LONDON, 15 September, 2020 −There is strong evidence that deteriorating environments caused by climate change are driving millions of people to resort to mass migration in their search for a better life, both within countries and across borders.

As temperatures rise these migrations will only increase, particularly in Latin America and India, which is predicted to overtake China as the country with the largest population by 2025.

An analysis of environment and migration, published in Nature Climate Change, of 30 studies of individual countries across the world shows that there is no one single factor that drives migration.

But most research has found that environmental hazards have a major influence. Rising temperature levels, changes in rainfall and single sudden events like hurricanes are all triggers.

Policies for improvement

The analysis, by the International Institute for Applied Systems Analysis (IIASA) in Austria and research partners across Europe, was undertaken to try to inform policy makers about how to avert mass human migration.

It points out that two of the most high-profile mass migration episodes in recent times – the Syrian refugee crisis in 2015 and the “migrant caravan” from Central America to the United States in 2018 – have been partly attributed to severe droughts in the countries concerned.

While some studies conclude that environmental factors were not the main driver of migration, most thought it was one of the primary causes. The analysis says governments should expect significantly higher migration flows in the future.

Perhaps surprisingly, given the publicity surrounding the issue, migrations were not centred on poor people trying to enter rich nations in Europe or North America. Instead, most movements were from the countryside to urban areas in the same country, particularly in agriculturally dependent countries, or from one middle-income country to another.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels”

People with particularly low incomes normally stayed where they were,  despite environmental pressures, because they had no way of financing a move, while richer people had the means to adapt to new circumstances and so they also stayed put.

“Environmental factors can drive migration, but the size of the effects depends on the particular economic and socio-political conditions in the countries,” explains the lead author Roman Hoffmann, from Germany’s Potsdam Institute for Climate Impact Research (PIK).

“In both low and high income countries, environmental impacts on migration are weaker – presumably because either people are too poor to leave and therefore essentially become trapped or, in wealthy countries, they have enough financial means to absorb the consequences. It is mainly in middle-income regions and those with a dependency on agriculture that we see strong effects.”

IIASA predicts future higher levels of environmental migration for countries in Central America, the Caribbean, Brazil and Argentina. In Africa it is the Sahel region south of the Sahara that is already drying out, and East Africa that has the highest potential for people migrating because of climate change.

Eyes on India

Perhaps the most disturbing prediction is that India, with 1.3 billion people and soon to be the most populous country in the world, is likely to see large migrations. The heat and floods in the country are already killing hundreds of people a year, and many millions who are still dependent on subsistence agriculture are struggling with changing climate conditions.

“Our research suggests that populations in Latin America and the Caribbean, several countries in sub-Saharan Africa – especially in the Sahel region and East Africa – as well as western, southern and south-east Asia, are particularly at risk,” says co-author Anna Dimitrova from the Vienna Institute of Demography of the Austrian Academy of Sciences.

While the report is aimed at preparing governments for migrations that will inevitably happen in the future, with difficult consequences for both the migrants and the host country, the research suggests the best way of averting the coming crisis is to tackle climate change and reduce further rises in temperatures.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels as well as simultaneously to enhance adaptive capacity, such as through improving human capital,” says Jesus Crespo Cuaresma, a researcher with the IIASA World Population Program and professor of economics at the Vienna University of Economics and Business. − Climate News Network

Slightest heat increase magnifies hurricane risk

The poorer and more vulnerable you are, the greater your hurricane risk. Even a tiny heat rise can spell disaster.

LONDON, 11 September, 2020 – Any climate change at all will mean a hurricane risk for the storm-prone Caribbean, even if global average temperatures are contained to a rise of no more than 1.5°C by 2100. But a rise of 2°C could be disastrous: the hurricane hazard could grow fivefold.

The figures – each representing a rise above the long-term average for most of human history – are significant. In 2015 195 nations, including the US, signed up to the Paris Agreement – a promise to contain the rise in global heating to “well below 2°C” by the century’s end. The undeclared but widely-understood intention was a limit of 1.5°C.

In the last century, in response to a rise in carbon dioxide emissions from fossil fuel use, planetary average temperatures have already risen by 1°C, and the Atlantic states of the US and the islands of the Caribbean have been hit by a series of ever more devastating windstorms, as ocean temperatures warm and make hurricanes more probable.

And researchers warn that as global heating continues – with forecasts of a rise of more than 3°C by 2100 – more are on the way.

But the US is wealthy and resilient. British scientists report in the journal Environmental Research Letters that they decided to take a look at the probability of windstorm and heavy rainfall assault on the Caribbean, where half of the 44 million people of the archipelago live within 1.5kms of the coast, and where devastation can be so intense it could take six years to recover.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events”

So they used computer simulations to generate thousands of synthetic hurricanes, under three climate scenarios: present day conditions; a world that kept global heating to no more than 1.5C; and one in which nations let rip and hit the 2°C limit.

They found that extreme rainfall events of the kind which typically happen once every hundred years at present do indeed become more numerous in a world that sticks to its implicit Paris promise. But in a 2°C warmer world, calamitous hurricanes became five times more frequent.

When Hurricane Maria hit Puerto Rico in 2017, it delivered a quarter of a year’s average rainfall all at once, with appalling consequences. In a two-degree warmer world, such a storm could happen every 43 years. The storm that hit the Bahamas in 2019 could become 4.5 times more likely.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events and their catastrophic consequences, particularly for poorer countries which take many years to recover,” said Emily Vosper of the University of Bristol, who led the study.

“We expected extreme hurricanes to be more prevalent in the 2°C global warming scenario, but the scale of the projected increases was surprising, and should serve as a stark warning across the globe, underscoring the importance of keeping climate change under control.” – Climate News Network

The poorer and more vulnerable you are, the greater your hurricane risk. Even a tiny heat rise can spell disaster.

LONDON, 11 September, 2020 – Any climate change at all will mean a hurricane risk for the storm-prone Caribbean, even if global average temperatures are contained to a rise of no more than 1.5°C by 2100. But a rise of 2°C could be disastrous: the hurricane hazard could grow fivefold.

The figures – each representing a rise above the long-term average for most of human history – are significant. In 2015 195 nations, including the US, signed up to the Paris Agreement – a promise to contain the rise in global heating to “well below 2°C” by the century’s end. The undeclared but widely-understood intention was a limit of 1.5°C.

In the last century, in response to a rise in carbon dioxide emissions from fossil fuel use, planetary average temperatures have already risen by 1°C, and the Atlantic states of the US and the islands of the Caribbean have been hit by a series of ever more devastating windstorms, as ocean temperatures warm and make hurricanes more probable.

And researchers warn that as global heating continues – with forecasts of a rise of more than 3°C by 2100 – more are on the way.

But the US is wealthy and resilient. British scientists report in the journal Environmental Research Letters that they decided to take a look at the probability of windstorm and heavy rainfall assault on the Caribbean, where half of the 44 million people of the archipelago live within 1.5kms of the coast, and where devastation can be so intense it could take six years to recover.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events”

So they used computer simulations to generate thousands of synthetic hurricanes, under three climate scenarios: present day conditions; a world that kept global heating to no more than 1.5C; and one in which nations let rip and hit the 2°C limit.

They found that extreme rainfall events of the kind which typically happen once every hundred years at present do indeed become more numerous in a world that sticks to its implicit Paris promise. But in a 2°C warmer world, calamitous hurricanes became five times more frequent.

When Hurricane Maria hit Puerto Rico in 2017, it delivered a quarter of a year’s average rainfall all at once, with appalling consequences. In a two-degree warmer world, such a storm could happen every 43 years. The storm that hit the Bahamas in 2019 could become 4.5 times more likely.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events and their catastrophic consequences, particularly for poorer countries which take many years to recover,” said Emily Vosper of the University of Bristol, who led the study.

“We expected extreme hurricanes to be more prevalent in the 2°C global warming scenario, but the scale of the projected increases was surprising, and should serve as a stark warning across the globe, underscoring the importance of keeping climate change under control.” – Climate News Network

Pandemic’s impacts are damaging climate research

Climate research is suffering permanent damage from some of the Covid-19 pandemic’s impacts, a UN report says.

LONDON, 9 September, 2020 − Whatever else the coronavirus onslaught is doing to humankind, some of the pandemic’s impacts are clear. It is making it harder for researchers to establish just what effect climate change is having on the planet.

A group of United Nations and other agencies is today launching a report, United in Science 2020, (webcast at 1600 hours New York time) which it calls “a high-level compilation of the latest climate science information”. It is being launched by the UN secretary-general, António Guterres, with a virtual link to his counterpart at the World Meteorological Organisation,  Petteri Taalas, in Geneva.

Much of what the report says will already be familiar, but its detailed finding that the pandemic is causing long-term damage to climate change monitoring is sobering.

Science advances by combining knowledge of the past with experience of the present and then combining them to forecast the probable future. That is how climate scientists have been able very recently to state that their earlier worst case scenario isn’t just an awful warning, but describes what is happening right now.

Several contenders have vied to be identified as the one who wrote: “You cannot manage what you cannot measure.” Which of them − if any − really did write that may not matter much. But it certainly matters for today’s researchers to know where the biosphere came from and where it is now if they are to have any idea where we shall all be in a few years.

Recalled to port

So it’s alarming that United in Science 2020, in its section on earth system observations, says: “The Covid-19 pandemic has produced significant impacts on the global observing systems, which in turn have affected the quality of forecasts and other weather, climate and ocean-related services.

“The reduction of aircraft-based observations by an average of 75% to 80% in March and April degraded the forecast skills of weather models. Since June, there has been only a slight recovery. Observations at manually-operated weather stations, especially in Africa and South America, have also been badly disrupted.”

In March this year, it says, nearly all oceanographic research vessels were recalled to home ports. Commercial ships have been unable to contribute vital ocean and weather observations, and ocean buoys and other systems could not be maintained.

Four “valuable” full-depth ocean surveys of variables such as carbon, temperature, salinity, and water alkalinity, completed only once every decade, have been cancelled. Surface carbon measurements from ships, which cast light on the evolution of greenhouse gases, also effectively stopped.

The impacts on climate change monitoring are long-term. They are likely to prevent or restrict measurement of glaciers and the thickness of permafrost, usually conducted at the end of the thawing period.

In an ominous warning the report notes that the overall disruption of observations will introduce gaps in the historical time series of Essential Climate Variables, vital for understanding what is happening to the planetary climate.

“The reduction of aircraft-based observations by an average of 75% to 80% in March and April degraded the forecast skills of weather models”

The report’s authors are also concerned about climate and water, where they expect the pandemic’s impacts to intensify existing problems. By 2050, they say, the number of people at risk of floods will increase from 1.2 billion now to 1.6 bn.

In the early to mid-2010s, 1.9 bn people, or 27% of the global population, lived in potential severely water-scarce areas. In 2050, this number will increase to between 2.7 and 3.2 bn people.

It is estimated that central Europe and the Caucasus have already reached peak water, and that the Tibetan Plateau region will do so between 2030 and 2050.

Runoff from snow cover, permafrost and glaciers in this region provides up to 45% of the total river flow, so a decrease would affect water availability for 1.7 bn people.

United in Science 2020 also says the world is a very long way from living up to its promises, with the targets of the Paris Agreement on climate change nowhere near being met.

The UN’s Emissions Gap Report 2019 compares “where we are likely to be and where we need to be” on cutting emissions of greenhouse gases (GHGs). The annual series of Gap Reports use gigatonnes (Gt) as units of measurement: one gigatonne is a billion metric tons.

Record emissions

Another frequent formula is GtCO2e, an abbreviation for “gigatonnes of equivalent carbon dioxide”. That’s a simplified way to put emissions of various GHGs on a common footing by expressing them in terms of the amount of carbon dioxide that would have the same global warming effect.

The 2019 Report says GHG emissions reached a record high of 55.3 GtCO2e in 2018. It continues: “There is no sign of GHG emissions peaking in the next few years; every year of postponed peaking means that deeper and faster cuts will be required.

“By 2030, emissions would need to be 25% and 55% lower than in 2018 to put the world on the least-cost pathway to limiting global warming to below 2 ̊C and 1.5°C respectively” [the two Paris Agreement targets].

The Gap in 2030 is estimated at 12-15 gigatonnes if the world is to limit global warming to below 2 °C. For the 1.5 °C goal, it is estimated at 29-32 Gt, roughly equivalent to the combined emissions of the world’s six largest emitters.

That’s an awful lot of GHGs which, as things stand, are going to be adding their heat to a torrid world a decade from now. − Climate News Network

Climate research is suffering permanent damage from some of the Covid-19 pandemic’s impacts, a UN report says.

LONDON, 9 September, 2020 − Whatever else the coronavirus onslaught is doing to humankind, some of the pandemic’s impacts are clear. It is making it harder for researchers to establish just what effect climate change is having on the planet.

A group of United Nations and other agencies is today launching a report, United in Science 2020, (webcast at 1600 hours New York time) which it calls “a high-level compilation of the latest climate science information”. It is being launched by the UN secretary-general, António Guterres, with a virtual link to his counterpart at the World Meteorological Organisation,  Petteri Taalas, in Geneva.

Much of what the report says will already be familiar, but its detailed finding that the pandemic is causing long-term damage to climate change monitoring is sobering.

Science advances by combining knowledge of the past with experience of the present and then combining them to forecast the probable future. That is how climate scientists have been able very recently to state that their earlier worst case scenario isn’t just an awful warning, but describes what is happening right now.

Several contenders have vied to be identified as the one who wrote: “You cannot manage what you cannot measure.” Which of them − if any − really did write that may not matter much. But it certainly matters for today’s researchers to know where the biosphere came from and where it is now if they are to have any idea where we shall all be in a few years.

Recalled to port

So it’s alarming that United in Science 2020, in its section on earth system observations, says: “The Covid-19 pandemic has produced significant impacts on the global observing systems, which in turn have affected the quality of forecasts and other weather, climate and ocean-related services.

“The reduction of aircraft-based observations by an average of 75% to 80% in March and April degraded the forecast skills of weather models. Since June, there has been only a slight recovery. Observations at manually-operated weather stations, especially in Africa and South America, have also been badly disrupted.”

In March this year, it says, nearly all oceanographic research vessels were recalled to home ports. Commercial ships have been unable to contribute vital ocean and weather observations, and ocean buoys and other systems could not be maintained.

Four “valuable” full-depth ocean surveys of variables such as carbon, temperature, salinity, and water alkalinity, completed only once every decade, have been cancelled. Surface carbon measurements from ships, which cast light on the evolution of greenhouse gases, also effectively stopped.

The impacts on climate change monitoring are long-term. They are likely to prevent or restrict measurement of glaciers and the thickness of permafrost, usually conducted at the end of the thawing period.

In an ominous warning the report notes that the overall disruption of observations will introduce gaps in the historical time series of Essential Climate Variables, vital for understanding what is happening to the planetary climate.

“The reduction of aircraft-based observations by an average of 75% to 80% in March and April degraded the forecast skills of weather models”

The report’s authors are also concerned about climate and water, where they expect the pandemic’s impacts to intensify existing problems. By 2050, they say, the number of people at risk of floods will increase from 1.2 billion now to 1.6 bn.

In the early to mid-2010s, 1.9 bn people, or 27% of the global population, lived in potential severely water-scarce areas. In 2050, this number will increase to between 2.7 and 3.2 bn people.

It is estimated that central Europe and the Caucasus have already reached peak water, and that the Tibetan Plateau region will do so between 2030 and 2050.

Runoff from snow cover, permafrost and glaciers in this region provides up to 45% of the total river flow, so a decrease would affect water availability for 1.7 bn people.

United in Science 2020 also says the world is a very long way from living up to its promises, with the targets of the Paris Agreement on climate change nowhere near being met.

The UN’s Emissions Gap Report 2019 compares “where we are likely to be and where we need to be” on cutting emissions of greenhouse gases (GHGs). The annual series of Gap Reports use gigatonnes (Gt) as units of measurement: one gigatonne is a billion metric tons.

Record emissions

Another frequent formula is GtCO2e, an abbreviation for “gigatonnes of equivalent carbon dioxide”. That’s a simplified way to put emissions of various GHGs on a common footing by expressing them in terms of the amount of carbon dioxide that would have the same global warming effect.

The 2019 Report says GHG emissions reached a record high of 55.3 GtCO2e in 2018. It continues: “There is no sign of GHG emissions peaking in the next few years; every year of postponed peaking means that deeper and faster cuts will be required.

“By 2030, emissions would need to be 25% and 55% lower than in 2018 to put the world on the least-cost pathway to limiting global warming to below 2 ̊C and 1.5°C respectively” [the two Paris Agreement targets].

The Gap in 2030 is estimated at 12-15 gigatonnes if the world is to limit global warming to below 2 °C. For the 1.5 °C goal, it is estimated at 29-32 Gt, roughly equivalent to the combined emissions of the world’s six largest emitters.

That’s an awful lot of GHGs which, as things stand, are going to be adding their heat to a torrid world a decade from now. − Climate News Network

Rivers flood, seas rise – and land faces erosion

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network