Tag Archives: Warming

Wild flowers and bees contend with climate heat

Many alpine flowers could soon fade out. Some bees may be buzzing off. The wild things are victims of climate heat.

LONDON, 9 February, 2021 − Thanks to climate heat, this could be the last farewell to mossy saxifrage, to alpine wormwood and mignonette-leafed bittercress. With them could go plants most people could hardly name: dwarf cudweed, alpine stonecrop, mossy cyphel, cobweb houseleek and two kinds of hawkweed. All of them are mountain-dwellers, hardy little plants that depend for their existence on alpine glaciers.

And almost everywhere in the world, high-altitude rivers of ice are in retreat. Global heating, climate change and human disturbance alter both the conditions for growth and the rich variety of life.

In the same week that one team of researchers listed the alpine flowers threatened with extinction, another team of scientists assembled an inventory of observations of wild bees, to find that a quarter of the world’s 20,000 bee species have not been recorded in the last 25 years.

Bees and flowers are interdependent: they evolved together and would perish together. But climate change threatens to take a selective toll on a range of alpine plants − beloved of gardeners but also important in liqueurs and medicines − as glaciers retreat in the mountainous regions.

These little flowers are to be found variously in the Sierra Nevada in Spain, the Apennines in Italy, along the spine of the Alps in Switzerland and Austria, and even in the highlands of Scotland.

And one day, according to a new study in the journal Frontiers in Ecology and Evolution, many or all of them could be locally extinct.

“Something is happening to the bees, and something needs to be done … The next step is prodding policymakers into action while we still have time. The bees cannot wait”

The wildflowers listed in the first two sentences − Saxifraga bryoides, Artemisia genipi, Cardamine resedifolia, Leucanthemopsis alpina, Gnaphalium supinum, Sedum alpestre, Minuartia sedoides, Sempervivum arachnoideum, Hieracium staticifolium and H. glanduliferum − could all go, and another suite of alpine opportunists could take advantage of their living space.

Californian researchers report that they looked at 117 plant species and matched them with geological evidence from four glaciers in the Italian Alps, and then used computational systems to calculate how plant communities have changed over the last five thousand years, and what might happen as the glaciers continue to retreat.

They found that as the glaciers disappear, more than one in five of their sample alpines could also vanish. The loss of that 22% however could be to the benefit of around 29% of the surveyed species, among them the snow gentian, Gentiana nivalis and the dwarf yellow cinquefoil Potentialla aurea. Some alpines would probably not be affected: among them alpine lovage or Ligusticum mutellina and Pedicularis kerneri, a variety of lousewort.

The authors make no mention of one alpine almost everybody in the world could name: Leontopodium nivale or edelweiss. But what happens to even the most insignificant wild plants matters to everybody.

“Plants are the primary producers at the basis of the food web that sustained our lives and economies, and biodiversity is the key to healthy ecosystems − biodiversity also represents an inestimable cultural value that needs to be properly supported,” said Gianalberto Losapio, a biologist at Stanford University in the US.

Growing interest

Meanwhile in Argentina researchers decided to take advantage of citizen science to check on some of the flower world’s biggest fans, the wild bees. There has been huge concern about observed decline in insect abundance, as wild ecosystems are colonised by humans and global average temperatures rise to change the world’s weather systems.

But over the same decades, there has also been a dramatic increase in informed interest in the wild things, among gardeners, bird-watchers and butterfly lovers, and an exponential rise in records available to an international network of databases called the Global Biodiversity Information Facility.

And, say researchers in the journal One Earth, as global records soar, the number of bee species listed in those records has gone down. Around 25% fewer species were recorded between 2006 and 2015 than were listed in the 1990s.

Wild bees have a role in the pollination of about 85% of the world’s food crops. Without the bees, many wild flowers could not replicate.

“It’s not exactly a bee cataclysm yet, but what we can say is that wild bees are not exactly thriving,” said Eduardo Zattara, a biodiversity researcher at CONICET-Universidad Nacional del Comahue.

“Something is happening to the bees, and something needs to be done. We cannot wait until we have absolute certainty because we rarely get there in the natural sciences. The next step is prodding policymakers into action while we still have time. The bees cannot wait.” − Climate News Network

Many alpine flowers could soon fade out. Some bees may be buzzing off. The wild things are victims of climate heat.

LONDON, 9 February, 2021 − Thanks to climate heat, this could be the last farewell to mossy saxifrage, to alpine wormwood and mignonette-leafed bittercress. With them could go plants most people could hardly name: dwarf cudweed, alpine stonecrop, mossy cyphel, cobweb houseleek and two kinds of hawkweed. All of them are mountain-dwellers, hardy little plants that depend for their existence on alpine glaciers.

And almost everywhere in the world, high-altitude rivers of ice are in retreat. Global heating, climate change and human disturbance alter both the conditions for growth and the rich variety of life.

In the same week that one team of researchers listed the alpine flowers threatened with extinction, another team of scientists assembled an inventory of observations of wild bees, to find that a quarter of the world’s 20,000 bee species have not been recorded in the last 25 years.

Bees and flowers are interdependent: they evolved together and would perish together. But climate change threatens to take a selective toll on a range of alpine plants − beloved of gardeners but also important in liqueurs and medicines − as glaciers retreat in the mountainous regions.

These little flowers are to be found variously in the Sierra Nevada in Spain, the Apennines in Italy, along the spine of the Alps in Switzerland and Austria, and even in the highlands of Scotland.

And one day, according to a new study in the journal Frontiers in Ecology and Evolution, many or all of them could be locally extinct.

“Something is happening to the bees, and something needs to be done … The next step is prodding policymakers into action while we still have time. The bees cannot wait”

The wildflowers listed in the first two sentences − Saxifraga bryoides, Artemisia genipi, Cardamine resedifolia, Leucanthemopsis alpina, Gnaphalium supinum, Sedum alpestre, Minuartia sedoides, Sempervivum arachnoideum, Hieracium staticifolium and H. glanduliferum − could all go, and another suite of alpine opportunists could take advantage of their living space.

Californian researchers report that they looked at 117 plant species and matched them with geological evidence from four glaciers in the Italian Alps, and then used computational systems to calculate how plant communities have changed over the last five thousand years, and what might happen as the glaciers continue to retreat.

They found that as the glaciers disappear, more than one in five of their sample alpines could also vanish. The loss of that 22% however could be to the benefit of around 29% of the surveyed species, among them the snow gentian, Gentiana nivalis and the dwarf yellow cinquefoil Potentialla aurea. Some alpines would probably not be affected: among them alpine lovage or Ligusticum mutellina and Pedicularis kerneri, a variety of lousewort.

The authors make no mention of one alpine almost everybody in the world could name: Leontopodium nivale or edelweiss. But what happens to even the most insignificant wild plants matters to everybody.

“Plants are the primary producers at the basis of the food web that sustained our lives and economies, and biodiversity is the key to healthy ecosystems − biodiversity also represents an inestimable cultural value that needs to be properly supported,” said Gianalberto Losapio, a biologist at Stanford University in the US.

Growing interest

Meanwhile in Argentina researchers decided to take advantage of citizen science to check on some of the flower world’s biggest fans, the wild bees. There has been huge concern about observed decline in insect abundance, as wild ecosystems are colonised by humans and global average temperatures rise to change the world’s weather systems.

But over the same decades, there has also been a dramatic increase in informed interest in the wild things, among gardeners, bird-watchers and butterfly lovers, and an exponential rise in records available to an international network of databases called the Global Biodiversity Information Facility.

And, say researchers in the journal One Earth, as global records soar, the number of bee species listed in those records has gone down. Around 25% fewer species were recorded between 2006 and 2015 than were listed in the 1990s.

Wild bees have a role in the pollination of about 85% of the world’s food crops. Without the bees, many wild flowers could not replicate.

“It’s not exactly a bee cataclysm yet, but what we can say is that wild bees are not exactly thriving,” said Eduardo Zattara, a biodiversity researcher at CONICET-Universidad Nacional del Comahue.

“Something is happening to the bees, and something needs to be done. We cannot wait until we have absolute certainty because we rarely get there in the natural sciences. The next step is prodding policymakers into action while we still have time. The bees cannot wait.” − Climate News Network

Scientists say world’s huge ice loss is speeding up

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

US pays rising costs for climate’s flood damage

America’s rainfall patterns are changing with the global climate − and making catastrophic flood damage even more costly.

LONDON, 21 January, 2021 − Climate change alone has cost the United States a total of $73 billion in flood damage in the last 30 years.

The figure is significant: floods are an expensive fact of life. But Californian scientists are now sure that more than one-third of the costs of US floods must be attributed to the global heating driven by human use of fossil fuels.

The news comes hard on the heels of a second finding: that over the last century, the count of what hydrologists call “extreme streamflow” events in Canada and the US has increased significantly. This confirms that droughts are on the increase − and so are floods.

Such findings matter to engineers and city planners, and to insurers, and each resolves some long-standing uncertainties.

Because floods and droughts are part of the challenge of living close to a constant flow of water, researchers have never been too sure whether costly floods are on the increase or are just more obvious because population growth and urban spread mean that more people with more expensive property are increasingly at risk.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads”

A new study in the Proceedings of the National Academy of Sciences settles the matter of rising costs: researchers looked at 6,600 reports of flood damage and rainfall data between 1988 and 2017 and then applied sophisticated mathematical techniques to tease out the contribution from higher precipitation driven by higher average temperatures, driven in turn by ever-higher ratios of carbon dioxide in the atmosphere.

They decided that of the $199bn flood damage costs during those years, human-triggered climate change could account for 36%.

“The fact that extreme precipitation has been increasing and will likely increase is well-known, but what effect that has had on financial damages has been uncertain,” said Frances Davenport, of Stanford University.

“What we find is that, even in states where long-term mean precipitation hasn’t changed, in most cases the wettest events have intensified, increasing the financial damages relative to what would have occurred without the changes in precipitation.”

Higher temperatures mean more evaporation. Higher temperatures mean a bigger burden of water vapour in the atmosphere. So higher rainfall is inevitable.

Variable impacts

But repeated studies have found this will happen unevenly: those places already rainy will see more rain. Other regions can expect longer, more intense dry spells.

A second team of US researchers reports in the journal Science Advances that they looked at streamflow data from 541 North American stations since 1910.

They found that in the US west and south-east, the frequency of “extreme low-flow events” has been on the increase, particularly during summer and autumn. In zones where rivers were likely to be fed by melting snow, there was a discernible rise in flood events. Once again, this is a finding with practical consequences.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads,” said Evan Dethier, of Dartmouth College in New Hampshire. “The changes to river flows that we found are important for those who manage or depend on this type of infrastructure.” − Climate News Network

America’s rainfall patterns are changing with the global climate − and making catastrophic flood damage even more costly.

LONDON, 21 January, 2021 − Climate change alone has cost the United States a total of $73 billion in flood damage in the last 30 years.

The figure is significant: floods are an expensive fact of life. But Californian scientists are now sure that more than one-third of the costs of US floods must be attributed to the global heating driven by human use of fossil fuels.

The news comes hard on the heels of a second finding: that over the last century, the count of what hydrologists call “extreme streamflow” events in Canada and the US has increased significantly. This confirms that droughts are on the increase − and so are floods.

Such findings matter to engineers and city planners, and to insurers, and each resolves some long-standing uncertainties.

Because floods and droughts are part of the challenge of living close to a constant flow of water, researchers have never been too sure whether costly floods are on the increase or are just more obvious because population growth and urban spread mean that more people with more expensive property are increasingly at risk.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads”

A new study in the Proceedings of the National Academy of Sciences settles the matter of rising costs: researchers looked at 6,600 reports of flood damage and rainfall data between 1988 and 2017 and then applied sophisticated mathematical techniques to tease out the contribution from higher precipitation driven by higher average temperatures, driven in turn by ever-higher ratios of carbon dioxide in the atmosphere.

They decided that of the $199bn flood damage costs during those years, human-triggered climate change could account for 36%.

“The fact that extreme precipitation has been increasing and will likely increase is well-known, but what effect that has had on financial damages has been uncertain,” said Frances Davenport, of Stanford University.

“What we find is that, even in states where long-term mean precipitation hasn’t changed, in most cases the wettest events have intensified, increasing the financial damages relative to what would have occurred without the changes in precipitation.”

Higher temperatures mean more evaporation. Higher temperatures mean a bigger burden of water vapour in the atmosphere. So higher rainfall is inevitable.

Variable impacts

But repeated studies have found this will happen unevenly: those places already rainy will see more rain. Other regions can expect longer, more intense dry spells.

A second team of US researchers reports in the journal Science Advances that they looked at streamflow data from 541 North American stations since 1910.

They found that in the US west and south-east, the frequency of “extreme low-flow events” has been on the increase, particularly during summer and autumn. In zones where rivers were likely to be fed by melting snow, there was a discernible rise in flood events. Once again, this is a finding with practical consequences.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads,” said Evan Dethier, of Dartmouth College in New Hampshire. “The changes to river flows that we found are important for those who manage or depend on this type of infrastructure.” − Climate News Network

World still warms in 2020 as greenhouse gases fall

Greenhouse gases have fallen during 2020. But that’s no reason for congratulations, in a year of climate drama.

LONDON, 11 December, 2020 − The year of the coronavirus − the year of global lockdown − meant a record fall in emissions of the greenhouse gases that drive global warming: by December there had been 34 billion tonnes of carbon dioxide from fossil fuel combustion worldwide, a fall of 7% compared with 2019, according to a new study.

If governments followed the economic shutdown with what the UN calls a “green pandemic recovery”, then by 2030 greenhouse gas emissions could fall by up to 25%. That remains a “big if.” Right now the planet is heading towards an end-of-century average temperature rise of a calamitous 3°C, according to a second report.

And a third summary of the last 12 months finds the pandemic changed almost nothing, says the World Meteorological Organisation (WMO). The year looks to be one of the three warmest on record, in the warmest decade on record. The warmest six years ever recorded have all happened since 2015.

The news in the journal Earth System Science Data, that humankind managed not to add 2.4 bn tonnes of CO2 to the atmosphere because car journeys fell by half and airline flights dwindled at the peak of the lockdowns from Covid-19, should be encouraging.

“There is at least a one in five chance of [the world] temporarily exceeding 1.5°C by 2024. 2020 has been yet another extraordinary year for our climate”

To be on track to meet the promises made under the Paris Agreement of 2015, humankind has to reduce emissions by around 1 to 2 billion tonnes a year for the next ten years. Nobody can yet say whether the decline will continue, or whether emissions will rebound.

“All the elements are not yet in place for sustained decreases in global emissions, and emissions are slowly edging back to 2019 levels”, warned Corinne Le Quéré, of the University of East Anglia, UK. “Government actions to stimulate the economy at the end of the Covid-19 pandemic can also help lower emissions and tackle climate change.”

Here is the message of the United Nations Environment Programme’s latest Emissions Gap Report. Examining the gap between what nations promised to do in Paris, and what is actually happening, it warns that a 7% drop in emissions during 2020 translates to a reduction in global warming by 2050 of no more than 0.01°C.

If nations stepped into economic recovery with plans to advance renewable energy and save fossil fuel use, a 25% emissions cut could indeed create a chance of meeting the 2°C limit promised in the Paris Agreement. But it wouldn’t get the world to the real goal of a rise of no more than 1.5°C by 2100.

Roasting Arctic

Greenhouse gases continue to inflict a relentless burden. Right now the world is already 1.2°C warmer than at any time for almost all of human history, thanks to profligate fossil fuel use over the last century. And, says the WMO’s secretary-general Petteri Taalas, “there is at least a one in five chance of it temporarily exceeding 1.5°C by 2024.”

Ocean heat has reached record levels and 80% of the blue planet experienced at least one marine heatwave in the last year, says a summary of the year based on evidence from January to October. In the Siberian Arctic, temperatures were 5°C above normal. The Arctic summer sea ice was the second-lowest since records began 42 years ago. In California’s Death Valley in August, the thermometer hit 54.4°C, the highest anywhere in the world for at least the last 80 years.

“2020 has, unfortunately, been yet another extraordinary year for our climate. We saw new extreme temperatures on land, sea and especially in the Arctic. Wildfires consumed vast areas in Australia, Siberia, the US West Coast and South America, sending plumes of smoke circumnavigating the globe,” Professor Taalas said.

“We saw a record number of hurricanes in the Atlantic, including unprecedented back-to-back category 4 hurricanes in Central America in November. Flooding in parts of Africa and South-east Asia led to massive population displacement and undermined food security for millions.” − Climate News Network

Greenhouse gases have fallen during 2020. But that’s no reason for congratulations, in a year of climate drama.

LONDON, 11 December, 2020 − The year of the coronavirus − the year of global lockdown − meant a record fall in emissions of the greenhouse gases that drive global warming: by December there had been 34 billion tonnes of carbon dioxide from fossil fuel combustion worldwide, a fall of 7% compared with 2019, according to a new study.

If governments followed the economic shutdown with what the UN calls a “green pandemic recovery”, then by 2030 greenhouse gas emissions could fall by up to 25%. That remains a “big if.” Right now the planet is heading towards an end-of-century average temperature rise of a calamitous 3°C, according to a second report.

And a third summary of the last 12 months finds the pandemic changed almost nothing, says the World Meteorological Organisation (WMO). The year looks to be one of the three warmest on record, in the warmest decade on record. The warmest six years ever recorded have all happened since 2015.

The news in the journal Earth System Science Data, that humankind managed not to add 2.4 bn tonnes of CO2 to the atmosphere because car journeys fell by half and airline flights dwindled at the peak of the lockdowns from Covid-19, should be encouraging.

“There is at least a one in five chance of [the world] temporarily exceeding 1.5°C by 2024. 2020 has been yet another extraordinary year for our climate”

To be on track to meet the promises made under the Paris Agreement of 2015, humankind has to reduce emissions by around 1 to 2 billion tonnes a year for the next ten years. Nobody can yet say whether the decline will continue, or whether emissions will rebound.

“All the elements are not yet in place for sustained decreases in global emissions, and emissions are slowly edging back to 2019 levels”, warned Corinne Le Quéré, of the University of East Anglia, UK. “Government actions to stimulate the economy at the end of the Covid-19 pandemic can also help lower emissions and tackle climate change.”

Here is the message of the United Nations Environment Programme’s latest Emissions Gap Report. Examining the gap between what nations promised to do in Paris, and what is actually happening, it warns that a 7% drop in emissions during 2020 translates to a reduction in global warming by 2050 of no more than 0.01°C.

If nations stepped into economic recovery with plans to advance renewable energy and save fossil fuel use, a 25% emissions cut could indeed create a chance of meeting the 2°C limit promised in the Paris Agreement. But it wouldn’t get the world to the real goal of a rise of no more than 1.5°C by 2100.

Roasting Arctic

Greenhouse gases continue to inflict a relentless burden. Right now the world is already 1.2°C warmer than at any time for almost all of human history, thanks to profligate fossil fuel use over the last century. And, says the WMO’s secretary-general Petteri Taalas, “there is at least a one in five chance of it temporarily exceeding 1.5°C by 2024.”

Ocean heat has reached record levels and 80% of the blue planet experienced at least one marine heatwave in the last year, says a summary of the year based on evidence from January to October. In the Siberian Arctic, temperatures were 5°C above normal. The Arctic summer sea ice was the second-lowest since records began 42 years ago. In California’s Death Valley in August, the thermometer hit 54.4°C, the highest anywhere in the world for at least the last 80 years.

“2020 has, unfortunately, been yet another extraordinary year for our climate. We saw new extreme temperatures on land, sea and especially in the Arctic. Wildfires consumed vast areas in Australia, Siberia, the US West Coast and South America, sending plumes of smoke circumnavigating the globe,” Professor Taalas said.

“We saw a record number of hurricanes in the Atlantic, including unprecedented back-to-back category 4 hurricanes in Central America in November. Flooding in parts of Africa and South-east Asia led to massive population displacement and undermined food security for millions.” − Climate News Network

China and Australia face a climate tipping point

Once again, scientists warn that at least part of the world could be facing a climate tipping point. Two parts, in fact.

LONDON, 8 December 2020 − The grasslands of northern China and Mongolia could be about to lurch into a climate tipping point, an irreversible sequence of heat and drought.

This is a landscape that helped shape world history. The Hun forces that humbled the western Roman Empire 16 centuries ago, and the conquering hordes led by Genghis Khan that commanded most of the Asian continent and threatened Europe eight centuries later, both emerged from tribes of nomad herdsmen from its grasslands. Now it could itself be about to be reconfigured by human-driven climate change.

And that same anthropogenic climate tipping point poses the same threat to great tracts of south-east Australia: water could become more scarce, bush fires could become more frequent, and winds could begin to blow away the parched soils in droughts that could last decades, or even centuries.

Both studies are based on evidence from the past, and both on the story told by preserved annual growth rings. The warning from inner East Asia is based on the testimony of tree stumps and timbers from the last 260 years, say researchers in the journal Science.

“They’re alarming findings, in a long list of alarming findings…if humans continue to warm the planet, this is the future we may all be looking at”

The patterns of tree growth suggest that the recent consecutive summers marked by both heat and drought are new events, and could increase in frequency.

The high plains of central Asia can be very cold in winter, very hot in summer. But soil moisture normally evaporates to cool the air at the surface. In a sustained drought, the air becomes hotter. In recent years, the region’s lakes have been shrinking in extent − and in number.

“The result is more heatwaves, which means more soil water losses, which means more heatwaves − and where this might end, we cannot say,” said Deliang Chen of the University of Gothenburg in Sweden, one of the research team.

He and his co-authors warn bluntly that the double impact of sustained heat and prolonged drought “is potentially irreversible beyond a tipping point in the East Asian climate system.”

Mega-drought link

The evidence from Australia is based on a much more distant past, and preserved in stalagmites deep in a cave in New South Wales. Researchers write in the journal Scientific Reports that during a warm interval in the last Ice Age, from 129,000 to 116,000 years ago, global temperatures rose to levels much as they are today, and perhaps slightly warmer.

And the record of lower falls of snow, higher temperatures and ever-scarcer water, preserved in the ancient annual growths of underground calcium carbonate, provided the scientists with a hint of what to expect in a world of global heating driven by ever-increasing use of fossil fuels, and ever-greater destruction of natural ecosystems.

“We found that, in the past, a similar amount of warming has been associated with mega-drought conditions all over south-eastern Australia. These drier conditions prevailed for centuries, sometimes for more than 1000 years,” said Hamish McGowan of the University of Queensland, who led the study.

“They’re alarming findings, in a long list of alarming findings that climate scientists have released over the last few decades. We hope that this new research allows for new insights to our future climate and the risks it may bring, such as drought and associated bushfires. But importantly, if humans continue to warm the planet, this is the future we may all be looking at.” − Climate News Network

Once again, scientists warn that at least part of the world could be facing a climate tipping point. Two parts, in fact.

LONDON, 8 December 2020 − The grasslands of northern China and Mongolia could be about to lurch into a climate tipping point, an irreversible sequence of heat and drought.

This is a landscape that helped shape world history. The Hun forces that humbled the western Roman Empire 16 centuries ago, and the conquering hordes led by Genghis Khan that commanded most of the Asian continent and threatened Europe eight centuries later, both emerged from tribes of nomad herdsmen from its grasslands. Now it could itself be about to be reconfigured by human-driven climate change.

And that same anthropogenic climate tipping point poses the same threat to great tracts of south-east Australia: water could become more scarce, bush fires could become more frequent, and winds could begin to blow away the parched soils in droughts that could last decades, or even centuries.

Both studies are based on evidence from the past, and both on the story told by preserved annual growth rings. The warning from inner East Asia is based on the testimony of tree stumps and timbers from the last 260 years, say researchers in the journal Science.

“They’re alarming findings, in a long list of alarming findings…if humans continue to warm the planet, this is the future we may all be looking at”

The patterns of tree growth suggest that the recent consecutive summers marked by both heat and drought are new events, and could increase in frequency.

The high plains of central Asia can be very cold in winter, very hot in summer. But soil moisture normally evaporates to cool the air at the surface. In a sustained drought, the air becomes hotter. In recent years, the region’s lakes have been shrinking in extent − and in number.

“The result is more heatwaves, which means more soil water losses, which means more heatwaves − and where this might end, we cannot say,” said Deliang Chen of the University of Gothenburg in Sweden, one of the research team.

He and his co-authors warn bluntly that the double impact of sustained heat and prolonged drought “is potentially irreversible beyond a tipping point in the East Asian climate system.”

Mega-drought link

The evidence from Australia is based on a much more distant past, and preserved in stalagmites deep in a cave in New South Wales. Researchers write in the journal Scientific Reports that during a warm interval in the last Ice Age, from 129,000 to 116,000 years ago, global temperatures rose to levels much as they are today, and perhaps slightly warmer.

And the record of lower falls of snow, higher temperatures and ever-scarcer water, preserved in the ancient annual growths of underground calcium carbonate, provided the scientists with a hint of what to expect in a world of global heating driven by ever-increasing use of fossil fuels, and ever-greater destruction of natural ecosystems.

“We found that, in the past, a similar amount of warming has been associated with mega-drought conditions all over south-eastern Australia. These drier conditions prevailed for centuries, sometimes for more than 1000 years,” said Hamish McGowan of the University of Queensland, who led the study.

“They’re alarming findings, in a long list of alarming findings that climate scientists have released over the last few decades. We hope that this new research allows for new insights to our future climate and the risks it may bring, such as drought and associated bushfires. But importantly, if humans continue to warm the planet, this is the future we may all be looking at.” − Climate News Network

More carbon may benefit trees less than thought

Earlier tree growth results from more atmospheric carbon. It may mean earlier leaf fall too, muddying climate calculations.

LONDON, 4 December, 2020 − As springs arrive earlier, and the growing season gets longer with ever-milder winters, Swiss scientists have identified a paradox: global warming driven by more carbon in ever-higher greenhouse gas emissions could actually trigger unexpectedly earlier autumn leaf change.

So even as winters get later, milder and shorter, that glorious display of autumn colour in leaves as they turn old and die could arrive a little ahead of time.

So far the finding, based on computer simulation, is tentative, applying only to observed deciduous forests in central Europe. But if confirmed, and if it matches reality more widely across the planet, then it may mean that the forests of the world actually start to take up less carbon than climate scientists had calculated.

In effect, this could prove to be another mechanism with which climate change driven by global heating could actually permit further heating, if only because trees − as agencies to absorb atmospheric carbon − might find that more carbon in the atmosphere simply means they take up all they can absorb earlier in the extended growing season.

For the moment, a higher ratio of carbon dioxide in the atmosphere, driven by ever-greater reliance on fossil fuels, has simply extended the active life of a deciduous tree. Spring in Europe now arrives two weeks earlier than it did 100 years ago, and autumn senescence about six days later.

Absorption controlled

It is a given of climate science that forest growth absorbs vast levels of atmospheric carbon that would otherwise accelerate global heating. And it has been a consistent finding that more atmospheric carbon seems to fertilise and intensify green growth wherever plants can survive.

But a new study in the journal Science by scientists at the Swiss Federal Institute of Technology, now known as ETH Zurich, suggests that the mechanisms that regulate plant growth in deciduous forests might subtly control the levels of carbon that a tree can absorb.

Phenology is the science of when things happen in the natural world − first bud, flowering and first leaf and so on − and the scientists could call on timed records of 434,226 observations at 3,855 locations in central Europe, of six species of tree.

They developed a model of autumn phenology that accounted for all the factors that must influence plant growth − atmospheric concentrations of carbon dioxide, summer temperatures, daylight length and rainfall among them.

“Seasonal CO2 uptake will probably increase to a lesser degree with rising temperatures than older models predicted”

They tested their simulation on the evidence so far, to find that their model predicted the timing of leaf senescence between 1948 and 2015 with up to 42% more accuracy than any previous models. And then they extended it to a warmer world.

Until now, researchers have assumed that by the end of the century autumn senescence will be happening two or even three weeks later. “Our new model suggests the contrary. If photosynthesis continues to increase, leaves will senesce three to six days earlier than they do today,” said Deborah Zani, first author.

“This means that the growing season will be extended by only eight to 12 days by the end of the century, around two or three times less than we previously thought.”

Research like this is a reminder of the migraine-inducing challenge climate scientists forever face, of calculating the global carbon budget. This is the traffic of carbon from fossil fuels to humans and then to vegetation, sediments and ocean.

Smaller carbon appetite

It is a rule of thumb that green foliage “fixes” vast quantities of carbon every year and stores a big percentage of that for a very long time, in timber, roots and soil. So the preservation and extension of the world’s great forests is part of the climate plan. Researchers from ETH Zurich even calculated that massive global planting could dramatically reduce atmospheric carbon ratios.

And while there is plenty of evidence that higher levels of carbon can fertilise growth, the outcomes are not simple. With more carbon comes more heat to increase drought and dangers of fire; heat itself can affect germination and there is evidence that overall, trees may be growing shorter and dying younger in a world of climate change.

Confronted with a forest of puzzles, researchers simply have to go back to the basics of how trees manage life’s ever-changing challenges. And on the evidence of the latest study, it seems that in those years with extra photosynthesis in spring and summer, leaf senescence begins earlier.

Ten per cent more sunlight means a burst of photosynthetic activity that will advance senescence by as many as eight days. It is as if each oak tree, beech, birch, chestnut, rowan or larch knew it had only so much carbon to fix and, when it had done, went into an earlier dormancy.

Which could mean that temperate forests have a limited appetite for atmospheric carbon. “Seasonal CO2 uptake will probably increase to a lesser degree with rising temperatures than older models predicted,” said Constantin Zohner, co-author and also from ETH Zurich. − Climate News Network

Earlier tree growth results from more atmospheric carbon. It may mean earlier leaf fall too, muddying climate calculations.

LONDON, 4 December, 2020 − As springs arrive earlier, and the growing season gets longer with ever-milder winters, Swiss scientists have identified a paradox: global warming driven by more carbon in ever-higher greenhouse gas emissions could actually trigger unexpectedly earlier autumn leaf change.

So even as winters get later, milder and shorter, that glorious display of autumn colour in leaves as they turn old and die could arrive a little ahead of time.

So far the finding, based on computer simulation, is tentative, applying only to observed deciduous forests in central Europe. But if confirmed, and if it matches reality more widely across the planet, then it may mean that the forests of the world actually start to take up less carbon than climate scientists had calculated.

In effect, this could prove to be another mechanism with which climate change driven by global heating could actually permit further heating, if only because trees − as agencies to absorb atmospheric carbon − might find that more carbon in the atmosphere simply means they take up all they can absorb earlier in the extended growing season.

For the moment, a higher ratio of carbon dioxide in the atmosphere, driven by ever-greater reliance on fossil fuels, has simply extended the active life of a deciduous tree. Spring in Europe now arrives two weeks earlier than it did 100 years ago, and autumn senescence about six days later.

Absorption controlled

It is a given of climate science that forest growth absorbs vast levels of atmospheric carbon that would otherwise accelerate global heating. And it has been a consistent finding that more atmospheric carbon seems to fertilise and intensify green growth wherever plants can survive.

But a new study in the journal Science by scientists at the Swiss Federal Institute of Technology, now known as ETH Zurich, suggests that the mechanisms that regulate plant growth in deciduous forests might subtly control the levels of carbon that a tree can absorb.

Phenology is the science of when things happen in the natural world − first bud, flowering and first leaf and so on − and the scientists could call on timed records of 434,226 observations at 3,855 locations in central Europe, of six species of tree.

They developed a model of autumn phenology that accounted for all the factors that must influence plant growth − atmospheric concentrations of carbon dioxide, summer temperatures, daylight length and rainfall among them.

“Seasonal CO2 uptake will probably increase to a lesser degree with rising temperatures than older models predicted”

They tested their simulation on the evidence so far, to find that their model predicted the timing of leaf senescence between 1948 and 2015 with up to 42% more accuracy than any previous models. And then they extended it to a warmer world.

Until now, researchers have assumed that by the end of the century autumn senescence will be happening two or even three weeks later. “Our new model suggests the contrary. If photosynthesis continues to increase, leaves will senesce three to six days earlier than they do today,” said Deborah Zani, first author.

“This means that the growing season will be extended by only eight to 12 days by the end of the century, around two or three times less than we previously thought.”

Research like this is a reminder of the migraine-inducing challenge climate scientists forever face, of calculating the global carbon budget. This is the traffic of carbon from fossil fuels to humans and then to vegetation, sediments and ocean.

Smaller carbon appetite

It is a rule of thumb that green foliage “fixes” vast quantities of carbon every year and stores a big percentage of that for a very long time, in timber, roots and soil. So the preservation and extension of the world’s great forests is part of the climate plan. Researchers from ETH Zurich even calculated that massive global planting could dramatically reduce atmospheric carbon ratios.

And while there is plenty of evidence that higher levels of carbon can fertilise growth, the outcomes are not simple. With more carbon comes more heat to increase drought and dangers of fire; heat itself can affect germination and there is evidence that overall, trees may be growing shorter and dying younger in a world of climate change.

Confronted with a forest of puzzles, researchers simply have to go back to the basics of how trees manage life’s ever-changing challenges. And on the evidence of the latest study, it seems that in those years with extra photosynthesis in spring and summer, leaf senescence begins earlier.

Ten per cent more sunlight means a burst of photosynthetic activity that will advance senescence by as many as eight days. It is as if each oak tree, beech, birch, chestnut, rowan or larch knew it had only so much carbon to fix and, when it had done, went into an earlier dormancy.

Which could mean that temperate forests have a limited appetite for atmospheric carbon. “Seasonal CO2 uptake will probably increase to a lesser degree with rising temperatures than older models predicted,” said Constantin Zohner, co-author and also from ETH Zurich. − Climate News Network

Rising ocean heat leaves fish gasping for oxygen

Lack of oxygen will leave some fish gasping as the thermometer rises. Deep time offers a guide to those at greatest risk.

LONDON, 2 December, 2020 − As global temperatures soar, the planetary menu could start to dwindle. Cod, sea bass and haddock will move to cooler and more distant waters. Tropical species relying on the shelter of coral reefs could simply disappear. Fish gasping for oxygen will struggle to survive.

And although the world’s marine catch is already under pressure from pollution, ocean acidification and overfishing, the real threat is now clear. As ocean temperatures rise, oxygen levels in the world’s seas will fall, and the most active fish could start to stifle.

Some sea creatures will survive: sharks, rays and other cartilaginous fish will do better than the bony ones. Bivalves that cling to rocks will also cling on to life.

But some types of fish could be pushed to their tolerance limits, says a new study in the journal Global Change Biology, and global heating driven by ever-higher carbon dioxide levels in the atmosphere will be the primary cause.

“Warm water contains less oxygen than cool water. This tends to affect organisms that consume the most oxygen, which can mean that actively mobile animals are particularly affected,” said Carl Reddin of the Museum of Natural History in Berlin, who headed the research.

Heading for 3°C

He and his colleagues set themselves a simple challenge: why do some groups of marine creatures go extinct more often than others? The steady decline in fish catches on traditional grounds already has one obvious explanation: humans have overfished, and polluted. So the scientists decided to take a long cool look at the past.

“The deep time fossil record, conversely, is free from human impacts, and documents extinctions during ancient episodes of rapid climate warming, or hyperthermals,” they write.

They looked back across the evidence preserved in the rocks over the last 300 million years and identified what they call “six global hyperthermal events that shared a rapid increase in tropical sea surface temperatures, generally greater than 2°C, with an onset duration less than 100,000 years.”

In effect, they were looking for global conditions that matched those now happening. In the last 100 years, planetary average temperatures have risen by 1°C, and although almost all the world’s nations met in 2015 and vowed to try to contain global heating by 2100 to “well below” 2°C, the planet is heading towards a rise of more than 3°C above the long-term average in the next eight decades.

The Berlin team found that those groups of marine animals that − on the evidence of the fossil record − were most vulnerable to global warming in the deep past looked very like those that seem most in trouble today, among them the bony fishes.

“The deep time fossil record documents extinctions during ancient episodes of rapid climate warming”

The idea is not new. Other marine biologists have repeatedly warned of oxygen depletion in and beyond the fishing grounds.

Separately, there has been evidence that higher temperatures have begun to change the nature of the oceans, and fishermen have begun to count the cost as their catch migrates to waters that are cooler.

What this latest study does is clear up the uncertainty. Overfishing remains a problem. Ocean acidification will certainly affect some shellfish and possibly also fish behaviour. Pollution has already increased the number of marine dead zones.

But beyond that, the problem is simply one of temperature, and the latest study identifies those groups or classes of marine creature most at risk from another rise in the planetary thermometer: those sensitive to “warming-induced seawater de-oxygenation,” the researchers report.

And they add: “In anticipation of modern warming-driven marine extinctions, the trends illustrated in the fossil record offer an expedient preview.” − Climate News Network

Lack of oxygen will leave some fish gasping as the thermometer rises. Deep time offers a guide to those at greatest risk.

LONDON, 2 December, 2020 − As global temperatures soar, the planetary menu could start to dwindle. Cod, sea bass and haddock will move to cooler and more distant waters. Tropical species relying on the shelter of coral reefs could simply disappear. Fish gasping for oxygen will struggle to survive.

And although the world’s marine catch is already under pressure from pollution, ocean acidification and overfishing, the real threat is now clear. As ocean temperatures rise, oxygen levels in the world’s seas will fall, and the most active fish could start to stifle.

Some sea creatures will survive: sharks, rays and other cartilaginous fish will do better than the bony ones. Bivalves that cling to rocks will also cling on to life.

But some types of fish could be pushed to their tolerance limits, says a new study in the journal Global Change Biology, and global heating driven by ever-higher carbon dioxide levels in the atmosphere will be the primary cause.

“Warm water contains less oxygen than cool water. This tends to affect organisms that consume the most oxygen, which can mean that actively mobile animals are particularly affected,” said Carl Reddin of the Museum of Natural History in Berlin, who headed the research.

Heading for 3°C

He and his colleagues set themselves a simple challenge: why do some groups of marine creatures go extinct more often than others? The steady decline in fish catches on traditional grounds already has one obvious explanation: humans have overfished, and polluted. So the scientists decided to take a long cool look at the past.

“The deep time fossil record, conversely, is free from human impacts, and documents extinctions during ancient episodes of rapid climate warming, or hyperthermals,” they write.

They looked back across the evidence preserved in the rocks over the last 300 million years and identified what they call “six global hyperthermal events that shared a rapid increase in tropical sea surface temperatures, generally greater than 2°C, with an onset duration less than 100,000 years.”

In effect, they were looking for global conditions that matched those now happening. In the last 100 years, planetary average temperatures have risen by 1°C, and although almost all the world’s nations met in 2015 and vowed to try to contain global heating by 2100 to “well below” 2°C, the planet is heading towards a rise of more than 3°C above the long-term average in the next eight decades.

The Berlin team found that those groups of marine animals that − on the evidence of the fossil record − were most vulnerable to global warming in the deep past looked very like those that seem most in trouble today, among them the bony fishes.

“The deep time fossil record documents extinctions during ancient episodes of rapid climate warming”

The idea is not new. Other marine biologists have repeatedly warned of oxygen depletion in and beyond the fishing grounds.

Separately, there has been evidence that higher temperatures have begun to change the nature of the oceans, and fishermen have begun to count the cost as their catch migrates to waters that are cooler.

What this latest study does is clear up the uncertainty. Overfishing remains a problem. Ocean acidification will certainly affect some shellfish and possibly also fish behaviour. Pollution has already increased the number of marine dead zones.

But beyond that, the problem is simply one of temperature, and the latest study identifies those groups or classes of marine creature most at risk from another rise in the planetary thermometer: those sensitive to “warming-induced seawater de-oxygenation,” the researchers report.

And they add: “In anticipation of modern warming-driven marine extinctions, the trends illustrated in the fossil record offer an expedient preview.” − Climate News Network

Global heating may go on for five more centuries

Global heating now means more warming for 500 years ahead, even if all greenhouse emissions stop. Or is that too simple?

LONDON, 20 November, 2020 − Norwegian scientists have mapped the future of the Earth in a regime of climate change and have come to an uncomfortable conclusion: it’s likely that global heating will persist until around the year 2500.

Even if human beings immediately ceased all use of fossil fuels that spill greenhouse gases into the planetary atmosphere, the world would be committed to warming for the next five centuries, they suggest.

By then global temperatures would be at least 3°C higher, and sea levels three metres higher, than they would have been in 1850. Even with a dramatic halt to the emissions that fuel global heating, they warn in the journal Scientific Reports, the Arctic ice would go on melting, water vapour would continue to build up in the atmosphere, the permafrost would continue to thaw and vast reservoirs of ancient carbon that had been trapped in the once-frozen ground would escape into the atmosphere.

The message − one that comes hedged with caution − is that to keep continental temperatures and sea levels as they were for most of human history, nations should have started to reduce greenhouse gas emissions six decades ago.

And to slow the warming that might now be inexorable, nations must unite to somehow remove 33 billion tonnes of carbon dioxide (CO2) − an almost unimaginable volume − from the atmosphere every year from now on.

Challenged by colleagues

Caution is necessary because, as the researchers themselves point out, the finding presents an extremely simple model of cause and effect on a simulated planet not unlike Earth, but without the untidy mosaic of natural and human processes that directly influence the rate at which CO2 builds up in the atmosphere.

And the two scientists who wrote the study directly urge other climate researchers to check their findings with more sophisticated simulations. They have made a stab at predicting the future, and they know it could be wrong.

But if it isn’t wrong, then the message is that profligate human use of fossil fuels, combined with heedless destruction of many of the planet’s natural ecosystems, and then topped with the massive construction of human cities, industries and travel networks, may have already pushed the planet past a tipping point, beyond which the slide into potentially catastrophic climate change has become inexorable.

And they are not the first to make such a suggestion. Nor are they the first to warn that what had once been trailed as a notional “worst case” scenario has of late increasingly begun to look like modern reality.

The finding has been comprehensively challenged by British scientists, not because it could be wrong, but because the simulation is too simple, and doesn’t incorporate many of the processes that happen in the real world. One distinguished researcher called it “a toy model”.

“To keep global warming to just 1.5°C this century we already know we will have to have negative carbon emissions from 2050 to 2100”

But almost all who commented also conceded that to steer the planet away from permanent and devastating climate change, nations may have left concerted and sustained action a bit late.

Reduction of carbon emissions to zero in the next three decades would be just a start. And the world would go on warming for some time, just as a reaction to the extra carbon dioxide already spilled into the atmosphere in the last three decades.

“To keep global warming to just 1.5°C this century we already know we will have to have negative carbon emissions from 2050 to 2100,” said Mark Maslin, a climatologist at University College, London.

“If this study is confirmed, then we may have to continue drawing down carbon dioxide from the atmosphere way beyond the end of this century. And I would suggest that if we have been able to successfully deal with climate change in this century, we really will not have to worry about dealing with a much smaller warming over the next 400 years.”

But even as both the authors and their critics warn that the outcome should be treated with caution, other research has almost coincidentally begun to suggest that the world may be nearing a tipping point.

Positive feedback?

Last month German scientists contemplated the increasing loss of ice in the Arctic − all the sea ice could have vanished in summer before mid-century − and in the mountain regions worldwide, and reasoned that, instead of reflecting radiation back into space, the darker ocean or rock revealed beneath the ice would absorb it, to increase rates of warming.

They warn in Nature Communications that this process alone could increase long-term global warming by 0.43°C, to accelerate yet more thawing of the permafrost: an example of the vicious circle that could go on delivering climate change by exactly the kind of positive feedback the Norwegian scientists fear.

And in one respect, their fellow scientists agree with them: further warming is already “baked in” to the future climate. Even if the world turns off greenhouse gas emissions right now, global heating will continue for decades. For how long, and how swiftly, is difficult to calculate.

“Even if the paper is right in every respect and we are already committed to at least 3°C warming if we stop emissions tomorrow, this warming will take 500 years,” said Andrew Watson, of the University of Exeter.

“This is preferable to 3°C warming over 100 years, which would be far more disruptive and might happen if we don’t cut emissions.” − Climate News Network

Global heating now means more warming for 500 years ahead, even if all greenhouse emissions stop. Or is that too simple?

LONDON, 20 November, 2020 − Norwegian scientists have mapped the future of the Earth in a regime of climate change and have come to an uncomfortable conclusion: it’s likely that global heating will persist until around the year 2500.

Even if human beings immediately ceased all use of fossil fuels that spill greenhouse gases into the planetary atmosphere, the world would be committed to warming for the next five centuries, they suggest.

By then global temperatures would be at least 3°C higher, and sea levels three metres higher, than they would have been in 1850. Even with a dramatic halt to the emissions that fuel global heating, they warn in the journal Scientific Reports, the Arctic ice would go on melting, water vapour would continue to build up in the atmosphere, the permafrost would continue to thaw and vast reservoirs of ancient carbon that had been trapped in the once-frozen ground would escape into the atmosphere.

The message − one that comes hedged with caution − is that to keep continental temperatures and sea levels as they were for most of human history, nations should have started to reduce greenhouse gas emissions six decades ago.

And to slow the warming that might now be inexorable, nations must unite to somehow remove 33 billion tonnes of carbon dioxide (CO2) − an almost unimaginable volume − from the atmosphere every year from now on.

Challenged by colleagues

Caution is necessary because, as the researchers themselves point out, the finding presents an extremely simple model of cause and effect on a simulated planet not unlike Earth, but without the untidy mosaic of natural and human processes that directly influence the rate at which CO2 builds up in the atmosphere.

And the two scientists who wrote the study directly urge other climate researchers to check their findings with more sophisticated simulations. They have made a stab at predicting the future, and they know it could be wrong.

But if it isn’t wrong, then the message is that profligate human use of fossil fuels, combined with heedless destruction of many of the planet’s natural ecosystems, and then topped with the massive construction of human cities, industries and travel networks, may have already pushed the planet past a tipping point, beyond which the slide into potentially catastrophic climate change has become inexorable.

And they are not the first to make such a suggestion. Nor are they the first to warn that what had once been trailed as a notional “worst case” scenario has of late increasingly begun to look like modern reality.

The finding has been comprehensively challenged by British scientists, not because it could be wrong, but because the simulation is too simple, and doesn’t incorporate many of the processes that happen in the real world. One distinguished researcher called it “a toy model”.

“To keep global warming to just 1.5°C this century we already know we will have to have negative carbon emissions from 2050 to 2100”

But almost all who commented also conceded that to steer the planet away from permanent and devastating climate change, nations may have left concerted and sustained action a bit late.

Reduction of carbon emissions to zero in the next three decades would be just a start. And the world would go on warming for some time, just as a reaction to the extra carbon dioxide already spilled into the atmosphere in the last three decades.

“To keep global warming to just 1.5°C this century we already know we will have to have negative carbon emissions from 2050 to 2100,” said Mark Maslin, a climatologist at University College, London.

“If this study is confirmed, then we may have to continue drawing down carbon dioxide from the atmosphere way beyond the end of this century. And I would suggest that if we have been able to successfully deal with climate change in this century, we really will not have to worry about dealing with a much smaller warming over the next 400 years.”

But even as both the authors and their critics warn that the outcome should be treated with caution, other research has almost coincidentally begun to suggest that the world may be nearing a tipping point.

Positive feedback?

Last month German scientists contemplated the increasing loss of ice in the Arctic − all the sea ice could have vanished in summer before mid-century − and in the mountain regions worldwide, and reasoned that, instead of reflecting radiation back into space, the darker ocean or rock revealed beneath the ice would absorb it, to increase rates of warming.

They warn in Nature Communications that this process alone could increase long-term global warming by 0.43°C, to accelerate yet more thawing of the permafrost: an example of the vicious circle that could go on delivering climate change by exactly the kind of positive feedback the Norwegian scientists fear.

And in one respect, their fellow scientists agree with them: further warming is already “baked in” to the future climate. Even if the world turns off greenhouse gas emissions right now, global heating will continue for decades. For how long, and how swiftly, is difficult to calculate.

“Even if the paper is right in every respect and we are already committed to at least 3°C warming if we stop emissions tomorrow, this warming will take 500 years,” said Andrew Watson, of the University of Exeter.

“This is preferable to 3°C warming over 100 years, which would be far more disruptive and might happen if we don’t cut emissions.” − Climate News Network

Africa’s resistance grows as climate crisis worsens

Battered by storms and droughts during a tough 2019, Africa’s resistance to the climate crisis left no room for passivity.

LONDON, 29 October, 2020 – Attempting to come to any general conclusions on the state of a vast, varied and complex continent may be a tricky business, but Africa’s resistance to the climate crisis shows it rejects any idea of settling for victimhood.

A new report, State of the Climate in Africa 2019, published by the World Meteorological Organization (WMO), makes that clear.

It reaches some grim conclusions. Increased temperatures, changing rainfall patterns, rising sea levels and more extreme weather are threatening human health and safety across the continent, says the report.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest and contributing to food insecurity, population displacement and stress on water resources”, says Petteri Taalas, the WMO secretary-general.

“In recent months we have seen devastating floods, an invasion of desert locusts and now face the looming spectre of drought because of a La Niña event”, he says. “The human and economic toll has been aggravated by the Covid-19 pandemic.”

Killer cyclone

Drought caused considerable damage in 2019, particularly across southern Africa. Much of East Africa also suffered drought but then, late in the year, there was torrential rain and serious flooding and landslides in the region.

The trend, says the report, is for continuing increases in temperature: 2019 was among the three warmest years ever recorded in Africa. The WMO predicts that rainfall is likely to decrease over northern and southern regions but increase over the Sahel.

There are also likely to be more weather-related extreme events. In March 2019 Cyclone Idai hit the coast of Mozambique and went on to devastate large areas of Malawi, Zimbabwe and surrounding countries.

Described as the most destructive cyclone ever recorded in the southern hemisphere, Idai killed hundreds of people and displaced several hundred thousand.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest”

Sea levels are rising well above the global average in many parts of Africa, the report says. Coastal degradation and erosion is a major challenge, particularly in West Africa. More than 50% of the coastlines in Benin, Côte d’Ivoire, Senegal and Togo are eroding – a trend likely to continue in future years.

The knock-on effects of these changes in climate are considerable. Approximately 60% of the total population of Africa is dependent on agriculture for a living.

Heat and drought, plus flood damage in some areas, are likely to reduce crop productivity. Changes in climate are also leading to pest outbreaks.

In what it describes as the worst case climate change scenario, the report says crop yields could drop by 13% by mid-century across West and Central Africa, 11% in North Africa and 8% in the eastern and southern regions of the continent. Rice and wheat crops would be particularly badly affected.

Combatting the crisis

Increased heat and continually changing rainfall patterns are also likely to lead to the spread of disease – and a fall-off in economic production in many countries.

But the report does point to some positive changes, showing Africa’s resistance to the crisis. Though the continent is responsible for only a small percentage of the world’s greenhouse gas emissions, many countries in Africa are taking measures aimed at tackling climate change.

Solar power is becoming more widespread, with several large-scale projects planned. Early warning systems monitoring the approach of such cataclysmic events as Cyclone Idai are being installed across the continent.
Farm incomes in many areas are increasing, due to the application of more efficient cultivation methods, such as micro-irrigation. But good planning, based on reliable data, is essential, the report says.

“The limited uptake and use of climate information services in development planning and practice in Africa is due in part to the paucity of reliable and timely climate information”, says Vera Songwe, the executive secretary of the United Nations Economic Commission for Africa. – Climate News Network

Battered by storms and droughts during a tough 2019, Africa’s resistance to the climate crisis left no room for passivity.

LONDON, 29 October, 2020 – Attempting to come to any general conclusions on the state of a vast, varied and complex continent may be a tricky business, but Africa’s resistance to the climate crisis shows it rejects any idea of settling for victimhood.

A new report, State of the Climate in Africa 2019, published by the World Meteorological Organization (WMO), makes that clear.

It reaches some grim conclusions. Increased temperatures, changing rainfall patterns, rising sea levels and more extreme weather are threatening human health and safety across the continent, says the report.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest and contributing to food insecurity, population displacement and stress on water resources”, says Petteri Taalas, the WMO secretary-general.

“In recent months we have seen devastating floods, an invasion of desert locusts and now face the looming spectre of drought because of a La Niña event”, he says. “The human and economic toll has been aggravated by the Covid-19 pandemic.”

Killer cyclone

Drought caused considerable damage in 2019, particularly across southern Africa. Much of East Africa also suffered drought but then, late in the year, there was torrential rain and serious flooding and landslides in the region.

The trend, says the report, is for continuing increases in temperature: 2019 was among the three warmest years ever recorded in Africa. The WMO predicts that rainfall is likely to decrease over northern and southern regions but increase over the Sahel.

There are also likely to be more weather-related extreme events. In March 2019 Cyclone Idai hit the coast of Mozambique and went on to devastate large areas of Malawi, Zimbabwe and surrounding countries.

Described as the most destructive cyclone ever recorded in the southern hemisphere, Idai killed hundreds of people and displaced several hundred thousand.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest”

Sea levels are rising well above the global average in many parts of Africa, the report says. Coastal degradation and erosion is a major challenge, particularly in West Africa. More than 50% of the coastlines in Benin, Côte d’Ivoire, Senegal and Togo are eroding – a trend likely to continue in future years.

The knock-on effects of these changes in climate are considerable. Approximately 60% of the total population of Africa is dependent on agriculture for a living.

Heat and drought, plus flood damage in some areas, are likely to reduce crop productivity. Changes in climate are also leading to pest outbreaks.

In what it describes as the worst case climate change scenario, the report says crop yields could drop by 13% by mid-century across West and Central Africa, 11% in North Africa and 8% in the eastern and southern regions of the continent. Rice and wheat crops would be particularly badly affected.

Combatting the crisis

Increased heat and continually changing rainfall patterns are also likely to lead to the spread of disease – and a fall-off in economic production in many countries.

But the report does point to some positive changes, showing Africa’s resistance to the crisis. Though the continent is responsible for only a small percentage of the world’s greenhouse gas emissions, many countries in Africa are taking measures aimed at tackling climate change.

Solar power is becoming more widespread, with several large-scale projects planned. Early warning systems monitoring the approach of such cataclysmic events as Cyclone Idai are being installed across the continent.
Farm incomes in many areas are increasing, due to the application of more efficient cultivation methods, such as micro-irrigation. But good planning, based on reliable data, is essential, the report says.

“The limited uptake and use of climate information services in development planning and practice in Africa is due in part to the paucity of reliable and timely climate information”, says Vera Songwe, the executive secretary of the United Nations Economic Commission for Africa. – Climate News Network

Antarctic depths warm far beyond oceanic average

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network