Tag Archives: Warming

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

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

Climate heat melts Arctic snows and dries forests

Fires now blaze under Arctic snows, where once even the wettest rainforests burned. Climate change delivers unlikely outcomes.

LONDON, 12 October, 2020 − The northern polar region isn’t just warming: it’s also smoking, as the rising heat thaws the Arctic snows. Researchers have identified a new class of fire hazard.

High above the Arctic Circle, fires that flared a year ago continued to smoulder under the snow through the winter to flare up again − two months earlier than usual, and on a scale not seen before.

And if the notion of fire and ice seems a surprise, prepare for the idea of a blazing rainforest. In a second and separate study, researchers exploring the climate lessons from the deep past 90 million years ago have found that, if the atmosphere is rich enough in oxygen, then even the wettest foliage can ignite and burn, to consume perhaps up to 40% of the world’s forest.

Scientists from the US report in Nature Geoscience that they have identified an unexpected threat from “zombie fires” which, despite heavy snowmelt, they say “can smoulder in carbon-rich peat below the surface for months or years, often only detectable through smoke released at the surface, and can even occur through cold winter months.”

“The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The impacts are really long-lasting”

They warn that in the fast-changing climate of the highest northern latitudes, the evidence from last year and this suggest that extreme temperatures and drier conditions mean there is a lot more surface fuel in the Arctic to catch fire and melt the Arctic snows.

Dwarf shrubs, sedges, mosses and grasses are invading the tundra, to join the surface peat, and even the bogs, fens and marches of the tundra are now burning. In all, 50% of the detected fires above 65°North − many in the Russian Arctic − happened on permafrost: that is, on ever-icy soils.

“It’s not just the amount of burned area that is alarming,” said Merritt Turetsky of the University of Colorado at Boulder, and one of the authors. “There are other trends we noticed in the satellite data that tell us how the Arctic fire regime is changing and what this spells for our climate future.”

Wildfires are on the increase now, in a world in which climate change has delivered hotter and drier conditions for many regions. Unexpectedly, according to a second study in Nature Geoscience, fossilized evidence in rocks in Utah has delivered evidence of massive and sustained forest fires, in the form of polycyclic aromatic hydrocarbons preserved in black shales laid down in the Cretaceous.

Huge absorption rate

Researchers pieced together a story of dramatic climate change 94 million years ago, when carbon dioxide built up in the atmosphere, and land and sea plants began to absorb it from the atmosphere on a massive scale. Microbial respiration stepped up too, and parts of the ocean became increasingly low in oxygen.

During 100,000 years of this, so much carbon had been buried in the ground or the oceans that – with the release of molecular oxygen, the O2 in CO2 − atmospheric oxygen levels began to increase. And with that, the scientists say, so did the probability of forest fires, even in wet forest ecosystems. Altogether, perhaps 30% to 40% of the planet’s forests were consumed by fire over 100 millennia.

“One of the consequences of having more oxygen in the atmosphere is that it’s easier to burn fires. It’s the same reason you blow on embers to stoke a fire,” said Garrett Boudinot, then at the University of Boulder Colorado and now with the Colorado Wildlife Council, who led the research.

“This finding highlights the prolonged impacts of climate change. The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The history of climate change in Earth history tells us that the impacts are really long-lasting.” − Climate News Network

Fires now blaze under Arctic snows, where once even the wettest rainforests burned. Climate change delivers unlikely outcomes.

LONDON, 12 October, 2020 − The northern polar region isn’t just warming: it’s also smoking, as the rising heat thaws the Arctic snows. Researchers have identified a new class of fire hazard.

High above the Arctic Circle, fires that flared a year ago continued to smoulder under the snow through the winter to flare up again − two months earlier than usual, and on a scale not seen before.

And if the notion of fire and ice seems a surprise, prepare for the idea of a blazing rainforest. In a second and separate study, researchers exploring the climate lessons from the deep past 90 million years ago have found that, if the atmosphere is rich enough in oxygen, then even the wettest foliage can ignite and burn, to consume perhaps up to 40% of the world’s forest.

Scientists from the US report in Nature Geoscience that they have identified an unexpected threat from “zombie fires” which, despite heavy snowmelt, they say “can smoulder in carbon-rich peat below the surface for months or years, often only detectable through smoke released at the surface, and can even occur through cold winter months.”

“The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The impacts are really long-lasting”

They warn that in the fast-changing climate of the highest northern latitudes, the evidence from last year and this suggest that extreme temperatures and drier conditions mean there is a lot more surface fuel in the Arctic to catch fire and melt the Arctic snows.

Dwarf shrubs, sedges, mosses and grasses are invading the tundra, to join the surface peat, and even the bogs, fens and marches of the tundra are now burning. In all, 50% of the detected fires above 65°North − many in the Russian Arctic − happened on permafrost: that is, on ever-icy soils.

“It’s not just the amount of burned area that is alarming,” said Merritt Turetsky of the University of Colorado at Boulder, and one of the authors. “There are other trends we noticed in the satellite data that tell us how the Arctic fire regime is changing and what this spells for our climate future.”

Wildfires are on the increase now, in a world in which climate change has delivered hotter and drier conditions for many regions. Unexpectedly, according to a second study in Nature Geoscience, fossilized evidence in rocks in Utah has delivered evidence of massive and sustained forest fires, in the form of polycyclic aromatic hydrocarbons preserved in black shales laid down in the Cretaceous.

Huge absorption rate

Researchers pieced together a story of dramatic climate change 94 million years ago, when carbon dioxide built up in the atmosphere, and land and sea plants began to absorb it from the atmosphere on a massive scale. Microbial respiration stepped up too, and parts of the ocean became increasingly low in oxygen.

During 100,000 years of this, so much carbon had been buried in the ground or the oceans that – with the release of molecular oxygen, the O2 in CO2 − atmospheric oxygen levels began to increase. And with that, the scientists say, so did the probability of forest fires, even in wet forest ecosystems. Altogether, perhaps 30% to 40% of the planet’s forests were consumed by fire over 100 millennia.

“One of the consequences of having more oxygen in the atmosphere is that it’s easier to burn fires. It’s the same reason you blow on embers to stoke a fire,” said Garrett Boudinot, then at the University of Boulder Colorado and now with the Colorado Wildlife Council, who led the research.

“This finding highlights the prolonged impacts of climate change. The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The history of climate change in Earth history tells us that the impacts are really long-lasting.” − Climate News Network

Greenland’s ice loss likely to hit 12,000-year high

Greenland’s ice loss could be more this century than at any time in the history of civilization − and perhaps much more.

LONDON, 5 October, 2020 − By the end of this century Greenland’s ice loss will probably be higher than in any century during the last 12,000 years.

Even if humans take immediate drastic action to reduce greenhouse gas emissions, this new record loss will happen. And if − as seems the case − nations go on burning ever more fossil fuels and destroying ever more natural forest, then this ice loss will be four times greater than at any period in human history, according to a new study.

US, Canadian and Danish scientists report in the journal Nature that they used geological evidence and detailed computer simulations to model the past and future loss of ice from the northern hemisphere’s biggest land-borne store − Greenland bears enough ice to raise global sea levels by six metres or more − and measure possible rates of change.

On their reckoning, shortly after the end of the last Ice Age around 12,000 years ago, Greenland’s ice loss was up to 6,000 billion tonnes in the course of 100 years. That, for the entire span from then till now, stayed the record.

They calculate that the rate of loss now, based on measurements in the first 18 years of this century, could still be slightly greater, even if the 195 nations that promised in Paris in 2015 to co-operate to keep global heating to a level “well below” 2°C above the annual average for most of human history, actually kept that promise.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet”

But if the world’s economies continue using fossil fuels under the notorious business-as-usual scenario, then the mass of ice shed from Greenland before the close of the century could be anywhere between 8,800 billion tonnes and 35,900 billion tonnes.

“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability of the ice sheet over the past 12,000 years.

“We’ll blow that out of the water if we don’t make severe reductions to greenhouse gas emissions,” says Jason Briner, a geologist at the University of Buffalo in New York.

“If the world goes on a massive energy diet,” he adds, “our model predicts that the Greenland Ice Sheet’s rate of mass loss this century will be only slightly higher than anything experienced in the past 12,000 years.”

If on the other hand the world follows what has always been − for climate modellers − the worst case scenario, then, he warns, “the rate of mass loss could be about four times the highest values experienced under natural climate variability over the past 12,000 years.”

‘Eye-opening’ timeline

The latest study supports a flurry of alarming observations and conclusions about Greenland’s ice sheet just in the last few months. Other teams of researchers have found that ice loss from the island is possibly irreversible, that that loss is accelerating in an Arctic region that is warming as fast as or faster than all previous “worst case” predictions, and at a rate that suggests climate scientists may even have to redefine what used to be considered Arctic conditions.

The latest study is one of a series that take the long view of climate history: it is important to separate where possible the effect of natural cycles that would anyway deliver changing conditions, from human-driven or anthropogenic change that could tip the global climate into a new and potentially catastrophic state.

“We have long timelines of temperature change, past to present to future, that show the influence of greenhouse gases on Earth’s temperature. And now, for the first time, we have a long timeline of the impacts of that temperature − in the form of Greenland Ice Sheet melt − from past to present to future. And what it shows is eye-opening,” says Professor Briner.

“Our findings are yet another wake-up call, especially for countries like the US. Americans use more energy per person than any other nation in the world.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet.” − Climate News Network

Greenland’s ice loss could be more this century than at any time in the history of civilization − and perhaps much more.

LONDON, 5 October, 2020 − By the end of this century Greenland’s ice loss will probably be higher than in any century during the last 12,000 years.

Even if humans take immediate drastic action to reduce greenhouse gas emissions, this new record loss will happen. And if − as seems the case − nations go on burning ever more fossil fuels and destroying ever more natural forest, then this ice loss will be four times greater than at any period in human history, according to a new study.

US, Canadian and Danish scientists report in the journal Nature that they used geological evidence and detailed computer simulations to model the past and future loss of ice from the northern hemisphere’s biggest land-borne store − Greenland bears enough ice to raise global sea levels by six metres or more − and measure possible rates of change.

On their reckoning, shortly after the end of the last Ice Age around 12,000 years ago, Greenland’s ice loss was up to 6,000 billion tonnes in the course of 100 years. That, for the entire span from then till now, stayed the record.

They calculate that the rate of loss now, based on measurements in the first 18 years of this century, could still be slightly greater, even if the 195 nations that promised in Paris in 2015 to co-operate to keep global heating to a level “well below” 2°C above the annual average for most of human history, actually kept that promise.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet”

But if the world’s economies continue using fossil fuels under the notorious business-as-usual scenario, then the mass of ice shed from Greenland before the close of the century could be anywhere between 8,800 billion tonnes and 35,900 billion tonnes.

“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability of the ice sheet over the past 12,000 years.

“We’ll blow that out of the water if we don’t make severe reductions to greenhouse gas emissions,” says Jason Briner, a geologist at the University of Buffalo in New York.

“If the world goes on a massive energy diet,” he adds, “our model predicts that the Greenland Ice Sheet’s rate of mass loss this century will be only slightly higher than anything experienced in the past 12,000 years.”

If on the other hand the world follows what has always been − for climate modellers − the worst case scenario, then, he warns, “the rate of mass loss could be about four times the highest values experienced under natural climate variability over the past 12,000 years.”

‘Eye-opening’ timeline

The latest study supports a flurry of alarming observations and conclusions about Greenland’s ice sheet just in the last few months. Other teams of researchers have found that ice loss from the island is possibly irreversible, that that loss is accelerating in an Arctic region that is warming as fast as or faster than all previous “worst case” predictions, and at a rate that suggests climate scientists may even have to redefine what used to be considered Arctic conditions.

The latest study is one of a series that take the long view of climate history: it is important to separate where possible the effect of natural cycles that would anyway deliver changing conditions, from human-driven or anthropogenic change that could tip the global climate into a new and potentially catastrophic state.

“We have long timelines of temperature change, past to present to future, that show the influence of greenhouse gases on Earth’s temperature. And now, for the first time, we have a long timeline of the impacts of that temperature − in the form of Greenland Ice Sheet melt − from past to present to future. And what it shows is eye-opening,” says Professor Briner.

“Our findings are yet another wake-up call, especially for countries like the US. Americans use more energy per person than any other nation in the world.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet.” − 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

Seas and forests are muddying the carbon budget

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

Abnormal heat spreads floods and wildfires globally

From the Arctic Circle to tropical Africa, abnormal heat is bringing mayhem and destruction and costing lives.

LONDON, 17 September, 2020 – Across the planet, abnormal heat is exacting a lethal toll. The west coast of the US is up in flames. Over recent months unprecedented high temperatures have been melting permafrost in Siberia, within the Arctic Circle. Fires have spread; many thousands of acres of taiga have been laid waste.

Across many parts of Africa unseasonable torrential rains are causing loss of life and crops.

Climate scientists are careful about attributing any one severe weather event to climate change until all data is gathered and a proper analysis is made.

But looking at various weather patterns around the world, fundamental changes in climate are happening – most related to big increases in temperature.

Along the western seaboard of the US people are having to cope not only with a prolonged drought but with temperatures which are way above normal.

As the ground and brush at the base of trees dries out, the ideal conditions for wildfires are set.

Over recent days more than 40,000 people in the state of Oregon have been told to evacuate their homes: dozens of people are believed to be missing in the mayhem caused by the fires.

“The debate is over.This is a climate damn emergency. This is real and it’s happening”

Kate Brown, Oregon’s governor, says that over three days recently more than 1,400 square miles of land was destroyed by fire – nearly double the amount burned over a typical year in the state.

“We have never seen this amount of uncontained fire”, said Brown.

“While our state reels from this horrific fire storm of hot weather, high winds and drought conditions, this will not be a one-time event.

“Unfortunately it is the bellwether of the future. We are feeling the acute impacts of climate change.”

Last month a group of Oregon’s leading industrialists launched a court action against Governor Brown, saying she overstepped her authority by introducing measures aimed at cutting carbon emissions in the state.

Further south in California, wildfires continue to burn. The skies of San Francisco and other cities have turned red in recent days. Smoke from the fires is causing severe air quality problems.

Gavin Newsom, California’s governor, launched an angry attack on President Trump and others who are sceptical about climate change, while visiting an area of the state destroyed by fire.

Africa inundated

“The debate is over” said Newsom. “This is a climate damn emergency. This is real and it’s happening.”

Studies say that since the early 1970s California has registered a more than fivefold increase in the annual incidence of forest fires.

A similar growing trend in abnormal heat and wildfires is being recorded in many parts of Siberia: soaring temperatures have been a big factor. In one Siberian town temperatures reached 38°C in mid-June – 18°C above the usual daytime temperature for the time of year.

Less reported on but a cause of death and hardship to some of the world’s poorest countries are floods that have been destroying homes and crops across large areas of the African continent.

In Somalia, still trying to establish itself as a functioning fully independent state in the face of terrorist attacks, nearly a million people have been affected by severe flooding in recent months.

Sudan and Ethiopia have also been subject to widespread flooding.

According to data from the US National Oceanic and Atmospheric Administration (NOAA), torrential rains and floods are affecting both east and west Africa. In Nigeria, Africa’s most populous state, thousands of homes have been destroyed and crops ruined. – Climate News Network

From the Arctic Circle to tropical Africa, abnormal heat is bringing mayhem and destruction and costing lives.

LONDON, 17 September, 2020 – Across the planet, abnormal heat is exacting a lethal toll. The west coast of the US is up in flames. Over recent months unprecedented high temperatures have been melting permafrost in Siberia, within the Arctic Circle. Fires have spread; many thousands of acres of taiga have been laid waste.

Across many parts of Africa unseasonable torrential rains are causing loss of life and crops.

Climate scientists are careful about attributing any one severe weather event to climate change until all data is gathered and a proper analysis is made.

But looking at various weather patterns around the world, fundamental changes in climate are happening – most related to big increases in temperature.

Along the western seaboard of the US people are having to cope not only with a prolonged drought but with temperatures which are way above normal.

As the ground and brush at the base of trees dries out, the ideal conditions for wildfires are set.

Over recent days more than 40,000 people in the state of Oregon have been told to evacuate their homes: dozens of people are believed to be missing in the mayhem caused by the fires.

“The debate is over.This is a climate damn emergency. This is real and it’s happening”

Kate Brown, Oregon’s governor, says that over three days recently more than 1,400 square miles of land was destroyed by fire – nearly double the amount burned over a typical year in the state.

“We have never seen this amount of uncontained fire”, said Brown.

“While our state reels from this horrific fire storm of hot weather, high winds and drought conditions, this will not be a one-time event.

“Unfortunately it is the bellwether of the future. We are feeling the acute impacts of climate change.”

Last month a group of Oregon’s leading industrialists launched a court action against Governor Brown, saying she overstepped her authority by introducing measures aimed at cutting carbon emissions in the state.

Further south in California, wildfires continue to burn. The skies of San Francisco and other cities have turned red in recent days. Smoke from the fires is causing severe air quality problems.

Gavin Newsom, California’s governor, launched an angry attack on President Trump and others who are sceptical about climate change, while visiting an area of the state destroyed by fire.

Africa inundated

“The debate is over” said Newsom. “This is a climate damn emergency. This is real and it’s happening.”

Studies say that since the early 1970s California has registered a more than fivefold increase in the annual incidence of forest fires.

A similar growing trend in abnormal heat and wildfires is being recorded in many parts of Siberia: soaring temperatures have been a big factor. In one Siberian town temperatures reached 38°C in mid-June – 18°C above the usual daytime temperature for the time of year.

Less reported on but a cause of death and hardship to some of the world’s poorest countries are floods that have been destroying homes and crops across large areas of the African continent.

In Somalia, still trying to establish itself as a functioning fully independent state in the face of terrorist attacks, nearly a million people have been affected by severe flooding in recent months.

Sudan and Ethiopia have also been subject to widespread flooding.

According to data from the US National Oceanic and Atmospheric Administration (NOAA), torrential rains and floods are affecting both east and west Africa. In Nigeria, Africa’s most populous state, thousands of homes have been destroyed and crops ruined. – 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