Tag Archives: Prediction

North Pole may be clear water by mid-century

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network

Paris climate goals may be beyond reach

Scientists find carbon dioxide is more potent than thought, meaning the Paris climate goals on cutting greenhouse gases may be unattainable.

LONDON, 23 January, 2020 − The fevered arguments about how the world can reach the Paris climate goals on cutting the greenhouse gases which are driving global heating may be a waste of time. An international team of scientists has learned more about the main greenhouse gas, carbon dioxide (CO2) − and it’s not good news.

Teams in six countries, using new climate models, say the warming potential of CO2 has been underestimated for years. The new models will be used in revised UN temperature projections next year. If they are accurate, the Paris targets of keeping temperature rise below 2°C − or preferably 1.5°C − will belong to a fantasy world.

Vastly more data and computing power has become available since the current Intergovernmental Panel on Climate Change (IPCC) projections were finalised in 2013. “We have better models now,” Olivier Boucher, head of the Institut Pierre Simon Laplace Climate Modelling Centre in Paris, told the French news agency AFP, and they “represent current climate trends more accurately”.

Projections from government-backed teams using the models in the US, UK, France and Canada suggest a much warmer future unless the world acts fast: CO2 concentrations which have till now been expected to produce a world only 3°C warmer than pre-industrial levels would more probably heat the Earth’s surface by four or five degrees Celsius.

“If you think the new models give a more realistic picture, then it will, of course, be harder to achieve the Paris targets, whether it is 1.5°C or two degrees Celsius,” Mark Zelinka told AFP. Dr Zelinka, from the Lawrence Livermore National Laboratory in California, is the lead author of the first peer-reviewed assessment of the new generation of models, published earlier this month in the journal Geophysical Research Letters.

“Climate sensitivity has been in the range of 1.5°C to 4.5°C for more than 30 years. If it is now moving to between 3°C and 7°C, that would be tremendously dangerous”

Scientists want to establish how much the Earth’s surface will warm over time if the amount of CO2 in the atmosphere doubles. The resulting temperature increase, known as Earth’s climate sensitivity, is a key indicator of the probable future climate. The part played in it by clouds is crucial.

“How clouds evolve in a warmer climate and whether they will exert a tempering or amplifying effect has long been a major source of uncertainty,” said Imperial College London researcher Joeri Rogelj, the lead author for the Intergovernmental Panel on Climate Change (IPCC) on the global carbon budget − the amount of greenhouse gases that can be emitted without exceeding a given temperature cap. The new models reflect a better understanding of cloud dynamics that reinforce the warming impact of CO2.

For most of the last 10,000 years the concentration of CO2 in the atmosphere was a nearly constant 280 parts per million (ppm). But at the start of the 19th century and of the industrial revolution, fuelled by oil, gas and coal, the number of CO2 molecules in the air rose sharply. Today the concentration stands at 412 ppm, a 45% rise − half of it in the last three decades.

Last year alone, human activity injected more than 41 billion tonnes of CO2 into the atmosphere, about five million tonnes every hour.

Impacts already evident

With only one degree Celsius of warming above historic levels so far, the world is already having to cope with increasingly deadly heatwaves, droughts, floods and tropical cyclones made more destructive by rising seas.

By the late 1970s scientists had settled on a probable climate sensitivity of 3°C (plus-or-minus 1.5°C), corresponding to about 560 ppm of CO2 in the atmosphere. That assessment remained largely unchanged − until now.

“Right now, there is an enormously heated debate within the climate modelling community,” said Earth system scientist Johan Rockström, director of Germany’s Potsdam Institute for Climate Impact Research.

“You have 12 or 13 models showing sensitivity which is no longer 3°C, but rather 5°C or 6°C with a doubling of CO2,” he told AFP. “What is particularly worrying is that these are not the outliers.”

Serious science

Models from France, the US Department of Energy, Britain’s Met Office and Canada show climate sensitivity of 4.9°C, 5.3°C, 5.5°C and 5.6°C respectively, Dr Zelinka said. “You have to take these models seriously − they are highly developed, state-of-the-art.”

Among the 27 new models examined in his study, these were also among those that best matched climate change over the last 75 years, suggesting a further validation of their accuracy.

But other models that will feed into the IPCC’s next major Assessment Report found significantly smaller increases, though almost all were higher than earlier estimates. Scientists will test and challenge the new models rigorously.

“The jury is still out, but it is worrying,” said Rockstrom. “Climate sensitivity has been in the range of 1.5°C to 4.5°C for more than 30 years. If it is now moving to between 3°C and 7°C, that would be tremendously dangerous.” − Climate News Network

Scientists find carbon dioxide is more potent than thought, meaning the Paris climate goals on cutting greenhouse gases may be unattainable.

LONDON, 23 January, 2020 − The fevered arguments about how the world can reach the Paris climate goals on cutting the greenhouse gases which are driving global heating may be a waste of time. An international team of scientists has learned more about the main greenhouse gas, carbon dioxide (CO2) − and it’s not good news.

Teams in six countries, using new climate models, say the warming potential of CO2 has been underestimated for years. The new models will be used in revised UN temperature projections next year. If they are accurate, the Paris targets of keeping temperature rise below 2°C − or preferably 1.5°C − will belong to a fantasy world.

Vastly more data and computing power has become available since the current Intergovernmental Panel on Climate Change (IPCC) projections were finalised in 2013. “We have better models now,” Olivier Boucher, head of the Institut Pierre Simon Laplace Climate Modelling Centre in Paris, told the French news agency AFP, and they “represent current climate trends more accurately”.

Projections from government-backed teams using the models in the US, UK, France and Canada suggest a much warmer future unless the world acts fast: CO2 concentrations which have till now been expected to produce a world only 3°C warmer than pre-industrial levels would more probably heat the Earth’s surface by four or five degrees Celsius.

“If you think the new models give a more realistic picture, then it will, of course, be harder to achieve the Paris targets, whether it is 1.5°C or two degrees Celsius,” Mark Zelinka told AFP. Dr Zelinka, from the Lawrence Livermore National Laboratory in California, is the lead author of the first peer-reviewed assessment of the new generation of models, published earlier this month in the journal Geophysical Research Letters.

“Climate sensitivity has been in the range of 1.5°C to 4.5°C for more than 30 years. If it is now moving to between 3°C and 7°C, that would be tremendously dangerous”

Scientists want to establish how much the Earth’s surface will warm over time if the amount of CO2 in the atmosphere doubles. The resulting temperature increase, known as Earth’s climate sensitivity, is a key indicator of the probable future climate. The part played in it by clouds is crucial.

“How clouds evolve in a warmer climate and whether they will exert a tempering or amplifying effect has long been a major source of uncertainty,” said Imperial College London researcher Joeri Rogelj, the lead author for the Intergovernmental Panel on Climate Change (IPCC) on the global carbon budget − the amount of greenhouse gases that can be emitted without exceeding a given temperature cap. The new models reflect a better understanding of cloud dynamics that reinforce the warming impact of CO2.

For most of the last 10,000 years the concentration of CO2 in the atmosphere was a nearly constant 280 parts per million (ppm). But at the start of the 19th century and of the industrial revolution, fuelled by oil, gas and coal, the number of CO2 molecules in the air rose sharply. Today the concentration stands at 412 ppm, a 45% rise − half of it in the last three decades.

Last year alone, human activity injected more than 41 billion tonnes of CO2 into the atmosphere, about five million tonnes every hour.

Impacts already evident

With only one degree Celsius of warming above historic levels so far, the world is already having to cope with increasingly deadly heatwaves, droughts, floods and tropical cyclones made more destructive by rising seas.

By the late 1970s scientists had settled on a probable climate sensitivity of 3°C (plus-or-minus 1.5°C), corresponding to about 560 ppm of CO2 in the atmosphere. That assessment remained largely unchanged − until now.

“Right now, there is an enormously heated debate within the climate modelling community,” said Earth system scientist Johan Rockström, director of Germany’s Potsdam Institute for Climate Impact Research.

“You have 12 or 13 models showing sensitivity which is no longer 3°C, but rather 5°C or 6°C with a doubling of CO2,” he told AFP. “What is particularly worrying is that these are not the outliers.”

Serious science

Models from France, the US Department of Energy, Britain’s Met Office and Canada show climate sensitivity of 4.9°C, 5.3°C, 5.5°C and 5.6°C respectively, Dr Zelinka said. “You have to take these models seriously − they are highly developed, state-of-the-art.”

Among the 27 new models examined in his study, these were also among those that best matched climate change over the last 75 years, suggesting a further validation of their accuracy.

But other models that will feed into the IPCC’s next major Assessment Report found significantly smaller increases, though almost all were higher than earlier estimates. Scientists will test and challenge the new models rigorously.

“The jury is still out, but it is worrying,” said Rockstrom. “Climate sensitivity has been in the range of 1.5°C to 4.5°C for more than 30 years. If it is now moving to between 3°C and 7°C, that would be tremendously dangerous.” − Climate News Network

Climate models predict bigger heat rise ahead

Scientists using new climate models say a bigger heat rise than expected is possible by the end of the century.

LONDON, 18 September, 2019 − Greenhouse gases are raising the Earth’s temperature faster than previously thought, according to new climate models due to replace those used in current UN projections − meaning a bigger heat rise by 2100 than thought likely.

Separate models at two French research centres suggest that by then average global temperatures could have risen by 6.5 to 7.0°C above pre-industrial levels if carbon emissions continue at their present rate, the website phys.org reports.

Scientists − and most of the world’s governments − finalised the Paris Agreement on climate change in 2015, undertaking to keep the warming increase to a maximum of 2°C, and if possible to only 1.5°C.

Almost two years ago, a UN report deemed it “very likely” that global temperatures would reach 3°C by 2100, even if the Paris goals were fully implemented. But the French warning suggests a planet with double that predicted increase. And as the increase would be only an average, some parts of the world would be even more seriously affected.

“What we need to do to keep warming to safe levels is extremely simple. Global greenhouse gas emissions need to decline today rather than tomorrow, and global CO2 emissions should be brought to net zero”

“With our two models, we see that the scenario known as SSP1 2.6 − which normally allows us to stay under 2°C − doesn’t quite get us there,” Olivier Boucher, head of the Institute Pierre Simon Laplace climate modelling centre in Paris, told the French news agency AFP.

With barely one degree Celsius of warming so far, the world is already having to cope with more heat waves, droughts, floods and extreme weather, much of it made more destructive by rising seas.

Beyond Paris, a new generation of about 30 models known collectively as CMIP6 − including the two revealed by France − will underpin the sixth assessment report by the Intergovernmental Panel on Climate Change (IPCC): the full report is due in 2022.

“CMIP6 clearly includes the latest modelling improvements”, even as important uncertainties remain, Joeri Rogelj, an associate professor at Imperial College London and an IPCC lead author, told AFP.

More accurate

These include increased supercomputing power and sharper representations of weather systems, natural and man-made particles, and how clouds evolve in a warming world.

“We have better models now,” said Dr Boucher. “They have better resolution, and they represent current climate trends more accurately.”

A core finding of the new models is that increased levels of CO2 in the atmosphere will warm the Earth’s surface more easily than earlier calculations had suggested. If confirmed, this higher “equilibrium climate sensitivity”, or ECS, means humanity’s carbon budget − our total emissions allowance − is likely to shrink.

The French models are among the first to be released, but others developed independently have come to the same unsettling conclusion, Dr Boucher said. “The most respected ones − from the United States, and Britain’s Met Office − also show a higher ECS” than the previous generation of models, he said.

Less adaptation time

“A higher ECS means a greater likelihood of reaching higher levels of global warming, even with deeper emissions cuts”, Boucher and two British scientists − Professor Stephen Belcher and Professor Rowan Sutton from the UK National Centre for Atmospheric Science − wrote in a blog earlier this year.

“Higher warming would allow less time to adapt and mean a greater likelihood of passing climate ‘tipping points’ such as thawing of permafrost, which would further accelerate warming.”

“Unfortunately, our global failure to implement meaningful action on climate change over recent decades has put us in a situation where what we need to do to keep warming to safe levels is extremely simple”, said Dr Rogelj.

“Global greenhouse gas emissions need to decline today rather than tomorrow, and global CO2 emissions should be brought to net zero.” − Climate News Network

Scientists using new climate models say a bigger heat rise than expected is possible by the end of the century.

LONDON, 18 September, 2019 − Greenhouse gases are raising the Earth’s temperature faster than previously thought, according to new climate models due to replace those used in current UN projections − meaning a bigger heat rise by 2100 than thought likely.

Separate models at two French research centres suggest that by then average global temperatures could have risen by 6.5 to 7.0°C above pre-industrial levels if carbon emissions continue at their present rate, the website phys.org reports.

Scientists − and most of the world’s governments − finalised the Paris Agreement on climate change in 2015, undertaking to keep the warming increase to a maximum of 2°C, and if possible to only 1.5°C.

Almost two years ago, a UN report deemed it “very likely” that global temperatures would reach 3°C by 2100, even if the Paris goals were fully implemented. But the French warning suggests a planet with double that predicted increase. And as the increase would be only an average, some parts of the world would be even more seriously affected.

“What we need to do to keep warming to safe levels is extremely simple. Global greenhouse gas emissions need to decline today rather than tomorrow, and global CO2 emissions should be brought to net zero”

“With our two models, we see that the scenario known as SSP1 2.6 − which normally allows us to stay under 2°C − doesn’t quite get us there,” Olivier Boucher, head of the Institute Pierre Simon Laplace climate modelling centre in Paris, told the French news agency AFP.

With barely one degree Celsius of warming so far, the world is already having to cope with more heat waves, droughts, floods and extreme weather, much of it made more destructive by rising seas.

Beyond Paris, a new generation of about 30 models known collectively as CMIP6 − including the two revealed by France − will underpin the sixth assessment report by the Intergovernmental Panel on Climate Change (IPCC): the full report is due in 2022.

“CMIP6 clearly includes the latest modelling improvements”, even as important uncertainties remain, Joeri Rogelj, an associate professor at Imperial College London and an IPCC lead author, told AFP.

More accurate

These include increased supercomputing power and sharper representations of weather systems, natural and man-made particles, and how clouds evolve in a warming world.

“We have better models now,” said Dr Boucher. “They have better resolution, and they represent current climate trends more accurately.”

A core finding of the new models is that increased levels of CO2 in the atmosphere will warm the Earth’s surface more easily than earlier calculations had suggested. If confirmed, this higher “equilibrium climate sensitivity”, or ECS, means humanity’s carbon budget − our total emissions allowance − is likely to shrink.

The French models are among the first to be released, but others developed independently have come to the same unsettling conclusion, Dr Boucher said. “The most respected ones − from the United States, and Britain’s Met Office − also show a higher ECS” than the previous generation of models, he said.

Less adaptation time

“A higher ECS means a greater likelihood of reaching higher levels of global warming, even with deeper emissions cuts”, Boucher and two British scientists − Professor Stephen Belcher and Professor Rowan Sutton from the UK National Centre for Atmospheric Science − wrote in a blog earlier this year.

“Higher warming would allow less time to adapt and mean a greater likelihood of passing climate ‘tipping points’ such as thawing of permafrost, which would further accelerate warming.”

“Unfortunately, our global failure to implement meaningful action on climate change over recent decades has put us in a situation where what we need to do to keep warming to safe levels is extremely simple”, said Dr Rogelj.

“Global greenhouse gas emissions need to decline today rather than tomorrow, and global CO2 emissions should be brought to net zero.” − Climate News Network

‘Small’ nuclear war could bring global cooling

Smoke from Canadian forest fires was so vast it bore comparison with a nuclear bomb’s mushroom cloud – and the global cooling that might unleash.

LONDON, 21 August, 2019 − If a nuclear war should ever break out, any survivors could have to cope not just with the immediate effects of blast and radioactivity, but with climate mayhem as well: global cooling with unknowable consequences.

The wildfires in the Canadian province of British Columbia in the summer of 2017 were the worst the region had ever seen. They were so bad that the smoke from the sustained blaze rose 23 kms into the upper stratosphere and stayed there for eight months.

And that has given US scientists the chance once again to model the consequences of a nuclear winter after thermonuclear war.

“This process of injecting soot into the stratosphere and seeing it extend its lifetime by self-lofting was previously modelled as a consequence of nuclear winter in the case of an all-out war between the United States and Russia, in which smoke from burning cities would change the global climate,” said Alan Robock, an environmental scientist at Rutgers University.

“Even a relatively small nuclear war between India and Pakistan could cause climate change unprecedented in recorded human history, and global food crises.”

“The observed rapid plume, latitudinal spread, and photochemical reactions provided new insight into potential global climate impacts from nuclear war”

Professor Robock and colleagues report in the journal Science that they used computer simulations and satellite observations to test an old worry: what happens when black carbon or other obstructions get into the stratosphere. Sulphate aerosols discharged to stratospheric heights from volcanoes have been observed to lower global average temperatures.

The eruption of Mt Pinatubo in the Philippines in 1991 blasted 20 million tonnes of sulphur dioxide into the stratosphere and lowered global temperatures by around 0.5°C, and the same observations have prompted scientists to propose an untested and potentially dangerous solution to runaway global heating, by spraying aerosols into the upper atmosphere.

The unprecedented fires in British Columbia that began in July 2017 provided them with experimental evidence: the devastation was so bad that 40,000 people were evacuated from their homes and the provincial government declared a state of emergency that lasted 10 weeks. Altogether the fires destroyed 1.2 million hectares of forest and caused $564m worth of damage.

What interested the US scientists was the smoke. It formed a pyrocumulonimbus cloud larger than any ever observed before and rose 12 kilometres. There was hardly enough mass in the plume to cool the planet in any measurable way, but it had bulk enough to provide information on how the cloud dispersed and how it lingered.

The soot in the cloud absorbed solar radiation and the air around each particle became hotter, which made it rise even further. Within two months, it had reached 23kms. The stratosphere is above the rain clouds, so there was nothing to wash the soot down again. The stratosphere is also home to the jet stream, and high winds took the soot around the whole hemisphere.

Future unpredictable

And that gave Professor Robock and his colleagues the chance to test models of what might happen if, instead of forest fires, the smoke had come from cities reduced to ash by a thermonuclear exchange.

The smoke from British Columbia held 300,000 tonnes of soot. A nuclear war between India and Pakistan however could put 15 million tonnes into the upper atmosphere, and a war between the US and Russia could generate 150 million tonnes.

Nobody knows what then might happen. More than 30 years ago, US scientists raised the spectre of nuclear winter: a world in which sunlight was weakened, summers were cancelled, and harvests failed.

The hypothesis was, thankfully, never put to the test, and in any case was challenged by other scientists. The Canadian fires, themselves perhaps made more devastating by global warming, delivered some vital clues. The next step is to apply the evidence from 2017 to see whether, after a nuclear war, the much-feared enduring winter would follow.

“The observed rapid plume, latitudinal spread, and photochemical reactions provided new insight into potential global climate impacts from nuclear war,” the scientists write. − Climate News Network

Smoke from Canadian forest fires was so vast it bore comparison with a nuclear bomb’s mushroom cloud – and the global cooling that might unleash.

LONDON, 21 August, 2019 − If a nuclear war should ever break out, any survivors could have to cope not just with the immediate effects of blast and radioactivity, but with climate mayhem as well: global cooling with unknowable consequences.

The wildfires in the Canadian province of British Columbia in the summer of 2017 were the worst the region had ever seen. They were so bad that the smoke from the sustained blaze rose 23 kms into the upper stratosphere and stayed there for eight months.

And that has given US scientists the chance once again to model the consequences of a nuclear winter after thermonuclear war.

“This process of injecting soot into the stratosphere and seeing it extend its lifetime by self-lofting was previously modelled as a consequence of nuclear winter in the case of an all-out war between the United States and Russia, in which smoke from burning cities would change the global climate,” said Alan Robock, an environmental scientist at Rutgers University.

“Even a relatively small nuclear war between India and Pakistan could cause climate change unprecedented in recorded human history, and global food crises.”

“The observed rapid plume, latitudinal spread, and photochemical reactions provided new insight into potential global climate impacts from nuclear war”

Professor Robock and colleagues report in the journal Science that they used computer simulations and satellite observations to test an old worry: what happens when black carbon or other obstructions get into the stratosphere. Sulphate aerosols discharged to stratospheric heights from volcanoes have been observed to lower global average temperatures.

The eruption of Mt Pinatubo in the Philippines in 1991 blasted 20 million tonnes of sulphur dioxide into the stratosphere and lowered global temperatures by around 0.5°C, and the same observations have prompted scientists to propose an untested and potentially dangerous solution to runaway global heating, by spraying aerosols into the upper atmosphere.

The unprecedented fires in British Columbia that began in July 2017 provided them with experimental evidence: the devastation was so bad that 40,000 people were evacuated from their homes and the provincial government declared a state of emergency that lasted 10 weeks. Altogether the fires destroyed 1.2 million hectares of forest and caused $564m worth of damage.

What interested the US scientists was the smoke. It formed a pyrocumulonimbus cloud larger than any ever observed before and rose 12 kilometres. There was hardly enough mass in the plume to cool the planet in any measurable way, but it had bulk enough to provide information on how the cloud dispersed and how it lingered.

The soot in the cloud absorbed solar radiation and the air around each particle became hotter, which made it rise even further. Within two months, it had reached 23kms. The stratosphere is above the rain clouds, so there was nothing to wash the soot down again. The stratosphere is also home to the jet stream, and high winds took the soot around the whole hemisphere.

Future unpredictable

And that gave Professor Robock and his colleagues the chance to test models of what might happen if, instead of forest fires, the smoke had come from cities reduced to ash by a thermonuclear exchange.

The smoke from British Columbia held 300,000 tonnes of soot. A nuclear war between India and Pakistan however could put 15 million tonnes into the upper atmosphere, and a war between the US and Russia could generate 150 million tonnes.

Nobody knows what then might happen. More than 30 years ago, US scientists raised the spectre of nuclear winter: a world in which sunlight was weakened, summers were cancelled, and harvests failed.

The hypothesis was, thankfully, never put to the test, and in any case was challenged by other scientists. The Canadian fires, themselves perhaps made more devastating by global warming, delivered some vital clues. The next step is to apply the evidence from 2017 to see whether, after a nuclear war, the much-feared enduring winter would follow.

“The observed rapid plume, latitudinal spread, and photochemical reactions provided new insight into potential global climate impacts from nuclear war,” the scientists write. − Climate News Network

Carbon rise could cause cloud tipping point

The planet’s temperature could zoom in an ever more greenhouse world, as researchers identify a dangerous possible cloud tipping point.

LONDON, 27 February, 2019 − Climate scientists have confirmed a high-level hazard, a cloud tipping point, that could send global warming into a dramatic upwards spiral.

If carbon dioxide concentrations in the atmosphere become high enough, the clouds that shade and cool some of the tropical and subtropical oceans could become unstable and disperse. More radiation would slam into the ocean and the coasts, and surface temperatures could soar as high as 8°C above the levels for most of human history.

And this dramatic spike would be independent of any warming directly linked to the steady rise in carbon dioxide concentrations themselves, the scientists warn.

In Paris in 2015, a total of 195 nations vowed to take steps to contain global warming to “well below” a maximum of 2°C above the average before the start of the Industrial Revolution, powered by the exploitation of fossil fuels.

In the last 200 years, levels of the greenhouse gas carbon dioxide in the atmosphere have increased from 288 parts per million to around 410 ppm and the average global temperature has already increased by about 1°C.

“Our results show that there are dangerous climate change thresholds that we have been unaware of”

Researchers have repeatedly warned that the Paris promises have yet to be turned into coherent and consistent action, and that if the world goes on burning coal, oil and natural gas on a “business as usual” scenario, catastrophic consequences could follow.

Now US researchers warn in the journal Nature Geoscience that they know a bit more about the climate mechanisms by which global warming could accelerate.

If carbon dioxide ratios climb to 1,200 ppm – and without drastic action this could happen in the next century – then the Earth could reach a tipping point, and the marine stratus clouds that shade one-fifth of the low-latitude oceans and reflect between 30% and 60% of shortwave radiation back into space could break up and scatter.

The sunlight they normally block would slam into the deep blue sea, to warm the planet even faster.

Avoidance possible

“I think and hope that technological changes will slow carbon emissions so that we do not actually reach such high CO2 concentrations,” said Tapio Schneider, an environmental scientist at the Jet Propulsion Laboratory, the research centre managed for the US space agency NASA by the California Institute of Technology.

“But our results show that there are dangerous climate change thresholds that we have been unaware of.”

The role of clouds in the intricate interplay of sunlight, forests, oceans, rocks and atmosphere that controls the planet’s climate has been the subject of argument. Do clouds really slow warming? And if so, by how much, and under what conditions?

There may not be a simple answer, although researchers are fairly confident that the thinning of clouds over the California coasts may have made calamitous wildfires in the state more probable.

So to resolve what Professor Schneider calls “a blind spot” in climate modelling, he and his colleagues worked on a small-scale computer simulation of one representative section of the atmosphere above the subtropical ocean, and then used supercomputers to model the clouds and their turbulent movement over a mathematical representation of the sea. And then they started to tune up the atmospheric concentrations of carbon dioxide.

Carbon threshold

They found that, once CO2 levels reached 1,200 ppm, the decks of stratocumulus cloud vanished, and did not reappear until CO2 levels dropped to well below this dangerous threshold.

If – and this has yet to happen – other researchers use different approaches to confirm the result, then the US scientists will have established a better understanding of one component of natural climate control.

The research may also illuminate a puzzle of climate history: 50 million or more years ago, during a geological epoch called the Eocene, the Arctic ice cap melted. Climate models have shown that, for this to happen, atmospheric carbon ratios would need to rise to 4,000 ppm.

These, the Caltech team, suggests, would be “implausibly high” CO2 levels. The latest study suggests this might be an overestimate: a mere 1,200 ppm would be enough to set the planetary thermometer soaring. − Climate News Network

The planet’s temperature could zoom in an ever more greenhouse world, as researchers identify a dangerous possible cloud tipping point.

LONDON, 27 February, 2019 − Climate scientists have confirmed a high-level hazard, a cloud tipping point, that could send global warming into a dramatic upwards spiral.

If carbon dioxide concentrations in the atmosphere become high enough, the clouds that shade and cool some of the tropical and subtropical oceans could become unstable and disperse. More radiation would slam into the ocean and the coasts, and surface temperatures could soar as high as 8°C above the levels for most of human history.

And this dramatic spike would be independent of any warming directly linked to the steady rise in carbon dioxide concentrations themselves, the scientists warn.

In Paris in 2015, a total of 195 nations vowed to take steps to contain global warming to “well below” a maximum of 2°C above the average before the start of the Industrial Revolution, powered by the exploitation of fossil fuels.

In the last 200 years, levels of the greenhouse gas carbon dioxide in the atmosphere have increased from 288 parts per million to around 410 ppm and the average global temperature has already increased by about 1°C.

“Our results show that there are dangerous climate change thresholds that we have been unaware of”

Researchers have repeatedly warned that the Paris promises have yet to be turned into coherent and consistent action, and that if the world goes on burning coal, oil and natural gas on a “business as usual” scenario, catastrophic consequences could follow.

Now US researchers warn in the journal Nature Geoscience that they know a bit more about the climate mechanisms by which global warming could accelerate.

If carbon dioxide ratios climb to 1,200 ppm – and without drastic action this could happen in the next century – then the Earth could reach a tipping point, and the marine stratus clouds that shade one-fifth of the low-latitude oceans and reflect between 30% and 60% of shortwave radiation back into space could break up and scatter.

The sunlight they normally block would slam into the deep blue sea, to warm the planet even faster.

Avoidance possible

“I think and hope that technological changes will slow carbon emissions so that we do not actually reach such high CO2 concentrations,” said Tapio Schneider, an environmental scientist at the Jet Propulsion Laboratory, the research centre managed for the US space agency NASA by the California Institute of Technology.

“But our results show that there are dangerous climate change thresholds that we have been unaware of.”

The role of clouds in the intricate interplay of sunlight, forests, oceans, rocks and atmosphere that controls the planet’s climate has been the subject of argument. Do clouds really slow warming? And if so, by how much, and under what conditions?

There may not be a simple answer, although researchers are fairly confident that the thinning of clouds over the California coasts may have made calamitous wildfires in the state more probable.

So to resolve what Professor Schneider calls “a blind spot” in climate modelling, he and his colleagues worked on a small-scale computer simulation of one representative section of the atmosphere above the subtropical ocean, and then used supercomputers to model the clouds and their turbulent movement over a mathematical representation of the sea. And then they started to tune up the atmospheric concentrations of carbon dioxide.

Carbon threshold

They found that, once CO2 levels reached 1,200 ppm, the decks of stratocumulus cloud vanished, and did not reappear until CO2 levels dropped to well below this dangerous threshold.

If – and this has yet to happen – other researchers use different approaches to confirm the result, then the US scientists will have established a better understanding of one component of natural climate control.

The research may also illuminate a puzzle of climate history: 50 million or more years ago, during a geological epoch called the Eocene, the Arctic ice cap melted. Climate models have shown that, for this to happen, atmospheric carbon ratios would need to rise to 4,000 ppm.

These, the Caltech team, suggests, would be “implausibly high” CO2 levels. The latest study suggests this might be an overestimate: a mere 1,200 ppm would be enough to set the planetary thermometer soaring. − Climate News Network

Extinction may silence advanced civilisations

ET hasn’t been in touch. Enduring silence may be the real message from distant and ancient galaxies, if advanced civilisations destroy the conditions for their own survival.

LONDON, 11 June, 2018 – US scientists have calculated the conditions for the survival of a civilisation – all advanced civilisations across the vast universe. Their calculations may explain why, so far, extraterrestrial beings have failed to get in touch.

They may also help explain why climate change driven by global warming could be both inevitable and potentially calamitous.

Entirely theoretical research of this kind is the basis of astrobiology: the attempt to understand why life exists in a seemingly hostile universe, and why, if it exists on Earth, it is not visible everywhere. For practical data, astrobiologists have only one instance of life, and one of intelligent advanced civilisation to work with: planet Earth.

Adam Frank, of the University of Rochester, New York, and colleagues report in the journal Astrobiology that they considered the evidence of a vanished civilisation on Earth – the mysterious culture that flourished on Easter Island in the Pacific and then vanished by about 1500AD.

Better insight

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses,” said Professor Frank.

“The point is to recognise that driving climate change may be something generic. The laws of physics demand that any young population, building an energy-intensive civilisation like ours, is going to have feedback on its planet. Seeing climate change in this cosmic context may give us better insight into what’s happening to us now and how to deal with it.”

The principle is that any civilisation must change its planet, and the most obvious way would be by exploiting resources in ways that might affect average planetary temperatures.

Under such circumstances the population could reach a peak – and then die off, leaving a few survivors. Or it could foresee the problems and go for sustainability rather than ever more growth. Or population and temperature could reach a peak, at which point the civilisation would collapse. Or – disconcertingly – the threatened civilisation could identify the looming disaster but fail to act in time.

Fatal delay

“The last scenario is the most frightening,” said Professor Frank. “Even if you did the right thing, if you waited too long, you could still have your population collapse.”

Geoscientists have already identified a new phase of Earth history: the planet has now entered an epoch informally called the Anthropocene. They have already established that, in principle, the build-up of greenhouse gases in the atmosphere as a consequence of the exploitation of fossil fuels could raise temperatures to a point that would make civilisation, and perhaps even life on Earth, unsustainable.

Professor Frank himself has explored these questions in earlier studies. In 2014, he and colleagues asked themselves how long an alien civilisation that had discovered fossil fuels, and therefore changed the conditions in which it evolved, could sustain itself.

Earlier this year he returned to the theme and asked how modern humans could ever know if some intelligent non-human civilisation had once ruled the planet and then obliterated itself. Easter Island’s vanished overlords, the people who built the vast stone statues that now stand in enigmatic silence over an impoverished landscape, become in such a case an object lesson.

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses”

Archaeological evidence suggests that a culture emerged perhaps 1600 years ago, population grew to a peak, resources were over-exploited, population collapsed and, with it, all memory of what once had been. If an isolated island had a maximum carrying capacity, then so ultimately would an isolated planet. Professor Frank sees global climate change as a planet’s response to civilisation.

“If you go through really strong climate change, then your carrying capacity may drop, because, for example, large-scale agriculture might be strongly disrupted. Imagine if climate change caused rain to stop falling in the Midwest. We wouldn’t be able to grow food, and our population would diminish,” he said.

“If you change the Earth’s climate enough, you might not be able to change it back. Even if you backed off and started to use solar or other less impactful resources, it could be too late, because the planet has already been changing.

“These models show we can’t just think about a population evolving on its own. We have to think about our planets and civilisations co-evolving.” – Climate News Network

ET hasn’t been in touch. Enduring silence may be the real message from distant and ancient galaxies, if advanced civilisations destroy the conditions for their own survival.

LONDON, 11 June, 2018 – US scientists have calculated the conditions for the survival of a civilisation – all advanced civilisations across the vast universe. Their calculations may explain why, so far, extraterrestrial beings have failed to get in touch.

They may also help explain why climate change driven by global warming could be both inevitable and potentially calamitous.

Entirely theoretical research of this kind is the basis of astrobiology: the attempt to understand why life exists in a seemingly hostile universe, and why, if it exists on Earth, it is not visible everywhere. For practical data, astrobiologists have only one instance of life, and one of intelligent advanced civilisation to work with: planet Earth.

Adam Frank, of the University of Rochester, New York, and colleagues report in the journal Astrobiology that they considered the evidence of a vanished civilisation on Earth – the mysterious culture that flourished on Easter Island in the Pacific and then vanished by about 1500AD.

Better insight

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses,” said Professor Frank.

“The point is to recognise that driving climate change may be something generic. The laws of physics demand that any young population, building an energy-intensive civilisation like ours, is going to have feedback on its planet. Seeing climate change in this cosmic context may give us better insight into what’s happening to us now and how to deal with it.”

The principle is that any civilisation must change its planet, and the most obvious way would be by exploiting resources in ways that might affect average planetary temperatures.

Under such circumstances the population could reach a peak – and then die off, leaving a few survivors. Or it could foresee the problems and go for sustainability rather than ever more growth. Or population and temperature could reach a peak, at which point the civilisation would collapse. Or – disconcertingly – the threatened civilisation could identify the looming disaster but fail to act in time.

Fatal delay

“The last scenario is the most frightening,” said Professor Frank. “Even if you did the right thing, if you waited too long, you could still have your population collapse.”

Geoscientists have already identified a new phase of Earth history: the planet has now entered an epoch informally called the Anthropocene. They have already established that, in principle, the build-up of greenhouse gases in the atmosphere as a consequence of the exploitation of fossil fuels could raise temperatures to a point that would make civilisation, and perhaps even life on Earth, unsustainable.

Professor Frank himself has explored these questions in earlier studies. In 2014, he and colleagues asked themselves how long an alien civilisation that had discovered fossil fuels, and therefore changed the conditions in which it evolved, could sustain itself.

Earlier this year he returned to the theme and asked how modern humans could ever know if some intelligent non-human civilisation had once ruled the planet and then obliterated itself. Easter Island’s vanished overlords, the people who built the vast stone statues that now stand in enigmatic silence over an impoverished landscape, become in such a case an object lesson.

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses”

Archaeological evidence suggests that a culture emerged perhaps 1600 years ago, population grew to a peak, resources were over-exploited, population collapsed and, with it, all memory of what once had been. If an isolated island had a maximum carrying capacity, then so ultimately would an isolated planet. Professor Frank sees global climate change as a planet’s response to civilisation.

“If you go through really strong climate change, then your carrying capacity may drop, because, for example, large-scale agriculture might be strongly disrupted. Imagine if climate change caused rain to stop falling in the Midwest. We wouldn’t be able to grow food, and our population would diminish,” he said.

“If you change the Earth’s climate enough, you might not be able to change it back. Even if you backed off and started to use solar or other less impactful resources, it could be too late, because the planet has already been changing.

“These models show we can’t just think about a population evolving on its own. We have to think about our planets and civilisations co-evolving.” – Climate News Network

Long-lived civilisation may be a dream

Astrobiology, the search for alien life, has a lesson for us here on Earth: our hope for a long-lived civilisation may not be sustainable.

LONDON, 19 April, 2018 – Humanity’s cherished hope that we are building a long-lived civilisation may be nothing more than a pipe-dream. Human endeavour, two scientists argue, may carry within it the seeds of its own destruction.

The two astrophysicists have turned one of the great questions in science into a way of examining the down-to-earth consequences of global warming, the pollution of the oceans with indestructible polymers, and the wholesale destruction of species in the last 300 years.

They put an innocent question: if there had been an advanced technological and industrial civilisation on Earth several hundred million years ago, how could anyone know? What marks would have been left by a race of intelligent reptiles with motorised transport, housing estates, international trade and an arms race?

In what they call the Silurian hypothesis – a reference not to the geological period long before the first creatures crawled from the sea onto the empty continents, but to a 1970 episode of the British television serial Dr Who – they turn to the only testbed available to contemporary Earthlings: the evidence of the Anthropocene, the geologists’ name for a new era that could be considered to have commenced with the Industrial Revolution.

“Burning fossil fuels may actually shut us down as a civilisation. What imprints would this or other kinds of industrial activity from a long-dead civilisation leave over tens of millions of years?”

If some alien or distant-future civilisation set out to study the Earth’s geological record, what signs would humans have left in the strata?

And almost immediately, their study confronts a paradox. “The longer human civilisation lasts, the larger the signal one would expect in the record. However, the longer a civilisation lasts, the more sustainable its practices would need to have become in order to survive,” they write in the International Journal of Astrobiology.

But the more sustainable a society, the smaller the footprint its agriculture, manufacture or energy generation would have made, and the smaller the signal in the geological record.

So the researchers, Adam Frank from the University of Rochester, New York and Gavin Schmidt, director of the Nasa Goddard Institute for Space Studies, set out to calculate the future signature of long-vanished human society.

Signs of change

They conclude that the burning of fossil fuels has already changed the carbon cycle in a way that would be recognisable in records of carbon isotopes. Global warming – a consequence of that fossil fuel combustion – would be detectable in the rocks.

Global agriculture would be signalled by increases of erosion and sedimentation rates over time, and plastic pollutants would be detectable for perhaps billions of years. And all-out thermonuclear war – were it to happen – would leave behind some unusual radioactive isotopes.

“As an industrial civilisation, we’re driving changes in the isotopic abundances because we’re burning carbon,” said Professor Frank. “But burning fossil fuels may actually shut us down as a civilisation. What imprints would this or other kinds of industrial activity from a long-dead civilisation leave over tens of millions of years?”

The latest study is not the only one to contemplate the paradox of a self-destroying civilisation. Last year an Arkansas mathematician considered the silence of the extraterrestrials.

Nothing heard

For 40 years, humans have been listening for the noise of other intelligent civilisations in the galaxy, and have heard nothing. Maybe, he suggested in the same journal, modern humans are typical of technological civilisations, and destroy either their planet, or themselves, almost as soon as they exploit technology.

Perhaps, he suggests, a technological civilisation that lasted for millions of years would not be typical.

The latest study, in essence, pursues the same logic. Human advance for the moment is not sustainable. The people of the Anthropocene have already tipped 12 billion tonnes of indestructible plastics into landfills, and created a technosphere that totals about 30 trillion tonnes. And by 2050, humans will have built another 25 million km of roads.

“You want to have a nice, large-scale civilisation that does wonderful things but that doesn’t push the planet into domains that are dangerous for itself, the civilisation,” said Professor Frank. “We need to figure out a way of producing and using energy that doesn’t put us at risk.” – Climate News Network

Astrobiology, the search for alien life, has a lesson for us here on Earth: our hope for a long-lived civilisation may not be sustainable.

LONDON, 19 April, 2018 – Humanity’s cherished hope that we are building a long-lived civilisation may be nothing more than a pipe-dream. Human endeavour, two scientists argue, may carry within it the seeds of its own destruction.

The two astrophysicists have turned one of the great questions in science into a way of examining the down-to-earth consequences of global warming, the pollution of the oceans with indestructible polymers, and the wholesale destruction of species in the last 300 years.

They put an innocent question: if there had been an advanced technological and industrial civilisation on Earth several hundred million years ago, how could anyone know? What marks would have been left by a race of intelligent reptiles with motorised transport, housing estates, international trade and an arms race?

In what they call the Silurian hypothesis – a reference not to the geological period long before the first creatures crawled from the sea onto the empty continents, but to a 1970 episode of the British television serial Dr Who – they turn to the only testbed available to contemporary Earthlings: the evidence of the Anthropocene, the geologists’ name for a new era that could be considered to have commenced with the Industrial Revolution.

“Burning fossil fuels may actually shut us down as a civilisation. What imprints would this or other kinds of industrial activity from a long-dead civilisation leave over tens of millions of years?”

If some alien or distant-future civilisation set out to study the Earth’s geological record, what signs would humans have left in the strata?

And almost immediately, their study confronts a paradox. “The longer human civilisation lasts, the larger the signal one would expect in the record. However, the longer a civilisation lasts, the more sustainable its practices would need to have become in order to survive,” they write in the International Journal of Astrobiology.

But the more sustainable a society, the smaller the footprint its agriculture, manufacture or energy generation would have made, and the smaller the signal in the geological record.

So the researchers, Adam Frank from the University of Rochester, New York and Gavin Schmidt, director of the Nasa Goddard Institute for Space Studies, set out to calculate the future signature of long-vanished human society.

Signs of change

They conclude that the burning of fossil fuels has already changed the carbon cycle in a way that would be recognisable in records of carbon isotopes. Global warming – a consequence of that fossil fuel combustion – would be detectable in the rocks.

Global agriculture would be signalled by increases of erosion and sedimentation rates over time, and plastic pollutants would be detectable for perhaps billions of years. And all-out thermonuclear war – were it to happen – would leave behind some unusual radioactive isotopes.

“As an industrial civilisation, we’re driving changes in the isotopic abundances because we’re burning carbon,” said Professor Frank. “But burning fossil fuels may actually shut us down as a civilisation. What imprints would this or other kinds of industrial activity from a long-dead civilisation leave over tens of millions of years?”

The latest study is not the only one to contemplate the paradox of a self-destroying civilisation. Last year an Arkansas mathematician considered the silence of the extraterrestrials.

Nothing heard

For 40 years, humans have been listening for the noise of other intelligent civilisations in the galaxy, and have heard nothing. Maybe, he suggested in the same journal, modern humans are typical of technological civilisations, and destroy either their planet, or themselves, almost as soon as they exploit technology.

Perhaps, he suggests, a technological civilisation that lasted for millions of years would not be typical.

The latest study, in essence, pursues the same logic. Human advance for the moment is not sustainable. The people of the Anthropocene have already tipped 12 billion tonnes of indestructible plastics into landfills, and created a technosphere that totals about 30 trillion tonnes. And by 2050, humans will have built another 25 million km of roads.

“You want to have a nice, large-scale civilisation that does wonderful things but that doesn’t push the planet into domains that are dangerous for itself, the civilisation,” said Professor Frank. “We need to figure out a way of producing and using energy that doesn’t put us at risk.” – Climate News Network

Hotter world than predicted may be here by 2100

A warmer world is likelier than thought. Image: Public domain

A hotter world could be on the way, unless nations act. That’s because the gloomiest predictions may not have been gloomy enough.

 

LONDON, 8 December, 2017 – Tomorrow may experience a hotter world than anyone had feared. Global warming, under the notorious “business-as-usual scenario” in which humans go on burning fossil fuels to power economic growth, could by 2100 be at least 15% warmer than the worst UN projections so far. And the spread of uncertainty in such gloomy forecasts has been narrowed as well.

Climate scientists had worked on the assumption that there was a 62% chance that the world would have warmed on average by more than 4°C if no action was taken to reduce greenhouse gas emissions.

But a new study has not only raised the stakes, it has narrowed the uncertainty. There is now a 93% chance that global warming will – once again, under the business-as-usual scenario – exceed 4°C by 2100.

And since, in Paris in 2015, the world’s nations met and agreed to keep overall global warming to “well below” 2°C,  even that figure represents “dangerous” global warming.  One degree higher would count as “catastrophic”. And a rise of beyond 5°C would deliver the world into an unknown and unpredictable period of change.

“If emissions follow a commonly-used business-as-usual scenario, there is a 93% chance that global warming will exceed 4°C by the end of this century”

Two US scientists report in the journal Nature that they went back to the climate models used as the basis for forecasts made by the UN’s Intergovernmental Panel on Climate Change and then matched the reasoning against observations.

In particular, they looked again at seasonal and monthly variability in climate and the latest thinking about energy use, and carbon dioxide emissions, and their impact on temperatures.

There has always been an argument about the long-term accuracy of climate models and what they can usefully predict about the real world by the century’s end. If anything, the new results suggest that tomorrow’s reality could be even worse.

“Our results suggest that it doesn’t make sense to dismiss the most-severe global warming projections based on the fact that climate models are imperfect in their simulation of the current climate,” said Patrick Brown, of the Carnegie Institution at Stanford University in California.

Deeper cuts

“On the contrary, we are showing that model shortcomings can be used to dismiss the least severe predictions.”

And, the authors warn: “Our results suggest that achieving any given global temperature stabilisation target will require steeper greenhouse gas emissions reduction than previously calculated.”

Climate models are only as good as the climate data on which they are based, and one source of uncertainty has been the effect of warming on cloud formation: a warmer world means more evaporation, which could mean more warmth is trapped in the atmosphere – or it could mean more clouds, which reflect more solar radiation back into space.

For decades, researchers have tried to calculate with precision the links between ratios of greenhouse gases released from the combustion of coal, natural gas and oil, and shifts in average planetary temperature.

Simpler evidence

One of the Carnegie authors, Ken Caldeira of the Institution’s global ecology lab, has so far calculated the rate at which carbon dioxide sets about warming the atmosphere, and the capacity of greenhouse gases to go on warming the world for millennia.

The latest conclusions have been based on simpler evidence: the accuracy with which their forecast models can “predict” the recent past.

Professor Caldeira said: “It makes sense that the models that do the best job at simulating today’s observations might be the models with the most reliable predictions.

“Our study indicates that if emissions follow a commonly-used business-as-usual scenario, there is a 93% chance that global warming will exceed 4°C by the end of this century. Previous studies have put this likelihood at 62%.” –  Climate News Network

A hotter world could be on the way, unless nations act. That’s because the gloomiest predictions may not have been gloomy enough.

 

LONDON, 8 December, 2017 – Tomorrow may experience a hotter world than anyone had feared. Global warming, under the notorious “business-as-usual scenario” in which humans go on burning fossil fuels to power economic growth, could by 2100 be at least 15% warmer than the worst UN projections so far. And the spread of uncertainty in such gloomy forecasts has been narrowed as well.

Climate scientists had worked on the assumption that there was a 62% chance that the world would have warmed on average by more than 4°C if no action was taken to reduce greenhouse gas emissions.

But a new study has not only raised the stakes, it has narrowed the uncertainty. There is now a 93% chance that global warming will – once again, under the business-as-usual scenario – exceed 4°C by 2100.

And since, in Paris in 2015, the world’s nations met and agreed to keep overall global warming to “well below” 2°C,  even that figure represents “dangerous” global warming.  One degree higher would count as “catastrophic”. And a rise of beyond 5°C would deliver the world into an unknown and unpredictable period of change.

“If emissions follow a commonly-used business-as-usual scenario, there is a 93% chance that global warming will exceed 4°C by the end of this century”

Two US scientists report in the journal Nature that they went back to the climate models used as the basis for forecasts made by the UN’s Intergovernmental Panel on Climate Change and then matched the reasoning against observations.

In particular, they looked again at seasonal and monthly variability in climate and the latest thinking about energy use, and carbon dioxide emissions, and their impact on temperatures.

There has always been an argument about the long-term accuracy of climate models and what they can usefully predict about the real world by the century’s end. If anything, the new results suggest that tomorrow’s reality could be even worse.

“Our results suggest that it doesn’t make sense to dismiss the most-severe global warming projections based on the fact that climate models are imperfect in their simulation of the current climate,” said Patrick Brown, of the Carnegie Institution at Stanford University in California.

Deeper cuts

“On the contrary, we are showing that model shortcomings can be used to dismiss the least severe predictions.”

And, the authors warn: “Our results suggest that achieving any given global temperature stabilisation target will require steeper greenhouse gas emissions reduction than previously calculated.”

Climate models are only as good as the climate data on which they are based, and one source of uncertainty has been the effect of warming on cloud formation: a warmer world means more evaporation, which could mean more warmth is trapped in the atmosphere – or it could mean more clouds, which reflect more solar radiation back into space.

For decades, researchers have tried to calculate with precision the links between ratios of greenhouse gases released from the combustion of coal, natural gas and oil, and shifts in average planetary temperature.

Simpler evidence

One of the Carnegie authors, Ken Caldeira of the Institution’s global ecology lab, has so far calculated the rate at which carbon dioxide sets about warming the atmosphere, and the capacity of greenhouse gases to go on warming the world for millennia.

The latest conclusions have been based on simpler evidence: the accuracy with which their forecast models can “predict” the recent past.

Professor Caldeira said: “It makes sense that the models that do the best job at simulating today’s observations might be the models with the most reliable predictions.

“Our study indicates that if emissions follow a commonly-used business-as-usual scenario, there is a 93% chance that global warming will exceed 4°C by the end of this century. Previous studies have put this likelihood at 62%.” –  Climate News Network

Lizards help to explain climate impacts

Lizards can shed light on the development of ecological niches and how the changing climate may affect the natural world.

LONDON, 23 November, 2017 – US scientists think lizards could help them one step nearer to an old dream: a kind of “periodic table” for ecology.

Just as the great insight of the Russian chemist Dmitri Mendeleev now means that chemists can understand better the relationships between elements, and make predictions about their responses, a classification of ecological niches could help biologists better understand the impact of climate change on the millions of species that share the Earth.

Such a project may never be completed, but a new study in The American Naturalist demonstrates that it has begun.

An ecological niche is a tangle of environmental conditions and biological behaviours that mean an insect, an amphibian, a reptile, bird or mammal is specialised to make the best of its short life. For example, fig wasps need fig trees to survive, and if there are 900 species of fig tree on the planet, 900 species of fig wasp will evolve to fill those ecological niches.

The researchers worked out what constitutes a niche: they chose habitat, diet, life history, metabolism and defence, and then listed between seven and 15 variables for each of those properties. Then they compiled all the data they could find about 134 species of lizard on four continents from 24 of the planet’s 38 surviving lizard families. And then they started to impose order on their material.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions”

They could do that because, even though Australian desert lizards are of entirely separate species from desert lizards in Africa, or America, they forage for food, stay lively or dormant at given times, reproduce and exploit their habitat in very similar ways. Evolutionary pressures mean that they have converged to fill similar ecological niches.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions and the invasive potential of species,” said Eric Pianka, a zoologist at the University of Texas at Austin, who led the study. 

“It will inform us about how niches have evolved in the past and even how they will evolve in the future, all of which has direct bearing on impacts of climate change.”

Climate change presents biologists with a problem: humans depend on the natural world in myriad ways; plant, fungus and animal species recycle the world’s air and water, conserve rainfall, pollinate crops, generate fruits and seeds for nourishment and chemicals for pharmaceuticals, fabrics for clothes and shelter.

They dispose of excrement and other biological waste, and each species in this intricate economy survives because it occupies an ecological niche.

Global risk

But the ecosystems that support such helpful networks are everywhere at risk because of climate change.  They are at hazard on a global scale and at the level of single nations or marine environments.

But without an intellectual framework that identifies the features that ecosystems, and ecological niches within those ecosystems, might have in common, conservation biologists won’t know where best to start.

What they do know is that conservation is vital, and that the creatures of the world are stronger because they are so many and so varied: yet another study from Switzerland involving 2,200 species in 450 different landscapes has just confirmed once again that the richer the variety of life in it, the more productive the landscape, and the better it is able to withstand change.

Now the scientists from Texas, Oklahoma and Argentina have confirmed, with what they call “the lizard niche hypervolume”, the possibility of a living equivalent of the periodic table that permits predictions that could be confirmed by observation or experiment, not just for lizards but for other families.

Separate niches

Lizards, like birds, inhabit trees, lay eggs and devour insects: unlike birds, they rely on the environment to maintain their temperature, so what would be one day’s food for a small bird might keep a lizard alive for a month.

It follows that birds and lizards occupy separate ecological niches. Ecologists have a potential structure or scaffolding into which to place their specimen animal and its ideal habitat and consider it in relation to other ecological niches.

But, as the researchers point out, so far only 2.2% of known lizards are included in their analysis, and environments are dynamic things: they change with time. There is a lot more to be done in researching clades, groupings of organisms which share a common ancestor and all of its descendants.

“As more periodic tables are created,” they write, “comparative analyses among more distantly-related clades (fish-frogs-salamanders-lizards-snakes-birds-mammals) will become possible, ultimately leading to a wider understanding of niche evolution among vertebrates.” – Climate News Network

Lizards can shed light on the development of ecological niches and how the changing climate may affect the natural world.

LONDON, 23 November, 2017 – US scientists think lizards could help them one step nearer to an old dream: a kind of “periodic table” for ecology.

Just as the great insight of the Russian chemist Dmitri Mendeleev now means that chemists can understand better the relationships between elements, and make predictions about their responses, a classification of ecological niches could help biologists better understand the impact of climate change on the millions of species that share the Earth.

Such a project may never be completed, but a new study in The American Naturalist demonstrates that it has begun.

An ecological niche is a tangle of environmental conditions and biological behaviours that mean an insect, an amphibian, a reptile, bird or mammal is specialised to make the best of its short life. For example, fig wasps need fig trees to survive, and if there are 900 species of fig tree on the planet, 900 species of fig wasp will evolve to fill those ecological niches.

The researchers worked out what constitutes a niche: they chose habitat, diet, life history, metabolism and defence, and then listed between seven and 15 variables for each of those properties. Then they compiled all the data they could find about 134 species of lizard on four continents from 24 of the planet’s 38 surviving lizard families. And then they started to impose order on their material.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions”

They could do that because, even though Australian desert lizards are of entirely separate species from desert lizards in Africa, or America, they forage for food, stay lively or dormant at given times, reproduce and exploit their habitat in very similar ways. Evolutionary pressures mean that they have converged to fill similar ecological niches.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions and the invasive potential of species,” said Eric Pianka, a zoologist at the University of Texas at Austin, who led the study. 

“It will inform us about how niches have evolved in the past and even how they will evolve in the future, all of which has direct bearing on impacts of climate change.”

Climate change presents biologists with a problem: humans depend on the natural world in myriad ways; plant, fungus and animal species recycle the world’s air and water, conserve rainfall, pollinate crops, generate fruits and seeds for nourishment and chemicals for pharmaceuticals, fabrics for clothes and shelter.

They dispose of excrement and other biological waste, and each species in this intricate economy survives because it occupies an ecological niche.

Global risk

But the ecosystems that support such helpful networks are everywhere at risk because of climate change.  They are at hazard on a global scale and at the level of single nations or marine environments.

But without an intellectual framework that identifies the features that ecosystems, and ecological niches within those ecosystems, might have in common, conservation biologists won’t know where best to start.

What they do know is that conservation is vital, and that the creatures of the world are stronger because they are so many and so varied: yet another study from Switzerland involving 2,200 species in 450 different landscapes has just confirmed once again that the richer the variety of life in it, the more productive the landscape, and the better it is able to withstand change.

Now the scientists from Texas, Oklahoma and Argentina have confirmed, with what they call “the lizard niche hypervolume”, the possibility of a living equivalent of the periodic table that permits predictions that could be confirmed by observation or experiment, not just for lizards but for other families.

Separate niches

Lizards, like birds, inhabit trees, lay eggs and devour insects: unlike birds, they rely on the environment to maintain their temperature, so what would be one day’s food for a small bird might keep a lizard alive for a month.

It follows that birds and lizards occupy separate ecological niches. Ecologists have a potential structure or scaffolding into which to place their specimen animal and its ideal habitat and consider it in relation to other ecological niches.

But, as the researchers point out, so far only 2.2% of known lizards are included in their analysis, and environments are dynamic things: they change with time. There is a lot more to be done in researching clades, groupings of organisms which share a common ancestor and all of its descendants.

“As more periodic tables are created,” they write, “comparative analyses among more distantly-related clades (fish-frogs-salamanders-lizards-snakes-birds-mammals) will become possible, ultimately leading to a wider understanding of niche evolution among vertebrates.” – Climate News Network

US cities face growing flood risks

As the seas rise, US cities can expect varied flood risks: some will have more of the worst floods, others more frequent familiar inundations.

LONDON, 13 June, 2017 – Sea level rise – driven by global warming and climate change – will bring new flood risks to America’s coastal cities.

Paradoxically, those conurbations already at risk of catastrophic floods driven by hurricanes can expect a greater number of “moderate” floods. And those cities that have little or no history of severe flooding can expect a greater level of risk from historically unprecedented inundation, according to a new study in the journal Environmental Research L.etters 

This is another step in what might be called prepare-for-the-future studies. Coastal flooding already costs cities on both east and west coasts an estimated $27bn a year. Researchers have been doing the arithmetic and so far forecast that – globally at least – sea level rise is going to cost $1 trillion by 2050, and $100 trillion by 2100.

Global problem

Sea level rise is happening everywhere, as ice caps and glaciers melt and the seas rise in response to global warming driven by prodigal human combustion of fossil fuels, and researchers have advanced from general warning to the kind of detail that could help city and state planners prepare to cope with flood risks.

European ports and estuary cities are at risk with projections of sea level rise of half a metre, and US coastal cities could one day face almost daily challenges at high tide.

Some of these risks are simply the inevitable consequence of living by the sea: a kind of littoral home truth. Others are more serious. One study has warned that the inundation levels may in decades be such as to create a new class of American climate refugee

Notoriously, the US president, Donald Trump, has in the past called climate change “a hoax” and withdrawn from the Paris Agreement in which the world’s nations agreed to work together to contain global warming. But the research goes on.

Risk details

In the latest study, scientists from two great US universities began to look at the fine detail of local risk. They calculated the “amplification factor” of hazard as the high tide mark: they assumed that the frequency of storms would remain unchanged and then they factored in projections of sea level rise.

And then they figured the effect of this rise on the frequency of floods that historically tend to happen once in a century, in places like Charleston – in the path of seasonal hurricanes – and Seattle, where catastrophic floods are rare.

They found that by 2050 the moderate floods – the kind that tend to happen once every 10 years – would recur 173 times more often in Charleston but only 36 times more often in Seattle.

“We hope that this study provides additional information that cities and municipalities can use to start planning…federal programmes for planning for climate adaptation are on the chopping block”

The really bad invasions of the sea, the kind that happen once every 500 years, would sweep over Charleston six times as often. Seattle would, on the other hand, see what had once been very rare events 273 times more often.

That is, of course, because even a modest rise in sea level makes a dangerous storm surge much more dangerous. “For example, to produce a six-foot flood, if the ocean is a foot higher, you only need as much storm surge as you would have previously needed to produce a five-foot flood,” said Robert Kopp, professor of earth and planetary science at Rutgers university, and one of the authors.

And his research colleague Michael Oppenheimer, professor of geosciences and international affairs at Princeton, said: “We hope that this study provides additional information that cities and municipalities can use to start planning the defence against climate change and sea-level rise.

“This is especially important as federal programmes for planning for climate adaptation are on the chopping block.” – Climate News Network