Tag Archives: Greenland

Underwater walls might avert sea level rise

Could a vast underwater wall in front of an unstable glacier prevent dangerous sea level rise? Or should everyone just move further inland?

LONDON, 10 October, 2018 – Two climate scientists believe they have a long-term solution to dangerous sea level rise by targeting the most vulnerable glaciers, especially those that could trigger a massive collapse of the ice sheets behind them.

A submarine wall big enough and wide enough could halt the flow of increasingly warm ocean water below the front of each glacier. The combination of warmer air temperatures and warmer waters that accompany human-triggered climate change is dangerous: it could for instance accelerate the already alarming retreat of the Thwaites Glacier in West Antarctica, which alone shores up enough ice to raise global sea levels by up to 3 metres.

The scientists don’t propose an immediate start. But they do want to explore ways of halting sea level rise driven by global warming that could soon be costing the world $50 trillion a year in economic losses, that could submerge small island states and turn 1 million people a year into climate migrants.

“We are not advocating that glacial geoengineering be attempted any time soon”, they warn in the journal The Cryosphere.

Their simplest option – a series of pillars to shore up a targeted glacier and keep it “grounded” – would require engineering comparable in scale to the excavation of the Suez canal, would be undertaken in the world’s harshest environment, and would have just a one in three chance of success.

“In the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse”

The researchers – John Moore, of Beijing Normal University in China, who also holds a post at the University of Lapland in Finland, and Michael Wolovick, of Princeton University in the US – have made this case before: they and others argued in March in Nature for what they call “managed collapse.”

In the latest study, they look at the challenge in greater detail. And they warn that even if targeted geoengineering of individual glaciers worked, it would only do so if humans stopped tipping ever more greenhouse gases into the atmosphere to fuel yet more global warming.

Nor do they argue that a submarine curtain wall to halt warming water across the front of the Thwaites glacier – up to 100 kms wide – is currently feasible. “But in the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse.”

And one of these is the Thwaites Glacier in Antarctica: another is the Jakobshaven Isbrae in Greenland. Both could be cases of what the scientists call marine ice sheet instability: as a glacier retreats from its grounding line, the ice lifts off the bedrock and begins to float.

If the bedrock slopes down towards the centre of the ice sheet, and warmer ocean currents wash beneath it, then the ice starts to stretch and thin, and retreat further. At some point, it would become much easier for thawing ice to flow into the sea, and start what could become a runaway collapse. Engineers could devise a way of slowing or halting the process.

Huge impact

The scientists argue that even a rise of 0.6m to 1.2 metres by 2100 could cause up to $50 trillion in economic damage, and the resultant flooding could force up to 200 million to 500 million people out of their homes at least for a few days or weeks: around a million or so every year would never go back.

Climate scientists have been arguing about geoengineering solutions – the so-called technofix – to climate change for more than a decade. Global answers, such as blocking sunlight with stratospheric soot and sulphate aerosols, or whitening the polar ice to make it more reflective, remain contentious.

But the Cryosphere proposals are much more limited, and the immediate dangers of sea level rise are not contested. Ice sheet collapse in Antarctica, for instance, could raise sea levels by more than 3 metres and even by as much as 19 metres over the next two or three centuries.

The researchers’ calculations suggest that in theory an engineering solution that blocked even 50% of the warm water getting under a glacier could offer a 70% chance of delaying or stopping ice sheet collapse.

Left behind

Countries already spend on coastal protection: their solution would require international co-operation at the highest political level, and intensive scientific research.

“Managing sea level rise at the source has the advantage of benefiting the entire world, while a strategy that relies only on local coastal protection is more of an every-nation-for-itself approach that may leave many poor countries behind,” they write.

“Perhaps, after careful consideration, we may conclude that glacial geoengineering is unworkable and the right answer is to invest heavily in coastal protection and retreat inland where that is not practical or economical.

“However, we owe it to the 400 million people who live within 5m of sea level to at least consider the alternatives.” – Climate News Network

Could a vast underwater wall in front of an unstable glacier prevent dangerous sea level rise? Or should everyone just move further inland?

LONDON, 10 October, 2018 – Two climate scientists believe they have a long-term solution to dangerous sea level rise by targeting the most vulnerable glaciers, especially those that could trigger a massive collapse of the ice sheets behind them.

A submarine wall big enough and wide enough could halt the flow of increasingly warm ocean water below the front of each glacier. The combination of warmer air temperatures and warmer waters that accompany human-triggered climate change is dangerous: it could for instance accelerate the already alarming retreat of the Thwaites Glacier in West Antarctica, which alone shores up enough ice to raise global sea levels by up to 3 metres.

The scientists don’t propose an immediate start. But they do want to explore ways of halting sea level rise driven by global warming that could soon be costing the world $50 trillion a year in economic losses, that could submerge small island states and turn 1 million people a year into climate migrants.

“We are not advocating that glacial geoengineering be attempted any time soon”, they warn in the journal The Cryosphere.

Their simplest option – a series of pillars to shore up a targeted glacier and keep it “grounded” – would require engineering comparable in scale to the excavation of the Suez canal, would be undertaken in the world’s harshest environment, and would have just a one in three chance of success.

“In the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse”

The researchers – John Moore, of Beijing Normal University in China, who also holds a post at the University of Lapland in Finland, and Michael Wolovick, of Princeton University in the US – have made this case before: they and others argued in March in Nature for what they call “managed collapse.”

In the latest study, they look at the challenge in greater detail. And they warn that even if targeted geoengineering of individual glaciers worked, it would only do so if humans stopped tipping ever more greenhouse gases into the atmosphere to fuel yet more global warming.

Nor do they argue that a submarine curtain wall to halt warming water across the front of the Thwaites glacier – up to 100 kms wide – is currently feasible. “But in the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse.”

And one of these is the Thwaites Glacier in Antarctica: another is the Jakobshaven Isbrae in Greenland. Both could be cases of what the scientists call marine ice sheet instability: as a glacier retreats from its grounding line, the ice lifts off the bedrock and begins to float.

If the bedrock slopes down towards the centre of the ice sheet, and warmer ocean currents wash beneath it, then the ice starts to stretch and thin, and retreat further. At some point, it would become much easier for thawing ice to flow into the sea, and start what could become a runaway collapse. Engineers could devise a way of slowing or halting the process.

Huge impact

The scientists argue that even a rise of 0.6m to 1.2 metres by 2100 could cause up to $50 trillion in economic damage, and the resultant flooding could force up to 200 million to 500 million people out of their homes at least for a few days or weeks: around a million or so every year would never go back.

Climate scientists have been arguing about geoengineering solutions – the so-called technofix – to climate change for more than a decade. Global answers, such as blocking sunlight with stratospheric soot and sulphate aerosols, or whitening the polar ice to make it more reflective, remain contentious.

But the Cryosphere proposals are much more limited, and the immediate dangers of sea level rise are not contested. Ice sheet collapse in Antarctica, for instance, could raise sea levels by more than 3 metres and even by as much as 19 metres over the next two or three centuries.

The researchers’ calculations suggest that in theory an engineering solution that blocked even 50% of the warm water getting under a glacier could offer a 70% chance of delaying or stopping ice sheet collapse.

Left behind

Countries already spend on coastal protection: their solution would require international co-operation at the highest political level, and intensive scientific research.

“Managing sea level rise at the source has the advantage of benefiting the entire world, while a strategy that relies only on local coastal protection is more of an every-nation-for-itself approach that may leave many poor countries behind,” they write.

“Perhaps, after careful consideration, we may conclude that glacial geoengineering is unworkable and the right answer is to invest heavily in coastal protection and retreat inland where that is not practical or economical.

“However, we owe it to the 400 million people who live within 5m of sea level to at least consider the alternatives.” – Climate News Network

High Arctic species respond to climate warming

The northern ocean is abuzz with life, but the composition of those high Arctic species is changing as the world gets warmer.

LONDON, 23 April, 2018 – Global warming is beginning to change the high Arctic species which make up the region’s most numerous occupants. Scientists who have been collecting spiders, mites, ticks, bugs, bees, wasps, ants, moths and springtails in the northeast of Greenland report that the arthropod population is starting to respond to the changing seasons.

Arthropods make up the largest variety of animals on the planet: this is a phylum of jointy-legged things with exoskeletons that includes spiders as well as flies, bees and butterflies as well as mites. In the tundra, the mass of arthropods is greater than that of birds or mammals.

Danish and US scientists report in the Royal Society journal Open Science that between 1996 and 2014, researchers collected 593,788 specimens of different arthropod groups around the Zackenberg research station and noted the way the species composition of a population changed with time and with the pattern of summer rainfall.

In this region, the winter temperatures fall to minus 30°C and average annual temperature is minus 9°C. The ground is more or less permanently frozen. But in the brief Arctic summer, temperatures can soar to between 3°C and 7°C and the Arctic fens, heaths and arid zones effervesce with life.

”We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances”

Compared with the past, the population is changing. There are more herbivores and creatures that parasitise other animals, but the detritivores – the creatures that consume carrion, excrement and decomposing plants – seem to be on the way down, with, the scientists say, potential implications for key ecosystem processes such as decomposition, nutrient cycling and primary productivity.

Change varied according to habitat: the changes in the composition of the community of arthropods were up to five times more extreme in the drier ecosystems. The implication of such research is that study of shorter-lived, tinier creatures may provide more information about adaptation and loss in the rapidly warming Arctic than, for instance, study of seals and polar bears.

And the insects do respond, even to subtle change: researchers four years ago noted that around 80 species of moth inside Finland’s Arctic seemed to be coping with warmer summers.

“Twenty years may not be long enough to detect changes in abundances of longer-lived species, like some mammals, but because of their short life spans, it’s a pretty long time for arthropods. Still, the fact that we can detect changes over 20 years in some of these animal groups at such a coarse taxonomic resolution is remarkable,” said Amanda Koltz, of Washington University in St Louis, who led the study.

“We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances.” – Climate News Network

The northern ocean is abuzz with life, but the composition of those high Arctic species is changing as the world gets warmer.

LONDON, 23 April, 2018 – Global warming is beginning to change the high Arctic species which make up the region’s most numerous occupants. Scientists who have been collecting spiders, mites, ticks, bugs, bees, wasps, ants, moths and springtails in the northeast of Greenland report that the arthropod population is starting to respond to the changing seasons.

Arthropods make up the largest variety of animals on the planet: this is a phylum of jointy-legged things with exoskeletons that includes spiders as well as flies, bees and butterflies as well as mites. In the tundra, the mass of arthropods is greater than that of birds or mammals.

Danish and US scientists report in the Royal Society journal Open Science that between 1996 and 2014, researchers collected 593,788 specimens of different arthropod groups around the Zackenberg research station and noted the way the species composition of a population changed with time and with the pattern of summer rainfall.

In this region, the winter temperatures fall to minus 30°C and average annual temperature is minus 9°C. The ground is more or less permanently frozen. But in the brief Arctic summer, temperatures can soar to between 3°C and 7°C and the Arctic fens, heaths and arid zones effervesce with life.

”We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances”

Compared with the past, the population is changing. There are more herbivores and creatures that parasitise other animals, but the detritivores – the creatures that consume carrion, excrement and decomposing plants – seem to be on the way down, with, the scientists say, potential implications for key ecosystem processes such as decomposition, nutrient cycling and primary productivity.

Change varied according to habitat: the changes in the composition of the community of arthropods were up to five times more extreme in the drier ecosystems. The implication of such research is that study of shorter-lived, tinier creatures may provide more information about adaptation and loss in the rapidly warming Arctic than, for instance, study of seals and polar bears.

And the insects do respond, even to subtle change: researchers four years ago noted that around 80 species of moth inside Finland’s Arctic seemed to be coping with warmer summers.

“Twenty years may not be long enough to detect changes in abundances of longer-lived species, like some mammals, but because of their short life spans, it’s a pretty long time for arthropods. Still, the fact that we can detect changes over 20 years in some of these animal groups at such a coarse taxonomic resolution is remarkable,” said Amanda Koltz, of Washington University in St Louis, who led the study.

“We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances.” – Climate News Network

North Atlantic ocean currents are slowing

The North Atlantic currents which help to warm north-west Europe have slowed significantly since the last century, scientists confirm.

LONDON, 12 April, 2018 – The Gulf Stream is slowing, the North Atlantic is cooling. An international scientific study has found new and harder evidence that one of the planet’s key heat pumps, the currents which exchange warmth between the tropics and the Arctic, are weaker today than at any time in the last thousand years.

The currents, known as the Atlantic overturning – its scientific name is the Atlantic Meridional Overturning Circulation, the AMOC – bring warm water north from the tropics and return south with cold water.

Earlier studies suggested strongly that any weakening of the AMOC would speed sea level rise on the US east coast and cool north-west Europe by up to 5°C.

Those studies made use of computer simulations. But the latest research is radically different. It is based on direct observation of what is happening in the ocean. And it is, in non-scientific language, hard evidence that the Gulf Stream is slowing down.

”The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system”

A team from Germany’s Potsdam Institute for Climate Impact Research (PIK) and the US National Oceanic and Atmospheric Administration has found evidence which it says not only supports the earlier predictions, but makes them hard to dispute.

In a study published in the journal Nature the researchers say analysis of sea surface temperature data shows that the AMOC has slowed down by roughly 15% since the middle of the 20th century, with human-made climate change a prime suspect.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the Atlantic overturning, also called the Gulf Stream system,” said the lead author, Levke Caesar from PIK. “It is practically like a fingerprint of a weakening of these ocean currents.”

For decades computer simulations have generally predicted that the AMOC will weaken in response to human-caused global warming. But whether this is already happening has until now been unclear, because of a lack of long-term direct current measurements.

Most robust

Not any more, though. “The evidence we’re now able to provide is the most robust to date,” says Stefan Rahmstorf of the Potsdam Institute, who conceived the study. “We’ve analysed all the available sea surface temperature data sets, comprising data from the late 19th century until the present.”

“The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system, and I see no other plausible explanation for it.”

The Atlantic overturning is driven by the differences in the density of the ocean water: when the warm, lighter water flows from south to north it becomes colder, denser and heavier, making it sink deeper and flow back southwards.

Global warming is not the only influence on the AMOC. Increased rainfall and meltwater from the Arctic sea ice and Greenland ice sheet are also diluting the waters of the northern Atlantic, reducing the salinity. Less saline water is less dense and so less heavy, making it harder for the water to sink from the surface to the ocean depths.

Second study

There have been long debates about whether the AMOC could collapse, which would constitute a tipping element in the Earth system. The PIK study does not consider the AMOC’s future, instead analysing how it has changed over the past century.

A second study, by a team including David Thornalley, from University College London,  in the same issue of Nature, looks into the Earth’s past climate to reconstruct Atlantic overturning changes over the past 1,600 years.

It provides independent confirmation for earlier conclusions that the weakness of the circulation today is unprecedented for more than a millennium at least.

“Several lines of evidence are coming together to a consistent picture now, all pointing at the same weakening since the 1950s,” says Professor Rahmstorf: “[They include] sub-polar Atlantic cooling, the warming inshore of the Gulf Stream, Thornalley’s proxy data for subsurface Atlantic temperatures, and earlier proxy data from deep sea corals showing water mass changes in the Gulf of Maine.” – Climate News Network

The North Atlantic currents which help to warm north-west Europe have slowed significantly since the last century, scientists confirm.

LONDON, 12 April, 2018 – The Gulf Stream is slowing, the North Atlantic is cooling. An international scientific study has found new and harder evidence that one of the planet’s key heat pumps, the currents which exchange warmth between the tropics and the Arctic, are weaker today than at any time in the last thousand years.

The currents, known as the Atlantic overturning – its scientific name is the Atlantic Meridional Overturning Circulation, the AMOC – bring warm water north from the tropics and return south with cold water.

Earlier studies suggested strongly that any weakening of the AMOC would speed sea level rise on the US east coast and cool north-west Europe by up to 5°C.

Those studies made use of computer simulations. But the latest research is radically different. It is based on direct observation of what is happening in the ocean. And it is, in non-scientific language, hard evidence that the Gulf Stream is slowing down.

”The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system”

A team from Germany’s Potsdam Institute for Climate Impact Research (PIK) and the US National Oceanic and Atmospheric Administration has found evidence which it says not only supports the earlier predictions, but makes them hard to dispute.

In a study published in the journal Nature the researchers say analysis of sea surface temperature data shows that the AMOC has slowed down by roughly 15% since the middle of the 20th century, with human-made climate change a prime suspect.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the Atlantic overturning, also called the Gulf Stream system,” said the lead author, Levke Caesar from PIK. “It is practically like a fingerprint of a weakening of these ocean currents.”

For decades computer simulations have generally predicted that the AMOC will weaken in response to human-caused global warming. But whether this is already happening has until now been unclear, because of a lack of long-term direct current measurements.

Most robust

Not any more, though. “The evidence we’re now able to provide is the most robust to date,” says Stefan Rahmstorf of the Potsdam Institute, who conceived the study. “We’ve analysed all the available sea surface temperature data sets, comprising data from the late 19th century until the present.”

“The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system, and I see no other plausible explanation for it.”

The Atlantic overturning is driven by the differences in the density of the ocean water: when the warm, lighter water flows from south to north it becomes colder, denser and heavier, making it sink deeper and flow back southwards.

Global warming is not the only influence on the AMOC. Increased rainfall and meltwater from the Arctic sea ice and Greenland ice sheet are also diluting the waters of the northern Atlantic, reducing the salinity. Less saline water is less dense and so less heavy, making it harder for the water to sink from the surface to the ocean depths.

Second study

There have been long debates about whether the AMOC could collapse, which would constitute a tipping element in the Earth system. The PIK study does not consider the AMOC’s future, instead analysing how it has changed over the past century.

A second study, by a team including David Thornalley, from University College London,  in the same issue of Nature, looks into the Earth’s past climate to reconstruct Atlantic overturning changes over the past 1,600 years.

It provides independent confirmation for earlier conclusions that the weakness of the circulation today is unprecedented for more than a millennium at least.

“Several lines of evidence are coming together to a consistent picture now, all pointing at the same weakening since the 1950s,” says Professor Rahmstorf: “[They include] sub-polar Atlantic cooling, the warming inshore of the Gulf Stream, Thornalley’s proxy data for subsurface Atlantic temperatures, and earlier proxy data from deep sea corals showing water mass changes in the Gulf of Maine.” – Climate News Network

Polar ice is melting fast in north and south

In the high latitudes in both hemispheres, the polar ice is in retreat. Two studies support fears for the ice caps, north and south.

LONDON, 10 April, 2018 – New studies have confirmed, once again, the rapid melting of the polar ice in both hemispheres.

A British team has used satellite data to reveal that the retreat of the all-important grounding line of many Antarctic glaciers has accelerated to five times the historic level. And US scientists have confirmed that in Arctic waters the West Greenland ice sheet is now melting faster than at any time in the last 450 years.

Both studies deliver ominous evidence of the long-term consequences of climate change due to profligate human use of fossil fuels. The Greenland icecap holds enough water to raise global sea levels by seven metres. The West Antarctic ice sheet – where the latest study has identified most of the change – holds enough water to raise sea levels by up to five metres.

The UK measure of Antarctic ice retreat is important because it confirms on a wider scale what individual measurements of glacier retreat have already shown: that increasingly warm southern ocean waters are melting the ice at depth.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise”

Depth in this study is critical: glaciers move slowly because the frozen rivers are “anchored” or grounded in bedrock as they flow off the continent, and then grounded again up to a kilometre deep off the continental shelf.

This applies a brake to the flow towards the open sea. The further from the coast the grounding line, the slower the glacier’s flow, the more stable the ice shelf, and the slower the consequent sea level rise.

Hannes Konrad of the University of Leeds in the UK and colleagues report in the journal Nature Geoscience that they used the European Space Agency’s satellite Cryosat-2 data to track the changes in the grounding line along 16,000 kilometres of southern polar coastline.

Around West Antarctica, more than a fifth of the ice sheet has retreated faster than the 25 metres or so a year that has been normal since the end of the last ice age. In some cases the retreat of the grounding line has been five times that rate. The retreat has been extreme in eight of the ice sheet’s 65 biggest glaciers.

Clear evidence

“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” Dr Konrad said.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

Far to the north, ice is also melting. Erich Osterberg of Dartmouth College in the US and colleagues report in the journal Geophysical Research Letters that they collected seven ice cores from a remote zone in the West Greenland ice sheet where meltwater trickles down into the deeper snow and then freezes again: this “new” ice in the compacted snow provides scientists with a record of melting over time.

Longer record

Researchers have been watching the apparent acceleration of the summer melting of Greenland’s ice for decades: they have monitored ever faster rates of glacier flow and tried to identify direct influences on the surface of the ice sheet that might accelerate overall melting.

But direct observation of the northern hemisphere’s largest concentration of ice began only about five decades ago. The Dartmouth cores provide a total of almost five centuries of summer melt patterns.

“The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see. The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast,” Dr Osterberg said.

“We see that West Greenland melt really started accelerating about 20 years ago. Our study shows that the rapid rise in the West Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century.” – Climate News Network

In the high latitudes in both hemispheres, the polar ice is in retreat. Two studies support fears for the ice caps, north and south.

LONDON, 10 April, 2018 – New studies have confirmed, once again, the rapid melting of the polar ice in both hemispheres.

A British team has used satellite data to reveal that the retreat of the all-important grounding line of many Antarctic glaciers has accelerated to five times the historic level. And US scientists have confirmed that in Arctic waters the West Greenland ice sheet is now melting faster than at any time in the last 450 years.

Both studies deliver ominous evidence of the long-term consequences of climate change due to profligate human use of fossil fuels. The Greenland icecap holds enough water to raise global sea levels by seven metres. The West Antarctic ice sheet – where the latest study has identified most of the change – holds enough water to raise sea levels by up to five metres.

The UK measure of Antarctic ice retreat is important because it confirms on a wider scale what individual measurements of glacier retreat have already shown: that increasingly warm southern ocean waters are melting the ice at depth.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise”

Depth in this study is critical: glaciers move slowly because the frozen rivers are “anchored” or grounded in bedrock as they flow off the continent, and then grounded again up to a kilometre deep off the continental shelf.

This applies a brake to the flow towards the open sea. The further from the coast the grounding line, the slower the glacier’s flow, the more stable the ice shelf, and the slower the consequent sea level rise.

Hannes Konrad of the University of Leeds in the UK and colleagues report in the journal Nature Geoscience that they used the European Space Agency’s satellite Cryosat-2 data to track the changes in the grounding line along 16,000 kilometres of southern polar coastline.

Around West Antarctica, more than a fifth of the ice sheet has retreated faster than the 25 metres or so a year that has been normal since the end of the last ice age. In some cases the retreat of the grounding line has been five times that rate. The retreat has been extreme in eight of the ice sheet’s 65 biggest glaciers.

Clear evidence

“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” Dr Konrad said.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

Far to the north, ice is also melting. Erich Osterberg of Dartmouth College in the US and colleagues report in the journal Geophysical Research Letters that they collected seven ice cores from a remote zone in the West Greenland ice sheet where meltwater trickles down into the deeper snow and then freezes again: this “new” ice in the compacted snow provides scientists with a record of melting over time.

Longer record

Researchers have been watching the apparent acceleration of the summer melting of Greenland’s ice for decades: they have monitored ever faster rates of glacier flow and tried to identify direct influences on the surface of the ice sheet that might accelerate overall melting.

But direct observation of the northern hemisphere’s largest concentration of ice began only about five decades ago. The Dartmouth cores provide a total of almost five centuries of summer melt patterns.

“The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see. The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast,” Dr Osterberg said.

“We see that West Greenland melt really started accelerating about 20 years ago. Our study shows that the rapid rise in the West Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century.” – Climate News Network

Arctic warming upsets ocean currents

Spells of Arctic warming have always come in fits and starts, but the current winter’s record-breaking extremes are puzzling scientists.

LONDON, 30 March, 2018 –There are indications from the present Arctic warming – tentative, inconclusive, but enough to arouse intense scientific interest – to suggest that the planet may now be close to one of the significant climate tipping points that could usher in drastic change.

At worst, some scientists now believe, the North Atlantic current, the northern part of the Gulf Stream, appears to be slowing. The current transports enough heat from tropical waters to the Arctic to keep north-west Europe’s temperature several degrees warmer than it would otherwise be.

If the North Atlantic current changes significantly, parts of Europe would cool and sea levels would rise. Parts of West Africa could experience more drought, and the Asian monsoon might also be affected. Reports that the current may change are not new, but recent evidence from the Arctic itself has given them new urgency.

In the high Arctic it is still deep winter, with temperatures dropping to –30°C.
But across large parts of the Arctic the temperature has been above freezing, even at the North Pole itself.

One Arctic weather station, at Cape Morris Jesup, in northern Greenland, has regularly recorded temperatures above zero, and this winter it has so far experienced 61 hours above freezing. The previous record, in 1980, was 16 hours to the end of April.

“Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought”

Scientists call these episodes – which are not unknown – warm intrusions, as they bring in moist, mild air. The present one is the largest on record.

The intrusions are linked to a decline in Arctic winter sea ice, which has undergone unusual melting and thinning, making it vulnerable to winter storms. The southern Arctic winds have blown this broken ice far to the north, to end in the central Arctic.

The result has been large gaps of open water in the ice pack, which in turn have released large amounts of heat into the atmosphere, melting more ice.

Scientists believe the abnormal warming of the last five Arctic winters is linked to this melting. Normally the cold winter surface water sinks towards the sea bed as it heads south out of the Arctic and is replaced by warm water which flows up from the tropics, a process called convection. But this is now being disrupted, with the warmer and less saline tropical water staying near the surface.

At the same time large quantities of fresh meltwater are pouring off the Greenland landmass, with the run-off thought to be diluting the salt water already in the sea.

Smallest extent

On 19 March NOAA reported that February’s average Arctic sea ice extent was the smallest in the 39-year record at 521,000 square miles (8.8%) below the 1981-2010 average, according to an analysis by the National Snow and Ice Data Center, using data from NOAA and NASA. The monthly extent was 62,000 sq m smaller than the previous record set just last year.

Scientists work by developing theories which, in their judgment, provide the best available explanation of the facts they observe. But observations improve, evidence from the physical world changes, and so they constantly refine and revise their theories – and sometimes replace them altogether.

That constant renewal of the current research is vigorously going ahead now in the Arctic, which is no stranger to weather and climate anomalies. There is evidence of similar interruptions to Arctic Ocean circulation in the past, but they did not persist, the journal New Scientist reports.

If newer research bears out the scientists’ findings so far, confirming that the present Arctic warming is growing stronger and happening more often, and that the interplay of wind, ice and meltwater is contributing to changes in convection, we may expect serious impacts on agriculture, weather and human wellbeing over a large part of the globe.

Marilena Oltmanns of the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, told the New Scientist: “Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought.” – Climate News Network

Spells of Arctic warming have always come in fits and starts, but the current winter’s record-breaking extremes are puzzling scientists.

LONDON, 30 March, 2018 –There are indications from the present Arctic warming – tentative, inconclusive, but enough to arouse intense scientific interest – to suggest that the planet may now be close to one of the significant climate tipping points that could usher in drastic change.

At worst, some scientists now believe, the North Atlantic current, the northern part of the Gulf Stream, appears to be slowing. The current transports enough heat from tropical waters to the Arctic to keep north-west Europe’s temperature several degrees warmer than it would otherwise be.

If the North Atlantic current changes significantly, parts of Europe would cool and sea levels would rise. Parts of West Africa could experience more drought, and the Asian monsoon might also be affected. Reports that the current may change are not new, but recent evidence from the Arctic itself has given them new urgency.

In the high Arctic it is still deep winter, with temperatures dropping to –30°C.
But across large parts of the Arctic the temperature has been above freezing, even at the North Pole itself.

One Arctic weather station, at Cape Morris Jesup, in northern Greenland, has regularly recorded temperatures above zero, and this winter it has so far experienced 61 hours above freezing. The previous record, in 1980, was 16 hours to the end of April.

“Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought”

Scientists call these episodes – which are not unknown – warm intrusions, as they bring in moist, mild air. The present one is the largest on record.

The intrusions are linked to a decline in Arctic winter sea ice, which has undergone unusual melting and thinning, making it vulnerable to winter storms. The southern Arctic winds have blown this broken ice far to the north, to end in the central Arctic.

The result has been large gaps of open water in the ice pack, which in turn have released large amounts of heat into the atmosphere, melting more ice.

Scientists believe the abnormal warming of the last five Arctic winters is linked to this melting. Normally the cold winter surface water sinks towards the sea bed as it heads south out of the Arctic and is replaced by warm water which flows up from the tropics, a process called convection. But this is now being disrupted, with the warmer and less saline tropical water staying near the surface.

At the same time large quantities of fresh meltwater are pouring off the Greenland landmass, with the run-off thought to be diluting the salt water already in the sea.

Smallest extent

On 19 March NOAA reported that February’s average Arctic sea ice extent was the smallest in the 39-year record at 521,000 square miles (8.8%) below the 1981-2010 average, according to an analysis by the National Snow and Ice Data Center, using data from NOAA and NASA. The monthly extent was 62,000 sq m smaller than the previous record set just last year.

Scientists work by developing theories which, in their judgment, provide the best available explanation of the facts they observe. But observations improve, evidence from the physical world changes, and so they constantly refine and revise their theories – and sometimes replace them altogether.

That constant renewal of the current research is vigorously going ahead now in the Arctic, which is no stranger to weather and climate anomalies. There is evidence of similar interruptions to Arctic Ocean circulation in the past, but they did not persist, the journal New Scientist reports.

If newer research bears out the scientists’ findings so far, confirming that the present Arctic warming is growing stronger and happening more often, and that the interplay of wind, ice and meltwater is contributing to changes in convection, we may expect serious impacts on agriculture, weather and human wellbeing over a large part of the globe.

Marilena Oltmanns of the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, told the New Scientist: “Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought.” – Climate News Network

Rising warmth risks Arctic dogs’ survival

Till recently an essential part of Greenland life, Arctic dogs now face a struggle to withstand rising temperatures and dwindling ice.

LONDON, 22 August, 2017 – Greenland’s Arctic dogs, a key part of the massive island’s life and culture, are disappearing.

According to local scientists and specialists in Denmark, the population of the dogs  – traditionally used for transporting people and goods across Greenland’s vast snowy landscape and also for sled racing – has fallen by more than 50% over the past 20 years.

Professor Morten Meldgaard of the Natural History Museum of Denmark, says global warming and the continuing melt of sea ice in the Arctic region is one of the main reasons for the decline in sled dog numbers.

The ice is not only reducing in area but also becoming thinner; local people no longer venture out on the ice as much as they once did to hunt and fish. Therefore fewer sled dogs are needed, and part of Greenland’s culture is dying.

“Many don’t know how fantastically unique the dog culture is,” says Meldgaard. “It’s part of Greenland’s identity, over 1,000 years old and the biggest working dog culture in the world.

Other causes

“Genetically, sled dogs are also extremely strong and resilient – we can be very proud of having a living sled dog culture and we should take care of it.” It’s estimated there are now fewer than 15,000 sled dogs left in Greenland

The decline in dog numbers is due to other factors besides changes in climate, says Meldgaard. Motorised snowmobiles are taking the place of dogs in many parts of the island. The price of food for the dogs has also been rising; fish waste, a traditional part of their diet, is not so plentiful as it once was, as catches decline.

The dogs are also becoming exposed to more infectious diseases. Scientists and medical experts say that rising temperatures in the Arctic and other regions can facilitate the spread of various diseases among both animal and human populations. 

In order to save the existing dog population, the Greenland government is investing nearly one million US dollars in a sled dog vaccination programme.

Helping the handicapped

Meldgaard and other scientists have put forward a series of recommendations aimed at halting the dogs’ decline.

“Traditional hunters and fishermen are under pressure, so we should find new ways to use sled dogs”, says Meldgaard. “There are many options; sled dogs can, for example, be used as transport for tourists, as companions to tourists in the field, or to help handicapped children.”

He and his team are also recommending that sled dogs be awarded UNESCO world heritage protection. “The goal is to find some way forward to create a sustainable dog culture”, says Meldgaard.

“The recommendations address both decision-makers and dog sled drivers. The hope is that they can help secure the dog population and the culture’s survival.”

“Sled racing is central to life in Greenland, especially for our young men. Besides fishing, there are few other activities. The future of our culture is in danger”

During an environmental expedition to the Arctic region, this correspondent also saw the impact rising temperatures were having on sled dogs.

In Illulissat, on Greenland’s west coast, packs of dogs roamed the town’s streets; they are used to being worked hard, and without activity they can be aggressive.

Local people take enormous pride in their teams of dogs. Sled racing is a central part of the culture, and the ever-increasing pace of the ice melt means races can no longer be held in many areas.

“Sled racing is central to life in Greenland, especially for our young men”, said a local geologist. “Besides fishing, there are few other activities. The future of our culture is in danger.” – Climate News Network

Till recently an essential part of Greenland life, Arctic dogs now face a struggle to withstand rising temperatures and dwindling ice.

LONDON, 22 August, 2017 – Greenland’s Arctic dogs, a key part of the massive island’s life and culture, are disappearing.

According to local scientists and specialists in Denmark, the population of the dogs  – traditionally used for transporting people and goods across Greenland’s vast snowy landscape and also for sled racing – has fallen by more than 50% over the past 20 years.

Professor Morten Meldgaard of the Natural History Museum of Denmark, says global warming and the continuing melt of sea ice in the Arctic region is one of the main reasons for the decline in sled dog numbers.

The ice is not only reducing in area but also becoming thinner; local people no longer venture out on the ice as much as they once did to hunt and fish. Therefore fewer sled dogs are needed, and part of Greenland’s culture is dying.

“Many don’t know how fantastically unique the dog culture is,” says Meldgaard. “It’s part of Greenland’s identity, over 1,000 years old and the biggest working dog culture in the world.

Other causes

“Genetically, sled dogs are also extremely strong and resilient – we can be very proud of having a living sled dog culture and we should take care of it.” It’s estimated there are now fewer than 15,000 sled dogs left in Greenland

The decline in dog numbers is due to other factors besides changes in climate, says Meldgaard. Motorised snowmobiles are taking the place of dogs in many parts of the island. The price of food for the dogs has also been rising; fish waste, a traditional part of their diet, is not so plentiful as it once was, as catches decline.

The dogs are also becoming exposed to more infectious diseases. Scientists and medical experts say that rising temperatures in the Arctic and other regions can facilitate the spread of various diseases among both animal and human populations. 

In order to save the existing dog population, the Greenland government is investing nearly one million US dollars in a sled dog vaccination programme.

Helping the handicapped

Meldgaard and other scientists have put forward a series of recommendations aimed at halting the dogs’ decline.

“Traditional hunters and fishermen are under pressure, so we should find new ways to use sled dogs”, says Meldgaard. “There are many options; sled dogs can, for example, be used as transport for tourists, as companions to tourists in the field, or to help handicapped children.”

He and his team are also recommending that sled dogs be awarded UNESCO world heritage protection. “The goal is to find some way forward to create a sustainable dog culture”, says Meldgaard.

“The recommendations address both decision-makers and dog sled drivers. The hope is that they can help secure the dog population and the culture’s survival.”

“Sled racing is central to life in Greenland, especially for our young men. Besides fishing, there are few other activities. The future of our culture is in danger”

During an environmental expedition to the Arctic region, this correspondent also saw the impact rising temperatures were having on sled dogs.

In Illulissat, on Greenland’s west coast, packs of dogs roamed the town’s streets; they are used to being worked hard, and without activity they can be aggressive.

Local people take enormous pride in their teams of dogs. Sled racing is a central part of the culture, and the ever-increasing pace of the ice melt means races can no longer be held in many areas.

“Sled racing is central to life in Greenland, especially for our young men”, said a local geologist. “Besides fishing, there are few other activities. The future of our culture is in danger.” – Climate News Network

Greenland’s shrinking cloud cover speeds melt

More sunshine penetrating Greenland’s shrinking cloud cover explains why its icy mountains are turning increasingly slushy.

LONDON, 2 July, 2017 – British and Belgian scientists think they understand why part of the Arctic is melting at a faster rate. For once, they don’t blame global atmospheric warming. But they have found a marked change during the last two decades, with Greenland’s shrinking cloud cover letting more sunshine reach the surface. So the link with climate change remains.

Their thesis, reported in the journal Science Advances, is that a drop in cloud cover and more summer sunshine means that more radiation hits the snows to deliver more energy for melting.

And they calculate that just a 1% reduction in summer cloud cover means an extra 27 billion metric tons of melting ice at the island’s surface. This is, roughly, the annual domestic water supply of the United States.

Their conclusion may not be the end of the matter, though. That Greenland’s ice is melting at an increasing rate is not in doubt.

Varied explanations

But previous studies have linked the acceleration to a darkening of the snows, to the insulating effects of cloud cover, and even to the temperature of the bedrock below the glaciers.

But Greenland has lost 4,000 billion tons of ice since 1995 and, for the moment, scientists think they can attribute much of this to an increase in direct summer sunlight.

“The impact of increased sunshine during summer is large, it explains about two-thirds of Greenland’s melting signal in recent decades,” said Stefan Hofer, a doctoral student at the University of Bristol, UK, who led the study.

“Until now we thought that the recent Greenland melt is caused almost exclusively by higher temperatures and the resulting feedbacks. Our study shows that there is more to the story than the local increase in temperatures. And the change in cloud cover isn’t just a blip, it’s been happening for the last two decades. That was a big surprise.”

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet”

That, however, is not the only contributing factor. The scientists found that although summer cloud cover decreased by an average of 0.9% a year between 1995 and 2009, this might be connected to a meteorological phenomenon called the North Atlantic Oscillation, a natural cycle that four years ago was linked to dramatic melting in Greenland.

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet,” said Jonathan Bamber, a geographer at the University of Bristol and president of the European Geosciences Union.

“These changes in large-scale circulation patterns during summer are especially pronounced over the Arctic and the North Atlantic. The state shift in atmospheric circulation is unprecedented in the observational record, which goes back as far as 1850.”

Professor Bamber continued: “This highly unusual state of the atmosphere has been linked to record low sea ice cover during summer over the Arctic Ocean. This highlights the coupled nature of the climate system and the consequences of changes in one component on another.” – Climate News Network

More sunshine penetrating Greenland’s shrinking cloud cover explains why its icy mountains are turning increasingly slushy.

LONDON, 2 July, 2017 – British and Belgian scientists think they understand why part of the Arctic is melting at a faster rate. For once, they don’t blame global atmospheric warming. But they have found a marked change during the last two decades, with Greenland’s shrinking cloud cover letting more sunshine reach the surface. So the link with climate change remains.

Their thesis, reported in the journal Science Advances, is that a drop in cloud cover and more summer sunshine means that more radiation hits the snows to deliver more energy for melting.

And they calculate that just a 1% reduction in summer cloud cover means an extra 27 billion metric tons of melting ice at the island’s surface. This is, roughly, the annual domestic water supply of the United States.

Their conclusion may not be the end of the matter, though. That Greenland’s ice is melting at an increasing rate is not in doubt.

Varied explanations

But previous studies have linked the acceleration to a darkening of the snows, to the insulating effects of cloud cover, and even to the temperature of the bedrock below the glaciers.

But Greenland has lost 4,000 billion tons of ice since 1995 and, for the moment, scientists think they can attribute much of this to an increase in direct summer sunlight.

“The impact of increased sunshine during summer is large, it explains about two-thirds of Greenland’s melting signal in recent decades,” said Stefan Hofer, a doctoral student at the University of Bristol, UK, who led the study.

“Until now we thought that the recent Greenland melt is caused almost exclusively by higher temperatures and the resulting feedbacks. Our study shows that there is more to the story than the local increase in temperatures. And the change in cloud cover isn’t just a blip, it’s been happening for the last two decades. That was a big surprise.”

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet”

That, however, is not the only contributing factor. The scientists found that although summer cloud cover decreased by an average of 0.9% a year between 1995 and 2009, this might be connected to a meteorological phenomenon called the North Atlantic Oscillation, a natural cycle that four years ago was linked to dramatic melting in Greenland.

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet,” said Jonathan Bamber, a geographer at the University of Bristol and president of the European Geosciences Union.

“These changes in large-scale circulation patterns during summer are especially pronounced over the Arctic and the North Atlantic. The state shift in atmospheric circulation is unprecedented in the observational record, which goes back as far as 1850.”

Professor Bamber continued: “This highly unusual state of the atmosphere has been linked to record low sea ice cover during summer over the Arctic Ocean. This highlights the coupled nature of the climate system and the consequences of changes in one component on another.” – Climate News Network

Call to unravel basic climate change

Science still cannot provide satisfactory explanations for some features of basic climate change, experts argue – and they want a global search for answers.

LONDON, 5 February, 2017 – A group of distinguished climate scientists has called for a massive international co-operation to understand absolutely basic climate change. And their call exposes the uncertainties that still make long-term climate predictions uncertain, unsatisfactory and sometimes unconvincing.

“Knowing that the globe is warming through human activity is like understanding that cancer is caused by runaway cell division,” said Christian Jakob, a climate scientist at Monash University in Australia, and one of the authors.

“It is just the start of the challenge. While global mean temperature provides the canvas, the details of future changes will emerge at regional levels. It’s at these levels that we will feel and need to adapt to the impact of climate change, economically and socially.”

The point is that there is no doubt that human action has set off a process of accelerating climate change, by clearing the forests, changing the natural cycles of the terrestrial landscape, and by excavating and burning colossal quantities of fossil fuels to release rising proportions of carbon dioxide into the Earth’s atmosphere.

But within that global understanding there remain three profound questions that have yet to be answered in the kind of detail that would permit accurate prediction.

Vanishing carbon

One is: where does the carbon go? For the last 10,000 years or so, carbon dioxide levels in the atmosphere remained more or less the same: plants photosynthesised tissues from atmospheric carbon, oceans dissolved atmospheric gases, rocks reacted with the atmosphere to form mineral carbonates, herbivores consumed plants, man and other carnivores devoured grazing animals, but the overall ratio of the greenhouse gas carbon dioxide remained the same.

But now, to make sense of the precise link between greenhouse gases and climate change, researchers must first understand in much greater detail how the oceans and the land absorb atmospheric carbon, and in what quantities.

The second question they outline, in an essay in the journal Nature Climate Change, is: how will the weather change with climate?

Climate is what farmers bank on when they plant rice rather than rye, weather is what they get with a sudden sustained summer drought, or a late spring ice storm, or torrential harvest time floods. So what, in a world 2°C warmer, or 4°C, would that mean for a community?

Regional focus

“To put it in a particularly Australian way, we don’t plan for a bushfire season based on what is happening to global average temperatures, we look at the temperature and humidity in our area instead,” said Professor Jakob.

Which raises the third great question: how does climate affect the habitability of the Earth and its regions? There have been warnings that climate change could bring lethal extremes of heat and humidity to parts of the Gulf region, and render conditions in parts of North Africa and the Middle East intolerable

There have been predictions that extremes of drought and flood could increase, too, in Australia. But scientists don’t yet understand precisely the way overall climatic conditions play out in regional geography.

“Until we focus on regional phenomena, in a place like Australia we may struggle to know exactly how rainfall, heat waves and sea level rise will change in different parts of our country,” said Sarah Perkins-Kirkpatrick, of the University of New South Wales, and a  co-author.

“We need to reveal these impacts so we can protect regional agriculture, infrastructure and the Australian environments we have all come to know and love, such as the Great Barrier Reef.”

“ . . . a growing influx of the best scientists’ talent is needed to prepare for the surprises to come” 

The scientists, from Germany, France, Australia, the US, the UK and Switzerland, want to build a global co-operation of the kind launched decades ago at CERN in Geneva to understand basic climate change as CERN worked to understand particle physics.

They call for advanced climate simulation systems that can model outcomes with ever greater precision and ever smaller scales, and for sustained, long-term observation of the machinery of the planetary climate system: among them the complexities of the water cycle, involving the evaporation of soil moisture, the formation of clouds and the conditions for rain and snow fall.

Only then could researchers understand why climate continues to surprise: why so much of the Arctic sea ice disappeared in the summer of 2007; why almost all of the surface of Greenland started to melt in 2012; why drought and heat waves hit Russia so harshly in 2010.

“The human spirit is alive in climate research, as witnessed by the responses to the surprises encountered in the past,” they conclude, “but a growing influx of the best scientists’ talent is needed to prepare for the surprises to come.” – Climate News Network

Science still cannot provide satisfactory explanations for some features of basic climate change, experts argue – and they want a global search for answers.

LONDON, 5 February, 2017 – A group of distinguished climate scientists has called for a massive international co-operation to understand absolutely basic climate change. And their call exposes the uncertainties that still make long-term climate predictions uncertain, unsatisfactory and sometimes unconvincing.

“Knowing that the globe is warming through human activity is like understanding that cancer is caused by runaway cell division,” said Christian Jakob, a climate scientist at Monash University in Australia, and one of the authors.

“It is just the start of the challenge. While global mean temperature provides the canvas, the details of future changes will emerge at regional levels. It’s at these levels that we will feel and need to adapt to the impact of climate change, economically and socially.”

The point is that there is no doubt that human action has set off a process of accelerating climate change, by clearing the forests, changing the natural cycles of the terrestrial landscape, and by excavating and burning colossal quantities of fossil fuels to release rising proportions of carbon dioxide into the Earth’s atmosphere.

But within that global understanding there remain three profound questions that have yet to be answered in the kind of detail that would permit accurate prediction.

Vanishing carbon

One is: where does the carbon go? For the last 10,000 years or so, carbon dioxide levels in the atmosphere remained more or less the same: plants photosynthesised tissues from atmospheric carbon, oceans dissolved atmospheric gases, rocks reacted with the atmosphere to form mineral carbonates, herbivores consumed plants, man and other carnivores devoured grazing animals, but the overall ratio of the greenhouse gas carbon dioxide remained the same.

But now, to make sense of the precise link between greenhouse gases and climate change, researchers must first understand in much greater detail how the oceans and the land absorb atmospheric carbon, and in what quantities.

The second question they outline, in an essay in the journal Nature Climate Change, is: how will the weather change with climate?

Climate is what farmers bank on when they plant rice rather than rye, weather is what they get with a sudden sustained summer drought, or a late spring ice storm, or torrential harvest time floods. So what, in a world 2°C warmer, or 4°C, would that mean for a community?

Regional focus

“To put it in a particularly Australian way, we don’t plan for a bushfire season based on what is happening to global average temperatures, we look at the temperature and humidity in our area instead,” said Professor Jakob.

Which raises the third great question: how does climate affect the habitability of the Earth and its regions? There have been warnings that climate change could bring lethal extremes of heat and humidity to parts of the Gulf region, and render conditions in parts of North Africa and the Middle East intolerable

There have been predictions that extremes of drought and flood could increase, too, in Australia. But scientists don’t yet understand precisely the way overall climatic conditions play out in regional geography.

“Until we focus on regional phenomena, in a place like Australia we may struggle to know exactly how rainfall, heat waves and sea level rise will change in different parts of our country,” said Sarah Perkins-Kirkpatrick, of the University of New South Wales, and a  co-author.

“We need to reveal these impacts so we can protect regional agriculture, infrastructure and the Australian environments we have all come to know and love, such as the Great Barrier Reef.”

“ . . . a growing influx of the best scientists’ talent is needed to prepare for the surprises to come” 

The scientists, from Germany, France, Australia, the US, the UK and Switzerland, want to build a global co-operation of the kind launched decades ago at CERN in Geneva to understand basic climate change as CERN worked to understand particle physics.

They call for advanced climate simulation systems that can model outcomes with ever greater precision and ever smaller scales, and for sustained, long-term observation of the machinery of the planetary climate system: among them the complexities of the water cycle, involving the evaporation of soil moisture, the formation of clouds and the conditions for rain and snow fall.

Only then could researchers understand why climate continues to surprise: why so much of the Arctic sea ice disappeared in the summer of 2007; why almost all of the surface of Greenland started to melt in 2012; why drought and heat waves hit Russia so harshly in 2010.

“The human spirit is alive in climate research, as witnessed by the responses to the surprises encountered in the past,” they conclude, “but a growing influx of the best scientists’ talent is needed to prepare for the surprises to come.” – Climate News Network

Cold war spurred Arctic climate research

Arctic

Western post-war scientific studies in the Arctic were primarily driven by military concerns about Soviet activities in the region.

LONDON, 28 January, 2017 – On the agenda at the secret meeting of scientists and the top brass of the US military was the increased melting of Arctic ice and changes in the climate.

Senior scientists told of an extended period of warming in remote areas of the north. The meeting was told that many Arctic Ocean ports were ice-free for longer periods; US national security was potentially being threatened by increased Soviet marine activity in the region.

The year was 1947 and the gathering was at the Pentagon, the US defence headquarters outside Washington. Thereafter, according to a study examining scientific research in the Arctic in the post-war period, US military activities in the region – particularly in Greenland – were radically ramped up.

The study uses recently declassified US and European archive material to illustrate how issues of national security acted as the main stimulus for environmental research in the Arctic and elsewhere in the period after WW2.

Russia in the lead

“Russia was far ahead in terms of Arctic research,” Matthias Heymann, an associate professor at Aarhus University in Denmark and one of the co-authors of the study, told Climate News Network.

“In the 1920s it had set up a number of research stations in the Arctic, collecting considerable amounts of data.”

Greenland became an important stop-over point for US military flights during WW2 but it was only in the late 1940s that the US and other western powers, conscious of the Arctic’s growing strategic importance, expanded their research in the region.

“This expansion didn’t happen just because geophysics is interesting and scientists happened to be interested in it. It was driven by military interests,” says Heymann.

 “The melting ice changed the military dynamic in the area and acted as a spur for more research”

 

Denmark had ruled Greenland – the world’s largest island – as a colony since 1814; after the war Copenhagen wanted the US military to leave the territory.

“From the outset of negotiations the US made it clear that Greenland was a very important piece of land,” said Heymann.

Washington offered to buy Greenland from Denmark for US$100 million. Denmark refused, but subsequently granted the US military access to various areas on the island.

Thousands of meteorologists were employed by the US military to carry out Arctic research. The US army, navy and air force all set up Arctic research stations and put funds into university programmes investigating the region’s environment.

Military concern about melting

“Earlier in the 20th century there was significant warming in northern regions,” Heymann said.

“Though climate research as we know it today didn’t exist back then, the melting ice changed the military dynamic in the area and acted as a spur for more research.”

The military base at Thule on Greenland’s northwest coast was built up to be the biggest such facility outside the US. In 1968 a US bomber carrying four nuclear warheads crashed near Thule; the exact circumstances of the crash and what, if any, pollution it caused are still not known.

The study details some of the work undertaken by western researchers in the post-war period; high-altitude meteorological analysis examined the composition of the atmosphere above the Arctic and how missiles might behave when passing through it.

The make-up of icebergs came under scrutiny; sounds they make as they move in the ocean waters could interfere with listening devices on submarines.

“All these efforts in the early cold war provided the basis for knowledge of the Arctic that is still of vital importance today,” says Heymann.

“The early cold war very much helped establish good sets of data – our knowledge of the Arctic would be much more limited without them.”

Climate change – in the Arctic and elsewhere – has come to be a major issue of  concern to the military in many countries.

A recent report by a group of senior American defence experts says the impacts of climate change present “significant and direct risks to US military readiness, operations and strategy”. – Climate News Network

 

 

 

 

 

 

 

 

 

 

Western post-war scientific studies in the Arctic were primarily driven by military concerns about Soviet activities in the region.

LONDON, 28 January, 2017 – On the agenda at the secret meeting of scientists and the top brass of the US military was the increased melting of Arctic ice and changes in the climate.

Senior scientists told of an extended period of warming in remote areas of the north. The meeting was told that many Arctic Ocean ports were ice-free for longer periods; US national security was potentially being threatened by increased Soviet marine activity in the region.

The year was 1947 and the gathering was at the Pentagon, the US defence headquarters outside Washington. Thereafter, according to a study examining scientific research in the Arctic in the post-war period, US military activities in the region – particularly in Greenland – were radically ramped up.

The study uses recently declassified US and European archive material to illustrate how issues of national security acted as the main stimulus for environmental research in the Arctic and elsewhere in the period after WW2.

Russia in the lead

“Russia was far ahead in terms of Arctic research,” Matthias Heymann, an associate professor at Aarhus University in Denmark and one of the co-authors of the study, told Climate News Network.

“In the 1920s it had set up a number of research stations in the Arctic, collecting considerable amounts of data.”

Greenland became an important stop-over point for US military flights during WW2 but it was only in the late 1940s that the US and other western powers, conscious of the Arctic’s growing strategic importance, expanded their research in the region.

“This expansion didn’t happen just because geophysics is interesting and scientists happened to be interested in it. It was driven by military interests,” says Heymann.

 “The melting ice changed the military dynamic in the area and acted as a spur for more research”

 

Denmark had ruled Greenland – the world’s largest island – as a colony since 1814; after the war Copenhagen wanted the US military to leave the territory.

“From the outset of negotiations the US made it clear that Greenland was a very important piece of land,” said Heymann.

Washington offered to buy Greenland from Denmark for US$100 million. Denmark refused, but subsequently granted the US military access to various areas on the island.

Thousands of meteorologists were employed by the US military to carry out Arctic research. The US army, navy and air force all set up Arctic research stations and put funds into university programmes investigating the region’s environment.

Military concern about melting

“Earlier in the 20th century there was significant warming in northern regions,” Heymann said.

“Though climate research as we know it today didn’t exist back then, the melting ice changed the military dynamic in the area and acted as a spur for more research.”

The military base at Thule on Greenland’s northwest coast was built up to be the biggest such facility outside the US. In 1968 a US bomber carrying four nuclear warheads crashed near Thule; the exact circumstances of the crash and what, if any, pollution it caused are still not known.

The study details some of the work undertaken by western researchers in the post-war period; high-altitude meteorological analysis examined the composition of the atmosphere above the Arctic and how missiles might behave when passing through it.

The make-up of icebergs came under scrutiny; sounds they make as they move in the ocean waters could interfere with listening devices on submarines.

“All these efforts in the early cold war provided the basis for knowledge of the Arctic that is still of vital importance today,” says Heymann.

“The early cold war very much helped establish good sets of data – our knowledge of the Arctic would be much more limited without them.”

Climate change – in the Arctic and elsewhere – has come to be a major issue of  concern to the military in many countries.

A recent report by a group of senior American defence experts says the impacts of climate change present “significant and direct risks to US military readiness, operations and strategy”. – Climate News Network

 

 

 

 

 

 

 

 

 

 

Arctic melting feeds on itself

Melting sea ice is affecting the closely-linked Arctic climate in a feedback that will speed up warming there, scientists say.

LONDON, 12 June, 2016 Scientists have established at least one factor in the record melting of northern Greenland in 2015. The Arctic itself played a hand in what happened.

In a process that engineers call positive feedback, high atmospheric pressure and clear skies over the Arctic region practically committed the northwest of Greenland to an episode of melting at record rates.

And because the Arctic is the fastest-warming region on Earth, and because atmosphere and ocean influence each other, the steady loss of sea ice each year has forced a change in wind patterns. This in turn has played back into the climatic machinery, according to a new study in Nature Communications

“How much and where Greenland melts can change depending on how things change elsewhere on Earth,” said Marco Tedesco, of Columbia University’s Lamont-Doherty Earth Observatory, who led the research.

“If loss of sea ice is driving changes in the jet stream, the jet stream is changing Greenland, and this, in turn, has an impact on the Arctic system as well as the climate. It’s a system, it is strongly interconnected, and we have to approach it as such.”

Worldwide impact

Greenland’s burden of ice is the greatest in the northern hemisphere, and second only to Antarctica’s. If Greenland’s ice all melted, sea levels would rise worldwide by seven metres.

So what scientists call “Arctic amplification” isn’t just a bit of climate science jargon, it is also a phenomenon that matters immensely to humans everywhere.

The process works like this. The Arctic is warming faster as the sea ice disappears. This is because solar radiation which would have been reflected by a sheet of ice is being absorbed by blue water, which speeds up the warming further.

And since the temperature difference between the Arctic and the tropics is narrowing, and since it’s the temperature difference that drives wind and ocean currents, then the jet stream that normally whizzes around the Arctic circle – thus keeping frozen air in one place and separating it from the warm breezes of the south – is, the theory goes, slowing, thus allowing warm moist air to penetrate into the north. And, it seems, to melt even more of Greenland.

Professor Tedesco has been observing the intricate interplay of snow, ice, wind and sunlight in Greenland for years. Last year he and others examined the record melt of 2012 to piece together the rate of flow of water to the seas.

“The conditions we saw in the past aren’t necessarily the conditions of the future. If humans change the forcing, we are going into uncharted territory”

Earlier this year he and others pinpointed a change in albedo – a measure of the reflectivity of snow on the island – that suggested that melting might accelerate.

The latest study doesn’t declare the process of Arctic amplification guilty as charged: science proceeds cautiously and the researchers say only that the melting process observed in 2015 is “consistent” with the hypothesis of Arctic amplification.

In fact, the jet stream swung north to latitudes never before observed at that time of year; the winds during July reversed their normal pattern, and southern Greenland – where melting has been at record levels for most of the decade – actually saw more snowfall and lower melting in 2015.

Climate change is happening, being driven by the human combustion of fossil fuels at unprecedented rates for more than a century. But how the climate will change is harder to guess. The suspicion is that – if the Arctic amplification process works in the way that scientists think it must do – then climate change in the Arctic can only accelerate. But right now, all researchers can do is watch, record and measure.

“The conditions we saw in the past aren’t necessarily the conditions of the future,” Professor Tedesco said. “If humans change the forcing, we are going into uncharted territory.” Climate News Network

Melting sea ice is affecting the closely-linked Arctic climate in a feedback that will speed up warming there, scientists say.

LONDON, 12 June, 2016 Scientists have established at least one factor in the record melting of northern Greenland in 2015. The Arctic itself played a hand in what happened.

In a process that engineers call positive feedback, high atmospheric pressure and clear skies over the Arctic region practically committed the northwest of Greenland to an episode of melting at record rates.

And because the Arctic is the fastest-warming region on Earth, and because atmosphere and ocean influence each other, the steady loss of sea ice each year has forced a change in wind patterns. This in turn has played back into the climatic machinery, according to a new study in Nature Communications

“How much and where Greenland melts can change depending on how things change elsewhere on Earth,” said Marco Tedesco, of Columbia University’s Lamont-Doherty Earth Observatory, who led the research.

“If loss of sea ice is driving changes in the jet stream, the jet stream is changing Greenland, and this, in turn, has an impact on the Arctic system as well as the climate. It’s a system, it is strongly interconnected, and we have to approach it as such.”

Worldwide impact

Greenland’s burden of ice is the greatest in the northern hemisphere, and second only to Antarctica’s. If Greenland’s ice all melted, sea levels would rise worldwide by seven metres.

So what scientists call “Arctic amplification” isn’t just a bit of climate science jargon, it is also a phenomenon that matters immensely to humans everywhere.

The process works like this. The Arctic is warming faster as the sea ice disappears. This is because solar radiation which would have been reflected by a sheet of ice is being absorbed by blue water, which speeds up the warming further.

And since the temperature difference between the Arctic and the tropics is narrowing, and since it’s the temperature difference that drives wind and ocean currents, then the jet stream that normally whizzes around the Arctic circle – thus keeping frozen air in one place and separating it from the warm breezes of the south – is, the theory goes, slowing, thus allowing warm moist air to penetrate into the north. And, it seems, to melt even more of Greenland.

Professor Tedesco has been observing the intricate interplay of snow, ice, wind and sunlight in Greenland for years. Last year he and others examined the record melt of 2012 to piece together the rate of flow of water to the seas.

“The conditions we saw in the past aren’t necessarily the conditions of the future. If humans change the forcing, we are going into uncharted territory”

Earlier this year he and others pinpointed a change in albedo – a measure of the reflectivity of snow on the island – that suggested that melting might accelerate.

The latest study doesn’t declare the process of Arctic amplification guilty as charged: science proceeds cautiously and the researchers say only that the melting process observed in 2015 is “consistent” with the hypothesis of Arctic amplification.

In fact, the jet stream swung north to latitudes never before observed at that time of year; the winds during July reversed their normal pattern, and southern Greenland – where melting has been at record levels for most of the decade – actually saw more snowfall and lower melting in 2015.

Climate change is happening, being driven by the human combustion of fossil fuels at unprecedented rates for more than a century. But how the climate will change is harder to guess. The suspicion is that – if the Arctic amplification process works in the way that scientists think it must do – then climate change in the Arctic can only accelerate. But right now, all researchers can do is watch, record and measure.

“The conditions we saw in the past aren’t necessarily the conditions of the future,” Professor Tedesco said. “If humans change the forcing, we are going into uncharted territory.” Climate News Network