Tag Archives: Ice melt

Antarctic warming speed-up alarms researchers

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 March, 2021 − Antarctic warming is accelerating: at least one of the southern continent’s ice shelves has been melting faster than ever. The polar summer of 2019-20 set a new record for temperatures above freezing point over the George VI ice shelf off the Antarctic Peninsula.

The finding is ominous: the ice shelves form a natural buttress that slows the rate of glacier flow from the continental bedrock. The faster the glaciers flow into the sea, the higher the hazard of sea level rise.

And a second study confirms that this is already happening in West Antarctica: researchers looked at 25 years of satellite observation of 14 glaciers in the Getz sector to find that meltwater is flowing into the Amundsen Sea ever faster. Between 1994 and 2018, these glaciers lost 315 billion tonnes of ice, enough to raise global sea levels by almost 1mm.

Melting rates in Antarctica have been a source of alarm for years. The latest studies confirm the picture of continuing melt.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 March, 2021 − Antarctic warming is accelerating: at least one of the southern continent’s ice shelves has been melting faster than ever. The polar summer of 2019-20 set a new record for temperatures above freezing point over the George VI ice shelf off the Antarctic Peninsula.

The finding is ominous: the ice shelves form a natural buttress that slows the rate of glacier flow from the continental bedrock. The faster the glaciers flow into the sea, the higher the hazard of sea level rise.

And a second study confirms that this is already happening in West Antarctica: researchers looked at 25 years of satellite observation of 14 glaciers in the Getz sector to find that meltwater is flowing into the Amundsen Sea ever faster. Between 1994 and 2018, these glaciers lost 315 billion tonnes of ice, enough to raise global sea levels by almost 1mm.

Melting rates in Antarctica have been a source of alarm for years. The latest studies confirm the picture of continuing melt.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

Weakening Gulf Stream may disrupt world weather

The Gulf Stream is growing feebler, the Arctic seas are gaining fresh water. Together they could affect the world’s weather.

LONDON, 2 March, 2021 − The Atlantic Conveyer, otherwise the Gulf Stream − that great flow of surface water pouring northwards that overturns in the Arctic and heads south again at great depth − is now weaker than at any point in the last 1,000 years, European scientists report.

And in a second, separate but related study, researchers have found that the Beaufort Sea, in the Arctic, has gained two-fifths more fresh water in the last 20 years: water that could flow into the Atlantic to affect the Conveyor, and with it, climatic conditions.

Scientists call it the Atlantic Meridional Overturning Circulation or just AMOC. Europeans know it as the Gulf Stream: the current that conveys tropic warmth to their coasts and keeps Britain and Western Europe at a temperature several degrees higher than latitude alone might dictate.

And for years, oceanographers and climate scientists have been observing a slowing of the flow, by as much as 15%. But direct measurement of the great current began only relatively recently in 2004: researchers needed to know whether the slowdown was part of a natural cycle, or a consequence of climate change driven by global heating.

Now they know a little more. European researchers report in Nature Geoscience that they looked for evidence of ocean circulation shifts in what they call “proxy evidence”: the story of climate change told by tree growth rings, ice cores, ocean sediments, corals and historical records, including naval logbooks.

The combined evidence of temperature patterns, the sizes of particles of ocean floor sediment and the salinity and density of sub-surface water helps build up a picture of the Atlantic current for the last 1,600 years.

“The Gulf Stream System moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow”

The verdict? Up to the 19th century, ocean currents were stable. The flow is now more sluggish than at any time in the last millennium.

This is roughly what climate models have predicted: the warm salty water moves north, cools, becomes more dense, sinks to the deep and flows back south. But the Arctic has begun to warm, Greenland to melt, and the flow of fresh water into the northern seas to intensify.

Since the flow is driven by the difference in temperatures, any change in the regional thermometer will play back into the rate of flow. And any extra arrival of fresh water could further slow the overturning circulation.

“The Gulf Stream system works like a giant conveyor belt, carrying warm surface water from the equator up north, and sending cold, low-salinity deep water back down south. It moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow,” said Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research, in Germany, one of the authors.

“For the first time, we have combined a range of previous studies and found they provide a consistent picture of the AMOC evolution over the past 1600 years. The study results suggest that it has been relatively stable until the late 19th century.

“With the end of the Little Ice Age in about 1850, the ocean currents began to decline, with a second, more drastic decline following since the mid-20th century.”

Outcome awaited

The change could have ominous consequences for European weather systems: it could also deliver more intense coastal flooding to the US eastern seaboard. If the current continues to weaken, the consequences could be catastrophic.

Which is why a new study in Nature Communications matters so much. US researchers tracked the flow of fresh water from the Beaufort Sea − melt water from glaciers, rivers and disappearing Arctic sea ice − through the Canadian Archipelago and into the Labrador Sea.

Arctic water is fresher than Atlantic water, and richer in nutrients. But this extra volume, measured at a total of 23,300 cubic kilometres, could also affect the rate of flow of the overturning circulation. That is because relatively fresh water is less dense than saline water, and tends to float on top.

Quite what role it could play is uncertain: the message is that, sooner or later, it will escape into the North Atlantic. Then the world will find out.

“People have already spent a lot of time studying why the Beaufort Sea fresh water has gotten so high in the past few decades,” said Jiaxu Zhang,  of the Los Alamos National Laboratory, first author. “But they rarely care where the freshwater goes, and we think that’s a much more important problem.” − Climate News Network

The Gulf Stream is growing feebler, the Arctic seas are gaining fresh water. Together they could affect the world’s weather.

LONDON, 2 March, 2021 − The Atlantic Conveyer, otherwise the Gulf Stream − that great flow of surface water pouring northwards that overturns in the Arctic and heads south again at great depth − is now weaker than at any point in the last 1,000 years, European scientists report.

And in a second, separate but related study, researchers have found that the Beaufort Sea, in the Arctic, has gained two-fifths more fresh water in the last 20 years: water that could flow into the Atlantic to affect the Conveyor, and with it, climatic conditions.

Scientists call it the Atlantic Meridional Overturning Circulation or just AMOC. Europeans know it as the Gulf Stream: the current that conveys tropic warmth to their coasts and keeps Britain and Western Europe at a temperature several degrees higher than latitude alone might dictate.

And for years, oceanographers and climate scientists have been observing a slowing of the flow, by as much as 15%. But direct measurement of the great current began only relatively recently in 2004: researchers needed to know whether the slowdown was part of a natural cycle, or a consequence of climate change driven by global heating.

Now they know a little more. European researchers report in Nature Geoscience that they looked for evidence of ocean circulation shifts in what they call “proxy evidence”: the story of climate change told by tree growth rings, ice cores, ocean sediments, corals and historical records, including naval logbooks.

The combined evidence of temperature patterns, the sizes of particles of ocean floor sediment and the salinity and density of sub-surface water helps build up a picture of the Atlantic current for the last 1,600 years.

“The Gulf Stream System moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow”

The verdict? Up to the 19th century, ocean currents were stable. The flow is now more sluggish than at any time in the last millennium.

This is roughly what climate models have predicted: the warm salty water moves north, cools, becomes more dense, sinks to the deep and flows back south. But the Arctic has begun to warm, Greenland to melt, and the flow of fresh water into the northern seas to intensify.

Since the flow is driven by the difference in temperatures, any change in the regional thermometer will play back into the rate of flow. And any extra arrival of fresh water could further slow the overturning circulation.

“The Gulf Stream system works like a giant conveyor belt, carrying warm surface water from the equator up north, and sending cold, low-salinity deep water back down south. It moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow,” said Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research, in Germany, one of the authors.

“For the first time, we have combined a range of previous studies and found they provide a consistent picture of the AMOC evolution over the past 1600 years. The study results suggest that it has been relatively stable until the late 19th century.

“With the end of the Little Ice Age in about 1850, the ocean currents began to decline, with a second, more drastic decline following since the mid-20th century.”

Outcome awaited

The change could have ominous consequences for European weather systems: it could also deliver more intense coastal flooding to the US eastern seaboard. If the current continues to weaken, the consequences could be catastrophic.

Which is why a new study in Nature Communications matters so much. US researchers tracked the flow of fresh water from the Beaufort Sea − melt water from glaciers, rivers and disappearing Arctic sea ice − through the Canadian Archipelago and into the Labrador Sea.

Arctic water is fresher than Atlantic water, and richer in nutrients. But this extra volume, measured at a total of 23,300 cubic kilometres, could also affect the rate of flow of the overturning circulation. That is because relatively fresh water is less dense than saline water, and tends to float on top.

Quite what role it could play is uncertain: the message is that, sooner or later, it will escape into the North Atlantic. Then the world will find out.

“People have already spent a lot of time studying why the Beaufort Sea fresh water has gotten so high in the past few decades,” said Jiaxu Zhang,  of the Los Alamos National Laboratory, first author. “But they rarely care where the freshwater goes, and we think that’s a much more important problem.” − Climate News Network

Alpine plants face risk from growing climate heat

Like many mountainous regions, the European Alps are warming fast. Alpine plants will suffer – and life below ground as well.

LONDON, 1 March, 2021 – The early melting of snow in the Alps is not just bad news for ardent skiers and for those who are dependent on the money they earn during the winter sports season: Alpine plants are in danger too.

Rising temperatures due to climate change are also having a negative impact deep below the surface of the ground.

New research by scientists at the University of Manchester in the UK demonstrates that warming in the area is threatening microbes which live in the Alpine soils.

The microbes play a critical role in supporting life forms above ground, recycling key nutrients upon which animals, plants – and humans – depend.

“More extreme advances in snowmelt timing are forecast for the end of the century”

The microbes also control the amount of carbon stored in the soil: if the cycle of microbial activity is disrupted, then more carbon is released into the atmosphere, resulting in further global warming.

Arthur Broadbent, lead author of a research paper in the ISME Journal,  says climate change is having an alarming impact on microbial communities in Alpine soils.

“Using a high-alpine experiment in the Austrian Alps, we discovered that spring snowmelt triggers an abrupt seasonal transition in soil microbial communities, which is closely linked to rapid shifts in carbon and nitrogen cycling”, he said.

During the winter, microbes in the Alpine soils depend on snow to act as an insulating blanket, allowing them to continue to work throughout the cold months.

Himalayan disaster

The researchers say that climate change in the Alps is taking place at double the rate of the global average. Separate research indicates that profound changes are happening in the Alps and in many other mountainous regions around the world.

In February a flash flood in Uttarakhand in northern India killed nearly 70 people, with 136 more missing and now presumed dead. Most scientists believe the warming climate was the cause of the glacier melt which triggered the disaster.

There are predictions that over the next 80 years more than 90% of glacier ice in the Alpine region will be lost due to ever-rising temperatures.

“Snowmelt is predicted to occur 50 to 130 days earlier in alpine regions due to climate change by the end of the century”, says Dr Broadbent.

Increased warming

“Using experimental manipulations, we demonstrated that earlier snowmelt, of even just 10 days, leads to an earlier seasonal transition in microbial communities and biogeochemical cycling.”

The research paper says that changes in the microbial cycle caused by snow melt will result in less carbon being retained in the soil and so have a negative impact on the growth and productivity of plants.

“This would negatively affect agricultural production and disrupt natural ecosystems. It will also alter annual carbon fluxes in these ecosystems with the potential to cause further climate warming.”

The authors conclude with a clear warning: “More extreme advances in snowmelt timing are forecast for the end of the century.” – Climate News Network

Like many mountainous regions, the European Alps are warming fast. Alpine plants will suffer – and life below ground as well.

LONDON, 1 March, 2021 – The early melting of snow in the Alps is not just bad news for ardent skiers and for those who are dependent on the money they earn during the winter sports season: Alpine plants are in danger too.

Rising temperatures due to climate change are also having a negative impact deep below the surface of the ground.

New research by scientists at the University of Manchester in the UK demonstrates that warming in the area is threatening microbes which live in the Alpine soils.

The microbes play a critical role in supporting life forms above ground, recycling key nutrients upon which animals, plants – and humans – depend.

“More extreme advances in snowmelt timing are forecast for the end of the century”

The microbes also control the amount of carbon stored in the soil: if the cycle of microbial activity is disrupted, then more carbon is released into the atmosphere, resulting in further global warming.

Arthur Broadbent, lead author of a research paper in the ISME Journal,  says climate change is having an alarming impact on microbial communities in Alpine soils.

“Using a high-alpine experiment in the Austrian Alps, we discovered that spring snowmelt triggers an abrupt seasonal transition in soil microbial communities, which is closely linked to rapid shifts in carbon and nitrogen cycling”, he said.

During the winter, microbes in the Alpine soils depend on snow to act as an insulating blanket, allowing them to continue to work throughout the cold months.

Himalayan disaster

The researchers say that climate change in the Alps is taking place at double the rate of the global average. Separate research indicates that profound changes are happening in the Alps and in many other mountainous regions around the world.

In February a flash flood in Uttarakhand in northern India killed nearly 70 people, with 136 more missing and now presumed dead. Most scientists believe the warming climate was the cause of the glacier melt which triggered the disaster.

There are predictions that over the next 80 years more than 90% of glacier ice in the Alpine region will be lost due to ever-rising temperatures.

“Snowmelt is predicted to occur 50 to 130 days earlier in alpine regions due to climate change by the end of the century”, says Dr Broadbent.

Increased warming

“Using experimental manipulations, we demonstrated that earlier snowmelt, of even just 10 days, leads to an earlier seasonal transition in microbial communities and biogeochemical cycling.”

The research paper says that changes in the microbial cycle caused by snow melt will result in less carbon being retained in the soil and so have a negative impact on the growth and productivity of plants.

“This would negatively affect agricultural production and disrupt natural ecosystems. It will also alter annual carbon fluxes in these ecosystems with the potential to cause further climate warming.”

The authors conclude with a clear warning: “More extreme advances in snowmelt timing are forecast for the end of the century.” – Climate News Network

Wild flowers and bees contend with climate heat

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

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

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

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

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

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

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

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

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

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

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

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

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

Growing interest

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Growing interest

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

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

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

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

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

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

Scientists say world’s huge ice loss is speeding up

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

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

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

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

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

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

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

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

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

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

‘Staggering’ loss

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

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

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

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

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

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

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

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

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

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

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

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

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

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

‘Staggering’ loss

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

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

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

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

World still warms in 2020 as greenhouse gases fall

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

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

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

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

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

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

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

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

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

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

Roasting Arctic

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Roasting Arctic

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

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

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

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

Polar link unites far extremes of north and south

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

Global heating may go on for five more centuries

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

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

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

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

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

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

Challenged by colleagues

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

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

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

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

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

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

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

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

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

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

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

Positive feedback?

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

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

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

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

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

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

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

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

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

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

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

Challenged by colleagues

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

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

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

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

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

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

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

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

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

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

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

Positive feedback?

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

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

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

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

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

Antarctic depths warm far beyond oceanic average

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

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

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

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

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

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

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

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

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

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

Ocean circulation risk

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Ocean circulation risk

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

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

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

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

Rising heat means more methane, warmer nights

Nights are warmer. So are northern lakes. And farm livestock are at greater risk of disease, thanks to rising heat.

LONDON, 20 October, 2020 − Global warming has already begun to alter the world perceptibly, with rising heat changing daily life for millions of people.

Over more than half the planet’s land surface, nights are now warming at a rate faster than the days, with unpredictable consequences for plant and animal life.

Warmer winters now mean that in Europe, Asia and North America, lakes that would once have frozen over are now increasingly sometimes ice-free even at the darkest moments of the year.

And ever-higher temperatures encourage the spread of infectious diseases, and unexpectedly with that, the hazard of yet more warming.

Increasing parasitic activity among farm animals could mean that infected cattle, sheep and goats can produce up to a third more methane. This natural gas is around 30 times more potent, as a greenhouse gas, than the same volume of carbon dioxide.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence”

The long-term consequences of any of these changes are difficult to foresee. British scientists report in the journal Global Change Biology that they searched the fine detail of global temperature, cloud cover, humidity and rainfall worldwide from 1983 to 2017 for any significant pattern of change, and found one.

Over more than half the terrestrial surface of the planet, there was a mean annual difference of at least 0.25°C between daytime and night-time warming.

In some places, days warmed more swiftly than nights. But disproportionately greater night-time warming happened over an area more than twice as large.

The agency at work appeared to be cloud cover: more clouds mean a cooler surface in daylight but a more effective blanket to retain warmth at night. Clear skies tend to mean hotter days and colder nights.

“We demonstrate that greater night-time warming is associated with climate becoming wetter, and this been shown to have important consequences for plant growth, and how species such as insects and mammals interact,” said Daniel Cox of Exeter University, UK, who led the research.

More ice-free lakes

“Conversely, we show that greater daytime warming is associated with drier conditions, combined with greater levels of overall warming, which increases vulnerability to heat stress and dehydration. Species that are only active at night or during the day will be particularly affected.”

Freezing winters play a vital role in the life of a northern lake. Canadian scientists report in the journal Geophysical Research Letters that they analysed almost eight decades of data − from 1939 to 2016 − for 122 lakes in Asia, Europe and America: the lakes included Baikal in Siberia, Geneva in Switzerland and Balaton in Hungary, Champlain and Michigan near the US- Canadian border, and Suwa in Japan, where records extend back to 1443.

They found that ice-free years have become three times more frequent since 1978, and 11% experienced at least one completely ice-free year since 1939. The trend was the same, everywhere they looked.

Lake ice is also vulnerable to rising heat. It is important to the winter recreation industry. It also plays a vital role in lake ecology. Without a sheath of winter ice, lakes stay warmer and stratify earlier to become more vulnerable to toxic algal blooms: this in turn is bad for fish, and for swimmers.

“Lake ice is becoming increasingly absent,” said Alessandro Filazzola of York University, Toronto, who led the study. “Even under low-carbon emissions scenarios, we’re going to have ice-free events.”

Methane’s rapid rise

Methane is a relatively short-lived but highly potent greenhouse gas: in the past decade it has increased rapidly in the atmosphere. About half of this increase comes from farm livestock.

US researchers report in the journal Trends in Ecology and Evolution that they looked at sheep studies to find that animals infected with intestinal worms produced up to 33% more methane per kilogram of food than uninfected animals. Dairy cows with mastitis − a bacterial infection − produce 8% more methane per litre of milk than uninfected animals.

Global livestock production could increase at the rate of 2.7% a year, according to UN forecasts. If so, between 2017 and 2050 methane production will soar by more than 20%. Throw parasitic worm infections into the forecasts and methane emissions from livestock could climb by up to 82% in the same period.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence,” said Vanessa Ezenwa of the University of Georgia, first author.

“If that’s happening for livestock diseases, and simultaneously higher prevalence is triggering increased methane release, you could end up with what we call a vicious cycle.” − Climate News Network

Nights are warmer. So are northern lakes. And farm livestock are at greater risk of disease, thanks to rising heat.

LONDON, 20 October, 2020 − Global warming has already begun to alter the world perceptibly, with rising heat changing daily life for millions of people.

Over more than half the planet’s land surface, nights are now warming at a rate faster than the days, with unpredictable consequences for plant and animal life.

Warmer winters now mean that in Europe, Asia and North America, lakes that would once have frozen over are now increasingly sometimes ice-free even at the darkest moments of the year.

And ever-higher temperatures encourage the spread of infectious diseases, and unexpectedly with that, the hazard of yet more warming.

Increasing parasitic activity among farm animals could mean that infected cattle, sheep and goats can produce up to a third more methane. This natural gas is around 30 times more potent, as a greenhouse gas, than the same volume of carbon dioxide.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence”

The long-term consequences of any of these changes are difficult to foresee. British scientists report in the journal Global Change Biology that they searched the fine detail of global temperature, cloud cover, humidity and rainfall worldwide from 1983 to 2017 for any significant pattern of change, and found one.

Over more than half the terrestrial surface of the planet, there was a mean annual difference of at least 0.25°C between daytime and night-time warming.

In some places, days warmed more swiftly than nights. But disproportionately greater night-time warming happened over an area more than twice as large.

The agency at work appeared to be cloud cover: more clouds mean a cooler surface in daylight but a more effective blanket to retain warmth at night. Clear skies tend to mean hotter days and colder nights.

“We demonstrate that greater night-time warming is associated with climate becoming wetter, and this been shown to have important consequences for plant growth, and how species such as insects and mammals interact,” said Daniel Cox of Exeter University, UK, who led the research.

More ice-free lakes

“Conversely, we show that greater daytime warming is associated with drier conditions, combined with greater levels of overall warming, which increases vulnerability to heat stress and dehydration. Species that are only active at night or during the day will be particularly affected.”

Freezing winters play a vital role in the life of a northern lake. Canadian scientists report in the journal Geophysical Research Letters that they analysed almost eight decades of data − from 1939 to 2016 − for 122 lakes in Asia, Europe and America: the lakes included Baikal in Siberia, Geneva in Switzerland and Balaton in Hungary, Champlain and Michigan near the US- Canadian border, and Suwa in Japan, where records extend back to 1443.

They found that ice-free years have become three times more frequent since 1978, and 11% experienced at least one completely ice-free year since 1939. The trend was the same, everywhere they looked.

Lake ice is also vulnerable to rising heat. It is important to the winter recreation industry. It also plays a vital role in lake ecology. Without a sheath of winter ice, lakes stay warmer and stratify earlier to become more vulnerable to toxic algal blooms: this in turn is bad for fish, and for swimmers.

“Lake ice is becoming increasingly absent,” said Alessandro Filazzola of York University, Toronto, who led the study. “Even under low-carbon emissions scenarios, we’re going to have ice-free events.”

Methane’s rapid rise

Methane is a relatively short-lived but highly potent greenhouse gas: in the past decade it has increased rapidly in the atmosphere. About half of this increase comes from farm livestock.

US researchers report in the journal Trends in Ecology and Evolution that they looked at sheep studies to find that animals infected with intestinal worms produced up to 33% more methane per kilogram of food than uninfected animals. Dairy cows with mastitis − a bacterial infection − produce 8% more methane per litre of milk than uninfected animals.

Global livestock production could increase at the rate of 2.7% a year, according to UN forecasts. If so, between 2017 and 2050 methane production will soar by more than 20%. Throw parasitic worm infections into the forecasts and methane emissions from livestock could climb by up to 82% in the same period.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence,” said Vanessa Ezenwa of the University of Georgia, first author.

“If that’s happening for livestock diseases, and simultaneously higher prevalence is triggering increased methane release, you could end up with what we call a vicious cycle.” − Climate News Network