Tag Archives: Prediction

Clouds slow down warming in the short term

clouds warming

New research shows that clouds block sunlight and reflect radiation back to space, impeding the rate of global warming. But for how long?

LONDON, 10 November, 2016 Scientists may be one step nearer to a solution of the riddle of the clouds: yes, they do damp down global warming, but this feedback effect may not last.

And, if so, the implication is that global warming due to rising carbon dioxide concentrations in the atmosphere has been underestimated, according to new research in the journal Nature Geoscience.

At the heart of the mystery is a puzzle easier to measure than to grasp: the behaviour of low-level clouds. Put crudely, clouds block sunlight and reflect radiation back into space. In a warming world the capacity of the atmosphere to hold water rises, so a warmer world could mean higher densities of cloud cover which would slow the rate of warming.

Uncertain evidence

But is that happening? The evidence so far has been uncertain. One group has reported that greater emissions of pollution have led to cloud formations that may have reduced overall warming. Yet other scientists have reported that they are not so sure.

Another group has calculated that low-level cloud over Greenland may even have accelerated the dramatic thaw of the northern hemisphere’s biggest reserves of ice in 2012. And a comprehensive study earlier this year has concluded that there are no easy answers.

The core of the problem is measurement over a long period of time: global air and sea surface temperatures have been carefully observed and recorded for more than a century. But scientific studies of cloud cover – literally, an overview date only from the satellite age.

Our results indicate that cloud feedback and climate
sensitivity calculated from recently observed trends
may be underestimated, since the warming
pattern during this period is so unique”

Most satellite data start around 1980, so linear trends over the last three decades are often used to make inferences about long-term global warming and to estimate climate sensitivity,” says Chen Zhou of the US Lawrence Livermore National Laboratory, who led the study.

Our results indicate that cloud feedback and climate sensitivity calculated from recently observed trends may be underestimated, since the warming pattern during this period is so unique.”

The US scientists matched satellite observations with climate models to see what could be happening over a long period of time. The message from the latest study is that cloud feedback is likely to be positive in the long term but has been negative over the last 30 years. So clouds have masked the intensity of warming, for now.

Anomalous clouds

The simulations predict that the planet will warm in ways that make low clouds – the ones that reflect most sunlight – less likely. But in the last 30 years, tropical surface temperatures have gone up in places where the air ascends and fallen where the air descends, to keep the lower atmosphere moist and cloudy.

But while increasing concentrations of carbon dioxide, released from car exhausts and factory chimneys in the combustion of fossil fuels, imply ever higher average global temperatures, this is not the only factor at work: volcanic eruptions, aerosol pollution and other agencies introduce natural variability. So short-term trends, the scientists argue, could be highly misleading.

Their study concludes: “Sea surface temperature pattern-induced low cloud anomalies could have contributed to the reduced warming between 1998 and 2013, and offer a physical explanation of why climate sensitivities estimated from recently observed trends are probably biased low.” Climate News Network

New research shows that clouds block sunlight and reflect radiation back to space, impeding the rate of global warming. But for how long?

LONDON, 10 November, 2016 Scientists may be one step nearer to a solution of the riddle of the clouds: yes, they do damp down global warming, but this feedback effect may not last.

And, if so, the implication is that global warming due to rising carbon dioxide concentrations in the atmosphere has been underestimated, according to new research in the journal Nature Geoscience.

At the heart of the mystery is a puzzle easier to measure than to grasp: the behaviour of low-level clouds. Put crudely, clouds block sunlight and reflect radiation back into space. In a warming world the capacity of the atmosphere to hold water rises, so a warmer world could mean higher densities of cloud cover which would slow the rate of warming.

Uncertain evidence

But is that happening? The evidence so far has been uncertain. One group has reported that greater emissions of pollution have led to cloud formations that may have reduced overall warming. Yet other scientists have reported that they are not so sure.

Another group has calculated that low-level cloud over Greenland may even have accelerated the dramatic thaw of the northern hemisphere’s biggest reserves of ice in 2012. And a comprehensive study earlier this year has concluded that there are no easy answers.

The core of the problem is measurement over a long period of time: global air and sea surface temperatures have been carefully observed and recorded for more than a century. But scientific studies of cloud cover – literally, an overview date only from the satellite age.

Our results indicate that cloud feedback and climate
sensitivity calculated from recently observed trends
may be underestimated, since the warming
pattern during this period is so unique”

Most satellite data start around 1980, so linear trends over the last three decades are often used to make inferences about long-term global warming and to estimate climate sensitivity,” says Chen Zhou of the US Lawrence Livermore National Laboratory, who led the study.

Our results indicate that cloud feedback and climate sensitivity calculated from recently observed trends may be underestimated, since the warming pattern during this period is so unique.”

The US scientists matched satellite observations with climate models to see what could be happening over a long period of time. The message from the latest study is that cloud feedback is likely to be positive in the long term but has been negative over the last 30 years. So clouds have masked the intensity of warming, for now.

Anomalous clouds

The simulations predict that the planet will warm in ways that make low clouds – the ones that reflect most sunlight – less likely. But in the last 30 years, tropical surface temperatures have gone up in places where the air ascends and fallen where the air descends, to keep the lower atmosphere moist and cloudy.

But while increasing concentrations of carbon dioxide, released from car exhausts and factory chimneys in the combustion of fossil fuels, imply ever higher average global temperatures, this is not the only factor at work: volcanic eruptions, aerosol pollution and other agencies introduce natural variability. So short-term trends, the scientists argue, could be highly misleading.

Their study concludes: “Sea surface temperature pattern-induced low cloud anomalies could have contributed to the reduced warming between 1998 and 2013, and offer a physical explanation of why climate sensitivities estimated from recently observed trends are probably biased low.” Climate News Network

Speed of Arctic changes defies scientists

The Arctic climate is changing so quickly that science can barely keep track of what is happening and predict the global consequences, the UN says.

LONDON, 29 September, 2016 In an unusually stark warning a leading international scientific body says the Arctic climate is changing so fast that researchers are struggling to keep up. The changes happening there, it says, are affecting the weather worldwide.

The World Meteorological Organisation (WMO) says: Dramatic and unprecedented warming in the Arctic is driving sea level rise, affecting weather patterns around the world and may trigger even more changes in the climate system.

The rate of change is challenging the current scientific capacity to monitor and predict what is becoming a journey into uncharted territory. 

The WMO is the United Nations’ main agency responsible for weather, climate and water.    

Its president, David Grimes, said: The Arctic is a principal, global driver of the climate system and is undergoing an unprecedented rate of change with consequences far beyond its boundaries.

Arctic collaboration

The changes in the Arctic are serving as a global indicator – like a canary in the coal mine – and are happening at a much faster rate than we would have expected.

He was speaking before addressing the first White House Science Ministerial meeting in Washington DC, held to develop international collaboration on Arctic science.

Climate change is causing global average temperatures to rise: 2014, 2015 and the first eight months of 2016 have all been record-breakers. The Arctic is warming at least twice as fast as the global average, in places even faster: the Canadian town of Inuvik has warmed by almost 4°C since 1948, about four times more than the global figure.

The increasing loss of Arctic sea ice is threatening polar bears across their range; melting sea ice is affecting the Arctic climate in a feedback loop; and scientists expect melting permafrost will release more carbon dioxide and methane

The WMO secretary-general, Petteri Taalas, said the Arctic changes had also been a factor in unusual winter weather patterns in North America and Europe. He said the thawing of the permafrost could release vast quantities of greenhouse gases into the atmosphere.

These are part of the vicious circles of climate change which are the subject of intense scientific research, he said.

The Arctic is a principal, global driver of the climate system and is undergoing an unprecedented rate of change with consequences far beyond its boundaries

Despite its certainty that the Arctic is in trouble, the WMO says it is hard to establish the implications of what is happening there. The Arctic makes up about 4% of the Earth’s surface, but the WMO says it is one of the most data-sparse regions in the world because of its remoteness and previous inaccessibility.

Lack of data and forecasts in the Arctic does impact on the quality of weather forecasts in other parts of the world. 

That’s a worry which is echoed at the other end of the planet. A study led by Dr Julie Jones, from the department of geography at the University of Sheffield, UK, says limited data on Antarctica’s climate is making it difficult for researchers to disentangle changes caused by human activity from natural climate fluctuations.

It was only when regular satellite observations began in 1979 that measurement of surface climate over the Antarctic and the Southern Ocean became possible, says the study, published in the journal Nature Climate Change

To gain a longer view, Dr Jones and her colleagues used a compilation of records from natural archives such as ice cores from the Antarctic ice sheet, which show how the region’s climate has changed over the last 200 years.

Separating signals

They confirmed that human-induced changes have caused the belt of prevailing westerly winds over the Southern Ocean to shift towards Antarctica.

But they conclude that for other changes, including regional warming and sea ice changes, the observations since 1979 are not yet long enough for the signal of human activity to be clearly separated from the strong natural variability.

The shift in the westerly winds has moved rainfall away from southern Australia. This year is set to be the country’s hottest on record.

Dr Jones said: “The Antarctic climate is like a giant jigsaw puzzle with most of the pieces still missing.

“There are some parts of the picture which are clear, particularly the way that climate change is causing westerly winds to shift southwards, but there are still huge gaps that we need to fill in order to fully understand how much human activity is changing weather in the region.” – Climate News Network

The Arctic climate is changing so quickly that science can barely keep track of what is happening and predict the global consequences, the UN says.

LONDON, 29 September, 2016 In an unusually stark warning a leading international scientific body says the Arctic climate is changing so fast that researchers are struggling to keep up. The changes happening there, it says, are affecting the weather worldwide.

The World Meteorological Organisation (WMO) says: Dramatic and unprecedented warming in the Arctic is driving sea level rise, affecting weather patterns around the world and may trigger even more changes in the climate system.

The rate of change is challenging the current scientific capacity to monitor and predict what is becoming a journey into uncharted territory. 

The WMO is the United Nations’ main agency responsible for weather, climate and water.    

Its president, David Grimes, said: The Arctic is a principal, global driver of the climate system and is undergoing an unprecedented rate of change with consequences far beyond its boundaries.

Arctic collaboration

The changes in the Arctic are serving as a global indicator – like a canary in the coal mine – and are happening at a much faster rate than we would have expected.

He was speaking before addressing the first White House Science Ministerial meeting in Washington DC, held to develop international collaboration on Arctic science.

Climate change is causing global average temperatures to rise: 2014, 2015 and the first eight months of 2016 have all been record-breakers. The Arctic is warming at least twice as fast as the global average, in places even faster: the Canadian town of Inuvik has warmed by almost 4°C since 1948, about four times more than the global figure.

The increasing loss of Arctic sea ice is threatening polar bears across their range; melting sea ice is affecting the Arctic climate in a feedback loop; and scientists expect melting permafrost will release more carbon dioxide and methane

The WMO secretary-general, Petteri Taalas, said the Arctic changes had also been a factor in unusual winter weather patterns in North America and Europe. He said the thawing of the permafrost could release vast quantities of greenhouse gases into the atmosphere.

These are part of the vicious circles of climate change which are the subject of intense scientific research, he said.

The Arctic is a principal, global driver of the climate system and is undergoing an unprecedented rate of change with consequences far beyond its boundaries

Despite its certainty that the Arctic is in trouble, the WMO says it is hard to establish the implications of what is happening there. The Arctic makes up about 4% of the Earth’s surface, but the WMO says it is one of the most data-sparse regions in the world because of its remoteness and previous inaccessibility.

Lack of data and forecasts in the Arctic does impact on the quality of weather forecasts in other parts of the world. 

That’s a worry which is echoed at the other end of the planet. A study led by Dr Julie Jones, from the department of geography at the University of Sheffield, UK, says limited data on Antarctica’s climate is making it difficult for researchers to disentangle changes caused by human activity from natural climate fluctuations.

It was only when regular satellite observations began in 1979 that measurement of surface climate over the Antarctic and the Southern Ocean became possible, says the study, published in the journal Nature Climate Change

To gain a longer view, Dr Jones and her colleagues used a compilation of records from natural archives such as ice cores from the Antarctic ice sheet, which show how the region’s climate has changed over the last 200 years.

Separating signals

They confirmed that human-induced changes have caused the belt of prevailing westerly winds over the Southern Ocean to shift towards Antarctica.

But they conclude that for other changes, including regional warming and sea ice changes, the observations since 1979 are not yet long enough for the signal of human activity to be clearly separated from the strong natural variability.

The shift in the westerly winds has moved rainfall away from southern Australia. This year is set to be the country’s hottest on record.

Dr Jones said: “The Antarctic climate is like a giant jigsaw puzzle with most of the pieces still missing.

“There are some parts of the picture which are clear, particularly the way that climate change is causing westerly winds to shift southwards, but there are still huge gaps that we need to fill in order to fully understand how much human activity is changing weather in the region.” – Climate News Network

Clouds’ climate impact defies simple analysis

The perennial question of how clouds affect the Earth’s climate takes another twist, with one study expecting cooling and another the opposite.

LONDON, 22 August, 2016 – Scientists have just been presented with new evidence on how tropical clouds’ climate impact affects rates of global warming, and therefore need to be factored into computer simulations of climate change over the next century.

Confusingly, one study says thin tropical clouds at 5km height are far more common than thought, and have a substantial cooling effect on climate.

The other suggests that as the world warms there will be fewer low-level clouds, which will therefore reflect less sunlight back into space and possibly push global temperatures to 2.3°C above the average for most of  human history.

The findings are not contradictory: the first, in Nature Communications, addresses evidence derived from space-borne study of clouds at mid-level right now. The second, in the American Meteorological Society’s Journal of Climate, examines changes with time in the prevalence of clouds at the lower levels.

Unpredictable

What both papers do is deliver a reminder that climate is a complex bit of machinery and that, as the great Danish physicist Niels Bohr is supposed to have said, prediction is very difficult, especially about the future. 

 For the Nature Communications study, Quentin Bourgeois of the Bolin Centre for Climate Research in Stockholm University and colleagues used space-borne instruments and numerical models to look at the mid-level clouds in the tropics and found that the cooling effect of these could be as large as the warming induced by the cirrus clouds at high level.

Since clouds cover more than 70% of the Earth’s surface at any time, and since different types of clouds impact climate differently, there should be no surprise that the overall effect of cloud cover in climate is a puzzle. 

One study has suggested researchers over-estimate the cooling effect of clouds. Another has attributed the dramatic thaw of Greenland’s icecap in 2012 to clouds, while other studies have concentrated on exploring the mechanisms and the dynamics of cloud formation. So both studies represent small pieces of a giant atmospheric jigsaw puzzle.

“Climate sensitivity is more likely situated in the upper half of previous estimates, probably around four degrees”

For the Journal of Climate study, two scientists from the Swiss Federal Institute of Technology, usually known as ETH Zurich, studied 15 years of radiometer data from Nasa satellites. These continuously measure how much sunlight is reflected back into space, and the variations in the data showed that, in the past, there have been fewer low-lying clouds than in the cooler years.

It follows that, as the world warms, the cloud cover at this altitude will tend to thin. The study suggests, not for the first time, that the 195 nations which in Paris in December agreed to contain global warming to less than 2°C have set an ambitious target.

All the observational data from this study suggest that if carbon dioxide in the atmosphere doubles then average global temperatures will rise substantially. Researchers like to call this climate sensitivity.

“It’s very unlikely that the climate sensitivity is less than 2.3°C,” said Tapio Schneider, one of the authors. “Climate sensitivity is more likely situated in the upper half of previous estimates, probably around four degrees.” – Climate News Network

The perennial question of how clouds affect the Earth’s climate takes another twist, with one study expecting cooling and another the opposite.

LONDON, 22 August, 2016 – Scientists have just been presented with new evidence on how tropical clouds’ climate impact affects rates of global warming, and therefore need to be factored into computer simulations of climate change over the next century.

Confusingly, one study says thin tropical clouds at 5km height are far more common than thought, and have a substantial cooling effect on climate.

The other suggests that as the world warms there will be fewer low-level clouds, which will therefore reflect less sunlight back into space and possibly push global temperatures to 2.3°C above the average for most of  human history.

The findings are not contradictory: the first, in Nature Communications, addresses evidence derived from space-borne study of clouds at mid-level right now. The second, in the American Meteorological Society’s Journal of Climate, examines changes with time in the prevalence of clouds at the lower levels.

Unpredictable

What both papers do is deliver a reminder that climate is a complex bit of machinery and that, as the great Danish physicist Niels Bohr is supposed to have said, prediction is very difficult, especially about the future. 

 For the Nature Communications study, Quentin Bourgeois of the Bolin Centre for Climate Research in Stockholm University and colleagues used space-borne instruments and numerical models to look at the mid-level clouds in the tropics and found that the cooling effect of these could be as large as the warming induced by the cirrus clouds at high level.

Since clouds cover more than 70% of the Earth’s surface at any time, and since different types of clouds impact climate differently, there should be no surprise that the overall effect of cloud cover in climate is a puzzle. 

One study has suggested researchers over-estimate the cooling effect of clouds. Another has attributed the dramatic thaw of Greenland’s icecap in 2012 to clouds, while other studies have concentrated on exploring the mechanisms and the dynamics of cloud formation. So both studies represent small pieces of a giant atmospheric jigsaw puzzle.

“Climate sensitivity is more likely situated in the upper half of previous estimates, probably around four degrees”

For the Journal of Climate study, two scientists from the Swiss Federal Institute of Technology, usually known as ETH Zurich, studied 15 years of radiometer data from Nasa satellites. These continuously measure how much sunlight is reflected back into space, and the variations in the data showed that, in the past, there have been fewer low-lying clouds than in the cooler years.

It follows that, as the world warms, the cloud cover at this altitude will tend to thin. The study suggests, not for the first time, that the 195 nations which in Paris in December agreed to contain global warming to less than 2°C have set an ambitious target.

All the observational data from this study suggest that if carbon dioxide in the atmosphere doubles then average global temperatures will rise substantially. Researchers like to call this climate sensitivity.

“It’s very unlikely that the climate sensitivity is less than 2.3°C,” said Tapio Schneider, one of the authors. “Climate sensitivity is more likely situated in the upper half of previous estimates, probably around four degrees.” – Climate News Network

Climate query as US tornado risk rises

Scientists say the climate behaves too capriciously for them to know for sure whether global warming caused by burning fossil fuels is to blame for a growing tornado threat.

LONDON, 7 March, 2016 – Tornadoes in the US are getting worse, with the numbers in any one outbreak and the hazard of ever more frequent outbreaks both on the increase.

And although climate change driven by global warming from human causes is under suspicion, nobody really knows for sure whether that is driving the pattern of change.

But change is certainly happening. New research published in Nature Communications has examined the pattern of outbreaks and found that the average number of tornadoes in any one outbreak has increased since 1954, and the chance of extreme – and therefore extremely destructive – outbreaks has also increased.

An outbreak is a large-scale weather event that can last for days, span huge regions and spawn multiple tornadoes. Continental America is used to these outbreaks, which is why a band of territory that spans central Texas, Illinois and Indiana, and embraces parts of Oklahoma, Kansas, Nebraska, Colorado and South Dakota, is known as Tornado Alley.

Devastating whirlwinds

The plains flanked by the Rockies and the Appalachian mountain chains are a corridor up which sweeps hot, moist air from the Gulf of Mexico, to meet cold, dry air from the mountains and the north. The encounter sets up the conditions for colossal thunderstorms, accompanied by devastating whirlwinds.

The largest recent outbreak was in 2011. It spawned 363 tornadoes across the US and Canada, claimed more than 350 lives, and did $11 billion worth of damage.

Around 1,000 tornadoes are reported in the US each year, with the top two per cent causing most of the death and devastation.

Winds can reach 300 kilometres an hour in a space a mile wide, destroying anything in the way. They uproot houses, blow cars into the air, turn towns into rubble, strip bark from trees and, in one reported instance, even tear asphalt off a highway.

Research such as this matters because it could help societies prepare better. One consistent prediction within climate research is that, as average global temperatures rise in response to greenhouse gas emissions from fossil fuel combustion, so does the likelihood that meteorological disasters could become more frequent, or more violent, or both.

“It could be global warming, but our usual tools are not up to the task of answering this question yet”

But although that seems to be the case over the last two decades – the UN Office for Disaster Risk Reduction (UNISDR) reported last year that the number of weather-related disasters had almost doubled – it does not mean that warmer years must be more calamitous.

Last year was declared the warmest since records began, and UNISDR reported 32 major droughts that affected more than 50 million people, but only 996 deaths in recorded storms, compared with the annual average of more than 17,000 in the preceding decade.

Caprice plays a powerful role in climate events − and that includes tornadoes, particularly in the US.

There is evidence that the tornado season is commencing ever earlier. Between 2005 and 2014, tornadoes claimed on average 110 lives in the US each year, and caused between $500m and $9.6bn worth of damage.

In 1925, one tornado that raced across Missouri, Illinois and Indiana killed 695 people and injured 2,027. In one 24-hour spell in 1974, a total of 148 tornadoes swept across 12 states from Michigan to Alabama, killing 309 people, injuring 5,300 and doing damage costing $600 million.

Future hazards

So tornadoes were destructive long before any concerns about global warming. And the new study – sponsored by, among other research agencies, a re-insurance giant – is concerned with any statistical or mathematical logic in tornado patterns that might provide a guide to future hazards.

“The science is still open,” says the study’s leader, Michael Tippett, senior prediction research scientist at Columbia University’s International Research Institute for Climate and Society.

“It could be global warming, but our usual tools, the observational record and computer models, are not up to the task of answering this question yet.”

That is because, although warming might favour the conditions for tornado formation, there is no certainty that any tornadoes will form, or cluster in an outbreak.

“When it comes to tornadoes, almost everything terrible that happens happens in outbreaks,” Tippett says. “If outbreaks contain more tornadoes than average, then the likelihood they’ll cause damage somewhere increases.”

But, ominously, while the total number of potentially dangerous tornadoes each year has not increased, the average number of tornadoes spawned in any one outbreak has risen by 50%. The average used to be 10, but now it is 15.

The conclusion is that the increase could be described by a mathematical tool called Taylor’s power law of scaling. And Joel Cohen, co-author of the study and director of the Laboratory of Populations based at both Rockefeller University and Columbia’s Earth Institute, says the number used to describe the rate of growth is “truly exceptional. It means that when it rains, it really, really, really pours.” – Climate News Network

Scientists say the climate behaves too capriciously for them to know for sure whether global warming caused by burning fossil fuels is to blame for a growing tornado threat.

LONDON, 7 March, 2016 – Tornadoes in the US are getting worse, with the numbers in any one outbreak and the hazard of ever more frequent outbreaks both on the increase.

And although climate change driven by global warming from human causes is under suspicion, nobody really knows for sure whether that is driving the pattern of change.

But change is certainly happening. New research published in Nature Communications has examined the pattern of outbreaks and found that the average number of tornadoes in any one outbreak has increased since 1954, and the chance of extreme – and therefore extremely destructive – outbreaks has also increased.

An outbreak is a large-scale weather event that can last for days, span huge regions and spawn multiple tornadoes. Continental America is used to these outbreaks, which is why a band of territory that spans central Texas, Illinois and Indiana, and embraces parts of Oklahoma, Kansas, Nebraska, Colorado and South Dakota, is known as Tornado Alley.

Devastating whirlwinds

The plains flanked by the Rockies and the Appalachian mountain chains are a corridor up which sweeps hot, moist air from the Gulf of Mexico, to meet cold, dry air from the mountains and the north. The encounter sets up the conditions for colossal thunderstorms, accompanied by devastating whirlwinds.

The largest recent outbreak was in 2011. It spawned 363 tornadoes across the US and Canada, claimed more than 350 lives, and did $11 billion worth of damage.

Around 1,000 tornadoes are reported in the US each year, with the top two per cent causing most of the death and devastation.

Winds can reach 300 kilometres an hour in a space a mile wide, destroying anything in the way. They uproot houses, blow cars into the air, turn towns into rubble, strip bark from trees and, in one reported instance, even tear asphalt off a highway.

Research such as this matters because it could help societies prepare better. One consistent prediction within climate research is that, as average global temperatures rise in response to greenhouse gas emissions from fossil fuel combustion, so does the likelihood that meteorological disasters could become more frequent, or more violent, or both.

“It could be global warming, but our usual tools are not up to the task of answering this question yet”

But although that seems to be the case over the last two decades – the UN Office for Disaster Risk Reduction (UNISDR) reported last year that the number of weather-related disasters had almost doubled – it does not mean that warmer years must be more calamitous.

Last year was declared the warmest since records began, and UNISDR reported 32 major droughts that affected more than 50 million people, but only 996 deaths in recorded storms, compared with the annual average of more than 17,000 in the preceding decade.

Caprice plays a powerful role in climate events − and that includes tornadoes, particularly in the US.

There is evidence that the tornado season is commencing ever earlier. Between 2005 and 2014, tornadoes claimed on average 110 lives in the US each year, and caused between $500m and $9.6bn worth of damage.

In 1925, one tornado that raced across Missouri, Illinois and Indiana killed 695 people and injured 2,027. In one 24-hour spell in 1974, a total of 148 tornadoes swept across 12 states from Michigan to Alabama, killing 309 people, injuring 5,300 and doing damage costing $600 million.

Future hazards

So tornadoes were destructive long before any concerns about global warming. And the new study – sponsored by, among other research agencies, a re-insurance giant – is concerned with any statistical or mathematical logic in tornado patterns that might provide a guide to future hazards.

“The science is still open,” says the study’s leader, Michael Tippett, senior prediction research scientist at Columbia University’s International Research Institute for Climate and Society.

“It could be global warming, but our usual tools, the observational record and computer models, are not up to the task of answering this question yet.”

That is because, although warming might favour the conditions for tornado formation, there is no certainty that any tornadoes will form, or cluster in an outbreak.

“When it comes to tornadoes, almost everything terrible that happens happens in outbreaks,” Tippett says. “If outbreaks contain more tornadoes than average, then the likelihood they’ll cause damage somewhere increases.”

But, ominously, while the total number of potentially dangerous tornadoes each year has not increased, the average number of tornadoes spawned in any one outbreak has risen by 50%. The average used to be 10, but now it is 15.

The conclusion is that the increase could be described by a mathematical tool called Taylor’s power law of scaling. And Joel Cohen, co-author of the study and director of the Laboratory of Populations based at both Rockefeller University and Columbia’s Earth Institute, says the number used to describe the rate of growth is “truly exceptional. It means that when it rains, it really, really, really pours.” – Climate News Network

Global warming can have adverse regional impacts

Calmer and cloudier weather across much of the Earth may have unwelcome effects at smaller scales, warming the Arctic and worsening drought risk. 

LONDON, 24 December, 2015  – The weather will be less stormy over the crowded landscapes of the US, Europe and Asia – and perhaps more cloudy in the high latitudes. Neither forecast is necessarily good news.

US climate scientists have found that cloud formation over the Arctic increases the chance of warming, and could accelerate the melting of the ice caps.

And researchers in Germany have looked at the lower summer storm counts and once again linked them with sustained extremes of heat and drought, or prolonged cold spells.

Both studies are based on the planet’s apparent response to global warming, driven by higher concentrations of greenhouse gases in the atmosphere, released by human combustion of coal, oil and natural gas.

And each is a reminder that the climate’s response to a steady rise in global average temperatures – and these are now 1°C above the average for most of human history – is difficult to predict, and sometimes against intuition.

Cloud heating

Christopher Cox of the US National Oceanic and Atmospheric Administration’s earth system laboratory in Boulder, Colorado and colleagues report in Nature Communications that although the Arctic is already one of the fastest-warming regions on Earth, clouds overhead – which normally reflect sunlight and cool the region below them – could turn up the thermostat.

They looked at the patterns of data from weather stations in Alaska, Canada and Greenland and found that clouds appeared to amplify regional warming.

“As the Arctic atmosphere warms and moistens, it becomes a better insulator. While we expected this to reduce the influence from clouds, which provide additional insulation, we found that clouds forming in the Arctic in these conditions appear to further warm the surface, especially in the fall and winter,” Dr Cox said.

And across the Atlantic, Jascha Lehmann and Dim Coumou of the Potsdam Institute for Climate Impact Research write in the journal Scientific Reports that they studied the link between storm tracks and surface weather extremes.

In 2014 the northeastern US experienced a severe and sustained cold spell, while California stayed stricken by drought. There was drought in China’s northern farmland and severe flooding in the UK.

“Our study highlights how sensitive regional weather conditions are to any changes in large-scale atmosphere dynamics”

And they found significant reductions in summer storm activity over as much as 80% of the land area in the mid-latitudes. In winter, the findings were more patchy – but there were pronounced reductions over the eastern US and large parts of Europe and Asia.

The Potsdam scientists have already made a link between storm frequency and extremes, but science works by replication, and confirmatory studies matter. The researchers think the change in pattern could be linked to changes in the jet stream that make some extremes of heat and cold more likely.

“Less of less severe storms in the mid-latitudes, this at first sight seems to be good news – but unfortunately it isn’t,” said Lehmann, a PhD candidate at Potsdam. “These storms have a moderating effect on land temperatures as they bring maritime air from the oceans to the continents, and a lack of them can thus favour extreme temperatures.”

But, as usual, further research is necessary: the scientists think they have established a link. Proving cause and effect is a different matter.

“Our study highlights how sensitive regional weather conditions are to any changes in large-scale atmosphere dynamics,” said Dr Coumou. “This can have serious impacts for people on the ground.” – Climate News Network

Calmer and cloudier weather across much of the Earth may have unwelcome effects at smaller scales, warming the Arctic and worsening drought risk. 

LONDON, 24 December, 2015  – The weather will be less stormy over the crowded landscapes of the US, Europe and Asia – and perhaps more cloudy in the high latitudes. Neither forecast is necessarily good news.

US climate scientists have found that cloud formation over the Arctic increases the chance of warming, and could accelerate the melting of the ice caps.

And researchers in Germany have looked at the lower summer storm counts and once again linked them with sustained extremes of heat and drought, or prolonged cold spells.

Both studies are based on the planet’s apparent response to global warming, driven by higher concentrations of greenhouse gases in the atmosphere, released by human combustion of coal, oil and natural gas.

And each is a reminder that the climate’s response to a steady rise in global average temperatures – and these are now 1°C above the average for most of human history – is difficult to predict, and sometimes against intuition.

Cloud heating

Christopher Cox of the US National Oceanic and Atmospheric Administration’s earth system laboratory in Boulder, Colorado and colleagues report in Nature Communications that although the Arctic is already one of the fastest-warming regions on Earth, clouds overhead – which normally reflect sunlight and cool the region below them – could turn up the thermostat.

They looked at the patterns of data from weather stations in Alaska, Canada and Greenland and found that clouds appeared to amplify regional warming.

“As the Arctic atmosphere warms and moistens, it becomes a better insulator. While we expected this to reduce the influence from clouds, which provide additional insulation, we found that clouds forming in the Arctic in these conditions appear to further warm the surface, especially in the fall and winter,” Dr Cox said.

And across the Atlantic, Jascha Lehmann and Dim Coumou of the Potsdam Institute for Climate Impact Research write in the journal Scientific Reports that they studied the link between storm tracks and surface weather extremes.

In 2014 the northeastern US experienced a severe and sustained cold spell, while California stayed stricken by drought. There was drought in China’s northern farmland and severe flooding in the UK.

“Our study highlights how sensitive regional weather conditions are to any changes in large-scale atmosphere dynamics”

And they found significant reductions in summer storm activity over as much as 80% of the land area in the mid-latitudes. In winter, the findings were more patchy – but there were pronounced reductions over the eastern US and large parts of Europe and Asia.

The Potsdam scientists have already made a link between storm frequency and extremes, but science works by replication, and confirmatory studies matter. The researchers think the change in pattern could be linked to changes in the jet stream that make some extremes of heat and cold more likely.

“Less of less severe storms in the mid-latitudes, this at first sight seems to be good news – but unfortunately it isn’t,” said Lehmann, a PhD candidate at Potsdam. “These storms have a moderating effect on land temperatures as they bring maritime air from the oceans to the continents, and a lack of them can thus favour extreme temperatures.”

But, as usual, further research is necessary: the scientists think they have established a link. Proving cause and effect is a different matter.

“Our study highlights how sensitive regional weather conditions are to any changes in large-scale atmosphere dynamics,” said Dr Coumou. “This can have serious impacts for people on the ground.” – Climate News Network

COP21: Planning and preparation can lessen the heavy human toll of natural disasters linked to climate change, survivors tell UN summit delegates. 

PARIS, 7 December, 2015 – More than half a million people have perished in 15,000 climate-related disasters since 1995, at a cost of $US2.97 trillion, according to new statistics released during the COP21 climate summit.  

This is the second such tally of devastation and death accumulated since COP1, the first meeting two decades ago of world governments to confront the challenge of climate change.

That the latest Global Climate Risk Index, compiled by the organisation Germanwatch, differs from the UN’s own recent estimates over the same two decades is partly because compilers used different approaches and criteria, partly an indicator of the innate difficulties of linking sustained suffering and loss to discrete meteorological events, and partly because Germanwatch does not include all the statistics from slowly-emerging events such as drought.

But both sets of figures confirm that as global temperatures creep ever higher, as a consequence of greater concentrations of greenhouse gases in the atmosphere, in turn because of human activity, extreme events present ever greater hazards in the form of storms, hail, tornadoes, storm surges, floods, landslides, ice storms, wildfires and droughts.

In 2014, the worst three affected countries were Serbia – hit by catastrophic floods that swept through southeast Europe that year – Afghanistan and Bosnia-Herzegovina. The three worst affected countries over the two decades are Honduras, Myanmar and Haiti, with the Philippines in fourth place, just above Nicaragua and Bangladesh.

Lower target

The Philippines, a vast archipelago of 7,000 large and small islands, is in the path of around 20 to 25 typhoons a year that increasingly hit communities that had once considered themselves relatively safe. The 190 nations attending COP21 have committed themselves to containing global warming to an average of 2°C above pre-industrial levels, but the Philippines is one of a large group that would prefer the world to aim for 1.5°C.

Tropical cyclones are linked to sea surface temperatures and could become more intense, more frequent or more extensive as temperatures rise, and tropical countries with vast coastlines are inevitably more likely to be in the path of the coming storms.

But the nations most at hazard have, under a UN umbrella programme, also been trying to anticipate the worst. And COP21 delegates heard that the Philippines government, for the first time, has started to keep tally not just of the statistics of catastrophe, but also of the disasters that did not happen.

Attitudes to hazard have changed. What had once been the country’s national disaster agency co-ordinating council is now a national disaster risk management council.

“We consider ourselves already survivors of climate change, and survivors have stories to tell”

Raymund Liboro, the Philippines assistant secretary for climate change and disaster risk reduction, told the conference: “While we consider ourselves as vulnerable, we do not consider ourselves helpless.”

One case in point was Typhoon Koppu, the thirteenth tropical cyclone to hit the nation in 2015. Winds reached 240 km an hour, prodigious quantities of rain were dumped on the hills, and in one region more than 1,000 millimetres of rain fell in 24 hours. It triggered a huge flow of debris that buried three townships.

Communities saved

In 2012, during a similar storm, more than 1,000 people died. But although Typhoon Koppu in October dislodged 41 million cubic metres of rock, rubble and forest from the mountainsides, it killed nobody. Forewarned, the authorities had evacuated all three communities and saved 7,000 families.

So the climate risk index and other sources of information served not just as a league table of human suffering, but also as an indicator of levels of future risk  and a reminder that meteorological hazard now bears the fingerprint of climate change.

With good information, Mr Liboro said, countries could begin to cope, mitigate, adapt and survive. “Behind those numbers are actual lives,” he said. “We consider ourselves already survivors of climate change, and survivors have stories to tell.” – Climate News Network

Harder rains set to fall as the world warms

Scientists pinpoint when global warming emerged – and predict increasingly greater climate extremes in hot, cold and wet weather trends. LONDON, 26 September, 2015 – In not quite the words of the singer Bob Dylan, a hard rain is going to fall. Australian scientists predict that precipitation extremes with large variability will emerge in the Northern Hemisphere in the coming decades as part of a “wettening trend”. In other words, an even harder rain will fall − and then you’ll really know that the climate has changed. Andrew King, a climate system scientist at the Climate Change Research Centre at the University of New South Wales and at the University of Melbourne, is lead author of a report in the journal Environmental Research Letters. He and colleagues say they have pinpointed the moment when global warming, as a result of human influences, emerged in the historic record in some parts of the world. They can now also predict when it will become even clearer in places so far untouched.

Story of warming

Although climate change can be predicted, it can only be identified after the event. That is because, while climate is the average of all the extremes of weather, the weather can get pretty extreme, even within a stable climate. From the late 1980s onwards, global average temperatures began to tell a consistent story of warming. But if those temperatures are now on the increase because of the continual rise in carbon dioxide concentrations in the atmosphere, as a consequence of the human exploitation of fossil fuels, then there must have been some moment in the past when the signs of change could have been detected, and when a new climate trend developed. Such questions sound academic, but the better humans understand the past, the more likely they are to be prepared for the future.

“It is likely to bring pronounced precipitation events, on top of the already existing trend towards increasingly wet winters”

So Dr King and his colleagues used state-of-the-art computer models to simulate not just climate change, but the way that extreme events have begun to change. “Both hot and cold extremes have already emerged across many areas,” they say. The scientists examined average and extreme temperatures because these would, of course, be most sensitive to global warming − and therefore evidence should show in historic records. “Remarkably, our research shows you could already see clear signs of global warming in the tropics by the 1960s, but in parts of Australia, south-east Asia and Africa it was visible as early as the 1940s,” Dr King says.

Changing pattern

First the scientists saw a rise in average temperatures; then the changing pattern of extremes of climate began to confirm the picture. There are exceptions: the continental US, especially on the East Coast, has yet to show any obvious warming signals, but these could appear in the next decade. And although greater warming means more evaporation and more precipitation, in many places this heavier rainfall is still so far within the range of “normal” extreme weather. “We expect the first heavy precipitation events with a clear global warming signal will appear during winters in Russia, Canada and northern Europe over the next 10 to 30 years,” says Ed Hawkins, a meteorologist at the University of Reading in the UK, and one of the report’s co-authors. “It is likely to bring pronounced precipitation events, on top of the already existing trend towards increasingly wet winters in these regions.” – Climate News Network

Scientists pinpoint when global warming emerged – and predict increasingly greater climate extremes in hot, cold and wet weather trends. LONDON, 26 September, 2015 – In not quite the words of the singer Bob Dylan, a hard rain is going to fall. Australian scientists predict that precipitation extremes with large variability will emerge in the Northern Hemisphere in the coming decades as part of a “wettening trend”. In other words, an even harder rain will fall − and then you’ll really know that the climate has changed. Andrew King, a climate system scientist at the Climate Change Research Centre at the University of New South Wales and at the University of Melbourne, is lead author of a report in the journal Environmental Research Letters. He and colleagues say they have pinpointed the moment when global warming, as a result of human influences, emerged in the historic record in some parts of the world. They can now also predict when it will become even clearer in places so far untouched.

Story of warming

Although climate change can be predicted, it can only be identified after the event. That is because, while climate is the average of all the extremes of weather, the weather can get pretty extreme, even within a stable climate. From the late 1980s onwards, global average temperatures began to tell a consistent story of warming. But if those temperatures are now on the increase because of the continual rise in carbon dioxide concentrations in the atmosphere, as a consequence of the human exploitation of fossil fuels, then there must have been some moment in the past when the signs of change could have been detected, and when a new climate trend developed. Such questions sound academic, but the better humans understand the past, the more likely they are to be prepared for the future.

“It is likely to bring pronounced precipitation events, on top of the already existing trend towards increasingly wet winters”

So Dr King and his colleagues used state-of-the-art computer models to simulate not just climate change, but the way that extreme events have begun to change. “Both hot and cold extremes have already emerged across many areas,” they say. The scientists examined average and extreme temperatures because these would, of course, be most sensitive to global warming − and therefore evidence should show in historic records. “Remarkably, our research shows you could already see clear signs of global warming in the tropics by the 1960s, but in parts of Australia, south-east Asia and Africa it was visible as early as the 1940s,” Dr King says.

Changing pattern

First the scientists saw a rise in average temperatures; then the changing pattern of extremes of climate began to confirm the picture. There are exceptions: the continental US, especially on the East Coast, has yet to show any obvious warming signals, but these could appear in the next decade. And although greater warming means more evaporation and more precipitation, in many places this heavier rainfall is still so far within the range of “normal” extreme weather. “We expect the first heavy precipitation events with a clear global warming signal will appear during winters in Russia, Canada and northern Europe over the next 10 to 30 years,” says Ed Hawkins, a meteorologist at the University of Reading in the UK, and one of the report’s co-authors. “It is likely to bring pronounced precipitation events, on top of the already existing trend towards increasingly wet winters in these regions.” – Climate News Network

Quantum leap taken in measuring greenhouse effect

New technique for analysing satellite data will allow scientists to predict more accurately how much the Earth will warm as a result of carbon dioxide emissions. LONDON, 8 July, 2015 – British scientists have devised a new way to observe the greenhouse world, enabling researchers to measure with exquisite accuracy how atmospheric carbon dioxide builds up, migrates, evolves and absorbs radiation. The technique will allow more accurate predictions about how much the Earth is likely to warm over the next few decades as a result of the inexorable rise in atmospheric CO2 – from car exhausts, power station chimneys and burning forests – that drives global warming and climate change. More than a century has elapsed since the Swedish Nobel laureate Svante Arrhenius first predicted the greenhouse effect, but scientists have until now only been able to establish the way CO2 absorbs light, with accuracies of about 5% at best.

Exploit laws

But Oleg Polyanksy and Jonathan Tennyson, professors in the Department of Physics and Astronomy at University College London, and colleagues report in the journal Physical Review Letters that they can exploit the laws of quantum mechanics to narrow the uncertainty to 0.3%. The consequence is that a range of dedicated satellite missions – among them Japan’s Greenhouse Gas Observing Satellite (GOSAT), the US space agency NASA’s Orbiting Carbon Observatory-2 (OCO-2) and potential European Space Agency missions such as CarbonSat − will not just be able to identify industrial sources of CO2 and map their spread, but watch the gas in action, slowly warming the planet by as much as 5°C by 2100.

“It is necessary to have a very precise answer to the question: how much radiation does one molecule of CO2 absorb?”

“Billions of dollars are currently being spent on satellites that monitor what seems to be the inexorable growth of CO2 in our atmosphere,” Professor Tennyson says. “To interpret their results, however, it is necessary to have a very precise answer to the question: how much radiation does one molecule of CO2 absorb? “Up until now, laboratory measurements have struggled to answer this question accurately enough to allow climate scientists to interpret their results with the detail their observations require.” The orbiting satellite has become the climate scientist’s most prolific data delivery machine. There are satellites measuring the shrinking of the ice caps and the rate at which the ice is melting. Besides an arsenal of weather monitors, satellites are using sophisticated sensors to monitor sea level rise, changes in ocean acidity and soil moisture, agricultural success in India, and even the energy spent in lighting up the world’s cities at night. Warming puzzle All these studies are part of the great global warming puzzle, but for most of the last 50 years, confirmation of what a greenhouse gas does has mainly rested on the match of CO2 levels in the atmosphere and the consequent rise in global average temperatures. The University College team, with colleagues in Russia, the US and Poland, tried another approach. They started with the exact quantum mechanical equations obeyed by a molecule such as CO2 , then harnessed computers and subtle laboratory technologies to measure the different “colours” or wavelengths of light absorbed by molecules. Each wavelength carries a precise energy, and highly-accurate measurements for small laboratory samples should enable researchers to scale up to equivalent accuracies for the entire atmosphere. That means that they will be able to observe the intricacies of global warming − more or less as it happens − from high orbit, and make increasingly accurate predictions about future global warming. – Climate News Network

New technique for analysing satellite data will allow scientists to predict more accurately how much the Earth will warm as a result of carbon dioxide emissions. LONDON, 8 July, 2015 – British scientists have devised a new way to observe the greenhouse world, enabling researchers to measure with exquisite accuracy how atmospheric carbon dioxide builds up, migrates, evolves and absorbs radiation. The technique will allow more accurate predictions about how much the Earth is likely to warm over the next few decades as a result of the inexorable rise in atmospheric CO2 – from car exhausts, power station chimneys and burning forests – that drives global warming and climate change. More than a century has elapsed since the Swedish Nobel laureate Svante Arrhenius first predicted the greenhouse effect, but scientists have until now only been able to establish the way CO2 absorbs light, with accuracies of about 5% at best.

Exploit laws

But Oleg Polyanksy and Jonathan Tennyson, professors in the Department of Physics and Astronomy at University College London, and colleagues report in the journal Physical Review Letters that they can exploit the laws of quantum mechanics to narrow the uncertainty to 0.3%. The consequence is that a range of dedicated satellite missions – among them Japan’s Greenhouse Gas Observing Satellite (GOSAT), the US space agency NASA’s Orbiting Carbon Observatory-2 (OCO-2) and potential European Space Agency missions such as CarbonSat − will not just be able to identify industrial sources of CO2 and map their spread, but watch the gas in action, slowly warming the planet by as much as 5°C by 2100.

“It is necessary to have a very precise answer to the question: how much radiation does one molecule of CO2 absorb?”

“Billions of dollars are currently being spent on satellites that monitor what seems to be the inexorable growth of CO2 in our atmosphere,” Professor Tennyson says. “To interpret their results, however, it is necessary to have a very precise answer to the question: how much radiation does one molecule of CO2 absorb? “Up until now, laboratory measurements have struggled to answer this question accurately enough to allow climate scientists to interpret their results with the detail their observations require.” The orbiting satellite has become the climate scientist’s most prolific data delivery machine. There are satellites measuring the shrinking of the ice caps and the rate at which the ice is melting. Besides an arsenal of weather monitors, satellites are using sophisticated sensors to monitor sea level rise, changes in ocean acidity and soil moisture, agricultural success in India, and even the energy spent in lighting up the world’s cities at night. Warming puzzle All these studies are part of the great global warming puzzle, but for most of the last 50 years, confirmation of what a greenhouse gas does has mainly rested on the match of CO2 levels in the atmosphere and the consequent rise in global average temperatures. The University College team, with colleagues in Russia, the US and Poland, tried another approach. They started with the exact quantum mechanical equations obeyed by a molecule such as CO2 , then harnessed computers and subtle laboratory technologies to measure the different “colours” or wavelengths of light absorbed by molecules. Each wavelength carries a precise energy, and highly-accurate measurements for small laboratory samples should enable researchers to scale up to equivalent accuracies for the entire atmosphere. That means that they will be able to observe the intricacies of global warming − more or less as it happens − from high orbit, and make increasingly accurate predictions about future global warming. – Climate News Network

England set for big increase in record warm years

Research using records dating back to 1659 indicates at least a 13-fold rise in the likelihood of human-influenced climate change pushing up temperatures in central England. LONDON, 1 May, 2015 − If you live in England, prepare for a future where distinctly warmer years are the new normal. An international team of researchers says the likelihood of record-breaking warm years is going to increase substantially because of human influence on the climate. Their study shows that the chance of England experiencing a record-breaking warm year, on a par with 2014, is at least 13 times higher. And there are signs that it could be even higher. The study, published in Environmental Research Letters, is based on climate model simulations and detailed analyses of the Central England Temperature (CET) record − the world’s longest instrumental temperature record, dating back to 1659. The results show that human activities have a large influence on extreme warm years in England − which is remarkable, the researchers say, because England is such a small region of the world.

Monthly recordings

The CET does not cover the whole of England, let alone Scotland or Wales or the rest of the British Isles. It has monthly recordings of average temperatures dating back to 1659, and recordings of average daily temperatures back to 1772. It is designed to represent the climate of the English Midlands, a roughly triangular area bounded by Lancashire in the north, Bristol in the south-west and London in the south-east. The researchers say the CET has undergone thorough and extensive quality control, which makes it an ideal resource for studying long-term temperature trends across the region. The lead author of the study is Dr Andrew King, a researcher at the ARC Centre of Excellence for Climate System Science at the University of Melbourne, Australia.

“It is remarkable that we get such a clear anthropogenic influence on temperatures in a relatively small area across central England”

He says: “When you look at average annual temperatures over larger regions of the world, such as the whole of Europe, there is a lower variability in temperatures from year to year, compared with smaller areas. “As a result of this low variability, it is easier to spot anomalies. This is why larger regions tend to produce stronger attribution statements, so it is remarkable that we get such a clear anthropogenic influence on temperatures in a relatively small area across central England.” The researchers calculated the probability of warm years caused by human influences by first using climate model simulations to calculate the likelihood of very warm years when there are only natural influences on the climate, and then when there are both natural and human influences.

Warmest years

The researchers then studied the CET and picked out the warmest years from the record since 1900. These were plotted onto a graph, which they used to calculate the likelihood of warm years happening now, and a century ago. The model-based method suggested (with 90% confidence) at least a 13-fold increase caused by human influences on the climate, while the observation-based approach suggested at least a 22-fold increase in the probability of very warm years in today’s climate compared with a century ago (again with 90% confidence). “Both of our approaches showed that there is a significant and substantial increase in the likelihood of very warm years occurring in central England,” Dr King says. According to the CET, 2014 was the warmest year on record in central England. During the last 60 years, rapid warming has been recorded in the CET in line with the human influence on the climate, with the highest average annual temperature of 10.93°C recorded in 2014. Dr King says he would expect that other areas near the UK would produce similar results. “We performed a similar attribution study for Europe as a whole and found a 35-fold increase in the likelihood of extremely warm years using model simulations.” − Climate News Network

Research using records dating back to 1659 indicates at least a 13-fold rise in the likelihood of human-influenced climate change pushing up temperatures in central England. LONDON, 1 May, 2015 − If you live in England, prepare for a future where distinctly warmer years are the new normal. An international team of researchers says the likelihood of record-breaking warm years is going to increase substantially because of human influence on the climate. Their study shows that the chance of England experiencing a record-breaking warm year, on a par with 2014, is at least 13 times higher. And there are signs that it could be even higher. The study, published in Environmental Research Letters, is based on climate model simulations and detailed analyses of the Central England Temperature (CET) record − the world’s longest instrumental temperature record, dating back to 1659. The results show that human activities have a large influence on extreme warm years in England − which is remarkable, the researchers say, because England is such a small region of the world.

Monthly recordings

The CET does not cover the whole of England, let alone Scotland or Wales or the rest of the British Isles. It has monthly recordings of average temperatures dating back to 1659, and recordings of average daily temperatures back to 1772. It is designed to represent the climate of the English Midlands, a roughly triangular area bounded by Lancashire in the north, Bristol in the south-west and London in the south-east. The researchers say the CET has undergone thorough and extensive quality control, which makes it an ideal resource for studying long-term temperature trends across the region. The lead author of the study is Dr Andrew King, a researcher at the ARC Centre of Excellence for Climate System Science at the University of Melbourne, Australia.

“It is remarkable that we get such a clear anthropogenic influence on temperatures in a relatively small area across central England”

He says: “When you look at average annual temperatures over larger regions of the world, such as the whole of Europe, there is a lower variability in temperatures from year to year, compared with smaller areas. “As a result of this low variability, it is easier to spot anomalies. This is why larger regions tend to produce stronger attribution statements, so it is remarkable that we get such a clear anthropogenic influence on temperatures in a relatively small area across central England.” The researchers calculated the probability of warm years caused by human influences by first using climate model simulations to calculate the likelihood of very warm years when there are only natural influences on the climate, and then when there are both natural and human influences.

Warmest years

The researchers then studied the CET and picked out the warmest years from the record since 1900. These were plotted onto a graph, which they used to calculate the likelihood of warm years happening now, and a century ago. The model-based method suggested (with 90% confidence) at least a 13-fold increase caused by human influences on the climate, while the observation-based approach suggested at least a 22-fold increase in the probability of very warm years in today’s climate compared with a century ago (again with 90% confidence). “Both of our approaches showed that there is a significant and substantial increase in the likelihood of very warm years occurring in central England,” Dr King says. According to the CET, 2014 was the warmest year on record in central England. During the last 60 years, rapid warming has been recorded in the CET in line with the human influence on the climate, with the highest average annual temperature of 10.93°C recorded in 2014. Dr King says he would expect that other areas near the UK would produce similar results. “We performed a similar attribution study for Europe as a whole and found a 35-fold increase in the likelihood of extremely warm years using model simulations.” − Climate News Network

World needs early warning of climate-linked disasters

A leading French government minister says the number of natural disasters connected to climate change has doubled in two decades, and is urging a global early warning system. LONDON, 15 March, 2015 − A senior French political leader, foreign minister Laurent Fabius, has told an international conference on how to reduce the risk from natural disasters that 70% of them are now linked to climate change, twice as many as twenty years ago. Mr. Fabius is the incoming president of this year’s round of negotiations by member states of the UN climate change convention, to take place in Paris in December. He said disaster risk reduction and the struggle against climate change went hand in hand: “It is necessary to tackle these problems together and not separately.” He was speaking against the background of two events which occurred thousands of miles apart on 14 March, linked by nothing except tragic coincidence. In the Japanese city of Sendai the third UN world conference on disaster risk reduction began a five-day meeting. In the South Pacific Cyclone Pam brought death and devastation to the 83-island nation of Vanuatu on a scale seldom recorded in the region. Vivien Maidaborn, executive director of Unicef New Zealand, said the disaster could prove one of the worst in Pacific history. “The sheer force of the storm, combined with communities just not set up to withstand it, could have devastating results for thousands across the region,” she said.

Hope shattered

A Unicef worker in Vanuatu described the cyclone as “15 to 30 minutes of absolute terror” for “everybody in this country” as it passed over. The president of Vanuatu, Baldwin Lonsdale, told the UN meeting: “I am speaking with you today with a heart that is so heavy… All I can say is that our hope for prospering into the future has been shattered.” The UN Secretary-General, Ban Ki-moon, opened the Sendai meeting, attended by 4,000 people from 186 countries, with a reminder that annual economic losses from natural disasters are now estimated to exceed US$ 300 billion annually. He said: “We can watch that number grow as more people suffer. Or we can dramatically lower that figure and invest the savings in development. Six billion dollars allocated each year can result in savings of up to US$360 billion by 2030.” A report released at the meeting, United for Disaster Resilience, prepared by insurance companies working with the UN Environment Programme’s Finance Initiative, said: “In the past decade, average economic losses from disasters were about US$190 billion per year, while average insured losses were about US$60 billion per year. This century, more than one million people have already lost their lives to disasters.”

Alert system

The UN Office for Disaster Risk Reduction, UNISDR, says global climate-related disasters between 1980 and 2011 included:

  • 3,455 floods
  • 2,689 storms
  • 470 droughts
  • 395 episodes of extreme temperature.

Mr Fabius said the creation of a worldwide early warning system for climate disasters could provide the most vulnerable countries, including small island developing states, with access to real-time weather and climate updates, information and communications technology, and with support for an SMS-based alert system. UNISDR’s PreventionWeb already links those working to protect communities against disaster risk. Since the last such disaster risk conference in 2005, the UN says, at least 700,000 people have died, 1.7 billion more have been affected, and economic losses from major reported disasters total US$1.4 trillion. The conference is working to prepare a new plan for reducing the risks of disasters. Margareta Wahlström, head of UNISDR, said: “After three years of consultation on a post-2015 framework which updates the current Hyogo Framework for Action, there is general agreement that we must move from managing disasters to managing disaster risk.” She said the framework would help to reduce existing levels of risk and avoid the creation of new ones. − Climate News Network

A leading French government minister says the number of natural disasters connected to climate change has doubled in two decades, and is urging a global early warning system. LONDON, 15 March, 2015 − A senior French political leader, foreign minister Laurent Fabius, has told an international conference on how to reduce the risk from natural disasters that 70% of them are now linked to climate change, twice as many as twenty years ago. Mr. Fabius is the incoming president of this year’s round of negotiations by member states of the UN climate change convention, to take place in Paris in December. He said disaster risk reduction and the struggle against climate change went hand in hand: “It is necessary to tackle these problems together and not separately.” He was speaking against the background of two events which occurred thousands of miles apart on 14 March, linked by nothing except tragic coincidence. In the Japanese city of Sendai the third UN world conference on disaster risk reduction began a five-day meeting. In the South Pacific Cyclone Pam brought death and devastation to the 83-island nation of Vanuatu on a scale seldom recorded in the region. Vivien Maidaborn, executive director of Unicef New Zealand, said the disaster could prove one of the worst in Pacific history. “The sheer force of the storm, combined with communities just not set up to withstand it, could have devastating results for thousands across the region,” she said.

Hope shattered

A Unicef worker in Vanuatu described the cyclone as “15 to 30 minutes of absolute terror” for “everybody in this country” as it passed over. The president of Vanuatu, Baldwin Lonsdale, told the UN meeting: “I am speaking with you today with a heart that is so heavy… All I can say is that our hope for prospering into the future has been shattered.” The UN Secretary-General, Ban Ki-moon, opened the Sendai meeting, attended by 4,000 people from 186 countries, with a reminder that annual economic losses from natural disasters are now estimated to exceed US$ 300 billion annually. He said: “We can watch that number grow as more people suffer. Or we can dramatically lower that figure and invest the savings in development. Six billion dollars allocated each year can result in savings of up to US$360 billion by 2030.” A report released at the meeting, United for Disaster Resilience, prepared by insurance companies working with the UN Environment Programme’s Finance Initiative, said: “In the past decade, average economic losses from disasters were about US$190 billion per year, while average insured losses were about US$60 billion per year. This century, more than one million people have already lost their lives to disasters.”

Alert system

The UN Office for Disaster Risk Reduction, UNISDR, says global climate-related disasters between 1980 and 2011 included:

  • 3,455 floods
  • 2,689 storms
  • 470 droughts
  • 395 episodes of extreme temperature.

Mr Fabius said the creation of a worldwide early warning system for climate disasters could provide the most vulnerable countries, including small island developing states, with access to real-time weather and climate updates, information and communications technology, and with support for an SMS-based alert system. UNISDR’s PreventionWeb already links those working to protect communities against disaster risk. Since the last such disaster risk conference in 2005, the UN says, at least 700,000 people have died, 1.7 billion more have been affected, and economic losses from major reported disasters total US$1.4 trillion. The conference is working to prepare a new plan for reducing the risks of disasters. Margareta Wahlström, head of UNISDR, said: “After three years of consultation on a post-2015 framework which updates the current Hyogo Framework for Action, there is general agreement that we must move from managing disasters to managing disaster risk.” She said the framework would help to reduce existing levels of risk and avoid the creation of new ones. − Climate News Network