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By Megan Darby
The scientists took measurements from icebreaker ship Oden. (Pic: Stockholm University/Stella Papadopoulou)
When researchers from Stockholm University found plumes of methane rising from the seabed, the chief scientist’s response was mild.
“This was somewhat of a surprise,” Örjan Gustafsson wrote in his blog .
When glaciologist and blogger Jason Box saw their findings, he put it rather more strongly: “That’s damn scary.”
The subject of Box’s concern was methane released from the ocean. Methane is a potent greenhouse gas, with around 20 times the warming effect of carbon dioxide.
What is more, the scientists suspect climate change could make such methane releases more likely, in a feedback loop.
Box, who has been studying the Greenland ice sheet’s sensitivity to weather and climate for 20 years, was already losing sleep about occasional spikes in methane levels in the area. He called these outlying results “dragon’s breath”.
While there was growing evidence of high methane levels over the Arctic Ocean, this Swedish study was the first to record methane bubbles rising to the surface.
Gustafsson and his team were exploring the Laptev Sea, on the edge of the Arctic.
From icebreaker ship Oden, they used sonar and chemical analysis to measure methane in the water.
They found plumes of the gas rising from depths of between 150m and 500m. Levels of dissolved methane in the water were between 10 and 50 times background levels.
Gustafsson said the gas may be released from methane hydrates collapsing on the sea bed.
“While there has been much speculation about the vulnerability of regular marine hydrates along the continental slopes of the Arctic rim, very few actual observations of methane releases due to collapsing marine hydrates on the Arctic slope have been made,” he blogged.
A “tongue” of warmer water from the Atlantic could be behind the breakdown of methane hydrates. There is some evidence that part of the ocean is getting warmer.
Box said the findings showed the importance of reducing man-made carbon emissions.
“Fossil fuel burning is the trigger mechanism poking the climate dragon,” he wrote. “The cautionary principle makes clear we have to keep this dragon in the ground.”
Rise in blocking-patterns – hot or wet weather remaining stuck over regions for weeks – causing frequent heatwaves or floods.
By Damian Carrington.
A man hangs on to a trash can as rain water gushes towards Albuquerque in New Mexico, US. Heavy rains caused flash flooding and road closures in the city earlier this month. Photograph: Roberto E. Rosales/AP
The work shows so-called “blocking patterns”, where hot or wet weather remains stuck over a region for weeks causing heatwaves or floods, have more than doubled in summers over the last decade. The new study may also demonstrate a link between the UK’s recent flood-drenched winter and climate change.
Climate scientists in Germany noticed that since 2000 there have been an “exceptional number of summer weather extremes, some causing massive damage to society”. So they examined the huge meanders in the high-level jet stream winds that dominate the weather at mid-latitudes, by analysing 35 years of wind data amassed from satellites, ships, weather stations and meteorological balloons. They found that blocking patterns, which occur when these meanders slow down, have happened far more frequently.
“Since 2000, we have seen a cluster of these events. When these high-altitude waves become quasi-stationary, then we see more extreme weather at the surface,” said Dr Dim Coumou, at the Potsdam Institute for Climate Impact Research. “It is especially noticeable for heat extremes.” The intense heatwaves in Russia in 2010, which saw 50,000 people die and the wheat harvest hit hard, and in western Europe in 2003, which saw 30,000 deaths, were both the result of blocking patterns. The Intergovernmental Panel on Climate Change concluded in 2011 that extreme weather would become more common as global warming heats the planet, causing both heatwaves and increasingly severe rain storms.
In 2010, heatwaves caused hundreds of wildfires across Russia. Above, a man tries to stop a fire near Dolginino village. Photograph: Artyom Korotayev/AFP/Getty Images.
The rise in blocking patterns correlates closely with the extra heating being delivered to the Arctic by climate change, according to the research which is published in the journal Proceedings of the National Academies of Science (PNAS). Coumou and his colleagues argue there are good physical reasons to think there is a causal link, because the jet streams are driven by the difference in temperature between the poles and the equator. As the Arctic is warming more quickly than lower latitudes, that temperature difference is declining, providing less energy for the jet stream and its meanders, which are called Rossby waves.
Prof Ted Shepherd, a climate scientist at the University of Reading, UK, but not involved in the work, said the link between blocking patterns and extreme weather was very well established. He added that the increasing frequency shown in the new work indicated climate change could bring rapid and dramatic changes to weather, on top of a gradual heating of the planet. “Circulation changes can have much more non-linear effects. They may do nothing for a while, then there might be some kind of regime change.”
Shepherd said linking the rise in blocking events to Arctic warming remained “a bit speculative” at this stage, in particular because the difference between temperatures at the poles and equator is most pronounced in winter, not summer. But he noted that the succession of storms that caused England’s wettest winter in 250 years was a “very good example” of blocking patterns causing extreme weather during the coldest season. “The jet stream was stuck in one position for a long period, so a whole series of storms passed over England,” he said.
Flooding in Northmoor Green (Moorland) in Somerset, UK, in February this year. Photograph: David Levene for The Guardian.
Coumou acknowledges his study shows a correlation – not causation – between more frequent summer blocking patterns and Arctic warming. “To show causality, computer modelling studies are needed, but it is questionable how well current climate models can capture these effects,” he said.
Prof Tim Palmer, at the University of Oxford, wrote in a PNAS article in 2013 that understanding changes to blocking patterns may well be the key to understanding changes in extreme weather, and therefore to understanding the worst impacts of climate change on society. But he said climate models might have to run down to scales of 1km to do so. “Currently, national climate institutes do not have the high-performance computing capability to simulate climate with 20km resolution, let alone 1km,” he wrote. “I look forward to the day when governments make the same investment in climate prediction as they have made in finding the Higgs boson.”
Firefighters cross a flooded intersection on Route 110 in Farmingdale, N.Y., on New York’s Long Island, Wednesday, Aug. 13, 2014. Stranded Long Island drivers have been rescued after a storm slammed Islip, N.Y., with over 13 inches of rain — an entire summer’s worth. (AP Photo/Frank Eltman)
DEER PARK, N.Y. (AP) — A storm has slammed a suburban New York area with over 13 inches of rain — an entire summer’s worth — and trapped drivers on flooded roads around Long Island.
The staggering total was recorded Wednesday at an airport in the hamlet of Ronkonkoma (rahn-KAHN’-kuh-muh) in the town of Islip (EYE’-slip). Joe Pollina of the National Weather Service says the area’s normal total for June, July and August is 11.75 inches.
The Southern State Parkway was closed around Baldwin and about 20 miles east in Deer Park, where cars were stuck in a couple of feet of water.
WPIX says fire crews in boats rescued drivers in Nesconset (nehs-KAHN’-seht).
Central and eastern Long Island roads that were still open had bumper-to-bumper traffic Wednesday.
The rain started around 6 p.m. Tuesday. It tapered off Wednesday morning.
Vehicles are submerged on a flooded section of the Northern State Parkway, near Route 107, in Jericho, N.Y., on New York’s Long Island, Wednesday Aug. 13, 2014. Stranded Long Island drivers have been rescued after a storm slammed Islip, N.Y., with over 12 inches of rain — an entire summer’s worth. (AP Photo/Newsday, Howard Schnapp) NYC LOCALS OUT
Human-caused global warming is causing the upper troposphere to become wetter.
by Water vapor emanating from steaming cooling towers of a Slovakian nuclear power plant. Photograph: Joe Klamar/AFP/Getty Images
We have long suspected that greenhouse gases which cause the Earth to warm would lead to a wetter atmosphere. The latest research published by Eul-Seok Chung, Brian Soden, and colleagues provides new insight into what was thought to be an old problem. In doing so, they experimentally verified what climate models have been predicting. The models got it right… again.
To be clear, this paper does not prove that water vapor is a greenhouse gas. We have known that for years. Nevertheless, the paper make a very nice contribution. The authors show that the long-term increase in water vapor in the upper troposphere cannot have resulted from natural causes – it is clearly human caused. This conclusion is stated in the abstract,
Our analysis demonstrates that the upper-tropospheric moistening observed over the period 1979–2005 cannot be explained by natural causes and results principally from an anthropogenic warming of the climate. By attributing the observed increase directly to human activities, this study verifies the presence of the largest known feedback mechanism for amplifying anthropogenic climate change.
As stated earlier, climate models have predicted this moistening – before observations were available. In fact, the models predicted that the upper troposphere would moisten more than the lower atmospheric layers. As the authors state,
Given the importance of upper-tropospheric water vapor, a direct verification of its feedback is critical to establishing the credibility of model projections of anthropogenic climate change.
To complete the experiments, the authors used satellite measurements of radiant heat. The emissions have changed but it wasn’t clear why they have changed. Changes could be caused by increases in temperature or from increased water vapor. To separate the potential effects, the authors compared the first set of experiments with others made at a different wavelength. That comparison provided a direct measure of the separate effect of moistening.
Next, the authors used the world’s best climate models to test whether the observed trends could be caused by natural changes in the Earth’s climate or whether they require a human influence. Sure enough, only the calculations that included human-emitted greenhouse gases matched the observations. The authors conclude that,
Concerning the satellite-derived moistening trend in recent decades, the relations of trend and associated range among three experiments lead to the conclusion that an increase in anthropogenic greenhouse gases is the main cause of increased moistening in the upper troposphere.
The authors then went further by showing that their computed results encompass third-party measurements only when the impacts of human-emitted greenhouse gases are included.
I chuckled when I asked Dr. Andrew Dessler about this study, and he told me,
Because of water vapor’s importance as a greenhouse gas, the water vapor feedback occupies a central role in the climate system. Over the years, our understanding of this process has increased steadily, and this paper is a very useful contribution. It nicely demonstrates that the observations of upper tropospheric moistening are unlikely to have arisen without the increase in carbon dioxide from human activities. At this point, I think it would be fair to say, “stick a fork in it, the water vapor feedback’s done.”
So once again, observations have confirmed the models and the scientists can check another item off their “to do” box.
Power plants and electricity distribution networks are particularly vulnerable to droughts and floods. Photograph: Stephen Hird/Reuters
Rising sea levels, extremes of weather and an increase in the frequency of droughts and floods will all play havoc with the world’s energy systems as climate change takes hold, a new report has found.
Energy companies are more often cited as part of the problem of climate change, generating the lion’s share of the world’s greenhouse gas emissions, amounting to around 40% of the total. But they will also suffer as global warming picks up pace, as generators – from nuclear reactors to coal-fired power plants – feel the brunt of the weather changes.
Many large plants are particularly at risk from droughts, because they need water to cool their facilities, and floods, because they lack protection from sudden storms. Electricity distribution networks are also likely to be affected.
The vulnerability of energy systems to natural shocks was shown starkly when the Fukushima nuclear plant in Japan had to be closed down following the 2011 tsunami, which prompted governments around the world to review their nuclear policies.
The World Energy Council (WEC), which compiled the study along with Cambridge University and the European Climate Foundation, urged generators to examine their vulnerability to climate change, saying that with suitable adaptations – such as protecting power plants from water shortages and building resilience into power networks – the worst of the problems could be avoided. (more…)