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Climate changes patterns are changing rapidly.
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Am I imagining it, or is the debate on climate change about to radically change?
Until now, the Intergovernmental Panel on Climate Change (IPCC) and other scientists who in overwhelming numbers warn that our climate is changing have always thrown in a kicker. They did not know, they said, whether or how those long-term changes affected current droughts, floods, winter storms, and other extreme weather events.
This was not just a quibble or failure to communicate effectively. The scientists had a point, just as tobacco lobbyists did when they argued that doctors could not prove that cigarettes caused any individual incidence of lung cancer. These caveats could have ended the debate, but human society has more than one way to make sense of the world in which we live.
With cigarettes, hard-hitting attorneys went to civil court to prove by a preponderance of evidence, much of it from tobacco industry files, that smoking directly caused disease and death, setting the purveyors of poison back on their heels with multi-million dollar awards to those who sued them.
With climate, who do you sue? Lacking a suitable courthouse, many environmental activists have made do politically and rhetorically with Professor George Lakoff's definition of "systemic causation." Even more dramatically, last year's Hurricane Sandy and this year's flooding and freezing have convinced much of the general public -- including my wife Anna -- that climate change has to be at fault. "Wild weather puts climate change back in the political debate," Australia's Sydney Morning Herald headlined a story last week. "Bitter cold in the United States might appear to contradict the notion of global warming, but with Britain's wettest winter and another hot summer in Australia, extreme weather events have pushed climate change back on the political agenda."
Those of us who prefer hard science have even more to celebrate. Last week, in an open letter to the Times of London, Britain's top weather scientists at the Met Office publicly blamed climate change for increasing the risk of flooding, which much of the country is now suffering.
"We have looked at the potential influence of climate change and all the evidence from observations, theory and models which show that a warming world leads to more intense daily and hourly rainfall," said the weather people, headed by Dame Julia Slingo. "When we add rising sea levels, then the risk to our communities from serious flooding and coastal inundation are increasing with climate change."
Dame Julia and her Met Office are holding back from saying that the storms themselves are "definitively linked to climate change," while climate change deniers cite scripture and verse from the IPCC and other climate scientists to argue that long-term climate could tell us nothing about short-term weather. In their rush to quote the devil, the deniers demonstrate just how game-changing the Met Office findings will become.
At its simplest, the Met Office argument cannot be logically denied, though logic has never stopped the deniers. "It is clear that global warming has led to an increase in moisture in the atmosphere, which means that when conditions are favorable to the formation of storms there is a greater risk of intense rainfall," explained one of Dame Julia's colleagues. "This is where climate change has a role to play in this year's flooding."
In other words, Met Office scientists cannot yet say whether global warming did or did not cause a particular rain storm in a particular place. But the warming -- or climate change -- did cause increased atmospheric moisture, which increases the risk that the rainfall will be more intense.
This is just the beginning. Met Office scientists are doing further research on whether "we are seeing more extremes, more often," and Dame Julia appears to be preparing public opinion for that conclusion. Both Prime Minister David Cameron and Labour leader Ed Miliband are doing the same.
Even more than the open letter, the official report behind it promises the likelihood of game-changing scientific breakthroughs on...
- the unusual, though not necessarily unprecedented winter storms and flooding in the UK
- the major perturbations to the Pacific and North Atlantic jets streams, driven in part by persistent rainfall over Indonesia and the tropical West Pacific
- the impact of a very intense polar vortex and exceptional stratospheric wind patterns on the North Atlantic jet stream
On all these, the Met Office scientists and their collaborators are probing "whether climate change contributed to the severity of the weather and its impacts." The ability to do all this has taken years to develop and has built on the work of, among others, Thomas Peterson, Principal Scientist at the National Climatic Data Center of the U.S. National Oceanic and Atmospheric Administration.
For the Met Office, the first step is to detect any change in the frequency of storminess or rainfall events that is more than just natural variability, which is particularly challenging in the UK, with its notoriously volatile weather from place to place and time to time. For all the difficulties, the evidence so far suggests an increase in both frequency and intensity.
Once the scientists have detected changes in weather, the bigger challenge is to see if they can attribute any part of them to man-made increases in greenhouse gases. This requires sophisticated computerized models on which the scientists can simulate what the climate would be with and without those man-made increases. These models have become available only in recent years and will be continuously perfected, which is why the Met Office and its collaborators will now be able to answer questions that their science could not previously even ask.
This could be the scientific breakthrough that environmental activists have needed. The political question is whether we can use it effectively to convince dithering government officials to turn away from the increasing production of greenhouse gases.
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