A new report from the IPCC implies that “climate exceptionalism”, the notion that global warming is a problem like no other, is coming to an end.
In science, more information is supposed to lead to better conclusions and greater consensus. The Intergovernmental Panel on Climate Change (IPCC), which published its latest report on March 31st, certainly has more information. The new study synthesises 73,000 published works (a quarter of them in Chinese). This represents a 100-fold increase in about 30 years. But consensus remains elusive. Richard Tol of Sussex University, in Britain, disparagingly appraised the report’s conclusions as “the four horsemen of the apocalypse”. The final version appears to have been fought over paragraph and comma between those (such as Dr Tol) who want to describe dispassionately what they think is happening and those who want to scare the world into taking action.
Every six or so years, the IPCC produces a three-part encyclopedia of the climate. This report is the second tranche of its latest effort. The first, on the science of climate change, came out last September. It argued that the process is accelerating even though the world’s surface temperatures are currently flatlining (a phenomenon most climate scientists regard as merely a pause in an upward trend). This, second, volume asks how the climate is affecting ecosystems, the economy and people’s livelihoods.
Profoundly, is the headline answer. It argues that climate change is having an impact on every ecosystem from the equator to the poles. It suggests that although there are some benefits to a warmer climate, most effects are negative and will get worse. It talks of “extreme weather events leading to breakdown of…critical services such as electricity, water supply and health and emergency services” and it sounds the alarm about “the breakdown of food systems, linked to warming”.
Behind such scares, though, lies a subtler story, in which the effects of global warming vary a lot, climate change is just one risk among many, and the damage it causes—and the possibility of reducing that damage—depend as much on other factors, such as health systems and rural development, as they do on global warming itself. […]
Until now, many [scientists and policymakers] have thought of the climate as a problem like no other: its severity determined by meteorological factors, such as the interaction between clouds, winds and oceans; not much influenced by “lesser” problems, like rural development; and best dealt with by trying to stop it (by reducing greenhouse-gas emissions). The new report breaks with this approach. It sees the climate as one problem among many, the severity of which is often determined by its interaction with those other problems. And the right policies frequently try to lessen the burden—to adapt to change, rather than attempting to stop it. In that respect, then, this report marks the end of climate exceptionalism and the beginning of realism.