Next Climate Panel Report on Global Warming Impacts
Scientists and diplomats are meeting in Yokohama, Japan, this week to hash out any final tweaks to the summary of the forthcoming Intergovernmental Panel on Climate Change report on current and anticipated impacts of human-driven global warming on people and ecosystems. The final summary will be released on March 31. It’s worth waiting until then, given the tendency for advance leaks to be selectively torqued toward “it’s worse than we thought” or “no worries” themes. But there are interesting hints emerging amid the noise. Der Spiegel has picked up on language that implies the climate panel is retreating from some 2007 statements on risks of widespread species extinctions (use Google Translate to get the idea). Matt McGrath of the BBC has found a mix of critics and supporters from within the ranks of authors. He reports thatRichard Tol, a University of Sussex economist focused on climate impacts, has asked that his name be pulled from the summary because of a tilt toward scientifically unsupported conclusions. (Here’s some of Tol’s recent peer-reviewed research.)
Fred Pearce, writing in Yale Environment 360, provides what I sense is the closest thing to a reality-based view of what’s coming. Here are a couple of excerpts, but I encourage you to click the link and read the piece in full:
The opener:
Batten down the hatches; fill the grain stores; raise the flood defenses. We cannot know exactly what is coming, but it will probably be nasty, the latest report from the UN’s Intergovernmental Panel on Climate Change (IPCC) will warn next week. Global warming will cause wars, displace millions of people, and do trillion-dollar damage to the global economy.
But careful readers will note a new tone to its discussion of these issues that is markedly different from past efforts. It is more humble about what scientists can predict in advance, and far more interested in how societies can make themselves resilient. It also places climate risks much more firmly than before among a host of other problems faced by society, especially by the poor. That tone will annoy some for taking the edge off past warnings, but gratify others for providing a healthy dose of realism….
He describes heightened uncertainty in models:
For parts of the world, model forecasts of regional climate change are diverging rather than converging. The more we know, it seems, the less we know for sure.
Caution is the watchword. Take the treatment of Africa. Last time, the chapter on that continent began with a declaration that up to a quarter of a billion Africans “are projected to be exposed to increased water stress due The draft report lays out eight ‘key risks,’ including sea level rise and storm surges that could affect hundreds of millions. to climate change.” This time, the leaked draft states simply that while “a reduction in precipitation is likely over North Africa … projected rainfall change over sub-Saharan Africa is uncertain.”
The same goes for Asia:
Asia has fallen into a similar forecasting limbo. Last time, the IPCC warned that there would be less water in most Asian river basins and up to a billion people could experience “increased water stress” as early as the 2020s. This time, “there is low confidence in future precipitation projections at a subregional level and thus in future freshwater availability in most parts of Asia.” Last time the IPCC predicted “an increase of 10 to 20% in tropical cyclone intensities” in Asia. This time it reports “low confidence in region-specific projections of [cyclone] frequency and intensity.”
But there are areas of high certainty, as well:
The leaked draft suggests growing agreement among climate modelers that Scandinavia and much of Canada will see more precipitation and that the southwestern U.S., southern Australia, the Middle East, southern Europe, and North Africa can expect more droughts and emptier rivers.
Southern Europe looks set to fry, with crops shriveling in the fields, reservoirs emptying, deserts spreading, tourists staying away, and demand for air conditioning going through the roof. Even its vineyards will suffer, though a reference in a March 2013 draft to Venice being “lost forever” beneath the waves has since been removed.
Over all, Pearce notes the report’s strong focus on strategies that can limit harms even with the persistent uncertainty in important regions and sectors. In other words, uncertainty bounded by science is a form of knowledge that can help shape smart policies — not an excuse for stasis.
His piece also reflects another important aspect of the report — its effort to place greenhouse-driven global warming among a host of factors shaping risks to humans and their planet:
The 2007 report was almost all about the impacts of climate change. Most of this report, and in particular most of the summary for policymakers, is about resilience and adaptation to inevitable climate change.
Central to that new take is setting climate change in a context of other risks, uncertainties and mega-trends such as poverty and social inequality, urbanization, and the globalization of food systems. What some call “climate exceptionalism” — the idea that climate change is something of an entirely different order to other threats faced by the world — has been rooted out. Here climate change is painted as pervasive, since nobody can avoid it wholly, but as usually only one among many pressures, especially on the poor.
Fonte: The New York Times
