Mark Lennihan/AP - This aerial photo from Oct. 31, 2012, shows the New York skyline and harbor. The vast destruction wreaked by Hurricane Sandy’s storm surge in New York could have been prevented with a sea barrier.
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The U.N. Intergovernmental Panel on Climate Change said that climate change is already hurting the poor, wreaking havoc on the infrastructure of coastal cities, lowering crop yields, and endangering various plant and animal species.
But the Nobel Peace Prize-winning group said that climate change’s effects will grow more severe and that spending and planning are needed to guard against future costs, much as people buy insurance against a range of possible accidents or health problems.
The report said that damage from climate change and the costs of adapting to it could cause the loss of several percentage points of gross domestic product in low-lying developing countries and island states. It added that climate change could “indirectly increase risks of violent conflicts in the form of civil war and inter-group violence” by “amplifying” poverty and economic shocks.
The summary of the report, ratified at a five-day meeting in Yokohama, Japan, avoided specific forecasts or timetables, but it described a range of likelihoods and outcomes in an attempt to give decision-makers the tools to set priorities to combat those effects.
Scientists who helped to write the report said that such efforts to adapt could include constructing emergency cyclone and flood shelters like those in parts of Bangladesh, moving generators out of New York City basements that flooded during Hurricane Sandy, changing farming techniques to cope with higher temperatures, and conserving water and curbing pollution in areas threatened with more-frequent droughts.
“The focus is as much on identifying effective responses as on understanding challenges,” Chris Field, co-chairman of IPCC working group writing the report, said in a statement last week.
“There is a more optimistic tone about our ability to adapt to some of these things,” said Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University and one of the report’s authors. “We’ve had some bad heat waves and coastal storms, and we have a better idea of what we need to do. Whether we will ever do it, I don’t know.”
But he cautioned that “everyone agrees that if we don’t slow the warming down, our prospects for adaptation are not good.”
The approach opened the door to discussion in the report of extremely bad climate scenarios, even if their likelihood is relatively remote, just as a company might plan for a once-in-
a-century flood, earthquake or tornado.
a-century flood, earthquake or tornado.
An early draft of the report had estimated that governments would need to spend scores of billions of dollars a year on adaptation efforts, according to a person who saw the early version, but the final summary made no mention of how much money might be needed. Before the Yokohama meeting, the Obama administration opposed setting a figure on adaptation spending.
“The IPCC’s new report underscores the need for immediate action in order to avoid the most severe impacts of climate change,” said President Obama’s science adviser, John P. Holdren. “It reflects scientists’ increased confidence that the kinds of harm already being experienced as a result of climate change are likely to worsen as the world continues to warm.”
The IPCC report said, “Responding to climate-related risks involves decision-making in a changing world, with continuing uncertainty about the severity and timing of climate-change impacts, and with limits to the effectiveness of adaptation.”
The report is Part 2 of a four-part assessment by the IPCC, and it is the product of thousands of papers and hundreds of scientists, who voted on the final version early Sunday morning in Japan.
“For the first time, we have measured in terms of risk so each of the climate risks could be weighed against each other and compared with the risk of this versus the risk of something else,” Oppenheimer said.
“A big part of what makes this assessment different from before is we tried to frame everything in terms of risk,” said Jonathan Overpeck, a professor of geosciences at the University of Arizona who also worked on the report. “We did that because we deal with day-to-day life by managing risks, and a big part of managing our large corporations is assessing risks and managing those risks.”
The “very high confidence” category of climate-change effects included exacerbating more-intense heat waves and fires, increased food- and water-borne diseases, and a steady rise in sea level in certain regions, such as the East Coast of the United States.
The report reiterated warnings that world leaders and businesses must act to slow climate change, not just adapt to it. “Increasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts,” the report said. It said that some of the effects of warming could have “cascading effects.”
The report attached a “medium confidence” rating to some of those events, but it highlighted the danger of “abrupt and irreversible regional-scale change” if high temperatures hurt the ability of the Arctic boreal tundra or Amazon forest to store carbon dioxide.
But the most likely damage from climate changes will be linked to rising sea levels and temperatures. Those changes could turn the advantages of growing coastal cities into vulnerabilities if interlocking transportation, electrical and information systems fail, Oppenheimer said.
“I teach my students that the answer to every economic question is ‘It depends,’ ” said Gary Yohe, an economics and environmental studies professor at Wesleyan University and a co-author of the report. “You don’t want to be poor, you don’t want to be young, you don’t want to be old, and you don’t want to live along the coast.”
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