As diplomats try to piece together a complicated new global agreement to reduce greenhouse gas emissions, a sweeping new study out by the U.K. government today takes a hard look at what could happen if they fail.
The worst-case scenario assessment of what a world in which global average temperatures climb far above the threshold considered safe warns of crop deterioration to in the midwestern United States, chronic water shortage along the Tigris-Euphrates River Basin, and 100-year flood events becoming 40 times more likely in Shanghai and 200 times more likely in New York.
Despite emissions pledges from the United States, European Union and China, along with more than a dozen other countries and more from nations like India and Brazil expected, the study finds that "it is very likely" the world will continue on a medium-to-high-emissions pathway for the next few decades. If countries' goals are realized, the highest-emissions scenarios could be avoided, but that would mean India would displace much of its planned coal-fired power plants with renewable energy -- and emissions would even then be "far in excess" of safe levels.
But, the report argues, "an honest assessment of risk is no reason for fatalism." Instead, the authors say, the world needs even more clear-eyed examinations of what the big effects of small changes in the climate will mean for global security, in order to encourage solutions.
"The greatest risks of climate change arise when thresholds are crossed. What has been gradual becomes sudden; what has been inconvenient becomes intolerable," the study cautions. "The greatest reductions will be won in the same way. Gradual, incremental measures will not be enough. We must seek out non-linear, discontinuous, transformational change."
The study, commissioned by the United Kingdom's Foreign and Commonwealth Office, was co-produced by some of the world's leading research universities and climate experts from China and India. The authors don't try to sugarcoat the policies needed, noting that they won't all be easy to put in place and that governments will have to make some hard decisions about how much priority to give climate change.
But they also maintain the importance of being explicit about the risks of not acting, despite the chance that some might been "overwhelmed" by the scale of the problem. The study noted anthropologist Jared Diamond's theory that societies sometimes make "disastrous" decisions by making the analogy that those farthest downstream from a dam are often the least concerned about the possibility of its bursting. The study's authors said they wanted to make the point that "we can all choose whether or not to look up at the dam."
Pondering the 'unthinkable'
Where climate risk is concerned, they said, "Governments can choose either to ignore it, or to send their best experts to inspect it closely. We have taken the view that it is better to be well informed than not. As the American nuclear strategist Albert Wohlstetter wrote during the Cold War, 'We must contemplate some extremely unpleasant possibilities, just because we want to avoid them.'"
Among the most unpleasant possibilities, they say, is that too few studies even exist to understand the impacts of a 4-degree-Celsius or higher rise in global temperatures above preindustrial levels on crops, ecosystems, health, poverty and human security.
Meanwhile, military leaders like retired U.S. Navy Vice Adm. Lee Gun told authors preparing the report that they foresee the risk of terrorism rising if already-struggling governments are further weakened by the impacts of extreme weather events.
Speaking to ClimateWire last week while in Washington D.C., Baroness Joyce Anelay, who serves as the United Kingdom's Foreign and Commonwealth Office minister, said she hopes the report brings home to country leaders the consequences of the decisions they have to make on climate change. Countries are expected to finish a global agreement in Paris in December.
"This is a very practical approach, and it's the right time to do it because of the international agreement," Anelay said. "We don't want another Copenhagen where people sign an agreement and go away thinking, 'That's it.'"
She called for a deal that keeps global temperature rise "as close to 2 degrees Celsius as possible," citing the so-called guardrail that many scientists have identified as the threshold beyond which impacts could be catastrophic. She also acknowledged, as most leaders by now have, that the cuts currently on the table are not enough to meet that goal, but insisted that the deal must strive for the most ambition possible and include ways to build continuously upon that.
"I think the success will be an international agreement that makes promises on as close to 2 degrees as possible," Anelay said.