It notes that some amount of “irreversible” climate disruption is already locked in, but things can also get much, much worse. Additional global warming could wreak havoc across the globe, potentially leading to food shortages, the flooding of major cities, and mass extinctions.
Perhaps the most relevant sections are about how to avoid this fate, something the world’s nations will be discussing over the next year of UN climate talks. To avoid the worst outcomes, the world would need to act immediately and drastically, reducing emissions 41 to 72 percent below 2010 levels by mid-century. We’d then need to keep cutting and possibly be taking carbon-dioxide back out of the atmosphere by 2100. That won’t be easy. And the task gets all the harder if countries delay action or if they rule out certain controversial technologies, like nuclear power or carbon capture for coal plants.
He makes a grim observation:
[Y]early greenhouse-gas emissions have kept rising fast in recent decades. If this keeps up, we’re likely on pace for between 3.7°C and 4.8°C rise in average temperatures by the end of the century. The World Bank, for one, thinks that would be a disaster – because “there is no certainty that adaptation to a 4°C world is possible.”
And let us remember that “adaptation” refers to the human race. Our fellow species on planet earth are already dying out in vast numbers. But Allen McDuffee finds a nugget of hope in the analysis:
We already have technology, the report points out, that could play a major role in helping to end our dependence on fossil fuels. “It is technically feasible to transition to a low-carbon economy,” Youba Sokona, co-chair of one of the IPCC’s working groups, says. “But what is lacking are appropriate policies and institutions. The longer we wait to take action, the more it will cost to adapt and mitigate climate change.”
And Elizabeth Shogren suggests the international political climate is gradually improving:
In six weeks, the negotiators will gather in Peru. That meeting is supposed to prepare the way for the conference in Paris in December 2015, which aims to reach an agreement to replace the Kyoto Protocol. Kyoto required developed countries to reduce greenhouse gas emissions by specific amounts. It was a legally binding treaty—except that it never bound the United States, then the largest emitter, which never ratified it. And it never bound China, now the largest emitter, because all developing countries were exempt.
The argument between developed and developing countries—about who should do how much to “mitigate” climate change through reduced emissions—has always been one of the main obstacles to an agreement that actually makes a difference. But the chasm is less deep than it used to be, said Laurence Tubiana, the French diplomat charged with organizing the Paris conference. “All countries, including less developed countries, are saying their contribution will have a mitigation part,” Tubiana said on a visit to Washington last month. “Even Mali will have emissions reductions. That’s really unprecedented.”
Meanwhile, Constantine Samaras wishes the report emphasized the need for greater investment in energy R&D:
Governments define their near-term and long-term priorities line item by line item on every fiscal year budget. In 2000, the U.S. Federal R&D budget for “activities to develop technologies to deter, prevent, or mitigate terrorist acts” was $511 million. In the aftermath of the terrorist attacks of September 11, 2001, the R&D budget for counterterrorism grew to almost $2.7 billion in 2003. …
The impacts from climate change also pose risks to the United States, but policymakers are responding to these risks with much less seriousness than the response to terrorism. … U.S. energy technology and global change research R&D budgets have been relatively flat and completely unrepresentative of the challenge. We correctly reacted to counterterrorism with enhanced R&D after 2001, yet on energy and climate change we’re effectively just muddling through.
And Chris Mooney contends that global warming may be even worse than the IPCC makes it out to be:
According to a number of scientific critics, the scientific consensus represented by the IPCC is a very conservative consensus. IPCC’s reports, they say, often underestimate the severity of global warming, in a way that may actually confuse policymakers (or worse). The IPCC, one scientific group charged last year, has a tendency to “err on the side of least drama.” And now, in a new study just out in the Bulletin of the American Meteorological Society, another group of researchers echoes that point. In scientific parlance, they charge that the IPCC is focused on avoiding what are called “type 1” errors – claiming something is happening when it really is not (a “false positive”) – rather than on avoiding “type 2” errors – not claiming something is happening when it really is (a “false negative”). The consequence is that we do not always hear directly from the IPCC about how bad things could be.
Just as well that we had a thorough airing of these issues in the current Congressional campaign, isn’t it?