I don’t recall when I first heard about climate change. It was before Jim Hansen, then director of NASA’s Institute for Space Studies in Manhattan, testified before the U.S. Congress on June 23, 1988. Then, he told the Senate Energy and Natural Resources Committee, “It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here.”
I am 48 years old; I have been hearing about climate change most of my life. We have been waffling the whole time. Yet until recently there was some sense, however inchoate, that significant changes were still avoidable if we acted. It’s now clear to everyone except the most inveterate climate-change skeptics that what Hansen told Congress in 1988 is the case: climate change is here. As Ken Caldeira, a climate scientist at the Carnegie Institution for Science, writes in “Stop Emissions!”, part of this issue’s coverage of climate change: “Already, in the middle latitudes of the Northern Hemisphere, average temperatures are increasing at a rate that is equivalent to moving south about 10 meters (30 feet) each day.” We failed to act in time.
What’s left to be discovered is how bad it will be, how fast it will happen, and what we will do about it. The first great unknown is how quickly we will abandon coal, petroleum, and natural gas. If we burn all available fossil-fuel resources and dump the resulting carbon dioxide into the air, global average temperatures could rise as much as 9 °C; mammals might not be able to live at the waist of the Earth. That probably won’t happen, but to limit temperature increases, we must swiftly deploy the low-carbon energy technologies that we do understand, such as solar and wind power, while researching and developing solutions to energy problems that still elude us, like how to store the electricity generated by renewable sources or generate power from safer, cheaper nuclear reactors. These efforts will require smart energy policies, international treaties, and a significant increase in the amount nations spend on energy R&D.
Other unknowns are the climate’s sensitivity to increases in atmospheric carbon dioxide and the impact those temperature increases will have. David Rotman, MIT Technology Review’s editor, argues (see “Hot and Violent”), “No one knows how climate change will transform our lives. Not only is it uncertain how much elevated levels of carbon dioxide in the atmosphere will raise temperatures and affect precipitation in different parts of the world, but there remains much to learn about how these changes will reduce agricultural productivity, damage human health, and affect economic growth.” Could climate change, Rotman asks, “lead to a far more violent world?”
At least 2 °C of global warming, which was once thought the upper band of what we could bear as a civilization, now seems locked in. More may be likely. We must begin to imagine the social, economic, agricultural, and engineering implications of living in that future, and plan accordingly. It will be hotter; seas will rise and flood cities; there will be more droughts and storms, and crops will fail; the nations will fight; and refugees will stream from the poor parts of the world.
Faced with all this, it’s easy to recall the words of Job 3:25—“The thing which I greatly feared is come upon me, and that which I was afraid of is come unto me.” But it’s never too late until it’s too late; life goes on unless it doesn’t. We have to decide what we want to do next. That’s the moral imperative and the practical reality. Don’t panic.
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