The New York Review of Books

Rowland Mathiasson/Roadside Attractions

Bjørn Lomborg in Greenland, 2009; from Ondi Timoner’s film Cool It

We are at a dramatic moment in the story of global warming. We’ve known, as a society, about the climate change crisis for just over twenty years, from the day in June 1988 when the NASA scientist James Hansen testified before Congress that the planet was heating up because we were burning so much fossil fuel and hence emitting so much carbon dioxide.

By 2010—the warmest year on record, according to most of the planet’s record-keepers—the earth was getting a taste of what global warming feels like in its early stages. Nineteen nations set new all-time temperature records, itself a record; in early summer Pakistan set the new all-time high for Asia at 128 degrees. That warmth accelerated the already rapid melt of the Greenland ice sheet; in some areas the melt season lasted fifty days longer than average. Meanwhile, record heat in central Russia triggered wildfires and drought, spooking the Kremlin enough that it suspended all grain exports to the rest of the world, which helped push the price of wheat sharply higher.

Most ominously, the pace of record-breaking deluge and flood surged. Because warm air holds more water vapor than cold (the atmosphere is about 4 percent moister than forty years ago), scientists have warned that we’re increasing the possibility of greater downpours; country after country found itself on the wrong side of those odds in 2010, Pakistan most desperately. (Six months after the summer flooding there, the Red Cross reported in January that four million people were still homeless.)

It’s a trend that’s continued into the new year, despite cold snaps in parts of North America and Western Europe: Jeff Masters, the meteorologist whose WunderBlog is the Internet’s go-to site for weather data, reported that the first three weeks of 2011 saw “an entire [typical] year’s worth of mega-floods,” with remarkable events in the Australian states of Queensland and Victoria, the Rio de Janeiro region of Brazil, Sri Lanka, the Philippines, and South Africa. Oscillations in Pacific Ocean temperatures drive some of the flooding, but it’s the combination with the extra atmospheric moisture provided by global warming that leads to what Masters calls a “much increased chance of unprecedented floods.”

Notably, these effects are occurring with a temperature increase of slightly less than one degree Celsius, and with atmospheric CO2 concentrations of only 390 parts per million; researchers say that without dramatic action to move our economy off fossil fuels, those numbers will reach four degrees or more, and 550 parts per million or higher, by century’s end.

Meanwhile, 2010 also saw the end of the first wave of attempts to deal politically with climate change. A two-decade effort with the Kyoto Protocol of 1997 as its high point, it relied on mobilizing elite opinion, and focused on so-called “cap-and-trade” solutions to climate change. These measures would have placed limits …