Twenty-seven years ago, when the world briefly awoke to the threats of global warming and tropical deforestation, scientists could only speculate on what changes might come in the future. Now, one need only look and observe.
Nineteen years ago, I went to Antarctica to report for Time magazine on the ways in which global warming was affecting the frozen continent. One concern was the stability of the West Antarctic Ice Sheet (or WAIS).
In 1996, scientists had detected an increase in the velocity of the so-called “ice streams,” which transport ice from the interior of the immense glacier to the shore. The fear was that as WAIS diminished, salt water might intrude under the ice and eventually cause it to float, raising sea level around the world, and inundating large swaths of Florida, not to mention Bangladesh, Indonesia and other low lying areas that are home to hundreds of millions of people.
This year, Eric Rignot, a scientist with NASA’s Jet Propulsion Laboratory, published a study confirming these fears with the stark conclusion that the ice sheet is in a state of “irreversible decline,” and in early May, Princeton University researchers released a new study confirming the accelerating melting.
The great ice sheet won’t collapse any time soon, but it’s a chilling thought in a warming world that an ice sheet that has been stable through the entire time modern humans have existed has now begun to come apart.
More than 20 years ago, INPE, Brazil’s Space Agency published studies arguing that continued cutting of the Amazon was diminishing the vast forest’s ability to recycle moisture. Water – it used to be seven trillion tons each year – evaporated from the Amazon forest rises above the forest, bounces south along the Andes, and then is carried by prevailing winds, first across the dryer areas of southern Brazil and then, after traversing the Atlantic, to South Africa, where it nourishes the corn crop. Since then, the forest has shrunk by an area equivalent to the size of Texas, and now residents of Sao Paulo, the hemisphere’s largest city, desperately scrabble for water after multiple years of drought have desiccated the reservoirs.
And of course, at the same time, California is trying to cope with the worst drought in its modern history. This drought was predicted 18 years ago by Richard Seager of Columbia University, who in 1998 published a paper in Science arguing that a warming world shifted the global precipitation patterns pole ward leaving California and other mid-latitude regions in a rain shadow. Exacerbating California’s problems has been a diminished snowpack – this year at 6 percent of normal. Ordinarily, the snowpack stores water and then melting acts as a meter, delivering water during the dry summer months. Tim Barnett of Scripps Oceanographic Institute first predicted 15 years ago that the combination of drought and warming would have this result.
Are you seeing the pattern here? Time and again, the world’s best scientists have done their job and made predictions based on the best available evidence, only to watch in dismay as their predictions come true because an oblivious world fails to act.
Many other predictions made about the likely consequences of global warming have come to pass: more extreme weather events (a drumbeat of such studies the mid-1990s, with the most recent published in Nature Climate Change on April 27); the disappearance of arctic sea; the collapse of fish populations in the Pacific; and even the series of frigid winters in the Northeast, fueled by a slowdown of the ocean circulation pattern that distributes heat from the tropics to the North Atlantic (predicted by Wallace Broecker of Lamont-Doherty Earth Observatory in an article in Science in 1997, and now back in the news).
Can it be said unequivocally that the drought in California is related to climate change, or that Sao Paulo’s water crisis is tied to cutting of the Amazon, or that there is, in fact undeniable evidence of an increase in extreme weather events? Nope, weather might be the most complicated phenomenon on the planet, influenced at any given time by myriad cycles as well as by such disparate factors as air pollution, land, even the expansion of cities, as well as the difficulty of obtaining consistent measurements on a global scale.
As new predictions of past decades come to pass, however, it makes it harder to explain these changes as coincidence. And there are quite unequivocal signals of a warming planet. Sea level rise, resulting from increased melting of ice and the thermal expansion of the oceans, offers a mute, global signal of a warming planet. Moreover, sea level is rising much faster than predicted, possibly because ice sheets in Greenland and Antarctica are melting more rapidly than predicted.
Could any of these unfortunate events have been prevented? Of course! Fifty years ago, Rachel Carson published Silent Spring, which warned that unchecked use of DDT would lead to the collapse of bird populations. The United States and other developed nations banned the pesticide, and bird populations have recovered to the point where bald eagles visit New York City (China ignored the warnings about DDT, and has suffered the silent spring that Carson predicted). Dealing with greenhouse gas emissions is vastly more complicated, but it is highly likely that the world would be in a better position to fight the threat now had it begun to take action in 1988.
Now we’ve gone backwards. Thanks to a campaign to discredit the threat of climate change financed by the fossil fuel industry and vigorously promoted by Fox News and other right-leaning media, fewer Americans think global warming is human caused than they did eight years ago, according to a recent study conducted by Anthony Leiserowitz* of Yale University.
Think about that: even as predictions of past decades have become reality, the American attitude about global warming has shifted towards “prove it.” One thing is certain: we’ve forfeited the right to say, “Nobody saw this coming.”
