Coral is dying due to climate change and temperature increases in the oceans. According to some projections, coral reefs—often called the “rain forests of the sea” because of the dazzling diversity of creatures they house—could be completely gone by the end of the century.
/ Published February 6, 2013
As weather patterns change and the earth warms, as coral reefs disappear, sea levels rise and Arctic sea ice melts, Smith professors of many disciplines struggle with the question, What does climate change mean for the planet?
Taking into consideration the intricacies of the topic, their answers are complex.
Professor of Biological Sciences L. David Smith, a marine biologist and director of the college’s environmental science and policy program, says the dangers of the rapacious rate at which humans are consuming fossil fuels have been apparent for at least twenty years. He is now seeing how predictions made in the early 1990s by climate scientists are coming true at a rate even faster than many had feared.
L. David Smith
The oceans, from the tropics to the poles, are visibly changing right now. Coral reefs worldwide are dying because of slight temperature increases and the acidification of ocean water as it absorbs carbon dioxide. According to some projections, coral reefs—often called the “rain forests of the sea” because of the dazzling diversity of creatures they house—could be completely gone by the end of the century, says Smith. The follow-on effects would be “calamitous” for coastal communities that rely on the reefs as a first line of natural defense against erosion and hurricanes or typhoons. Coastal economies that depend on fishing and tourism would be devastated.
Meanwhile, in the past few years, the ice in the Arctic has been melting at an alarming rate, according to Tom Litwin, adjunct associate professor of biological sciences and director of the Clark Science Center, who works in that region.
Indeed, according to the U.S. National Snow and Ice Data Center, Arctic sea ice extent for December 2012 “remained far below average, driven by anomalously low ice conditions in the Kara, Barents and Labrador seas.”
“We’re there,” Litwin says of ice loss in the Arctic. “The question now is how intense this period is going to be...We are already seeing changes that are undeniable.” Litwin explored these changes in the four-part series "On Thin Ice in the Bering Sea," which he created and co-produced for PBS’s Nova “Extreme Ice" program.
He, Smith and other faculty members agree that it is already too late to head off some kind of major disruption. “As a planet, we own climate change,” says Litwin. “The question is, can we dampen the trajectory?” Already, he says, “sea-level rise predictions range from startling to extreme.”
Until recently, it has been controversial in policy circles to talk about adapting to, rather than preventing, climate change, according to Greg White, professor of government and Elizabeth Mugar Eveillard ’69 Faculty Director of the Global Studies Center. Now, he says, “People are seeing that this is the future, and that even the best case scenarios are pretty bad.”
White, who has been tuned into the alarm bells of the past 20 years, is happy that adapting to climate change is now part of public discourse. “We really do have to think in those terms; at the same time we can’t stop thinking about mitigation.” He is appalled at the level of denial among large swaths of the American electorate, while also taking heart from signs that climate change is becoming a mainstream issue as more people come to terms with the enormity of what awaits.
Referring to the work of James E. Hansen, who is chief of the Goddard Institute for Space Studies, White says, “There is a ton of climate change in the pipeline. The system is stoked—even if you were to stop emissions right now, there is enough pent-up and built-up momentum that it’s going to continue to warm and affect precipitation patterns and weather.”
Economic modeling in many realms is already taking climate change into consideration, explains Susan Sayre, assistant professor of economics. In some of her work on the resources that provide California’s water, calculations on the economics of whether to build a pipeline are based on an assumption that it will operate for 30 to 50 years. If weather patterns change during that time, all bets are off. “There is an added uncertainty because climate change is hanging over everyone’s head,” says Sayre. “It increases the probability of really bad outcomes.”
Climate consciousness now informs specifications that engineers use in designing and updating public works projects as well, observes Andrew Guswa, a hydrologist and professor in the engineering department and director of the Center for the Environment, Ecological Design and Sustainability. As the earth warms, we expect longer periods of drought and more intense flooding, he explains. Each region will experience climate change differently, says Guswa, but “pretty much everywhere the cycle will be intensified; we will get a larger percentage of our rain in shorter, more intense periods.”
As a physicist, Nathanael Fortune sees climate as a broad system that includes the circulation of carbon dioxide. If there were no carbon dioxide in the atmosphere, the earth would be “a frozen ball of ice.” If too much carbon dioxide goes into the atmosphere too fast, we could veer off in the other direction, he explains. One doesn’t have to look too deeply into paleoclimatology—the study of past climates—to find extremes never experienced by and very likely to be hostile to human life.
Building on this long, inclusive view of climate, geologist Amy Rhodes is keenly aware that conditions suitable for sustaining civilization could end up being a brief interlude. “The planet has undergone lots of changes in its giant history,” says Rhodes, an associate professor of geosciences. “It is really only in the last 10,000 years that we’ve had stable climate in the current condition.” We don’t have to look too far back in Earth’s history to find analogues to our climate future, she says.
“Earth experienced a sustained warm period during the middle Pliocene period, just over 3 million years ago. During this time, climate scientists estimate, average global temperatures were about 3.6 to 5.4 degrees Fahrenheit warmer than today.”
Consequently, the ice sheets over Greenland and Antarctica were greatly reduced, resulting in sea levels up to 25 meters higher than the present. Today, concerns over climate change driven by the burning of fossil fuels has prompted earth scientists to take a new look at the Pliocene climate using data derived from so-called proxies, like ice cores, stalactites, seed pods and lake sediments. “If our future is anything like the mid-Pliocene, the impact on today’s coastal areas could be catastrophic,” says Rhodes.
Whether humans can survive the path we are on now is an open question, according to Fortune, who is a professor of physics. The only prediction he can make with certainty is that we are entering a period of unpredictability. The physics underlying a world with 450 parts per million (ppm) of carbon dioxide in the atmosphere is depressing to contemplate. We are nearing 400 ppm and adding an average net gain of 2 ppm each year. Because the warming of the oceans is already underway, says Fortune, NASA’s Hansen believes we need to return to a carbon dioxide level of 350 ppm.
“We are running an experiment of ‘can we adapt?’ and ‘can we live?’ with not only a warmer climate but a more unpredictable one,” says Fortune. “It’s not an experiment I would suggest we run, but we are already committed to part of that experiment.”
If carbon dioxide in the atmosphere reaches 450 to 500 ppm, says Fortune, “that takes us back to a period before the ice ages, back when there was no ice in Antarctica or the Arctic and reptiles roamed Alaska...a climate that precedes the invention of agriculture. The evidence from the deep past is that if we continue on the path we are on now, we might reach a world that we haven’t seen since the extinction of the dinosaurs.”
Yet Fortune finds reason for hope. “I’m pessimistic in that we aren’t doing anything to give ourselves a chance. I’m optimistic in the sense that we know what to do if we were to do it. I am a realist in the sense that we can’t avoid living with the consequences of our past behavior. There’s already going to be climate disruption, there’s already going to be warming, and it’s going to affect us adversely. But we don’t have to go off the cliff.”