Predicting the Planet's Fate

Perhaps it’s common knowledge that the effects of drastic worldwide climate shift would be bad. Real bad. Speculation about what the future holds includes radical theories about the possible changes we could expect to see in our lifetime.

Despite their speculative nature, some Harvard professors outline these theories in their courses. Whether ideas of a resurgent ice age or new Saharas popping up across the globe are applicable or not, they illustrate the uncertainty behind the scientific community’s vision of our environmental future.

Ironically, one theoretical outcome of global warming entails the cooling of atmospheric temperature in the northern hemisphere. This idea was taken to an epic extreme in the film “The Day After Tomorrow,” which saw a shivering Jake Gyllenhaal racing against time through the frozen streets of Manhattan. The theory has its roots in a process known as the thermohaline circulation, by which ocean currents move heat from the equator to the northern regions of the globe. If polar ice caps were to melt and add water to the Atlantic, then this circulation of heat might be halted and cause cooling in the north.

However, according to Professor of Earth and Planetary Sciences Daniel P. Schrag, we are unlikely to witness any changes paralleling a global deep freeze or a new ice age. Instead, the consequences of a disruption to the thermohaline circulation are more likely to simply mitigate the predicted effects of global warming. “The important thing is that part of the world, Scandinavia and Europe, is likely to warm by 4-6 degrees Celsius over the next 100 years,” Schrag says. “So this [effect] will just cause these areas to return to normal.”

Another possible scenario to look forward to in the coming decades is the possible desiccation of the Amazon rainforest. Plants respond in strange ways to changes in the atmospheric level of carbon dioxide. According to the theory of Amazon basin collapse, the vegetation of the rainforest will react to high carbon dioxide concentration by closing their stomates, the parts of plants that act as portals for carbon intake and water release. Since the plants release less water, there would be less water in the atmosphere, perhaps leading the ecosystem to spiral into draught.

Professor Paul R. Moorcroft referred to this theory in his class Biological Sciences 55 but says he’s not necessarily a proponent of it. “There have been simulations that support this,” he says. “There has been a prediction that this will happen by 2050.” But he also says that other predictions directly conflict with this assessment. When pressed for his personal opinion, he is firm. “If you asked me whether I believed that theory, my answer would be no,” he says.

So if professors are not necessarily in agreement with these doomsday predictions, why do they make a point of explaining them in class? ESPP concentrator Simi Bhat ‘08, a student in Moorcroft’s class last spring, says that she sees the teaching of these ideas as a precautionary measure. “I think the professors feel obligated to address these long-term projections just so we know more about them” she says. “I think that they believe that we’ll do something to address the problems.”

According to Pforzheimer Professor of Science and Technology Studies Sheila Jasanoff ’64, the uncertainty about what the future holds in store is a motivating factor behind the teaching of these theories. “We don’t know how fast these climate changes are going to happen,” she says. “The margin of uncertainty about any of these problems is great enough that we could be very badly surprised.” The fact that our lens into the future is cloudy provides an impetus to teach these ideas in a cautionary context.

One consequence Schrag can predict with confidence: global climate change will disrupt ecosystems and animal populations. He offers a colorful example of the quandary that the most vulnerable of the earth’s animals would face. “Now there are some organisms like polar bears that live in cold weather, and they’re just screwed,” he said. “What do you do if you’re adapted to a world that has a lot of sea ice, and the sea ice disappears?”

Even if these theories probably won’t come true, they’re good to keep in mind. Next, they might be coming for us: what do you do with a creature that’s adapted to a world with a lot of dry land...