Film: The Day After Tomorrow
Authors: Shakoor Hajat
Journal: BMJ (2004)

Global warming gets the Hollywood treatment in The Day After Tomorrow, a disaster movie where the threat to humanity comes from nature itself as a result of changes in the world's climate. In Roland Emmerich's film extreme weather events induced by human activity lash down on the northern hemisphere, with devastating consequences. The resonance of the scenario is heightened by some breathtaking special effects and by the claim that it could one day happen—but how real is the science behind all this?​this?




Figure 1





The Day After Tomorrow was reported to be a “carbon neutral” production

Credit: PA PICSELECT/TWENTIETH CENTURY FOX




The premise stems from the fact that rapid melting of polar ice, brought about by global warming, could alter the flow of ocean currents. The United Kingdom, for example, is partly warmed by the Gulf stream, a current of warm water that flows from the Gulf of Mexico past the western shores of Britain. Once this stream reaches the Arctic, the water at the surface of the sea becomes cooler and denser because of bitter winds and then sinks to the bottom of the ocean and flows back south. This creates a conveyor belt effect as water is regularly circulated; but an increase in fresh water from melting ice at the polar caps could desalinate the water to such an extent that a slowing down or even switching off of the Gulf stream could occur. If it did, it has been proposed that the United Kingdom's average temperature could fall by up to 5°C, and it could happen quickly—in a matter of a decade or two.​two.




Figure 2





Taken by storm: but how real is the science behind the film?

Credit: PA PICSELECT/TWENTIETH CENTURY FOX




However, climate simulations run by the Hadley Centre for Climate Prediction and Research show that although the Gulf stream could indeed slow down—by about 20% by the middle of the century—if carbon dioxide is emitted in ever increasing quantities, it would be unlikely to switch off completely. So the scenario of another ice age is an unlikely one, but we still need a better understanding of the earth's climate system for any predictions to be more robust.

The Day After Tomorrow presents the worst case scenario, with New York suffering in just six days the kind of weather related disasters that could be expected over 100 years of the most severe climate change. What happens to the rest of the world is somewhat glossed over, with the British contingent at the Hedland Centre (a nod to Hadley?) succumbing gracefully and so quickly that not even the gritters could be held responsible. What was welcome in the film, however, was the political comment that rich countries would have to drop the debt owed to them by poorer countries in order for their citizens to gain entry as environmental refugees fleeing south to escape the cold. Also, the movie does, to its credit, realistically portray the US administration as being very sceptical towards the scientific theories put forward by Dennis Quaid's climatologist character. The US economy is more fragile than the climate, announces the US vice president at a delegation in a snow covered New Delhi.

Interestingly, the movie was reported to be a carbon neutral production: any carbon emissions entering the atmosphere as a direct result of the making of the film, and thereby contributing to global warming, were offset by actions to help compensate for those emissions, such as planting trees and using “green” energy. This claim suggests that the production team was aware of the movie's scientific and political message. The threat of global warming is real, the exact consequences and timescales proposed in The Day After Tomorrow may not be, but this entertaining Hollywood block-buster does no harm in raising awareness of a serious issue.