February 27, 2008
The Day After Tomorrow Questions
The Day After Tomorrow (20th Century Fox, 2004, directed by Roland Emmerich) is, first and foremost, a disaster movie. Perhaps the greatest and most far-fetched of all ice age movies. Like all disaster movies, it tends to play fast and loose with time scales for the purpose of making a compelling plot, in this case, taking the impact of three centuries of predicted global warming and compressing it into three weeks of on screen time.The science behind our The Day After Tomorrow questions ranges from questionable to laughable, from the perspective of real scientists doing real climate studies. And the science is pretty clearly and obviously warped to serve the purpose of the plot.
How So?
For example, the glacier engulfing New York City has grown by nearly 1,200 kilometers in 3 months – in the middle of summer. Let's run some numbers real quick. 1,200 kilometers in 3 months is 1,200 kilometres in roughly 90 days, which is a bit over 13.3 kilometers of glacier growth per day, on a path several hundred kilometers wide.And nobody noticed this in time to evacuate New York? I guess the people who lived in Rochester or Buffalo were killed in their sleep? Along with everybody at the United States Weather Bureau. Ice has a density of roughly 0.9 grams per cubic centimeter (it floats in water). Assuming that glacier extended down from Hudson Bay to the Hudson River, it's covering nearly 30,000 square kilometers in area, to about 3 kilometers deep, for a total volume of 90,000 kilometers. Let's approximate and say that's around 80,000 cubic kilometers of water, or 80 million cubic meters of water, or about 80 million tons of water.
How much water?
Hurricane Katrina, which devastated New Orleans in 2005, dropped about 4 million tons of water on the city. The movie wants us to believe that 20 Katrinas hitting the densely populated Eastern Seaboard of the United States and Canada, dropping all of its water as snow, and there were still enough people in New York that there was a science fair for Sam Hall to go to?Even the most incredible (in the classical sense of the word, meaning unbelievable) predictions for global warming don't go the extremes that the science in this movie went to. The likely trend lines for climate change indicate a rise of roughly a degree Centigrade over the course of the 21st century; while there are terror scenarios (such as all the Antarctic ice sliding into the ocean at once), they're all low probability events, and the speed of changes caused by global climate change is, sadly, much too glacial to make an engrossing movie.
The total impact of global warming may be much more tragic than merely natural disasters – they may spark wars over grazing and crop lands, or famines, or mass migrations of people, causing genocidal conflicts like those in Rwanda….but that'd doesn't make for cool teaser shots of Manhattan under a kilometer of ice.
So, enjoy The Day After Tomorrow as good popcorn entertainment, but save some salt on the side to take with its scientific message.