THE NEXT ICE AGE
The oceans crash against skyscrapers, making aquatic tunnels of Manhattan streets. Heavy layers of snow pile on endlessly, burying entire civilizations in canopies of white. Eventually, liquid turns to ice, and life as we know it is threatened by an eternal freeze.
This is the harrowing disaster scenario of The Day After Tomorrow, a 2004 science-fiction film directed by Roland Emmerich and starring Jake Gyllenhaal. Based on an imagined future of accelerated global warming, the movie was a major box office hit — it grossed more than $500 million worldwide — but climatologists quickly took aim at its scientific value. Yahoo! featured The Day After Tomor
row in a top-10 list of scientifically inaccurate movies, while Duke University paleoclimatologist William Hyde declared, “This movie is to climate science as Frankenstein is to heart transplant surgery.”
The extreme cooling trends depicted are caused by a collapse of the Atlantic Meridional Overturning Circulation, or AMOC, a North Atlantic Ocean water circulation system that moderates temperatures north of the equator. When the movie was released, however, there had yet to be research examining such an event’s potential aftermath.
Now, a University of Southampton climate study published in Nature Scientific Reports indicates that we were naive to feel safe from the disaster depicted in The
Day After Tomorrow.
“The basic scenario of the AMOC as a result of global warming is not completely out of the blue or unthinkable,” the study’s author, Sybren Drijfhout, told the Washington Post.
According to the oceanography and climate physics professor, current warming patterns not only indicate that a collapse of the AMOC is possible, but also that resulting consequences would resemble The Day After Tomorrow, though not to the same extremes.
Using an advanced climate model at Germany’s Max-Planck Institute to simulate both conditions of global warming and conditions of an AMOC collapse, Drijfhout’s team discovered that global temperatures could register a drop of up to10 degrees C: three times stronger than concurrent warming trends.
In a properly functioning circulatory system, the AMOC produces a milder climate downstream of the North Atlantic by bringing warm, salty surface water from the Indian Ocean and the South Atlantic to the northern hemisphere.
But this system depends on the connection of surface waters flowing to the north and deeper waters flowing to the south that can occur within just a few sinking ranges in the North Atlantic. These ranges exist only where water on the surface sufficiently nears the freezing point such that it becomes dense and heavy enough to sink to the bottom.
With the Greenland ice sheet melting as a result of climate change, the AMOC’s essential process is slowing down. If we’re not careful, Drijfhout said, it may produce an effect comparable to The Day After Tomorrow.
The colder temperatures would hit Western Europe the hardest, while Americans would have to contend with floods.
The United Kingdom, the Netherlands and Denmark would likely experience a severe temperature drop, and sea levels on the U.S. East Coast could rise over a metre.
“This would affect hundreds of millions of people,” Drijfhout said. “At least temporarily, Europe would suffer conditions that would look like the Little Ice Age of the Middle Ages.”