A friend and I were watching some old James Bond movies and talking about their grandiose evil plans. The conversation turned to melting the polar ice caps and flooding the world. His idea was to use a solar reflector; mine was to use nuclear weapons. Since neither of us knows any evil geniuses, we decided to consult a benevolent genius. So Cecil, how would you melt the polar ice caps? -- Miguel Valdespino
The thing to realize is the magnitude of what we're trying to accomplish.
According to the U.S. Geological Survey, there are 33 million cubic kilometers of ice in the polar regions. This is grounded ice, sitting on land or the sea floor in or near Antarctica and Greenland. There's also floating ice, such as that covering the North Pole part of the year. But the USGS ignores this, since (a) the ocean level won't rise when it melts (floating ice displaces a volume of water equal to its weight-think about it), and (b) floating ice is a drop in the planetary bucket.
Assuming an average polar ice temperature of minus 22 degrees Fahrenheit, melting it all will take 11.3 yottajoules of energy. How much is that? Well, yotta- is the biggest metric prefix we've got-it means "add 24 zeros." Annual world energy consumption is something like 500 quintillion joules. Multiply that by about 22,000 and you've got 11.3 yottajoules, which is-I have to say this-a lotta joules.
How to deliver it? At the earth's distance from the sun we receive about 1.4 kilowatts of solar energy per square meter, half of which makes it through the atmosphere to the surface. (I'll ignore atmospheric heating.) So theoretically we could position giant mirrors in space to reflect sunlight onto the poles.
Problem: to get the job done in 20 years, our bank of mirrors will need to be the size of North America. Then, too, it'll be nearly impossible to keep the mirrors aimed properly, and the melting ice will create sun-blocking cloud cover, slowing the process.
What about the nuclear option? Estimates of the total world nuclear arsenal vary, but a reasonable guess is a combined yield of 5,000 megatons. Even assuming we could pump all the blast energy into the ice and not have any of it leak away, it'd still be less than a hundredth of what we need.
Fossil fuels, then? Good luck-those 11.3 yottajoules are more than a thousand times the energy contained in the entire world's proved oil reserves. Throw in all the globe's coal and natural gas and, once again, we still don't get to even one percent of what's required.
OK, Plan D. What if we live out one of Mick Jagger's few unfulfilled fantasies and paint it black-that is, all the ice and snow? It'll soak up a lot more solar energy that way, but now our melt time will be around 750 years.
Maybe we can do better. See how this grabs you. We come up with a process that traps energy in the atmosphere rather than letting it radiate away, perhaps involving an accumulation of gases such as carbon dioxide or methane that would be transparent to incoming solar radiation but a barrier to surface heat. Sort of a, you know, greenhouse effect.
The beauty of this scheme is that once the heat built up to a certain point, cascading events would take you the rest of the way. Melting ice would release additional carbon dioxide and methane trapped within, accelerating warming. Thawing permafrost would release still more CO2, and if the oceans got toasty enough you could end up with a major release of frozen methane on the seabed, a process thought to have caused the Great Permian Extinction.
The problem from a cinematic standpoint is that no one genius, however evil, could pull this stunt off. The only way to generate enough CO2 would be combustion on a staggering scale-you'd need to enlist the bulk of the earth's population in a decades-long campaign to burn through a significant fraction of the planet's organic materials. Even if the plan were technically feasible, nobody would buy it as a movie premise.
Everybody pitches in to melt ice caps? Come on, you think we're all fools?