"Burning all fossil fuels could result in the planet being not only ice-free but human-free."
That's a direct quote from our nation's top climate scientist, Dr. James Hansen. The good doctor, and longtime head of NASA's Goddard Institute for Space Studies, just quit his day job, apparently so that he could spend more time making apocalyptic pronouncements.
Unfortunately, nobody's more qualified to make such predictions than Dr. Hansen. As the veritable founder of American climate science, he was the first to effectively recognize and sound the alarm regarding the threat of an excess accumulation of carbon dioxide in the atmosphere.
In recent years, Hansen has spent an increasingly large chunk of his time working to raise public awareness about climate change—writing books, getting arrested protesting at the White House, doing talking head spots on cable, all while continuing to research the nature of the beast he was facing down. Since he began his activism, that many-tentacled beast has only grown more ornery. Worldwide emissions haven't slowed a single puff of carbon-filled smoke. The Arctic is melting, and so is Antarctica. Temps are rising faster than predicted.
And that's the subject of a white paper Hansen published last night, which aims to clear up some of the questions he's received in the wake of his departure. The biggest chunk of it focuses on "The Venus Syndrome"—the question of whether global warming might ever get so bad that our climate resembles that of the totally inhospitable second planet from the sun.
His answer is: well, almost.
Hansen explains that "if we burn all the fossil fuels it is certain that sea level would eventually rise by tens of meters. The only argument is how soon the rise of several meters needed to destroy habitability of all coastal cities would occur. It is also possible that burning all fossil fuels would eventually set off a hyperthermal event, a mini-runaway."
By mini-runaway, he means an event fed by feedback loops like melting permafrost or, as happened during the Paleocene, the mass melting methane hydrates (yeah, that's the stuff Japan is currently trying to mine). See, as ocean and air temps rise, more methane-rich stuff like permafrost and hydrates melt. Methane traps more heat than carbon, and speeds the warming. This amplification effect means drastic warming can be triggered much faster than current models predict.
But could it ever get as nasty as Venus? Hansen says yes, theoretically. "Earth can 'achieve' Venus-like conditions, in the sense of ~90 bar surface pressure, only after first getting rid of its ocean via escape of hydrogen to space," he writes. "This is conceivable if the atmosphere warms enough that the troposphere expands into the present stratosphere."
Hansen goes deeper into the science, dive into the paper here. But his conclusions should be read by everyone, so I'll quote him at length:
The picture that emerges for Earth sometime in the distant future, if we should dig up and burn every fossil fuel, is ... an ice-free Antarctica and a desolate planet without human inhabitants. Although temperatures in the Himalayas may have become seductive, it is doubtful that the many would allow the wealthy few to appropriate 6 this territory to themselves or that humans would survive with the extermination of most other species on the planet. ... But it is not an exaggeration to suggest, based on best available scientific evidence, that burning all fossil fuels could result in the planet being not only ice-free but human-free.
Bear in mind, these are the words of a scientist, not a preacher going on about the rapture. This is how the nation's top climate scientist imagines the future: a desolate, sweltering wasteland where the rich, ensconced in their Himalayan fortresses, battle to keep the barbarians at the gate. Again—that's a vision sprouting from the prognosis of science, not apocalyptic sci-fi. If we want to be sure to prevent it from playing out, maybe we'd better keep some carbon in the ground, just to be safe.