IT鈥橲 not exactly a natural icebreaker, but Earth scientists are talking a lot about ice right now. I met quite a few of them at the in Vienna, Austria. One particularly eye-opening moment came when from Delft University of Technology in the Netherlands showed me how his computer models indicate that half of Alpine glaciers are doomed by mid-century, whatever action we now take to curb carbon emissions.
If anything, the models seem a conservative representation of facts on the ground. A few days later, NASA was highlighting satellite imagery of an Arctic glacier slipping at a rate that was 鈥渟imply nuts鈥�, according to one researcher involved: , compared with 20 metres a year in 2013. And we have recently learned how increased rainfall in Greenland is melting way more ice than anyone expected.
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If Greenland starts to go green, we have a real problem. The ice cap there is up to 3 kilometres deep and contains enough water to raise sea levels by several metres. It is looking increasingly vulnerable. A study just out in the journal PNAS has looked at almost half a century of data to conclude that Greenland鈥檚 annual ice mass loss has . This year鈥檚 melt season , a month early.
So much bad news begins to wash over you 鈥� and that鈥檚 exactly the researchers鈥� main worry. , an author of the PNAS paper, says what surprises him the most is how much science people need before contemplating action.
If Alpine glaciers disappear, that鈥檚 a blow to the region鈥檚 tourism and hydroelectric industries. But perhaps we can tolerate the loss of skiing holidays. Perhaps we should anyway. Greenland is in a different league: an unfolding environmental problem with incalculable, global economic risk attached.
It is 鈥� still, just 鈥� not too late to act. Debate is ongoing about when we will reach climate tipping points where feedback processes kick in to accelerate melting, potentially wiping out Greenland鈥檚 ice sheet. But the dynamics of ice mean melting doesn鈥檛 increase linearly as the world warms. We also know there was a significant Greenland ice sheet 130,000 years ago, when summer temperatures were several degrees warmer. So every fraction of a degree of warming avoided helps avert the worst.
Some researchers are already reviving talk of geoengineering our way from catastrophe. Injecting cooling sulphates into the atmosphere could reduce Greenland鈥檚 ice loss by 10 per cent by 2070, according to modelling by a team at Beijing Normal University, also presented in Vienna. But even if that is technically feasible, the uncertain global impacts make it a political no-go. Countries at a recent UN meeting even .
The answer isn鈥檛 sexy: deep, rapid cuts in fossil fuel use. This past week, I have been talking to instigators of the Extinction Rebellion movement. The detail of their demands might be unrealistic, but they have created resonance. The climate certainly has tipping points. Can societies have them too?
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Adam is New Scientist鈥榮 chief reporter.
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