16 june 2018

An Ocean Doesn’t Cool Off Again by Itself

The South Pole is melting now too. Irreversibly. Will it influence climate policy? “The urgency was already extreme”

By Paul Luttikhuis. NRC Handelsblad, 16-17 June 2018

[Original title: "Een oceaan koelt niet vanzelf weer af". English translation by 4C]

Antarctica has for years defied climate change. While the average temperature on earth has climbed and in the North Pole area and on Greenland there have been disturbing signals of rapidly melting ice, while glaciers are diminishing nearly everywhere in the world and the atmosphere has become skittish – even over the Netherlands, as we have noticed in recent months – the coldest continent has escaped the warming. At least it seemed that way.

Extensive research published this week in the periodical Nature puts paid to the idea that Antarctica has hardly been bothered by the changing climate. Using satellite measurements, the researchers demonstrate that the ice is really melting on the western side of the South Pole area. It also appears that the melting has been accelerating in the last five years.

“You can’t escape it”, says Michiel van den Broeke in Davos, where he is participating in a scientific congress. A professor of polar meteorology at the University of Utrecht, Van den Broeke is one of the authors of the research. He adds immediately: “The uncertainties are still as large after this research.”

We now know that the southern ocean is warming. But how warm will it get? How fast? How will the enormous mass of ice on it react? These are as yet unanswered questions. That doesn’t, however, mean that we can lean back easily until the answers are there, says Van den Broeke. He assumes that we’ll be able to speak with more certainty about what’s happening in Antarctica around 2030. But, he says, we can’t wait for that.

“The equilibrium has been disturbed. And a warmer ocean doesn’t cool off by itself,” Van den Broeke says. “That process is practically irreversible. You have to try as far as possible to slow it down.” And you do that by reducing greenhouse gas emissions, which bear responsibility for the warming of the earth. The scientific panel of the UN (IPCC) has ben calling for that, he says, since the 1990’s.

One and a half degrees

The Antarctica research is appearing at a sensitive moment. At the request of the UN climate negotiators who prepared the Paris Agreement, the IPCC is working on a special interim report about what we need to do to limit the global temperature increase to one and a half degrees Celsius (the increase is now one degree in relation to the beginning of the industrial era). That report is to be published in October, but press agency Reuters has gotten the almost definitive draft, and last Thursday they published the conclusions.

According to the IPCC, it’s still possible to keep the temperature increase under one and a half degree Celsius. But that will require a tremendous effort: major changes in life style, large scale reforestation to take carbon dioxide out of the atmosphere, a greatly reduced use of energy and another economic construction. And that has to be done in twenty years. Because if we continue on our present trajectory, the one and half degrees will be passed around 2040 – with, according to the IPCC, great damage to the economy.

Heleen de Coninck, researcher in international energy and climate policy at the Radboud University in Nijmegen, is one of the authors of the IPCC report. She won´t discuss its contents before the publication of the definitive version. But she can say something about what she considers the relation to be between the Antarctica research and the new IPCC report. It’s a fine piece of research, she thinks, but it won’t have noticeable consequences for climate policy. It’s rather evidence that we have to act quickly, she says in a telephone conversation. “The urgency was already very high.”

But the IPCC is shifting the emphasis in the concern of climate science to judging the the impact of climate change and what we can do about it. Physical science remains the basis, but social-scientific insights and economic research become more important. You need them to carry out the expensive transformation with as little damage as possible to vulnerable groups. “That brings about research results that can be less easily expressed in statistics,” says De Coninck,

Extra sensitive

That makes the new IPCC report extra sensitive. It becomes a question of behavioral science, of world-view, of the direction of policy and economy. That gives less certainty than numbers, but by the end of the year, the report should help climate negotiators in developing the Paris Agreement and in deciding about extras measures (and extra money) to reach its targets.

The Antarctic research plays no role in the new IPCC report simply because it appeared after the deadline for new input. The report summary has already been submitted for the judgement of the signatories of the climate accord. What strikes De Coninck is the irreversibility of what is happening in Antarctica. “This again shows that the sea level rise will continue for some time, even if we bring the emission of greenhouse gases to a halt now. For low-lying islands. The question is whether they become uninhabitable decades earlier or later. That’s the hard, unjust conclusion.”

>>> Back to list