Say what? There isn’t much that surprises me anymore in the rarefied air that is climate science today. This headline made me do a double take, and the sentence that followed, blaming “unusually low temperatures”, even more so. Here’s a NASA satellite derived image in a science story from 2001 on the Arctic ozone:
And the mechanism, it seems “weather” has a major role:
NASA researchers using 22 years of satellite-derived data have confirmed a theory that the strength of “long waves,” bands of atmospheric energy that circle the Earth, regulate the temperatures in the upper atmosphere of the Arctic, and play a role in controlling ozone losses in the stratosphere. These findings will also help scientists predict stratospheric ozone loss in the future.
There’s no hint of this in the press release. Instead they say:
For several years now scientists have pointed to a connection between ozone loss and climate change…
Arctic on the verge of record ozone loss – Arctic-wide measurements verify rapid depletion in recent days
Potsdam/Bremerhaven, March 14th, 2011.
Unusually low temperatures in the Arctic ozone layer have recently initiated massive ozone depletion. The Arctic appears to be heading for a record loss of this trace gas that protects the Earth’s surface against ultraviolet radiation from the sun. This result has been found by measurements carried out by an international network of over 30 ozone sounding stations spread all over the Arctic and Subarctic and coordinated by the Potsdam Research Unit of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) in Germany.
“Our measurements show that at the relevant altitudes about half of the ozone that was present above the Arctic has been destroyed over the past weeks,” says AWI researcher Markus Rex, describing the current situation. “Since the conditions leading to this unusually rapid ozone depletion continue to prevail, we expect further depletion to occur.”
The changes observed at present may also have an impact outside the thinly populated Arctic. Air masses exposed to ozone loss above the Arctic tend to drift southwards later. Hence, due to reduced UV protection by the severely thinned ozone layer, episodes of high UV intensity may also occur in middle latitudes. “Special attention should thus be devoted to sufficient UV protection in spring this year,” recommends Rex.
Ozone is lost when breakdown products of anthropogenic chlorofluorocarbons (CFCs) are turned into aggressive, ozone destroying substances during exposure to extremely cold conditions. For several years now scientists have pointed to a connection between ozone loss and climate change, and particularly to the fact that in the Arctic stratosphere at about 20km altitude, where the ozone layer is, the coldest winters seem to have been getting colder and leading to larger ozone losses. “The current winter is a continuation of this development, which may indeed be connected to global warming,” atmosphere researcher Rex explains the connection that appears paradoxical only at first glance. “To put it in a simplified manner, increasing greenhouse gas concentrations retain the Earth’s thermal radiation at lower layers of the atmosphere, thus heating up these layers. Less of the heat radiation reaches the stratosphere, intensifying the cooling effect there.” This cooling takes place in the ozone layer and can contribute to larger ozone depletion. “However, the complicated details of the interactions between the ozone layer and climate change haven’t been completely understood yet and are the subject of current research projects,” states Rex. The European Union finances this work in the RECONCILE project, a research programme supported with 3.5 million euros in which 16 research institutions from eight European countries are working towards improved understanding of the Arctic ozone layer.
In the long term the ozone layer will recover thanks to extensive environmental policy measures enacted for its protection. This winter’s likely record-breaking ozone loss does not alter this expectation. “By virtue of the long-term effect of the Montreal Protocol, significant ozone destruction will no longer occur during the second half of this century,” explains Rex. The Montreal Protocol is an international treaty adopted under the UN umbrella in 1987 to protect the ozone layer and for all practical purposes bans the production of ozone-depleting chlorofluorocarbons (CFCs) worldwide today. CFCs released during prior decades however, will not vanish from the atmosphere until many decades from now. Until that time the fate of the Arctic ozone layer essentially depends on the temperature in the stratosphere at an altitude of around 20 km and is thus linked to the development of earth’s climate.
This is a joint statement of the following institutions. The persons mentioned in each case are also at your disposal as contacts.
Hugo De Backer, Royal Meteorological Institute of Belgium, +32 2 3730594, Hugo.DeBacker@meteo.be
Tom McElroy, Environment Canada, +1 416 739 4630, Tom.McElroy(at)ec.gc.ca
David W. Tarasick, Air Quality Res. Div., Environ. Canada, +1 416 739-4623, david.tarasick(at)ec.gc.ca
Kaley A. Walker, Univ. Toronto, Dep. of Physics, +1 416 978 8218, kwalker(at)atmosp.physics.utoronto.ca
Karel Vanicek, Solar and Ozone Observatory, Czech Hydromet. Inst., +420 495260352, vanicek(at)chmi.cz
Niels Larsen, Danish Climate Center, Danish Meteorological Institute, +45-3915-7414, nl(at)dmi.dk
Rigel Kivi, Arctic Research Center, Finnish Meteorological Institute, +358 405424543, rigel.kivi(at)fmi.fi
Esko Kyrö, Arctic Research Center, Finnish Meteorological Institute, +358 405527438, esko.kyro(at)fmi.fi
Sophie Godin-Beekmann, Gerard Ancellet, LATMOS CNRS-UPMC, +33 1442747 67 / 62, email@example.com, gerard.ancellet(at)latmos.ipsl.fr
Hans Claude, Wolfgang Steinbrecht, Deutscher Wetterdienst Hohenpeißenberg, +49 8805 954 170 / 172, hans.claude(at)dwd.de, wolfgang.steinbrecht(at)dwd.de
Franz-Josef Lübken, Leibniz-Institut für Atmosphärenphysik, +49 38293 68 100, luebken(at)iap-kborn.de
Dimitris Balis, Aristotle University of Thessaloniki, +30 2310 998192, firstname.lastname@example.org
Costas Varotsos, University of Athens, +30 210 7276838, covar(at)phys.uoa.gr
Christos Zerefos, Academy of Athens, +30 210 8832048, zerefos(at)academyofathens.gr
Neil Harris, European Ozone Research Coordinating Unit, University of Cambridge, +44 1223 311797, Neil.Harris(at)ozone-sec.ch.cam.ac.uk
Cathrine Lund Myhre, NILU – Norwegian Institute for Air Research, +47-63898042, clm(at)nilu.no
Valery Dorokhov, Central Aerological Observatory , +7 499 206 9370, vdor(at)starlink.ru
Vladimir Yushkov, Central Aerological Observatory +7 495 408-6150, vladimir(at)caomsk.mipt.ru
Natalya Tsvetkova, Central Aerological Observatory +7 495 408-6150, nat(at)caomsk.mipt.ru
Concepción Parrondo, Manuel Gil , INTA, +34 91 5201564, email@example.com, gilm(at)inta.es
René Stübi, Federal Office of Meteorology and Climatology, MeteoSwiss, +41 26 662 62 29, rene.stubi(at)meteoswiss.ch
Geir O. Braathen, World Meteorological Organization, +41 22 730 82 35, GBraathen(at)wmo.int
Ross J. Salawitch, Univ. of Maryland, MD, +1 626 487 5643, rjs(at)atmos.umd.edu
Francis J. Schmidlin, NASA/GSFC/Wallops Flight Facility, +1 757 824 1618, francis.j.schmidlin(at)nasa.gov