Global Warming Causes Cold Winters – A Research Error

  • Date: 10/04/13
  • Ulli Kulke, Die Welt

The cold and snow are extreme this year. Researchers say this is due to global warming. An uncalled assumption, behind of which seems to be a logical reason.

At night it is colder than outside. Similar to this dictum, which stands as a symbol of nonsense, sounds what we hear and read from some climate scientists about the icy winter and especially about March these days: that man-made global warming of all things were responsible for the cold of the last few weeks.

The Alfred Wegener Institute for Polar and Marine Research (AWI) and the Potsdam Institute for Climate Impact Research (PIK) promotes this theory. The claim sounds contradictory. Behind it hides a quite logical relationship, at least at first view. But ultimately, it is difficult to reconcile this claim with the – unfathomable – events between heaven and earth.

We will have a few days or even weeks to ponder it. Still, no real spring weather is in sight, who or whatever may be responsible for that. The news of recent days anything but hopeful: Large parts of Poland are without electricity due to heavy snowfall, Moscow, which is used to cold, announces record snowfalls, in Germany, the winter break for ferry services is still in place in many places, the spring business ruined for plant growers, the brave people who went swimming in Berlin’s Wannsee had almost have to resort to the pickaxe. Slowly, fingers should be crossed that we still experience a spring in 2013 at all.

The relationship between “warming and ice”, which some climate scientists are now promoting again, might work as follows: As it gets warmer, the Arctic sea ice melts (which happened last summer indeed to a record low). The darker water reflects less sunlight than the glistening ice (the “albedo” effect is weaker).

The result: the northern North Atlantic is heating up as a black car in the Italian summer. This reduces the difference between the Arctic and the tropical Atlantic, between Iceland low and Azores high: The air pressure difference, the “North Atlantic Oscillation” (NAO) weakens.


The Atlantic determines our weather

This oscillation, however, is the force with which the Atlantic determines our weather. If it is weak, we are no longer exposed to the mild coastal climate, but to the extreme continental climate from the east: hot during the summer, cold in the winter. The Potsdam Institute (PIK) thinks that particularly the Barents-Kara Sea in the north of Scandinavia and Western Russia as the place that is determining our winter weather.

There, a warmer sea would create a high pressure area, which – like all the high pressure areas – would rotate the winds clockwise around it and thus pushes the cold, north-eastern continental air to us. That is the theory.

First: The whole thing would have sounded more credible if not for years, at times of milder winters, climate researchers had spread the message that global warming would definitely allow no more winter weather in Germany; snow would a thing of the past. If now, after the winters got icier again the last decade, the contrary is claimed, it sounds very arbitrary.

It raises the suspicion that, no matter how the weather and the climate develops, everything can be explained by climate change caused by carbon dioxide. Additionally, the climate scientists, who are now struggling for credibility, have in earlier years, when meteorologists made the cyclical NAO fluctuations responsible for the time warmer winters in the 1990s, always fought this view and did not admit no other causes than man-made global warming, and certainly no natural ones.


No global warming for one and a half decades

Too late for a credible u-turn, you could say. This, however, is true also for another reason. It has not warmed globally for a good decade and a half. Despite the fact that the carbon dioxide emissions continue to rise faster, the temperature remains stubbornly stagnant (the British Met Office predicts that the standstill will continue until at least 2017).

But if only now, in the summer of 2012, the Arctic ice is melting to a record minimum, it is difficult, therefore, to blame this on man-made global warming. The cause is likely to be the very special local climate conditions and trends, almost detached from the rest of world, which are still largely unknown. This means that even if the above mentioned hypothesis were coherent in itself, the basic assumptions would still be shaky.

A look into the past does not really confirm the renewed vision of climate scientists either. The last record ice melting – in the summer of 2007 – was followed by a winter in Germany, which was more than two degrees warmer than the long term average. Also, one would think that the dwindling albedo effect – if at all – affects the air currents especially in the early winter months, coinciding with the melting ice.

This winter, however, the above-average cold started only at the end; and the climax only happened in the first – meteorological – month of spring, March. Since September 2012, however, the Arctic sea ice has frozen again in record time and is already back in the average range, while during the polar night the issue of solar reflectance is of secondary importance.


The impact of continental climate

Where the theory coincides with reality is that we have been under the influence of a continental climate for many weeks; that we are coupled to Russia meteorologically. This is nothing new; we know it from previous winters. We should not look to a wind direction, which is supposedly specified by a global warming, for an answer to the question why we are having a particularly cold winter with record temperatures this year.

The answer is located in the extreme cold that prevails in the place where our weather comes from: Russia. It is more the global frost, which gives us the cold winter. At our latitudes around the globe, this winter has been above average cold; only in the Atlantic region of Canada has it been significantly warmer than the long-term average.

In Russia, there were hundreds of cold dead in the past month; the winter hit the country with up to minus 60 degrees. In Moscow it is currently 4.5 degrees colder than normal. Traffic was paralysed in many ways, as in parts of the USA for that matter.

Not only interesting theories about the new cold currently penetrate from climate research to the public. The Potsdam Institute for Climate Impact Research is also of the opinion that the winter (December to February) has been rather “too” warm, thus warmer than the long-term average temperature. In this, they agree with the German Weather Service, while other German meteorologists, like Dominik Jung of, assert the opposite.

Both are right, the difference is due to different reference periods. While the former use as “long-term average” the years 1961 to 1990, the others use a later another thirty year period. Jung, for example, uses the period 1971 to 2000. The climate scientists from NASA compare the data even with the period 1981 to 2010.


Winter was felt too cold

The world got warmer between 1970 and 2000, especially in the 1990s. Because of this a comparison made with current temperatures will always be more dramatic the further back the reference period is. Some consider this to be untrustworthy. They claim the term “long-term average” suggest a timely comparison and not a comparison with long past years, when many people were not even alive.

Price increases, crime rates and other statistics would also not be compared with figures from the 1960s. For most people, who are used to warmer weather, the winter was too cold anyway.

The theory that global higher temperatures via the melting of the Arctic ice cause cold winter in this country may in itself not be illogical. That it can explain the current weather conditions in March may however be doubted.

Full story (in German)

Translation by Philipp Mueller