• by Julio Godoy (berlin)
• Monday, January 19, 2009
• Inter Press Service

'Where is global warming, now that we need it?' a comedian asked on German public television ARD. And across Europe people have been asking the same question: if the globe is getting warmer, why is Europe freezing?

But the question really is whether recent winters taken together have been too warm. Yes, say climate researchers, they have.

'There is a cognitive problem among the public,' Mojib Latif, climate researcher at the Leibniz Institute for Ocean Sciences at the University of Kiel, some 300 km west of Berlin, told IPS. 'Because winters over the past 20 years have been warmer than the older average, many now believe that this winter is particularly cold. But it is not.'

'Of course it is really cold right now,' Fortunat Joos, professor of climate and environmental physics at the University of Bern in Switzerland told IPS. 'But present temperatures represent only a fluctuation in the trend of the past 20 years. In general, the earth is getting warmer.

'In the past 20 years, only six winters were colder than this average. The other 14 winters were all warmer. And the winter of 2006/2007 was the warmest ever measured since 1864. That's why many people now believe that this winter is particularly cold. It is not. It is only a cognitive problem.'

Scientific research has established that the earth will continue to get warmer if no substantial reductions in the emission of greenhouse gases take place. And there is wide scientific agreement that anthropogenic - that is, human-provoked - rise of greenhouse gases such as carbon dioxide and methane is responsible for global warming.

A recent model of the evolution of climate in Europe carried out by the German Climate Computing Centre (DKRZ, after its German name) based in Hamburg, some 300 km west of Berlin, estimated that average temperatures in southern and central Europe might rise by well over three degrees Celsius by the end of the century.

The model predicts a rise of temperatures of up to five degrees in the Scandinavian countries.

The DKRZ climate modelling was carried out in December with the centre's new high-performance supercomputer, which exceeds the capacity of other climate modelling computer systems by approximately 60 times. The DKRZ also used a new data archive as input for the model.

'With a peak performance of more than 140 Teraflop/s (140 trillion floating point operations per second) the centre's new computer is among the largest supercomputers being used for scientific purposes,' Joachim Biercamp, software specialist at the DKRZ told IPS.

Biercamp said that the new supercomputer 'allows computing projections of future climate in more detail, because more complex processes and interactions can be included in the models. The spatial resolution of the climate models will be enhanced too. Thus also regional phenomena could be seized substantially more accurately than with older modelling systems.'

This enhancing of computer climate calculations leads to more precise estimations of rainfall, rise of temperatures, inundations and droughts, and permits predictions on changes in fauna and flora in a given region.

The new DKRZ research carried out in cooperation with climate experts from several German universities and research centres divided Europe into hundreds of thousands of cubes of 18 km a side. Most other models divide the earth into sections ten times larger. The DKRZ model also divided the next 92 years in periods of 72 seconds. The calculation of the climate evolution until 2100 took four months.

The model used four possible scenarios, with varying assumptions of global climate policy success (or failure) in reducing greenhouse gas emissions. While the most optimistic scenario assumes that the world community manages to drastically reduce greenhouse gas emissions in the immediate future, the most pessimistic one supposes steadily growing emissions.

A middle alternative was based on the likely consequences in line with the conclusions at the UN climate conference in Poznan in Poland last month. According to this projection, by 2100 average temperatures would rise 3.6 degrees in southern Europe, 3.1 degrees in Germany, and by up to five degrees in the Scandinavian countries.

Uwe Boehm of the Potsdam Institute of Climate Impact Research who participated in the DKRZ modelling, told IPS that the projected climate changes have several regional characteristics.

'In Germany, we could not establish a growing trend of torrential rain,' he said. 'Quite the contrary; summer rain would be reduced by a third, but compensated for by rain in other seasons. And the number of hot summer days per year, with temperatures above 25 Celsius degrees, might double, up to 47.'

Central European vegetation such as coniferous forests could not survive in such circumstances. Instead, new flora and fauna would migrate into the region.

In southern Europe, the consequences of climate change would be longer dry periods, with up to 60 percent less rain than today. 'That means severe droughts,' Boehm said.

© Inter Press Service (2009) — All Rights Reserved. Original source: Inter Press Service

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