Russia, the world's largest natural gas exporter with some 30 percent of proven global reserves, handles the majority of imports to Europe; in Germany, more than 30 percent of all gas used stems from fields in Siberia.

In 2006, Russia's record as a reliable supplier was questioned after a price row with Ukraine. The row, during which Russia temporarily shut off Ukrainian supplies, has worried politicians in Western Europe about the future of Europe's supplies.

But besides politics, a whole other problem could threaten Europe's gas imports -- cimate change. Russia's gas fields lie below a several-hundred-feet deep layer of permanently frozen ground -- permafrost. In western Siberia, entire pipeline systems are relying on the solidity of the year-round ice.

Over the past 30 years, however, the mean temperature in western Siberia rose by 5.4 degrees, resulting in gradual melting of the ground. As that process is releasing large amounts of greenhouse gases (such as methane), the melting even speeds up climate change.

Russian and British scientists have monitored temperatures and have warned officials that already tapped-in gas field infrastructure in western Siberia and the exploitation of future fields on the Yamal peninsula and eastern Siberia are threatened. The existing pipeline infrastructure would sink in the marsh, and even worse could happen: "The high-pressure oil and gas pipelines can explode," Roland Goetz, energy expert at the German Institute for International and Security Affairs, told United Press International. "Roughly half of all Russian fields are affected,"

The melting of the permafrost then would likely lead to a soaring of energy prices. All the existing infrastructure -- such as production facilities, pipelines, tanks, work housing and roads -- would have to be adapted to accommodate the softer ground, and such comprehensive construction work is very costly. In parts of Siberia, where production is planned to start in the course of the coming years, initial production costs would significantly rise. "Building and producing on the much softer ground is more expensive," Goetz said, costs that are naturally handed over to the consumer.

The Russian environment monitoring agency, Roshydromet, earlier this year published a report called "Strategic prediction for the period of up to 2010-2015 of climate change expected in Russia and its impact on sectors of the Russian national economy," in which the agency warns of the dangers of permafrost melting to the Russian energy sector, which makes up a major part of the country's economy and in recent years has transformed the country into an energy superpower.

In Moscow, however, officials have not showed any signs of concern yet.

"While there are many reports on permafrost melting coming out of Alaska, in Russia, this still is a taboo topic," Goetz said, referencing the policy of silence from the Kremlin when it comes to the issue.

The year 2007, when climate change will be on the agenda of the Group of Eight summit in Heiligendamm, Germany, could be a decisive year for climate protection; Russia won't be able to reverse the trend of rising greenhouse gases alone; the country itself is expected to emit more greenhouse gases as domestic energy consumption rises.

"A worldwide effort is needed to contain global warming," Goetz said. "This is by far the world's greatest problem, and, unlike energy supply problems, there comes a moment when you can't control climate change anymore."

For Russia, missing that moment could be costly.