January has seen temperatures in European Russia plunge 5 degrees Celsius below a 30-year average, but this is simply more evidence of man-made climate change, Russia's climatologists say.
"Nature is looking for a new balance," said Viktor Danelyan, director of the Institute of Water Problems at the Russian Academy of Sciencies, of the record warm temperatures in December, followed by January's freeze.
"What that equilibrium will be - no one can tell. Once the various regional factors stabilise, the climate will be warmer in general. And the weather volatility we are seeing today will settle down. We can only hope that the new equilibrium is not too warm, because that will negatively affect life on earth."
The debate over global warming has become increasingly bitter in recent months, with environmental activists blaming top polluting nations for failing to agree deeper emissions cuts at the Copenhagen climate summit in December.
eanwhile, in the so-called "Climategate" scandal, hacked scientists' e-mails were seized on by sceptics as evidence that data was being cherry-picked to support environmentalists' arguments.
Climatologists in Russia, where President Dmitry Medvedev has proposed to allow a small increase on current greenhouse gas emissions by 2020, agree that the weather here is becoming warmer, as least in part to man-made factors.
"The abnormally cold weather we are seeing does not contradict things," said Vladimir Katsov, a climatologist at the Voyeikov Geophysical Observatory in St. Petersburg. "So-called weather neuroses increase during periods of climate change."
But the problem is in oversimplifying a complex and ill-understood process, scientists say.
"There are a lot of periodic changes - short-term, long term, mid-term. They all overlap, and all this creates climate volatility." said Danelyan.
"The anthropogenic factor is adding to this natural volatility, leading to warming. If global warming was supposed to be happening naturally, now it's happening even faster."
When overlapping with natural factors, scientists say global warming results in erratic weather. For instance, climatologists believe that the recent cold spell in Europe is caused by Arctic oscillation, with lower atmospheric pressure contributing to cold Arctic air moving further south. "Arctic oscillation is a perfect example of a natural process of weather fluctuation, not connected to external or man-made factors," said Kattsov. But there's a catch - these natural fluctuations can act to offset or exacerbate anthropogenic global warming."
This year marks the start of an expected natural cold phase that will last for a few years, Danelyan said. "But there are other factors connected to regional peculiarities that were not foreseen. Because of the shrinking Arctic ice cap, Siberian winters are becoming harsher. This is in addition to the Arctic oscillation, and it's intensifying the cold snap."
But that doesn't mean that Siberian winters will get colder in the long run. A combination of natural periodic climate change and gas emissions will mean that the average global temperature - now 14 degrees Celsius - will increase by 0.75 degrees per decade. By cutting emissions, Kattsov says, we can reduce the temperature increase by 2 degrees.
"It's widely believed that an increase in average temperatures over the next few decades would be good for Russia," said Kattsov. "But a number of factors make Russia vulnerable. The thawing of permafrost is one of those. On the one hand, a shorter heating season is economically beneficial, but we shouldn't forget the southern regions, where hotter weather and heat waves will mean more energy spent on air conditioning."
Igor Podgorny, a Greenpeace official, said any benefit to agriculture from shorter winters would be offset by erratic weather. "Scientists have talked about erratic cold spells as a result of global warming," he said. "Late cold spells will freeze crops."
But Gennady Yeliseyev, who heads Russia's Meteorology Centre, remains reluctant to draw any conclusions from January's cold snap.
"The weather is not the same thing as climate," said Yeliseyev. "Volatile weather is part of a natural process ... If we get a lot of air from the south, from Africa, then we will have abnormally warm temperatures, which we saw a few years ago when the first snow came in late January.
If we get air from the north or east we'll have cold weather. These are all normal atmospheric processes."
Declining to comment on global warming, Yeliseyev was fatalistic about scientists' ability to understand the weather. "Long-term forecasts are only about 60 per cent to 70 per cent accurate," he said.
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