Russia's summer heat wave has dimmed prospects that northern countries will "win" from climate change thanks to factors such as longer crop-growing seasons or fewer deaths from winter cold, experts say.
Canada, Nordic countries and Russia have been portrayed as among a lucky few chilly nations where moderate climate change will mean net benefits such as lower winter heating bills, more forest and crop growth and perhaps more summer tourism.
Russia's two-month heat wave - blamed on global warming by President Dmitry Medvedev even though many experts say it is impossible to link individual weather events to climate change - is likely to shift the perceptions of risks.
"There ought to be, coming out of this, a greater awareness that many hazards come with climate change," said Kevin Trenberth, head of climate analysis at the U.S. National Center for Atmospheric Research in Boulder, Colorado.
"It's not a matter of a benign shift to a longer growing season" for northern nations, he said. Russia's heat wave doubled death rates in Moscow, wrecked a quarter of Russia's grain crop and may cut $14-billion from gross domestic product.
Many people in Nordic nations and Canada have grown aware of possible damaging side-effects of less chill weather, including the risk to forests and crops of insect pests normally kept in check by winter frosts.
But that belief is less widespread in Russia, where Prime Minister Vladimir Putin has in the past sometimes spoken about benefits of global warming. As president, in 2002 he joked that less icy weather would enable Russians to buy fewer fur coats.
"By and large, Canadians understand that there may be benefits but climate change is going to be bad," said Steven Guilbeault, of Canadian environmental group Equiterre. Extreme weather in 2010 "is going to help people understand the risks."
He said government policy did not match the urgency felt by the public. Canada's greenhouse gas emissions were 24 per cent above 1990 levels in 2008, despite a promise under the UN's Kyoto Protocol to cut them to 6 per cent below 1990 levels by 2008-12.
Russia's emissions were 33 per cent below 1990 levels in 2008, partly due to the collapse of high-polluting Soviet industries, and well within its Kyoto goal of keeping emissions below 1990 levels by 2012.
Moscow plans to let emissions rise from current levels by 2020, despite pleas by many nations for a tougher goal.
A study in Norway in June showed farming and forestry could benefit from moderate global warming, blamed mainly on emissions of greenhouse gases from burning fossil fuels.
"The immediate effects are in general benefits" to economic growth, said Asbjoern Aaheim, lead author at the Center for International Climate and Environmental Research, Oslo.
But there could be shocks, such as to fish stocks. And longer growing seasons were likely to have knock-on effects, such as more absence from work because of pollen-related illnesses.
Jay Gulledge, senior scientist at the Pew Center on Global Climate Change, said predictions of climate "winners" and "losers" inevitably ignored many risks, for instance on Russia from Pakistan's floods.
"Does Russia 'win' if the Taliban and other hardline extremists step in to fill the void left by an ineffectual government and international aid response to the floods in Pakistan?" he asked in a blog.