Warmth is, on the whole, a good thing when you are cold, a bad thing when you are hot. Generalizing to nations, the countries most likely to benefit by global warming are ones close to the poles. The habitable area of Canada, for example, is a narrow strip several thousand miles long bordered by the United States on one side, snow and ice on the other. A few degrees of warming would make it substantially wider, as well as making the currently inhabited parts a little more habitable.
Along similar lines, the countries most likely to lose by global warming are those where it is already too hot. India, for example. Which is why I was struck by a news story about the Prime Minister of Canada's plans to lecture the Prime Minister of India on the dangers of global warming.
Meanwhile, Putin has announced that he does not believe in AGW. My guess is that what that really means is that he is in favor of it. Russia is, after all, the only country in the world with a longer arctic boundary than Canada.
(Very low lying countries are also at risk from warming, but there are not many low enough to be seriously threatened by a meter of sea level rise, which is the upper bound of the current IPCC high emissions projection for 2100.)