First off, Lonborg is not a GW skeptic: he thinks it is real, but that the severity has often been greatly overstated, which even the scientists at IPCC will admit. Also, he does not mean that if we spend a few trillion dollars and deprive (by creating large deficits of energy) poor people all over the world of the few things they currently get to enjoy (like adequate food) we will decrease global temperature by 1 degree: he means we will limit the increase by one degree. Big difference. He is pointing out that taking a sledge hammer to the world economy will not really make much difference in temperature, but a big difference to people who will not be able to buy energy at the intentionally increased prices.
Lonborg points out that we will be able to adapt to the climate change, as people and animals have been doing throughout history, as we gradually change from fossil fuels as more desirable technologies mature. Some parts of the world - equatorial zones - may change drastically, but those nearer the poles (Minnesota, Canada) will likely gain a longer growing season and more tillable land.
But, Lonborg's main point is that if we spent these large sums of money and resources on things we can change: hunger, diseases like malaria and AIDS, and clean water, we could bring about some real improvement in the lives of millions of people world-wide.
My studies, which include a discussion with one of the leading scientists at IPCC, lead me to think that Lonborg makes a very good case. I don't know why so many reviewers ridicule Lonborg. This movie, if you really watch and listen, does not deny climate change. It does state that global poverty is not the best way to counteract global climate change.