Freeman Dyson has an interesting essay on heresy, global warming and much else. He argues that we don't know nearly enough to predict what will happen to climate, what the human contribution to climate change is, or whether likely changes are on net good or bad. In particular, we do not understand the biological part of the equation very well--the effect of increases in CO2 or changes in human land use on the amount of carbon tied up in topsoil.
When I point out how small the predicted effects are of global warming--a few degrees increase in temperature and a foot or so in sea level over the next century--a common response is that the average effects understate the costs. Dyson implies the opposite conclusion:
In humid air, the effect of carbon dioxide on radiation transport is unimportant because the transport of thermal radiation is already blocked by the much larger greenhouse effect of water vapor. The effect of carbon dioxide is important where the air is dry, and air is usually dry only where it is cold. Hot desert air may feel dry but often contains a lot of water vapor. The warming effect of carbon dioxide is strongest where air is cold and dry, mainly in the arctic rather than in the tropics, mainly in mountainous regions rather than in lowlands, mainly in winter rather than in summer, and mainly at night rather than in daytime. The warming is real, but it is mostly making cold places warmer rather than making hot places hotter. To represent this local warming by a global average is misleading.
One of the best bits of the essay deals not with global warming but with the tension between "naturalist" and "humanist" views of the world:
Here I must confess my own bias. Since I was born and brought up in England, I spent my formative years in a land with great beauty and a rich ecology which is almost entirely man-made. The natural ecology of England was uninterrupted and rather boring forest. Humans replaced the forest with an artificial landscape of grassland and moorland, fields and farms, with a much richer variety of plant and animal species. Quite recently, only about a thousand years ago, we introduced rabbits, a non-native species which had a profound effect on the ecology. Rabbits opened glades in the forest where flowering plants now flourish. There is no wilderness in England, and yet there is plenty of room for wild-flowers and birds and butterflies as well as a high density of humans. Perhaps that is why I am a humanist.