The upcoming election battles may be unique in offering for the first time a debate about global warming.
Neither Bush-Gore nor McCain-Obama chose to discuss the issue — maybe because they were not really that far apart. By contrast, Barack Obama has already announced that, if re-elected, he will make climate change an important priority — while Paul Ryan is an assertive skeptic on AGW (anthropogenic global warming).
The science of climate change is not just of academic interest, but has been leading to policies for large-scale changes in energy use and supply — with important economic consequences. The burden of proof for AGW therefore falls on those who call for such policies. They must demonstrate with reasonable certainty that human activities are causing global warming, that a future warming will produce significant economic and ecological damage, and that it would be more cost-effective to mitigate now rather than to adapt later. They must also be ready to respond to any critique of the underlying science.
A recent example of irresponsible AGW claims is a just-released statement by the American Meteorological Society — the same crew that cannot predict the weather three days in advance.