Scientists and amateur weather enthusiasts have given many accounts of what causes global warming—burning fossil fuels—and what the effects will be. New Jersey's governor Chris Christie gave his opinion that global warming had nothing to do with hurricane Sandy. Climate change experts would not agree with him on that, however.
The Intergovernmental Panel on Climate Change (IPCC), an international organization of climate scientists, has provided guidelines on which weather events are likely to be influenced by global warming. The IPCC reviews the scientific literature and publishes its findings. It uses the following rating system:
A conclusion is very likely if the IPCC finds there is a 90-100 per cent chance it is true.
A conclusion is likely if the IPCC finds there is a 66-100 per cent chance it is true.
The Union of Concerned Scientists (UCS) has prepared this graphic representation of IPCC conclusions:
Using this chart, you can easily see whether the IPCC believes a particular event is likely to be the result of global warming. Tornados and Hurricanes are not considered to be caused or worsened by global warming, largely because there is insufficient data on older events. The study of hurricanes was fragmentary until the advent of weather satellites in 1959 and our knowledge of them still increases all the time. So Hurricane Sandy may have been affected by global warming, but we have no way of knowing that.
Right now, scientists are not certain what effects global warming is having on hurricanes and tornados. They are learning more about these and other extreme weather phenomena all the time.
What we do know is that coastal flooding is very likely to be increased by global warming and this includes the flooding caused by Sandy. Governor Christie should have informed his constituents of this fact so that they could prepare for similar events in the future and be willing to vote for measures to lessen their damage. The strategy of Republicans like Christie has been to deny that global warming is a problem while at the same time planning to combat its effects.
The U.S. is a democracy. Decisions involving global warming affect all of us and we all should be informed about our options. Christie's decision to conceal the likely effects of global warming from his constituents represents the worst kind of politics. Politicians must provide voters the information they need to make informed decisions.
In the DC region, where I live, this summer has been marked by severe weather, in particular heavy downpours and extended heat waves. A glance at the chart reveals that these events are very likely made worse by global warming.
The Republican party has been captured by global warming deniers. Within the framework of American politics it is easy to believe that one party or the other is exaggerating or minimizing problems for its political benefit. The IPCC is an international organization, however, with little interest in or influence on American politics.
The western U.S. is currently suffering from severe droughts. The IPCC studies report that these droughts are likely to be made more severe by global warming. We can do nothing to reverse the global warming that has already occurred. We are likely or very likely (66% to 100% probability) to experience more and longer droughts in the future. The same is true for heavy rains, heat waves, and coastal flooding. We would be well advised to anticipate and plan for all of them.