Rain and Drought

Trend in contribution to total annual precipitation from very wet days
Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Figure 3.39, Cambridge University Press.

More water vapor held by a warmer atmosphere also leads to heavier rains and more snowfall. In particular, heavy rains are increasing in temperate zones. For example, in the continental United States, intense precipitation increased by 20% over the past century, while total precipitation increased 7%.

Graphic depicting Palmer Drought Severity Index 1900-2002
Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. FAQ 3.2, Figure 1, Cambridge University Press.

More evaporative power doesn't just mean more rain—paradoxically, it also means that some areas get drier as storm tracks shift. A 2004 study by the National Center for Atmospheric Research found that the percentage of Earth's land experiencing serious drought had more than doubled since the 1970s.

And, along with drought, wildfires have become more widespread recently across the U.S. and Canadian West.