In the last few months, as the severe California drought has garnered attention among scientists, policymakers, and media, there has been a growing debate about the links between the drought and climate change. The debate has been marked by considerable controversy, confusion, and opaqueness.
The confusion stems from the failure of some scientists, bloggers, reporters, and others to distinguish among three separate questions. All three questions are scientifically interesting. But the three are different in their nuance, their importance to policy, and their interest to politicians and water managers. Here are the three different questions:
Is the California drought caused by climate change?
Is the California drought, no matter the cause, influenced or affected by climate changes already occurring?
How will climate changes affect future drought risks in California?
These questions are not the same thing. Yet repeatedly, some have asked one question when they thought they were asking a different one. Some have been asked one question and intentionally or accidentally answered a different one. Some have confused an answer to one question as an answer to a different question.