John Nielsen-Gammon, Ph.D.
Texas State Climatologist
Regents Professor of Atmospheric Sciences
Texas A&M University
Drought is complicated. From year to year, the existence of drought is determined by lack of rainfall, but longer-term trends influence drought severity and drought impacts. These influences include temperature, humidity, rainfall intensity, rainfall variability, plant physiological responses to carbon dioxide, and ecological responses to climate. Some of these have well-established connections with climate change on a global scale, but local projections are more challenging. Potential impacts are both positive and negative, depending on the particular factor, and some factors can have opposing effects depending on the type of drought. Overall, it is clear that future droughts will be different from past droughts in several crucial aspects.