Does Global Warming Cause Intensified Interannual Hydroclimate Variability

AbstractThe idea that global warming leads to more droughts and floods has become commonplace without clear indication of what is meant by this statement. Here, the authors examine one aspect of this problem and assess whether interannual variability of precipitation P minus evaporation E becomes stronger in the twenty-first century compared to the twentieth century, as deduced from an ensemble of models participating in Coupled Model Intercomparison Project 3. It is shown that indeed interannual variability of P − E does increase almost everywhere across the planet, with a few notable exceptions such as southwestern North America and some subtropical regions. The variability increases most at the equator and the high latitudes and least in the subtropics. Although most interannual P − E variability arises from internal atmosphere variability, the primary potentially predictable component is related to the El Nino–Southern Oscillation (ENSO). ENSO-driven interannual P − E variability clearly increases in ...