What is now considered an unusually extreme drought conditions in North America, could be a normal state in that part of the American continent in the middle of this century because of global warming.

A team of scientists from U.S. national laboratories, Lawrence Berkeley and Lawrence Livermore, and U.S. Administration’s National Oceanic and Atmospheric Administration (NOAA for its acronym in English), has reached this conclusion after analyzing 19 different climate models of last generation.

Examining the balance between precipitation and evapotranspiration, the authors of the new research has found that global warming leads inexorably to drought, despite the many changes that may experience rainfall patterns over the next 100 years.

To determine the normal conditions of drought today, Michael Wehner, a climatologist of the laboratory in Berkeley, and colleagues studied the average conditions of rainfall and evapotranspiration balance for North America, based on data obtained from observations by the Center National Climate Data NOAA for the period between 1950 and 1999.

They then used global climate models (GCMs, for its acronym in English) for projections of balance between rainfall and evapotranspiration over this century.

These models show that the normal state for much of the continental United States and Mexico since the mid-to late century will be the characteristic of a drought in the now considered among severe and extreme. For Canada, the models indicate that drought today considered mild to moderate will be the normal state of that country.