Global warming is changing the pattern of wet and dry areas around the world. Scientists have broadly observed, and continue to expect, that climate change leads to dry regions getting drier, and wet regions wetter.
From 1979 to 2013, a study analyzing soil moisture from satellite data found that 30 percent of global land experienced robust moisture trends, with 22.16 percent becoming drier, and 7.14 percent becoming wetter.
Another study analyzing annual mean soil moisture trends from 1948 to 2010 identified significant trends for 40.6 percent of the global area, with 60.2 percent of this area experiencing drier conditions, and 39.8 percent wetter. The most prominent drying trends occurred in northern Africa, East Asia, eastern Australia, and southern Europe, whereas subtle increases in soil moisture were observed for the central US, South America, and western Australia.
By 2100, models project that many regions—including, the Mediterranean, Southwest US and southern Africa—are likely to get drier should greenhouse gas emissions continue unabated.
Hadley Cell Expansion
Model projections indicate that the Hadley Circulation will shift its downward branch poleward in both the Northern and Southern Hemispheres, causing drying as a result.
Scientists have already observed a poleward shift of the southern Hadley Cell.