View of Dead Sea in distance with a surface 400 meters below sea level
With global temperatures rising, water evaporation and the drying out of the earth's soils will increase. Although the atmosphere would hold more moisture, rainfall may not necessarily increase to the same degree. A warmer atmosphere, being able to hold more water, would precipitate less proportionately in the form of rain. As an example of this phenomenon, the world today contains numerous hot and humid regions (like the Persian Gulf) lacking significant rainfall.
One possible way to increase rainfall in dry regions is to create or expand water bodies upwind of the area of interest. The additional moisture in the air from evaporation off this water body could improve rainfall conditions. The Great Salt Lake in the American state of Utah, and its larger Pleistocene antecedent, is an example of such a hydrological phenomena.
Another indirect benefit from these new seas and lakes could be wilderness. Life beside these new water bodies and in other attractive places dedicated to the human environment could be offered the inhabitant of regions desired for wilderness restoration and enhancement.
Depressions Below Sea Level
There are a number of below sea level depressions on this planet that could serve as vessels for these recreated water bodies. Before and after images below illustrate some relatively easy examples of terraforming on earth - the expansion of the Dead and Salton Seas to the level of the world's oceans, the filling of the Qattara Depression in Egypt with water directed from the Mediterranean. Another relatively easy project would fill the Caspian Sea to sea level.