NOAA's National Center for Environmental Information,
drought ranks second in terms of national weather-related economic impacts, with
annual losses nearing $9 billion per year in the U.S.
Beyond direct economic impacts, drought can threaten drinking water supplies and
ecosystems, and contribute to food price increases.
Within the last decade, drought conditions have hit the Southeastern U.S., the
Midwest, and the Western U.S. According to the August 25, 2015,
U.S. Drought Monitor,
moderate to exceptional drought covers 29.5% of
the contiguous United States, a slight increase from last week’s 29.4%. The
worst drought categories (extreme to exceptional drought) also increased from
9.4% last week to 11.0%.
(See Figure 1 to right)
Global warming worsens drought as the temperature of the atmosphere increases
and the irony is the water that evaporates from a drying region often falls to
inundate someplace else.
The prolonged drought in California, which is the world’s eighth-largest
economy, now in its fourth year, has cut supplies of water used to be available
to irrigate crops.
In July 2015 the state ordered farmers to stop pumping water. The wells on
California’s farms have been pumping more water out of the region’s aquifer than
is replenished by rainfall, so that the land of the Central Valley is actually
sinking. The resulting damage to the aquifer is permanent, reducing its capacity
to hold water if and when rainfall returns.
In the estimation of
The Earth Institute of Columbia University, global warming
contributed between 8 and 27 percent to the severity of California's drought
and is playing a similar roll globally per the
U.S. Drought Portal map to the right (Figure 2).
Drought conditions are intensifying over the majority of Europe.
In Asia, drought continues, focused in the Southeast as well as around the
Indonesia is warning about the potential for failed crop harvests largely due
to El Nino.
In Africa, drought intensified and expanded in the equatorial region and in
the North. .
South African maize production is down an estimated 32%.
In South America, drought remains entrenched in Brazil and the Southern Andes
and while not expanding much in area, has intensified in many other
In Australia, drought indicators point to a slight easing of conditions in the
North while the Southwest is experiencing drought expansion.
Drought conditions are mitigated by moving atmospheric heat to deep water.