31 December 2010

Going to Extremes in 2010, part 2: the Droughts

This part of my summary of hydrologic extremes in 2010 is organized a little differently from that for floods, posted in part 1.  As flood events occur more discretely in time, that list was organized month-by-month over the year.  Meteorological and hydrologic droughts are more of a creeping phenomenon over time, and it is geography that distinguishes one drought from another over the same year.  Droughts appeared or showed their strength in several locations this year, especially under the influence of a summer heatwave in the Northern Hemisphere:
  • Africa: the Sahel region reported drought and famine conditions as early as January this year, a chronic occurrence when the tropical and monsoon rains don't quite make it far enough northward the previous summer.  As a consequence, these are the years in which desertification at the western and southern edges of the Sahara become more evident.
  • China: spring droughts and dust storms resulted from long-term effects of desertification, deforestation, large-scale drought, urban sprawl and overgrazing throughout eastern Asia, as well as El Niño conditions of the winter prior to the drought.  Agricultural production in China was reduced by nearly half, and more than 50M citizens were left short of water as early as March because of meager rainfall and drying reservoirs. Summer flooding during the East Asian Monsoon season only served to wash out dry and barren farmland in the southern areas of the country. 
  • Southeast Asia: Vietnam, Thailand and the Philippines were affected by the same drought that held China from the winter before, and a mild Southeast Asian Monsoon season did little to relieve conditions there.  Generally dry conditions in the region of the Mekong headwaters in China did little to help river flows downstream over the remainder of the year.
  • Russia: beginning in July, record high temperatures and little rainfall trapped under a strong Siberian high pressure system let to an outbreak of hundreds of forest and peatland fires across northern Ukraine and western Russia.  Moscow was enveloped in smoke and smog clouds for weeks, and crop failures occurred across the country.  Local and international response to the disaster was hampered further by information controls exerted by the Russian government.
  • North AmericaDrought conditions continued in the Southwest U.S., and the combination of El Niño impacts on the western U.S. and yet another weak North American Monsoon season led to ominous predictions of longer droughts and water resource shortages on the Colorado River.  Increasing variability in rainfall helped drought conditions take hold of the Southeast U.S., which is beginning to experience sustainability issues in water resources like the Southwest.  Even areas in Canada experienced wildfire outbreaks due to dry conditions in the spring.
And in the Southern Hemisphere, with less land area and overall population density compared with the global north, droughts still held their grip on key areas:
So 2010 has certainly been a year of extremes, including floods and droughts around the globe.  What will 2011 hold for all of us?

No comments: