Even faraway drought will destabilize the United States in two main ways:
1) Beginning in 2004, we started importing half of our food. Drought will make imports more expensive. Larry Rohter. Dec 12, 2004. South America Seeks to Fill the World’s Table. New York Times
2) Drought will cause millions of people in Central America to seek shelter in the USA, millions in Southwest America to migrate to other states, climate refugees in Africa will migrate to Europe, etc.
Less food due to drought and mass migrations, on top of declining oil, will make food even more scarce (in 2011, 1 in 6 people in the USA were on food stamps), and this will increase social unrest, which will affect transportation, factory production, and everything else. It’s all interconnected…
U.S. Southwest & Central America
As parts of Central America and the U.S. Southwest endure some of the worst droughts to hit those areas in decades, scientists have unearthed new evidence about ancient dry spells that suggest the future could bring even more serious water shortages.
North East America
At least 3 major dry spells have occurred in the Northeast within the last 6,000 years. The longest, which corresponds with a span of time known as the Medieval Warm Period, lasted some 500 years. The other two took place more than 5,000 years ago. They were shorter, only about 20 to 40 years, but likely more severe. “People don’t generally think about the Northeast as an area that can experience drought, but there’s geologic evidence that shows major droughts can and do occur. We still need to do more research before we can say with confidence how widespread or frequent droughts in the Northeast have been,” Peteet said.
Ancient Meso-American civilizations of the Mayans and Aztecs likely amplified droughts in the Yucatán Peninsula and southern and central Mexico by clearing rainforests to make room for pastures and farmland.
Converting forest to farmland can increase the reflectivity, or albedo, of the land surface in ways that affect precipitation patterns. “Farmland and pastures absorb slightly less energy from the sun than the rainforest because their surfaces tend to be lighter and more reflective,” explained Cook. “This means that there’s less energy available for convection and precipitation. Precipitation levels declined by a considerable amount — 10 to 20% — when deforestation was widespread. Drought, amplified by deforestation, was a key factor in the rapid collapse of the Mayan empire around 950 C.E. In 2010,
Jean Guerrero. 4 Feb 2012. Mexico Drought Chokes Cattle, Crops. Wall Street Journal: FRAILE, Mexico—The worst drought on record in various parts of Mexico has destroyed millions of acres of cropland and left millions of livestock without food, leading to fears about potential food shortages at a time when U.S. states like Texas are also suffering unusually dry weather. More than half of the national territory has fallen prey to the drought, with dried-up streams in northern states like Coahuila turning into cattle graves and some towns lying abandoned as people flee the drought. More than 3.7 million acres of agriculture have been lost, an area larger than Connecticut. Mexico is the main supplier of cattle to the U.S., which imported more than 1.23 million head of cattle from Mexico last year, according to the USDA, as well as a record 142 million pounds of beef and veal in the first 11 months of the year.
Sub Saharan Africa
Climate change, with its potential to redistribute water availability around the globe by increasing rainfall in some areas while worsening drought in others, might negatively impact crop yields in certain regions of the world. New research conducted by Princeton University hydrologist Justin Sheffield shows that areas of the developing world that are drought-prone and have growing population and limited capabilities to store water, such as sub-Saharan Africa, will be the ones most at risk of seeing their crops decrease their yields in the future. They also found that the area across sub-Saharan Africa experiencing drought will rise by as much as twofold by mid-21st century and threefold by the end of the century. For some regions of sub-Saharan Africa, the researchers found that agricultural productivity will likely decline by over 20 percent by mid-century due to drying and warming.
Rainfall patterns over east Africa have changed in a way that makes severe droughts more likely.
Last year’s drought occurred because BOTH of the region’s rainy seasons failed. The rain between October and December 2010 failed because of La Niña. The longer rain between March and May failed due to a sharp rise in sea-surface temperatures in the western tropical Pacific Ocean, while further east the ocean cooled. Ths does not bode well for the future. Marshall, M. 28 Jan 2012. East Africa may face recurring drought. NewScientist. p 14.
5 Dec 2011. Ancient Dry Spells Offer Clues About the Future of Drought. NASA/Goddard Space Flight Center. ScienceDaily.
W. deBuys. 13 Dec 2011. The ‘Age of Thirst’ in the American West Coming to a theatre near you: the greatest water crisis in the history of civilisation. Aljazeera.