FLOODS, tornadoes, earthquakes, tsunamis and other extreme natural phenomena have left a trail of destruction during the first half of 2011. But this could be just the start to a remarkable year of bad weather. Next up: drought. In the South, 14 states are now baking in blast-furnace conditions — from Arizona, which is battling the largest wildfire in its history, to Florida, where fires have burned some 200,000 acres so far. Worse, drought, unlike earthquakes, hurricanes and other rapid-moving weather, could become a permanent condition in some regions.
Climatologists call drought a “creeping disaster” because its effects are not felt at once. Others compare drought to a python, which slowly and inexorably squeezes its prey to death.
The great aridification of 2011 began last fall; now temperatures in many states have spiked to more than 100 degrees for days at a stretch. A high pressure system has stalled over the middle of the country, blocking cool air from the north. Texas and New Mexico are drier than in any year on record.
The deadly heat led to 138 deaths last year, more than hurricanes, tornadoes or floods, and it turns brush to tinder that is vulnerable to lightning strikes and human carelessness. Already this year, some 40,000 wildfires have torched over 5.8 million acres nationwide — and the deep heat of August is likely to make conditions worse before they get better.
Climatologists disagree about what caused this remarkable dry-out. But there is little disagreement about the severity of the drought — or its long-term implications. When I asked Richard Seager, who analyzed historical records and climate model projections for the Southwest for the Lamont-Doherty Earth Observatory at Columbia University, if a perpetual drought was possible there, he replied: “You can’t really call it a drought because that implies a temporary change. The models show a progressive aridification. You don’t say, ‘The Sahara is in drought.’ It’s a desert. If the models are right, then the Southwest will face a permanent drying out.”
Growing population has increased the burden on our water supply. There are more people on earth than ever, and in many places we are using water at unsustainable rates. Cultural shifts contribute to subtle, far-reaching effects on water supplies. In 2008, for the first time, more people lived in cities than in rural communities worldwide, and water is becoming urbanized. Yet some of the world’s biggest cities — Melbourne, Australia; Barcelona, Spain; and Mexico City — have already suffered drought emergencies. Further drying could lead to new kinds of disasters. Consider Perth, Australia: its population has surpassed 1.7 million while precipitation has decreased. City planners worry that unless drastic action is taken, Perth could become the world’s first “ghost city” — a modern metropolis abandoned for lack of water.