Lessons from 2012: Droughts, not Hurricanes, are the Greater Danger

The colossal devastation and loss of life wrought by Hurricane Sandy makes the storm one of the greatest disasters in U.S. history. The storm and its aftermath have rightfully dominated the weather headlines this year, and Sandy will undoubtedly be remembered as the most notable global weather event of 2012. But shockingly, Sandy is probably not even the deadliest or most expensive weather disaster this year in the United States--Sandy's damages of perhaps $50 billion will likely be overshadowed by the huge costs of the great drought of 2012. While it will be several months before the costs of America's worst drought since 1954 are known, the 2012 drought is expected to cut America's GDP by 0.5 - 1 percentage points, said Deutsche Bank Securities this week. “If the U.S. were growing at 4 percent, it wouldn’t be as big an issue, but at 2 percent, it’s noticed,” said Joseph LaVorgna, the chief U.S. economist at Deutsche. Since the U.S. GDP is approximately $15 trillion, the drought of 2012 represents a $75 - $150 billion hit to the U.S. economy. This is in the same range as the estimate of $77 billion in costs for the drought, made by Purdue University economist Chris Hurt in August. While Sandy's death toll of 113 in the U.S. is the second highest death toll from a U.S. hurricane since 1972, it is likely to be exceeded by the death toll from the heat waves that accompanied this year's drought. The heat waves associated with the U.S. droughts of 1980 and 1988 had death tolls of 10,000 and 7,500 respectively, according to NOAA's National Climatic Data Center, and the heat wave associated with the $12 billion 2011 Texas drought killed 95 Americans. With July 2012 the hottest month in U.S. history, I expect the final heat death toll in the U.S. this year will be much higher than Sandy's death toll.

Figure 1. The top-ten list of most expensive U.S. weather-related disasters from NOAA's National Climatic Data Center (NCDC) is dominated by hurricanes and droughts. Three of the top five disasters are droughts. The numbers for Hurricane Sandy and the 2012 drought are preliminary numbers from media sources, and are not from NCDC.

Drought: civilization's greatest natural enemy
People fear storms, and spectacular and devastating storms like Hurricane Sandy and Hurricane Katrina have stirred more debate in the U.S. about taking action against climate change than any other weather event. But I argue that this attention is misplaced. Drought is our greatest enemy. Drought impacts the two things we need to live--food and water. The history of civilization is filled with tales of great storms that have killed thousands and caused untold suffering and destruction. But cities impacted by great storms inevitably recover and rebuild, often stronger than before. I expect that New York City, the coast of New Jersey, and other areas battered by Sandy will do likewise. But drought can crash civilizations. Drought experts Justin Sheffield and Eric Wood of Princeton, in their 2011 book, Drought, list more than ten civilizations and cultures that probably collapsed because of drought. Among them: The Mayans of 800 - 1000 AD. The Anasazi culture in the Southwest U.S. in the 11th - 12th centuries. The ancient Akkadian Empire in Mesopotamia. The Chinese Ming Dynasty of 1500 - 1730. When the rains stop and the soil dries up, cities die and civilizations collapse, as people abandon lands no longer able to supply them with the food and water they need to live.

Figure 2. Ruins of the Cliff Palace at Mesa Verde National Park in Colorado. Beginning in 1150 AD, North America experienced a 300-year drought called the Great Drought. This drought has often been cited as a primary cause of the collapse of the ancient Anasazi civilization in the Southwest U.S., and abandonment of places like the Cliff Palace.

The coming great droughts
We should not assume that the 21st century global civilization is immune from collapse due to drought. If we continue on our current path of ever-increasing emissions of carbon dioxide, the hotter planet that we will create will surely spawn droughts far more intense than any seen in recorded history, severely testing the ability of our highly interconnected global economy to cope. The coming great drought disasters will occur at a time when climate change is simultaneously creating record rainfall and flooding in areas that happen to be in the way of storms. Global warming puts more heat energy into the atmosphere. That means more more water will evaporate from the oceans to create heavier rains and make storms stronger, and there will be more heat energy to increase the intensity of heat waves and droughts. It all depends upon if you happen to lie on the prevailing storm track or not which extreme you'll experience. In the future, if you're not being cooked in a record drought, you're going to be washed away in a record flood. Just ask the residents of the Midwest. In 2011, residents of the Midwest endured the largest floods on record on their three great rivers--the Mississippi, Missouri, and Ohio. In 2012, the same region endured their worst drought since 1954, and a top-ten warmest summer.

The nation's top scientific research group, the National Research Council, released an 18-month study on November 9, 2012, titled, "Climate and Social Stress: Implications for Security Analysis". They stated: “It is prudent to expect that over the course of a decade some climate events--including single events, conjunctions of events occurring simultaneously or in sequence in particular locations, and events affecting globally integrated systems that provide for human well-being--will produce consequences that exceed the capacity of the affected societies or global system to manage and that have global security implications serious enough to compel international response.” In other words, states will fail, millions will suffer famine, mass migrations and war will break out, and national and international agencies will be too overwhelmed to cope. We were very lucky that the 2012 U.S. drought did not occur the year following the great 2010 Russian drought. That drought drove up food prices to the highest levels since 1992, and helped trigger social unrest that led to the "Arab Spring" revolts that overthrew multiple governments. Severe droughts in back-to-back years in major world grain-producing areas could cause unprecedented global famine and unrest, and climate change is steadily increasing the odds of this happening.

Figure 3. Black Sunday: On April 14, 1935 a "Black Blizzard" hit Oklahoma and Texas with 60 mph winds, sweeping up topsoil loosened by the great Dust Bowl drought that began in the early 1930s.

Learning from the past: the great Dust Bowl of the 1930s

"The clouds appeared and went away, and in a while they did not try anymore."
- Nobel Prize-winning author John Steinbeck in his 1939 classic, The Grapes of Wrath, describing the weather in Oklahoma during the great Dust Bowl drought of the 1930s.

No disaster in American history caused more suffering than the legendary Dust Bowl drought of the 1930s, as year after year of desperately dry conditions across the Great Plains dried out farmlands, forcing 2.5 million people to leave their homes and seek a better life elsewhere. At its peak in July 1934, drought conditions covered an astonishing 80% of the contiguous U.S., making it our largest drought ever recorded. The true cost of the drought is impossible to calculate, but the amount of government assistance paid out was $13 billion in today's dollars. The heat waves that accompanied the drought killed at least 5,000 people, making it one of the deadliest disasters in U.S. history. Fortunately, a repeat of the dust storms and hardships of the 1930s Dust Bowl are much less likely now, because we learned from our mistakes. In a 2009 paper titled, Amplification of the North American "Dust Bowl" drought through human-induced land degradation, a team of scientists led by Benjamin Cook of the Lamont-Doherty Earth Observatory explained the situation that led up to the Dust Bowl:

During the 1920s, agriculture in the United States expanded into the central Great Plains. Much of the original, drought-resistant prairie grass was replaced with drought-sensitive wheat. With no drought plan and few erosion-control measures in place, this led to large-scale crop failures at the initiation of the drought, leaving fields devegetated and barren, exposing easily eroded soil to the winds. This was the source of the major dust storms and atmospheric dust loading of the period on a level unprecedented in the historical record.

Improved farming practices adopted after the great Dust Bowl allowed the Midwest to endure the great multi-year drought of 1951 - 1954 without the kind of damage the Dust Bowl caused. Those improved farming practices, in combination with the development of improved drought-resistant grains, have helped keep the damages from the 2012 drought down. But climate change has the potential to bring far more severe droughts to the U.S. than anything seen in American history. The great drought of 2012 is a harbinger of the future, and we have a significant challenge to meet if we are to continue feeding the world in the face of intensifying droughts during the coming decades. We need to stop the unsustainable pumping of our aquifers, move even more aggressively to develop improved drought-resistant grains, and practice better water conservation if we are to avoid future Dust Bowl-scale tragedies.

Renowned documentary film maker Ken Burns debuts his new film, "The Dust Bowl", on PBS this Sunday and Monday, November 18 and 19, 2012, from 8 - 10 pm EST. Catch the trailer at pbs.org. It promises to be a fascinating and highly relevant story, told by one of America's great story-tellers. PBS is also airing a show on Hurricane Sandy, Inside the Megastorm, on NOVA on Sunday night November 18, at 7 pm. I helped them out this week with fact checking and graphics for the show.

Jeff Masters