As unusually wicked tornadoes tear through the United States this spring, many people are wondering if Earth's destabilized climate is behind such strong storms. The science community has known for years that the spike in man-made greenhouse gases would lead to more severe weather—more flooding, droughts, and stronger storms—but it's not clear if this season's tornadoes are caused by a drastically changing climate. "There's not a clear picture on tornadoes. But the series several weeks ago were part of a very large storm system, and the numbers and strength are outside norms," explains Paul Epstein, MD, MPH, associate director of the Center for Health and Global Environment at Harvard University. "We have some ideas about why, but this is speculative at this point. Changing land temperatures and pressure gradients, and the pattern of the jet stream—affected by shrinking Arctic ice—may all be playing a role."
While Dr. Epstein notes it's too early to say this spring's tornado activity is part of a long-term trend—that question will take monitoring and analysis for a definitive answer—he is very clear about the effects climate change is already having on human health. In his new book, Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and What We Can Do about It (University of California Press, 2011), Dr. Epstein connects the dots, explaining how climate change is, and will continue to be, a threat to the general public and our health care system. Ignoring the problem is no longer an option, which is why the author is bringing climate destabilization to a personal level. "We're really sticking our heads in the sand about the impacts of climate change," says Dr. Epstein, who notes that the fossil-fuel-industry–funded doubt campaign has been working over the last several decades. "We need to bring it home so people understand that it's affecting their health, and how it's in their backyard. In the next 10 to 20 years, expect to see a lot of very wild, severe, punishing, disease-promoting, and costly extreme weather events."
Scientists have ascertained that a sharp spike in greenhouse gases in the atmosphere is causing stronger storms, including more powerful hurricanes. So how exactly does this work? "Global warming is causing climate change through the ocean," explains Dr. Epstein. Warmer seas mean faster water-evaporation rates, which fuels hurricanes, storms, and severe flooding. The warming leads to increased water vapor in the atmosphere. That, coupled with melting arctic, antarctic, and mountain glaciers, is transforming the water cycle, leading to much more intense precipitation events in the United States and elsewhere, Dr. Epstein says.
Deserts are also drying out faster, due to a shift in winds. And when it does rain, it pours. Since 1970, Dr. Epstein says there's a 7 percent increase in instances of events producing two inches of rain in a day; four-inches-in-a-day occurrences are up 20 percent, and events dumping half a foot have risen nearly 30 percent. All of these changes are leading to pest infestations in our forests and yards, higher rates of waterborne diseases, and other ailments outlined below.
Climate change and human health are connected—here's how the changes may be affecting you:
• Allergies. Researchers at Harvard and the U.S. Department of Agriculture (USDA) have discovered that excess CO2 levels—mainly from burning coal and oil—are creating super-charged ragweed plants brimming with much higher rates of hayfever-inducing pollen. Lewis Ziska, PhD, a veteran research plant physiologist with the USDA, found that jumping from preindustrial atmospheric carbon dioxide levels (280 ppm) to 1999 levels (370 ppm) doubled the amount of pollen ragweed produces. Interestingly, the high CO2 levels also create more potent pollen, which explains why lately it seems every allergy season is the worst ever. (Ziska also discovered that allergy season now lasts two to four weeks longer in many parts of the Northern Hemisphere.)
• Asthma. Allergies account for about half of asthma attack triggers, meaning skyrocketing pollen counts of fast-growing trees in the spring, and ragweed in the fall, are landing more people in the hospital for asthma symptoms. As climate change causes more heat waves, ground-level ozone also increases, priming allergic response.
• Heat-related deaths. Perhaps one of the most blatant occurrences signaling out-of-the-ordinary periods of high temperatures occurred in 2003, when a heat wave of unprecedented proportions killed more than 52,000 people in Europe. That summer, temperatures were a whopping 20 to 30 percent higher than the seasonal average across much of Europe. "The odds of such a heat wave happening by chance, based on climate trends from 1864 to 2002, were about one in 10 million," writes Dr. Epstein.
• Poison ivy outbreaks. Like ragweed, pesky poison ivy also thrives on higher carbon dioxide levels. A 2006 study found that increased carbon dioxide levels stimulate poison ivy to grow stronger and produce more urushiol, the oil that causes skin irritation.
• Dengue fever. A viral infection spread by mosquitoes,dengue fever is making a comeback in the U.S., in part due to more mosquito-friendly conditions brought on by climate-change–charged flooding. While generally not life-threatening the first time a person is infected, life-threatening brain swelling can occur after a person is bitten again by a infectious mosquito. Cases of West Nile virus, also a mosquito-borne disease, are also expected to increase.
• Infections from dirty water. Strong storms often bring major flooding, and create the perfect storm for infections from waterborne E. coli and other pathogens. After Hurricane Katrina, excess water and humidity also created ideal breeding conditions for mold and fungi, which can cause respiratory and even mental problems.
• Blown-out knees and heart attacks. Climate change isn't just about warming trends. Researchers suspect that stronger winter storms are a result of climate destabilization, too, and Dr. Epstein believes doctors are seeing more car accidents and orthopedic injury victims due to more inclement weather. Stronger winter storms could also mean a rise in people suffering cardiac arrest after cleaning up snow and ice.
• Lyme disease. Climate change is expanding the range where Lyme-infected ticks transmit the disease to people. Lyme disease has spread far beyond Connecticut, where it was first discovered, and now plagues nearly every state along the East Coast up to Canada. By 2080, researchers expect the Lyme disease zone in Canada to double.
• Meningitis. According to Dr. Epstein, shifts in ocean temperature and salinity are accelerating the sweeping of massive dust clouds from Africa to the Caribbean. These dust clouds can harbor bacteria, fungi, viruses, industrial chemicals, heavy metals, and even the bacteria that carries lethal meningitis.
For further reading, check out another book devoted to climate change's impacts on human health, Fevered: Why a Hotter Planet Will Hurt Our Health—And How We Can Save Ourselves
Originally Published: May 31, 2011
Published on: May 31, 2011