The growing concentration of atmospheric carbon has punctured Earth's climate equilibrium, said Dr. Paul Epstein, pushing the planet toward rapid transitions with serious implications for human and ecological health. Epstein, associate director of Harvard's Center for Health and the Global Environment, spoke with Amanda Staudt, a climate scientist from the National Wildlife Federation, at an event hosted by the Woodrow Wilson Center's Environmental Change and Security Program on June 16, 2009.
Climate Change Is Accelerating
Global warming appears to be advancing more quickly than predicted, Staudt cautioned, because "the developed world isn't reducing their emissions as quickly as anticipated … there are more and more emissions from the developing world, and they're increasing faster than expected … [and] some of our natural sinks are less efficient than what we had thought."
Epstein cited a 2000 NOAA study showing that "the oceans have warmed 20 times as much as has the atmosphere" over the past half-century, altering Earth's hydrological cycle and thus accelerating climate change.
No matter how drastically greenhouse gas emissions are cut, both experts warned, a litany of irreversible changes—including an increase in global average temperature and extreme weather events, desertification, sea-level rise, and species extinction—will continue.
Infectious Disease Increases
A warming climate will increase the range of many diseases, Epstein explained. "The clearest signal we have in terms of infectious disease is in the mountains of Africa, Asia, and Latin America," he said. "What we're seeing in Kilimanjaro, in the Tibetan Plateau, in the Andes, is that glaciers are retreating, plant communities are upwardly migrating, and mosquitoes that cause malaria, dengue fever, and so on are circulating at higher altitudes" and latitudes further from the equator. For example, malaria has appeared in Nairobi, a mile-high city, and chikungunya fever—previously confined to Indian Ocean littoral states—induced panic and warranted a front-page New York Times article when several residents of a small Italian town contracted it in 2007.
Extreme weather events help diseases proliferate. Heavy rainfall drives sanitation into clean water supplies, spreading E. coli, cryptosporidium, and other waterborne pathogens. Drought, meanwhile, has facilitated meningitis epidemics in Africa's Sahel region and the spread of disease-bearing mosquitoes that breed in buckets of water stored during periods of water scarcity.
Assault on Forests, Agriculture
Climate shifts have important consequences for the health of forests and agriculture. The "absence of killing frosts means that [mountain pine] beetles are overwintering, moving to higher altitudes, moving to higher latitudes, even getting in more generations each year," Epstein said. Drought "dries the resin that drowns the beetles as they try to drive through the bark," leaving pines trees in the Rocky Mountain Range vulnerable and posing acute economic and ecological challenges to dependent communities.
The higher frequency of droughts, floods, and heat waves, coupled with the spread of weeds, pests, and pathogens, could reduce agricultural production. In addition, studies have shown that many food crops (including cassava) contain higher levels of cyanide at earlier stages of growth as carbon concentrations rise, putting people who ingest them at risk.
Healthy Solutions to Climate Change
To address these challenges, several "stabilization wedges" with inherently healthy characteristics—forest conservation and restoration; agriculture reform; energy efficiency; and wind, solar, and geothermal power production—should be prioritized, Epstein advised. Other, less healthy options—including biofuels, nuclear power, and fossil fuel-based technologies—should undergo thorough lifecycle analyses before winning endorsement, he said.
The design and construction of healthy cities—"green roofs, green buildings, tree-lined streets, biking lanes, walking paths, open space, smart growth, public transport"—as well as a smart energy grid is an essential part of the solution, said Epstein. Countries should also move away from deregulation, privatization, and liberalization of the economy in favor of a system that contains sufficient regulation, public-private partnerships, and appropriate constraints.
"If we do this right," Epstein concluded, "it can be good for public health, good for security, good for the economy, and we certainly hope it'll stabilize the climate."
Drafted by Brian Klein and edited by Meaghan Parker.