On heels of Obama plan, researchers warn of climate link to diseases from cholera to asthma
“Often, these illnesses are aggravated by air pollution, pollution from the same sources that release carbon and contribute to climate change, and for the sake of all of our kids, we’ve got to do more to reduce it,” Obama said last year just before U.S. EPA announced its emissions-cutting proposal (ClimateWire, June 3, 2014).
The president again reiterated his case for cutting carbon emissions this week, bringing up his daughter’s troubles with asthma (ClimateWire, April 8).
The focus on the health argument — instead of just framing greenhouse gas rules as a way to avert sea-level rise or extreme weather — comes from the language of the authority Obama is invoking to limit carbon emissions. Under Section 111(d) of the Clean Air Act, EPA must “develop regulations for categories of sources which cause or significantly contribute to air pollution which may endanger public health or welfare.”
For pollutants like ozone and sulfur dioxide, the health effects are immediate, severe and well understood. But for carbon dioxide, a gas that isn’t toxic on its own, the impacts on emergency room visits, hospitalizations and fatalities aren’t as direct.
Nonetheless, the warming climate has profound effects on the medical sector, and evidence continues to mount that rising CO2 levels in the atmosphere are already having effects on heart disease, heat stroke, allergies and infection, researchers say.
“You have to give this administration a huge amount of credit for talking about climate change in a way that’s providing both states and communities a framework for talking about and responding to the challenges of climate change,” said Clifford Mitchell, director of environmental health coordination at the Maryland Department of Health and Mental Hygiene.
He spoke at a public health conference at the University of Maryland, College Park, yesterday about the need to get people to respond to climate change without paralyzing them with fear or despair. It’s a tricky balance when the consequences are so dire, but health officials aim to help by presenting more information to the public, as well as providing resources to help them respond to health problems stemming from heat waves, storms and floods, Mitchell said.
Warming worsens allergy season
Rita Colwell, a professor at the University of Maryland and a professor at the Johns Hopkins Bloomberg School of Public Health, noted that linking health to the climate is an idea that dates back to Hippocrates in the 4th century B.C. when he said, “Whoever wishes to pursue the science of medicine in a direct manner must first investigate the seasons of the year and what occurs in them.”
Colwell discussed some of her recent findings on cholera and climate change. Waterborne diseases like cholera infect 1.5 billion people annually, leading to 1.8 million deaths each year, and patterns of rainfall and flooding influence their spread.
Cholera has strong links to environmental variables, like sea surface temperatures, but human development is a major factor in infection risk, as well (ClimateWire, Jan. 6, 2015).
Conventional wisdom held that the Vibrio cholerae bacteria originated off the coast of Bangladesh, but recent genomic analyses found that the pathogen is naturally present in waters all over the world, causing infections in 50 countries. “Cholera is a global disease,” Colwell said. “It’s not a disease that’s ancient; it’s a disease we really have to deal with right now.”
The disease was once rampant in the United States, but better water management and infrastructure eradicated it. However, as the climate changes, sanitation systems may strain under pressure from floods and storms, raising the specter of a resurgence.
Noninfectious and chronic illnesses like heart failure and allergies may also worsen under a changing climate. Amir Sapkota, an associate professor of applied environmental health, observed that increased carbon dioxide directly raises pollen production in plants that cause allergies, and the warming it causes expands the geographic range of pollen production (ClimateWire, Nov. 10, 2014). The season for ragweed pollen, for example, has expanded by 27 days near the Canadian border between 1995 and 2011.
To respond, health officials are developing better forecasting tools to anticipate heat waves and infection outbreaks in the hopes of getting precautionary messages to the public sooner, while also providing options like cooling centers during heat waves or personal checkups on isolated and elderly residents in an area.
“Our hospital partners, in particular, do see a lot of homeless individuals who seek relief from the cold or the heat by visiting [emergency departments] more frequently, and that is an issue we work with them very closely on,” said Jennifer Martin, deputy director of the Office of Public Health Preparedness and Response at the Baltimore City Health Department.