Rollins researchers study the health effects
of global warming on multiple fronts
Climate change. Partisan politicians debate its reality, and many citizens see it as a faraway threat, something that endangers the future of polar bears but not them personally.
The health effects of global warming, however, are already being felt. Extreme weather events such as wildfires, droughts, and flooding are becoming more frequent, resulting in more injuries, deaths, and relocations. Heat and air pollution are sending people with asthma and other respiratory ailments to the emergency room. Diseases carried by mosquitoes, fleas, and ticks are expanding their territory—dengue has become endemic in Florida, Lyme disease has worked its way up to Canada and over to California, and some fear that malaria may re-emerge in the U.S.
Tie these health burdens—which are only likely to worsen—with the current administration’s decision to pull out of the Paris climate agreement and dismantle environmental regulations, and the call to action becomes more urgent. “The federal government’s actions might be a headwind from a funding perspective, but they are also very much a tailwind from an inspiration and motivation perspective,” says Daniel Rochberg, an instructor in environmental health who worked for the U.S. State Department as special assistant to the lead U.S. climate negotiators under presidents Bush and Obama. “As others have said, ‘We are the first generation to feel the sting of climate change, and we are the last generation that can do something about it.’ We have to get busy doing something about it.”
Rollins has gotten busy. Faculty researchers are building the science of climate impacts, strategies for reducing greenhouse gas emissions, and approaches for increasing resilience to climate change. Climate@Emory, a university-wide organization of concerned students, faculty, and staff, is partnering with other academic institutions, industries, and governments to support education and climate remediation efforts. Through Climate@Emory’s initiative, Emory University is an accredited, official observer to the UN climate talks and has sent students and faculty to the climate conferences in Paris in 2015 and in Marrakech in 2016. And, of course, Rollins is educating the next generation of scientists who will be dealing with the fallout of today’s climate decisions.
“For environmental scientists, it’s a challenging climate,” says Paige Tolbert, O. Wayne Rollins Chair of Environmental Health. “That means we have to be creative, because we can’t step aside and wait four years. It’s more critical than ever that we keep moving forward and make whatever contributions we possibly can.”
Response to climate change falls into two camps—mitigation (avoiding the unmanageable) and adaptation (managing the unavoidable).
While the former—reducing greenhouse gas emissions—is generally outside the public health purview, the profession can still play an important role. “Everything we can do to strengthen the world’s understanding of the health impacts of climate change strengthens the case for mitigation policy,” says Rochberg, who leads Climate@Emory.
The latter is solidly within the public health wheelhouse. “Measuring health impacts and devising interventions is what public health is built on,” says Karen Levy, associate professor of environmental health and epidemiology. “We have the knowledge and the tools to address water shortages, disease outbreaks, and sanitation issues. Investing in basic public health is perhaps the best climate change adaptation.”
Rollins researchers are tackling adaptation on several fronts:
Levy first became interested in studying diarrheal diseases more than a decade ago, when she noted the paucity of studies about the relationship between climate and the disease that kills more than 700,000 children under the age of five each year. In one expansive paper about the relationship between climate and health, there was just one paragraph on diarrheal diseases, and that paragraph cited only two small studies.
So she spent the next five-plus years doing a systematic review of all the data about the incidence of diarrheal disease she could get her hands on, which was not easy since surveillance in the African and Asian countries where it is most widespread is patchwork. She then gathered data about temperatures, rainfall, flooding, and other weather conditions and compiled a body of work about the rather complicated relationship between diarrheal disease and climate change.
Levy looked at Bangladesh, which has better records about the incidence of diarrhea than many developing countries. She found that a 1° C increase in mean monthly temperature was associated with an 8 percent increase in diarrhea associated with one common pathogen—Enterotoxigenic E. coli.
“Eight percent might not sound like much,” says Levy. “But that would translate into an estimated 800,000 additional deaths in the near term. And that is from diarrhea from one specific pathogen in one country.”
In another study, Levy looked at the link between heavy rainfall and diarrheal disease in 19 rural villages in Ecuador. She found that when heavy rainfall followed a period of drought, diarrhea rates rose by 39 percent. But when the heavy rainfall occurred during the rainy season, diarrhea rates actually fell.
The most likely explanation, according to Levy, is that human waste accumulates on the ground and in unsealed latrines during dry periods and is washed into rivers and water holes during a heavy rain. However, human waste can’t accumulate when light rains constantly wash it away. Also, communities that treated their water, usually by boiling or chlorination, escaped the drought/heavy rainfall spike in diarrhea.
Photo | Karen Levy studies the relationship between climate change and diarrheal diseases in tropical and subtropical regions. She has found increases in temperature and in rainfall can result in more diarrheal deaths.
Matthew Gribble is helping to build an understanding of the epidemiology of ciguatera fish poisoning (CFP). This is thought to be one of the world’s most common types of seafood poisoning, but exact numbers are hard to come by since its symptoms (vomiting, diarrhea, abdominal cramps, and blurred vision) mimic those of other types of food poisoning. Currently, there is no good way to test humans for CFP. The only way to officially confirm a case is to send a sample of the patient‘s fish meal to a lab to test for the toxin. As one can imagine, many cases are missed.
Preventing CFP is challenging. The toxin that causes CFP is tasteless, odorless, and colorless, so it’s difficult to identify infected fish. It is also hardy—you cannot bake, broil, fry, or freeze it out of the fish. It is found most commonly in popular reef fish, such as grouper and snapper, which become tainted by algal toxins.
Ciguatera-causing algae are abundant in the Caribbean, Pacific, and Indian oceans, and it may be expanding its territory as seas grow warmer. The impact will be felt most keenly in island communities that depend on reef fish for a main food source.
“This is partly a social justice story,” says Gribble. “These are not the communities that are driving climate change, but they are the ones being hammered by it.”
Photo | Matthew Gribble is building the body of evidence around ciguatera fish poisoning (CFP), one of the world’s most common types of seafood-related food poisoning. Warming oceans have spread CFP’s reach.
Climate modeling lays the foundation for action on climate change. Rollins researchers led by Yang Liu are on the cutting edge of climate modeling, using the latest scenarios and developing novel tools that allow the existing models to be brought down to a scale that is actionable for public health interventions.
To further explain, a climate modeling primer is useful. To make sure the research of different scientists can be compared apples-to-apples style, all climate models use a standard set of scenarios that include starting conditions, historical data, and projections. In the 1990s, one set of scenarios was introduced—the Special Report on Emissions Scenarios (SRES) standards. These scenarios were replaced with updated versions in 2014 called Representative Concentration Pathways (RCPs).
Most scientists are still working with the SRES standards because data for those is more readily available. Liu and his colleagues, however, are using the latest scenarios. “Our group is one of the few that is publishing based on RCPs,” says Liu. “Using the RCPs makes our work more relevant and comparable with the latest IPCC [Intergovernmental Panel on Climate Change] work.”
But even new scenarios are limited because they are based on very crude grid sizes. Each data point represents 10,000 to 20,000 square miles on average—the size of a small state. While such coarse resolution can be useful on a national level, it is not particularly helpful for city, county, or even state planning for climate mitigation and adaptation.
Scientists can refine the model in one of two ways to make it meaningful on a smaller scale—statistical downscaling and dynamical downscaling. The latter involves nesting another region-specific model within the global model—a highly complex undertaking and one that Liu’s team has mastered.
“We have developed our own downscaling methods rather than using publicly available models, and there is a big difference,” says Liu. “We completed our first study on our models in 2013, so by now we are proficient in downscaling. Other institutions have started coming to work with us as a resource for their modeling efforts.”
Most climate modeling researchers are in atmospheric sciences or physical sciences departments, and they may collaborate with researchers in the public health department. “We are the other way around,” says Liu. “We initiate our study objectives within the school of public health, and we decide how the models are run. So instead of getting creative in using whatever data is out there, we are able to generate data that is as suitable as possible for public health applications.”
Such applications include calculating how many extra deaths will occur in the 2050s due to heat waves at the county level or how much public health burden wild fires will place on the Rocky Mountain states. “With our climate models, we can talk about health impacts in a way that makes sense to policymakers,” says Liu. “Our goal is to provide meaningful scientific support for policymaking.”
Photo | Yang Liu leads a team that is on the cutting edge of climate modeling. Using the latest scenarios and sophisticated downscaling techniques, Liu creates climate models that can be actionable by policymakers.
Respiratory diseases, asthma
Rising temperatures result in increased air pollution levels, longer pollen seasons, and more frequent extreme weather events such as thunderstorms. All are bad news for people with asthma and other respiratory ailments.
Stefanie Sarnat, associate professor of environmental health, has been studying how these factors translate into emergency room visits. Looking at just one contributor to air quality—ozone, a known respiratory irritant—Sarnat found a 5 percent to 10 percent increase in ER visits by asthma patients on days with the highest concentrations of ozone compared with days with low levels. Using climate and air quality models, she and colleagues projected that Atlanta may experience an 8 percent increase in the number of days that exceed the 75 ppb US National Ambient Air Quality Standard for ozone by 2041.Given today’s Atlanta population, these higher ozone levels would result in 267 to 466 additional asthma ER visits per year.
Pollen may be even more troubling for asthma sufferers, since a large percentage of asthma cases are allergic. Sarnat found a 10 percent to 15 percent increase in ER visits on days with highest concentrations of pollen versus those with low levels, particularly among children.
Thunderstorms can also trigger asthma attacks. While pollen grains are usually too large to enter the smallest airways of the lungs when inhaled, rain can cause pollen grains to rupture and release particles tiny enough to be inhaled deeply; strong winds from thunderstorms can spread these particles far and wide. Sarnat found that a small increase in ER visits for asthma occurs after every thunderstorm.
All these findings are likely the tip of the iceberg, says Sarnat, since her team looks only at ER visits. It’s a safe bet that for every person who goes to the ER, many more visit doctors or use their quick-relief medicine.
Photo | Stefanie Sarnat investigates how air pollution, pollen levels, and thunderstorms impact emergency room visits for asthma.
“The Paris climate agreement was like establishing base camp,” says Rochberg. “Now we still need to go up the mountain.”
That ascent requires teamwork and partnerships, which he is working to build through Climate@Emory. His goal—nothing less than finding a way to get past partisan politics and work collaboratively on climate change.
Part of that equation involves science—working with scientists from around the state to improve the collective understanding of what climate change means for Georgia and what can best be done to address it. In May, Rochberg was instrumental in hosting, along with University of Georgia and Georgia Institute of Technology, a two-day workshop to draft the “Georgia Climate Research Roadmap.” Scientists, researchers, and environmental experts from across the state gathered at Emory to define a set of key climate research questions that could eventually aid climate change-related decision-making and planning for Georgia policymakers, scientists, communities, and service organizations. “The idea is there are tons of experts around the state working on this issue. We can and should do a better job of pulling them together, working to advance our understanding of climate change, and putting forward ideas of how to respond to the challenges it presents,” says Rochberg. “The workshop was a great step in that direction.”
Another part of the equation involves changing the partisan nature of the conversation about climate change in Georgia. Toward that end, Rochberg has two projects in the planning phase. First, he is working with partners at UGA, Georgia Tech, and elsewhere to create “Georgia Climate Stories.” These will be two- to three-minute videos of people from all over the state and from all walks of life—ranging from peach farmers to children with asthma—talking about what climate change means to them. “Now you’re no longer talking about politics,” says Rochberg. “You’re talking about what is happening to you.”
Second, he plans to organize a workshop tentatively
called “Red, Climate, and Blue.” It would bring together about 50 students from all over the state, half Democrats and half Republicans, all concerned about climate change. The workshop would encourage students to listen across political divides and develop an action plan for creating healthier conversations on climate change in their communities. “Students see climate change through a very different lens than their parents,” says Rochberg.
The final portion of the equation focuses on finding solutions. Teaming with Georgia Tech’s Climate and Energy Policy Lab, Climate@Emory has hosted two town hall meetings under the banner “Choosing Our Energy Future.” Participants from academia, government, NGOs, utilities, and the private sector discussed what the state can do to move forward on clean energy regardless of where federal policy goes.
“Starting around 2030, global temperatures will start trending according to the policy decisions we make today,” says Liu. “In 10 to 15 years, our current students will enter the prime of their careers. As tomorrow’s public health leaders, they are the ones who will have to answer to this serious challenge of climate change.”
Cognizant of this, Tolbert has beefed up the environmental health department, more than doubling faculty and students in the past seven years.
“By having all the new faculty come on board, we are able to tackle climate change issues from so many sides,” says Tolbert. “We have experts in water and sanitation issues, air quality issues, chronic and infectious disease ecology, and policy issues. We’ve revised the curriculum, adding courses and shifting the focus of others. The department has been intentionally positioning itself to make a contribution on climate change because we think this is one of the most important issues of our time.”
Climate@Emory offers a way for students from across the university to engage with faculty and staff on climate-related projects through the Emory Climate Analysis and Solutions Team, or ECAST. Ten such projects are currently under way supporting climate-related efforts at Emory, Atlanta, and DeKalb County.
Ian Buller 17PhD and Sam Peters 19PhD are working with the City of Atlanta’s Office of Sustainability to identify health co-benefits of the city’s Climate Action Plan. Finding few studies that focused on Atlanta, they broadened their literature review to other cities and were able to identify four broad public health benefits of climate mitigation: reduction in health care and emergency department visits; fewer cases of infections and poisonings; improved physical activity, mental health, and nutrition; and improved birth outcomes and childhood cancer rates.
While they did not get to the point of quantifying benefits, they laid the path for future efforts. “Right now, we are just laying out the general supporting evidence that is out there and identifying research gaps,” says Buller. “It could be a jumping off point for a whole research plan for Emory or partnerships with other institutions.”
The project could also help the city sell its plan to businesses and citizens. Says Peters, “If we can move the message away from ‘We need to save the planet’ toward a personalized message like, ‘Your child might have a better chance of avoiding an asthma attack if we can reduce emissions,’ we may be able to engage people in the conversation.”
Through its varied efforts, Rollins is positioning itself to help advance the science and interventions surrounding climate change. “Global warming will be a defining issue in the lifetimes of our students,” says Tolbert. “We will continue to devote as many resources as we possibly can to make significant contributions in understanding and meeting the challenge.”