As President Donald Trump looks to curb the government’s enforcement of climate regulations, experts are concerned about how the action might impact public health.
“The current federal political climate in the United States bodes ill for the future of the world’s climate and by extension for the health of people around the world, Americans included,” said Dr. Mona Sarfaty, director of the program on climate and health at George Mason University’s Center for Climate Change Communication.
Sarfaty helped prepare a report, released last month by the Medical Society Consortium on Climate and Health, that mapped how climate change threatens the health of people across the United States and how those threats vary by region.
Extreme temperatures and weather events, poor outdoor air quality, contaminated food and water, mosquito- and tick-borne infections, wildfires and stresses on mental health are the climate-related health risks identified in the report by practicing physicians.
“There’s a gap between the public’s understanding of the health implications of climate change and physicians’ understanding of the health implications of climate change,” Sarfaty said. “Most people are not aware that climate change is a danger to their health, and physicians see that risk.”
Globally, about 12.6 million people die each year due to environmental risk factors such as pollution, extreme weather or climate-related disease, according to the World Health Organization.
Between 2030 and 2050, climate change is expected to cause 250,000 additional deaths per year around the world, according to the WHO — including in the United States.
‘An increase in disease anywhere … can affect us all’
“I think Americans consider climate change as an ‘over there’ problem or confined to poor countries,” said Dr. Jonathan Patz, a professor and director of the Global Health Institute at the University of Wisconson-Madison, who was not involved in the consortium’s report.
“Climate change is already influencing the frequency of heatwaves, flooding events and famines, as well as epidemics of vector- and waterborne diseases,” he said. “But in a globalized world, an increase in disease anywhere in the world can affect us all.”
People along the East Coast might be at a greater risk of mosquito- and tick-borne infections as the climate becomes hotter and more humid, creating an ideal breeding environment for those disease-carrying insects, according to the report.
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Mosquitoes can transmit "dengue fever, Zika and West Nile virus, which has spread across the country and is popping up in outbreaks periodically, recently in Texas and Louisiana," Sarfaty said.
Although a number of factors played a role in the recent Zika virus outbreak, climate-related changes in the environment might have influenced the spread of mosquitoes carrying the virus, according to a document from the Centers for Disease Control and Prevention (PDF).
Extreme weather along the East Coast, especially in the summer, also has resulted in the spread of bacterial infections, Sarfaty said.
"When increased rainfall leads to flooding, there can be a mixing of stormwater and sewage that leads to bacterial contamination in the water. This has been a problem in recreational lakes in the Midwest," Sarfaty said. Bacterial contamination also can impact crops, leading to an increase in food-related infections.
"Warmer ocean water also makes a difference. Along the coast, there are cases of bacterial contamination in shellfish in the warmer months that have those waters more likely to cause infection when people swim there, especially if they have open cuts in their skin," she said. "There have been some cases off the coast of Florida where people have gotten skin infections."
Sarfaty added that areas along the Mississippi and Ohio rivers, such as in Missouri and Ohio, have experienced increased flooding in recent years, which also has led to a risk of contaminated water and water-related infections.
"There was an outbreak of cryptosporidiosis in Wisconsin some years ago that was related to one of these rain events," she said.
Both the East and West coasts of the United States are threatened by extreme summer heat, flooding, storms, drought, poor air quality that can impact breathing, allergies and the mental health problems that come with dealing with those health threats, according to the consortium's report.
"When people are displaced from their homes because of floods or extreme storms ... this loss of home and separation from family and community leads to mental health impacts that can be reflected in substance abuse, alcoholism, domestic strife or violence, depression or anxiety," Sarfaty said.
Meanwhile, the Great Plains and Midwest face a slightly different mix of climate change-related health impacts.
Is climate change making our food less nutritious?
Poor air quality, extreme weather and wildfires threaten the Great Plains, while food- and water-related infections and mosquito- and tick-borne diseases threaten the Midwest, according to the consortium's report.
"You've got Lyme disease spreading west into the Midwestern states, Michigan, Missouri, Ohio, certainly spreading further north into Canada and also south into Virginia. ... The tick that carries Lyme disease is now found in many more counties than it was before," Sarfaty said.
Changes in climate also have affected some crops and food sources in the Great Plains and Midwest, according to the consortium's report.
"One of the more recent findings that has been surprising to me is the increasing evidence that a carbon dioxide-enriched atmosphere is actually leading to crops that have lower nutritional value," Sarfaty said.
"So it's impacting the nutritional value of grains. That's something which has been increasingly documented, and of course it's very worrisome because the population depends on the growth of grains as a staple in our diet," she said.
The most widespread climate-related health problem
Most climate scientists agree that humans are causing the planet to warm by polluting the atmosphere with heat-trapping greenhouse gases. Carbon dioxide is the primary greenhouse gas emitted through human activities, such as burning fossil fuels like coal, natural gas and oil at power plants.
Fossil fuel pollutants can generate particulate matter, a complex mixture of tiny particles and liquid droplets in the atmosphere. Once inhaled, these small particles can impact your heart and lungs, with serious health effects.
"The most widespread health problems that physicians reported to us are lung and heart conditions related to poor air quality," Sarfaty said of the consortium's report.
"Between 60,000 to 80,000 Americans still die early from exposure to particulate air pollution, stemming mostly from burning fossil fuels," said Patz, the professor at the University of Wisconsin-Madison.
"This consortium also defines the reduction of fossil fuel combustion as one of the best interventions we can do to immediately improve our health, be it through clearer air quality to promoting physically active commuting in cities," he said.
Trump signed an executive order last month to review and possibly eliminate the Environmental Protection Agency's "Clean Power Plan," which was intended to regulate and cut greenhouse gas emissions from power plants.
The Industrial Revolution played a major role in expanding the use of burning coal, and humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the Industrial Revolution, about 150 years ago, according to NASA.
This atmospheric impact on the climate has worsened allergy symptoms, Sarfaty said.
Why your allergies may be going haywire
"Ragweed plants are very widespread on the East Coast and into the Midwest and a very common cause of allergies. Those plants actually have more potent allergen in them when they grow in higher-carbon-dioxide atmospheres," Sarfaty said.
"One of the things that we're beginning to hear is that, 'Oh, we don't have to worry about carbon dioxide, because carbon dioxide is plant food.' Well, it turns out that carbon dioxide is actually causing more virulent allergens," she said.
Sarfaty also said allergies and some other climate-related health effects tend to be more widespread than regional.
Extreme heat and wildfires are two that have swept most of the country. From 1999 to 2010, there were more than 7,000 heat-related deaths in the US, an average of about 618 per year, according to the CDC.
As for wildfires, the threat appears more along the West Coast, but there have been recent flareups in other parts of the country, according to the consortium's report. Last year, a wildfire raged through eastern Tennessee, leaving 14 people dead and 175 injured, and destroying more than 2,400 homes, businesses, and other properties.
Large wildfires now burn more than twice the area they did around 1970, according to the Center for Climate and Energy Solutions.
Just a 1-degree Celsius rise in the planet's average global temperature is expected to produce up to a 400% increase in areas burned by wildfires, according to a 2011 report from the National Research Council's Committee on Stabilization Targets for Atmospheric Greenhouse Gas Concentrations.
Smoke plumes from wildfires can impact the health of residents 100 miles away, Sarfaty said.
"They can cause increases to emergency rooms for all kinds of respiratory conditions and for cardiac conditions as well, including heart attacks and episodes of heart failure," she said.
"Air quality worsens with rising heat and/or wildfires; longer, more severe allergy conditions; and injuries related to extreme weather events," she said. "These most common conditions seen by physicians and associated with climate change are becoming so widespread that it's hard to cast them as strictly regional vulnerabilities."
'We have the opportunity to address this now'
Dr. Georges Benjamin, executive director of the American Public Health Association, said that as the climate continues to change, the health of more Americans could be affected.
"The wildfire risk on the West, the infectious disease risks in the Midwest and the East Coast are striking differences," Benjamin said.
"More people will find themselves directly impacted as environmental conditions get worse. We have the opportunity to address this now," he said. "At some point the climate changes become more difficult to reverse and many of the events like floods, severe storms and toxic air become so severe that communities will become uninhabitable."
A threat to inhabitability looms over other parts of the world.
As a result of climate change, scientists predict that areas in the Middle East and North Africa could become uninhabitable in the summers by 2100. This "may exacerbate humanitarian hardship and contribute to migration," according to a study published last year in the journal Climate Change.
Yet as mainstream medical societies are recognizing how much climate change threatens our health, communities can prepare for these health impacts, Patz said, giving a nod to the consortium's report.
"To be honest, I am not surprised by any content in the report and am extremely encouraged by mainstream medical societies now recognizing how much climate change threatens our health," he said. "What stood out to me is how these medical societies are already prioritizing prevention or mitigation of climate change as a major component to the response from the health-care sector."