Using a different approach, the study also found that an increase in average monthly temperatures to over 30 degrees Celsius (86 Fahrenheit), up from an average of 25 to 30, was correlated with a 0.5% increase in mental health issues.
That might seem like a small change, but Nick Obradovich, the study’s lead author and a scientist at MIT’s Media Lab, noted that those results, if consistent across the country, “would produce approximately 2 million additional individuals reporting mental health difficulties.”
Those challenges can turn deadly. A study published this year in the journal Nature Climate Change found that a rise of 1 degree Celsius in monthly temperatures correlated with a 0.68% increase in the United States suicide rate. Using that data, researchers estimate that climate change could be linked to over 14,000 suicides by 2050.
Though more research is needed to determine what exactly causes that increase in suicide, the study’s lead author said economic factors or biological changes might be to blame.
“As economic conditions worsen, that might also worsen mental health,” said Marshall Burke, an assistant professor in the Department of Earth System Science at Stanford University. There also might be “a plausible biological linkage between temperature, thermal regulation and how the brain regulates its own emotion.”
An increase in Type 2 diabetes
Rising temperatures are associated with an increase in Type 2 diabetes, according to a 2017 study published in the journal BMJ Open Diabetes Research & Care. However, researchers looked only at the correlation between temperatures and diabetes, so the study didn’t establish that temperatures necessarily caused the disease.
Still, researchers found that diabetes rates increased by about 4% for every 1 degree Celsius of warming in the United States. Worldwide, glucose intolerance rose by 0.17% per degree Celsius of warming.
Lead study author Lisanne Blauw, a researcher at Leiden University Medical Center in the Netherlands, said that “a 1-degree Celsius rise in environmental temperature could account for more than 100,000 new diabetes cases per year in the USA alone.”
Although calorie consumption and obesity are likely to be the biggest risk factors for diabetes, the study hypothesizes that warmer temperatures might decrease the activity of brown fat tissue, which burns fat and generates heat in colder weather.
“In warmer climates, brown fat may be less activated,” Blauw said, “which may causally lead to insulin resistance and diabetes.”
Respiratory problems and stroke
Most scientists agree that greenhouse gases like carbon dioxide are contributing to global warming, but those emissions aren’t just hurting the planet. Fossil fuel pollutants can also generate a mixture of solid particles and liquid droplets in the atmosphere that can enter your lungs and even your bloodstream.
That mixture, called particulate matter, can aggravate asthma, decrease lung function and increase your risk of cardiovascular events such as strokes, according to a study published last year in The Lancet. That same study estimated that over 8 million people die early due to air pollution every year.
A warming planet also means more wildfires, which routinely release smoke that further worsens air quality. A 2011 report from the National Research Council found that a warming of just 1 degree Celsius could lead to a 400% increase in the area of land burned by wildfires.
But it’s not just smoke and pollutants you’re inhaling; it’s pollen, too. Increases in carbon dioxide can trigger plants to produce more polle, which might explain why the pollen season seems to get worse each year.
A 2012 study presented at the American College of Allergy, Asthma and Immunology conference estimated that pollen counts were expected to reach 21,735 grains per cubic meter in 2040. In 2000, that number was just 8,455.
More car crashes and fewer food inspections
Even small changes in climate can impact human behavior, leading to an increase in fatal car accidents and a decrease in food safety inspections, according to a study published this year in PNAS.
Researchers analyzed data from more than 70 million police stops, more than 500,000 motor vehicle accidents and nearly 13 million food safety violations.
They found that above 29 degrees Celsius (84 Fahrenheit), police conduct fewer traffic stops, which can contribute to unsafe driving conditions. A 10-degree Celsius increase in maximum temperatures decreased traffic stops by 1.5%, according to the study, and that same temperature change amplified the risk of a fatal car crash by half a percentage point.
The researchers also found that health officials were less likely to conduct food safety inspections when temperatures exceeded 26 Celsius (79 Fahrenheit). Across the 750,000 restaurants and food production facilities they studied, they found that a 10-degree increase in temperatures translated to 8,000 fewer inspections per day.
When those facilities were inspected, though, hotter temperatures led to more violations, probably because pathogens like E. coli and salmonella grow faster in warmer weather.
Obradovich, the MIT Media Lab research scientist who co-authored the study, noted that “hot temperatures are basically bad for human functioning.” The crux of the idea, he said, was that “weather affects how we perform our duties and how we go about our daily lives and the risks that we experience.”
By Arman Azad, CNN