The study, released Tuesday in the journal PLOS Medicine, shows communities along the equator are likely to be most affected by rising global temperatures. In fact, the study indicates up to a 471 percent increase in heat wave deaths in the Australian cities of Brisbane, Sydney and Melbourne from 2031 to 2080 compared to 1971 to 2010.
Researchers used a computer model to estimate the number of deaths from heat waves in 412 communities across 20 countries for the years 2031 to 2080.
Lead researcher Yuming Guo said heat waves of the future will be more frequent, more intense and will last much longer “if we cannot find a way to mitigate the climate change and help people adapt to heat waves.
“There will be a big increase of heat wave-related deaths in the future, particularly in the poor countries located around the equator.”
Heat waves have broiled many countries around the world this summer, including the United States, where the temperature in May was 5.2 degrees above average and 3 degrees higher than the June average, according to the National Oceanic and Atmospheric Administration.
Temperature extremes can worsen chronic conditions such as cardiovascular disease, respiratory disease, cerebrovascular disease and diabetes-related conditions, according to 2016 study by the U.S. Centers for Disease Control and Prevention. People exposed to high temperatures are more likely to be admitted to a hospital for cardiovascular, kidney, and respiratory disorders, the CDC said.
Associate professor Antonio Gasparrini of the London School of Hygiene and Tropical Medicine and co-author of the PLOS study, said the study was the largest epidemiological approach on the projected impacts of heat waves from global warming. He said greenhouse gas emissions are the cause of rising global temperatures, and by reducing those emissions the world community can reduce the impact of heat waves – likely to increase in frequency and severity under a changing climate.
Human-caused greenhouse gases will become the main cause of heat waves in the western United States by the late 2020s and by the mid-2030s in the Great Lakes region, according to a recent study by the National Oceanic and Atmospheric Administration. Hosmay Lopez, a meteorologist at NOAA’s Atlantic Oceanographic Meteorological Laboratory and the University of Miami, says that “without human influence, half of the extreme heat waves projected to occur in the future wouldn’t happen.”
According to the CDC, rising concentrations of greenhouse gases leads to temperature increase, and affects people who are especially vulnerable to these changes including children, the elderly, and economically disadvantaged groups.
However, as people become more tolerant of the changes, their bodies are able to adapt to some extent, according to the CDC. But increasing tolerance of extreme temperatures in the United States may have peaked.
Higher temperatures can also increase human diseases, especially vector-borne diseases carried by fleas, ticks and mosquitos.
Because a warming climate means earlier spring seasons, shorter and milder winters, and hotter summers, conditions might become more hospitable for carriers of vector-borne diseases, according to CDC information.
Warmer temperatures mean increased development and survival of ticks, their animal hosts and the bacterium that cause Lyme disease, according to the CDC, which said climate change may also affect West Nile virus, another vector-borne disease.
Meanwhile, a Spanish study released last week indicates warmer temperatures mean people with illnesses such as diabetes are more susceptible to death in hotter climates.
Researchers in Barcelona studied data from 47 major cities in Spain for the summer months from 1980 to 2015. They compared average daily temperatures in those cities with 554,491 human deaths from circulatory and respiratory causes.
The study shows that as human populations were exposed to higher temperatures over time, they had an increased tolerance for the heat and reduced mortality.
But despite these advances, the risk of death remained high for people with respiratory diseases and particularly in women.
According to the CDC, heat waves are associated with increased hospital admissions for cardiovascular, kidney, and respiratory disorders. The CDC says also that some heat-related health risks have diminished in recent decades, possibly due to better forecasting, weather warning systems and increased access to air conditioning in the United States. However, urban heat islands combined with an aging population and increased urbanization will lead to more health issues in the future, the CDC said.
People with diabetes are at higher risk for illness or death in a heat wave or during extremely low temperatures.
According to a study released this month in PLOS, deaths caused by heart attack increase among people with diabetes during extreme heat events. According to this study, diabetes patients had a higher risk of acute myocardial infarction during extreme temperatures, and hospital admissions among diabetes patients rose sharply in high and low temperatures, with a stronger effect in low temperatures.