There are all kinds of dangers associated with climate change. Can we still have healthy lives amid rising seas and extreme weather?
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Mosquitoes thrive in Maricopa County in the U.S. state of Arizona these days. And they spread two killer diseases, local and federal public health officials say.
The county, home to Phoenix and Scottsdale, has seen an “unprecedented” outbreak of West Nile virus that killed more than 100 people in 2021, according to the U.S. Centers for Disease Control and Prevention (CDC). West Nile, which can cause a fatal inflammation of the brain and spinal cord, only arrived in the United States at the start of the 21st century, but has spread to all contiguous 48 states.
Warmer temperatures extend the breeding season of the mosquitoes that carry the virus, the CDC says.
Overall, almost 1,500 cases of West Nile virus were reported in Maricopa County in 2021 — likely an undercount, as most infections cause only mild disease. But 101 people died.
“This is the largest recorded WNV outbreak in a U.S. county, with more than four times the number of cases reported than the previous largest outbreak in Maricopa County during 2004,” CDC and state public health officials reported.
Climate change will affect us all.
It’s one of countless examples of how climate change already affects people’s health around the world. No one is completely safe from the effects of warmer temperatures, rising seas, worsening air pollution, droughts, floods and severe storms.
“Climate change is the biggest global health threat of the 21st century,” the World Health Organization (WHO) says. “Worldwide, only considering a few health indicators, additional 250,000 deaths per year will occur in the next decades as a result of climate change.”
Phoenix is just one example of a place where people are already dying due to the effects of climate change.
In addition to West Nile virus, the Phoenix area has seen home-grown cases of dengue virus, also carried by mosquitoes. Dengue is another potentially deadly virus that thrives in the tropics, but which is being seen more and more often in subtropical zones with warming temperatures that aid the spread of the mosquito species that can carry it.
Travellers can bring the virus with them, but in November 2022, a home-grown case was identified. Local mosquitoes were found to be carrying it.
The bugs that bite us
Tickborne diseases are also on the rise as warmer temperatures make for larger breeding grounds. Lyme disease is perhaps the best-known infection. The CDC gets reports of up to 30,000 cases a year and estimates the true number in the United States is in fact 300,000 a year.
“Studies provide evidence that climate change has contributed to the expanded range of ticks, increasing the potential risk of Lyme disease, such as in areas of Canada where the ticks were previously unable to survive,” the U.S. Environment Protection Agency (EPA) reports.
Another once rare tickborne infection: babesiosis. The CDC says the number of reported cases rose by 25% between 2011 and 2019 and says the disease is now endemic, meaning it’s permanently entrenched, in Maine, New Hampshire and Vermont.
These are rare but startling infections, affecting a handful of people in the world’s richest country. But mosquito-borne diseases such as malaria are threatening hundreds of millions of people globally.
Malaria already kills more than 600,000 people every year, most of them under the age of five, according to the WHO. But the warming temperature and disruption caused by climate change may be helping to further spread of the Anopheles mosquitoes that carries the malaria parasite.
The cooler, drier weather found at higher mountain elevations traditionally offer relief from biting mosquitoes. But in February, a team at Georgetown University in Washington, D.C. found warming temperatures may have been helping the mosquitoes take hold at higher altitudes across Africa.
Heat, floods and drought
The WHO estimates that the number of people in South America who are at risk from malaria will double from 25 million now to 50 million by 2080 because weather conditions will allow mosquitoes to spread the parasite year-round.
The health dangers caused by climate change extend far beyond infectious diseases, of course. Heat waves kill people directly — more than 166,000 between 1998 and 2017, according to the WHO. The WHO also found that 15,000 people in Europe died in heat waves in 2022 alone.
And flooding can cause a range of health problems that linger for months and even years.
The summer floods of 2022 in Pakistan are the latest example. Parts of the country got three times the normal rainfall between June and August, directly killing 1,500 people and destroying 1.7 million homes, according to the National Disaster Management Agency.
Months later, many remain homeless, according to the United Nations children’s agency UNICEF.
“Six months after unprecedented floods ravaged Pakistan, more than 10 million people living in flood-affected areas remain deprived of safe drinking water, leaving families with no alternative but to drink and use potentially disease-ridden water,” UNICEF said in a statement.
Smog in the suburbs and above small towns
Danger also comes from the air, as climate change worsens air pollution.
“For example, extremely hot days can lead to heat-related illness as well as poor air quality, by increasing the chemical reactions that produce smog,” the EPA reported.
Smog is a worldwide threat, and not just in cities. Dust blown by higher winds and smoke from wildfire threaten rural residents even more than city-dwellers.
“Exposure to poor air quality can result in the development and exacerbations of asthma, difficulty learning and susceptibility to bronchitis, cancers and chronic obstructive pulmonary disease in adulthood. Preterm birth, low birth weight and birth defects are associated with maternal exposures to poor air quality,” the EPA said in a report issued in April.
The climate has even affected the COVID pandemic. A team at Harvard University found in 2020 that just a small increase in exposure to fine dust in the air — called fine particulate matter — raised the death rate from COVID-19 by a measurable amount.
When food supplies are threatened famine follows.
Then there is drought. Beyond the obvious effects of crop failure, dead livestock and the resulting hunger, drought leads to large movements of refugees and the violence that almost inevitably follows.
The World Weather Attribution Initiative — which teams up scientists from Britain, India, the United States, the Netherlands, Switzerland and elsewhere — found warming temperatures tipped what would have been a dry spell in the Horn of Africa into a full-on drought lasting more than two years.
“At least 180,000 refugees from Somalia and South Sudan crossed into the drought-stricken areas of Kenya and Ethiopia,” they wrote in a report posted on their website. “Climate change has made events like the current drought much stronger and more likely; a conservative estimate is that such droughts have become about 100 times more likely.”
Finally, there are the mental health effects of all this. Post-traumatic stress disorder is one.
Consider the 2018 Camp Fire, one of the deadliest and most destructive wildfires in California history. According to a 2021 study from the University of California-San Diego, after the fire survivors showed rates of PTSD on par with war veterans, making them at risk as well for depression and anxiety. The American Psychological Association, meanwhile, reported similar rates of depression and PTSD for those who survive hurricanes and floods.
What can people do about these effects?
Staying cool, staying inside and drinking plenty of water helps the body cope with heat. People should check air quality and stay indoors when possible on days when the air quality index is poor and when there are wildfires, ash or other pollutants. Air cleaners and filters can help with better indoor air quality.
Clothing and insect repellent can protect against tick and mosquito bites, and cleaning up even the smallest amounts of standing water can help slow mosquito breeding.
Questions to consider:
- How is climate change affecting your community?
- What are people in your community doing about it?
- How does the threat of climate change make you feel and what do you think you can do about it?
Maggie Fox has been reporting on health and science for more than 20 years and is currently a consulting editor to Medscape and WebMD and a consultant on health and science news. She has covered conflict, politics and other international events from London, Hong Kong and Beirut. She has covered the cloning of Dolly the sheep, Ebola epidemics, stem cell technology, vaccine controversies and other stories for Reuters, CNN, National Journal and NBC News. She lives in Washington, DC.