Skip to main contentSkip to main content
You have permission to edit this article.

58% of human infectious diseases can be worsened by climate change

  • 0

Flooding from hurricanes like Irma in Florida can overwhelm sewer systems and spread pathogens in other ways. Brian Blanco/Getty Images

Climate change can exacerbate a full 58% of the infectious diseases that humans come in contact with worldwide, from common waterborne viruses to deadly diseases like plague, our new research shows.

Our team of environment and health scientists reviewed decades of scientific papers on all known pathogenic disease pathogens to create a map of the human risks aggravated by climate-related hazards.

The numbers were jarring. Of 375 human diseases, we found that 218 of them, well over half, can be affected by climate change.

Flooding, for example, can spread hepatitis. Rising temperatures can expand the life of mosquitoes carrying malaria. Droughts can bring rodents infected with hantavirus into communities as they search for food.

With climate change influencing more than 1,000 transmission pathways like those and climate hazards increasingly globally, we concluded that expecting societies to successfully adapt to all of them isn’t a realistic option. The world will need to reduce the greenhouse gas emissions that are driving climate change to reduce these risks.

Mapping climate health hazards

To be able to prevent global health crises, humanity needs a comprehensive understanding of the pathways and the magnitude with which climate change might affect pathogenic diseases.

We focused on 10 climate-related hazards linked to rising greenhouse gas emissions: atmospheric warming, heat waves, drought, wildfires, heavy precipitation, flooding, storms, sea-level rise, ocean warming and land cover change. Then we looked for studies discussing specific and quantifiable observations of human disease occurrences linked to those hazards.

In total, we reviewed over 77,000 scientific papers. Of those, 830 papers had a climatic hazard affecting a specific disease in an explicit place and/or time, allowing us to create a database of climatic hazards, transmission pathways, pathogens and diseases. An interactive map of every pathway between hazard and pathogen is available online.

Spaghetti chart showing pathways connecting climate disaster types, like flooding and heat, and specific types of pathogens, like bacteria and viruses.A simplified version of the pathogenic disease chart shows how different climate disasters interact with transmission pathways and pathogens. The full version is available at Camilo Mora, CC BY-ND

The largest number of diseases aggravated by climate change involved vector-borne transmission, such as those spread by mosquitoes, bats or rodents. Looking at the type of climate hazard, the majority were associated with atmospheric warming (160 diseases), heavy precipitation (122) and flooding (121).

How climate influences pathogen risk

We found four key ways climatic hazards interact with pathogens and humans:

1) Climate-related hazards bring pathogens closer to people.

In some cases, climate-related hazards are shifting the ranges of animals and organisms that can act as vectors for dangerous pathogenic diseases.

For example, warming or changes in precipitation patterns can alter the distribution of mosquitoes, which are vectors of numerous human pathogenic diseases. In recent decades, geographic changes in outbreaks of mosquito-borne diseases such as malaria and dengue have been linked to these climatic hazards.

A woman strokes her child's head next to other sleeping under a bed netChildren sleep under nets in Ethiopia to protect against malaria-spreading mosquitoes. Louise Gubb/Corbis via Getty Images

2) Climate-related hazards bring people closer to pathogens.

Climate disasters can also alter human behavior patterns in ways that increase their chances of being exposed to pathogens. For example, during heat waves, people often spend more time in water, which can lead to an increase in waterborne disease outbreaks.

Notably, Vibrio-associated infections increased substantially in Sweden and Finland following a heat wave in northern Scandinavia in 2014.

3) Climate-related hazards enhance pathogens.

In some cases, climate-related hazards have led to either environmental conditions that can increase opportunities for pathogens to interact with vectors or increase the ability of pathogens to cause severe illness in humans.

For example, standing water left by heavy precipitation and flooding can provide breeding grounds for mosquitoes, leading to increased transmission of diseases such as yellow fever, dengue, malaria, West Nile fever and leishmaniasis.

A person wearing trash bags around each leg to keep them dry crosses a flooded city street in New Jersey. An overturned trash can floats in the background.Many waterborne diseases can be spread by climate hazards like flooding and extreme downpours. Michael M. Santiago/Getty Images

Studies have shown that rising temperatures may also help viruses become more resistant to heat, resulting in increased disease severity as pathogens become better able to adapt to fever in the human body.

For instance, studies have suggested that rising global temperatures are leading to increased heat tolerance of fungal pathogens. The sudden appearance on multiple continents of treatment-resistant human infections of Candida auris, a fungus that was previously nonpathogenic to humans, has been associated with increasing global temperatures. Similarly, fungi in urban environments have been shown to be more heat tolerant than those in rural areas, which tend to be cooler.

Theories on the emergence of Candida auris. Click the image to zoom in. Arturo Casadevall, Dimitrios P. Kontoyiannis, Vincent Robert via Wikimedia, CC BY-ND

4) Climate-related hazards weaken the body’s ability to cope with pathogens.

Climate-related hazards can affect the human body’s ability to cope with pathogens in two key ways. They can force people into hazardous conditions, such as when disaster damage leads to people living in crowded conditions that might lack good sanitation or increase their exposure to pathogens.

Hazards can also reduce the body’s capacity to fight off pathogens, through malnutrition, for example. Living through climatic hazards may also induce increased cortisol production from stress, leading to a reduction in the human body’s immune response.

What to do about it

Climate change presents a significant threat to human lives, health and socioeconomic well-being. Our map shows just how extensive that threat can be. In our view, to dial back the risk, humanity will have to put the brakes on the human-caused greenhouse gas emissions fueling global warming.

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

This article is republished from The Conversation under a Creative Commons license.

Listen now and subscribe: Apple Podcasts | Google Podcasts | Spotify | RSS Feed | Omny Studio


* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Related to this story

Most Popular

For decades, millions of Egyptians have depended on the government to keep basic goods affordable. But a series of shocks to the global economy and Russia's invasion of Ukraine have endangered the social contract in the Middle East's most populous country, which is also the world's biggest importer of wheat. It is now grappling with double-digit inflation and a steep devaluation of its currency, prompting oil-rich Gulf Arab countries to once again step in with financial support as talks with the International Monetary Fund drag on. The possibility of food insecurity has raised concerns.

TUESDAY, Sept. 27, 2022 (HealthDay News) -- Home ownership may be the culmination of the American Dream, but a new study cautions that many people think they will be happier than they actually become once they are king or queen of their own castle.

Four people have pleaded guilty to misdemeanors for their roles in absentee ballot fraud in rural North Carolina during the 2016 and 2018 elections. These convictions Monday stemmed from an investigation that in part resulted in a do-over congressional election. The defendants were associated with Leslie McCrae Dowless, a political operative in Bladen County whom authorities called the ringleader of the ballot scheme. Dowless died this year before his case went to trial. The State Board of Elections has ordered a new election for the 2018 9th Congressional District because of all the fraud allegations. Cases against six other defendants are pending.

Since Oregon residents voted in 2020 to decriminalize hard drugs and dedicate hundreds of millions of dollars to treatment, few people have requested the services and the state has been slow to channel the funds. Oregon still has among the highest addiction rates in the country. Fatal overdoses have increased almost 20% over the previous year, with over a thousand dead. Steve Allen, behavioral health director of the Oregon Health Authority, acknowledges that Oregon’s experiment has had a rocky start. But he says a milestone has been reached, with more than $302 million being sent to facilities across the state to help people get off drugs.

Republicans have attacked Democratic Minnesota Gov. Tim Walz, after a judge took the rare public step of disputing the administration’s claim that the judge prevented it from cutting off payments to Feeding Our Future. The nonprofit is the target of a $250 million federal fraud case. The GOP candidates for Minnesota governor, attorney general and state auditor said Monday that Walz and other top Democrats should have done more to stop the alleged fraud in its early stages, before it became what federal prosecutors have called the largest pandemic-related fraud scheme in the country.

You may assume that having more money in retirement will make you happier. And you’d probably be right. But finances aren’t the only factor that contributes to a joyful post-employment period. Your health, relationships and sense of purpose play a significant role, too. Plus, research has found that a little bit of optimism can go a long way. If you want to enjoy a happier retirement, start by looking at the things you can control — your outlook on the world, your attitude about aging and your willingness to learn new things.

Get up-to-the-minute news sent straight to your device.


News Alerts

Breaking News