As climate change worsens and global temperatures rise, there has been a notable rise in diseases both new and old. In a recent Nature study, researchers found that 58% of diseases were intensified or aggravated as a result of climate change, with severe implications for global health. This is not a coincidence: many factors directly link climate change with higher disease burden. For example, the current rise in global temperatures allows a host of disease vectors, from mosquitos and ticks to bats and rodents, to spread and thrive in environments where they previously couldn’t.
Climate change has changed the range and behavior of various disease vectors, enabling disease spread. (Columbia University)
Global Impact
In much of the developed world and global North, the health burden of climate change appears relatively minor when compared to that of old age, which increases conditions like heart disease and Alzheimer’s. However, climate-driven disease has a far more acute impact on much of the global south, largely due to different climates, lower standards of living, poor sanitary conditions, and overcrowded populations. In regions such as Southeast Asia and Africa, climate change is already having a disastrous impact on public health. In addition to this, heat stress and extreme weather affect those regions far more than the rest of the world, further weakening health security.
The Ebola outbreak in 2014 was caused by a mix of low income and adverse poverty in West Africa which made combating the disease extremely difficult. While the largest outbreak of Ebola has subsided, there is currently another outbreak in Uganda, with similar causes to the 2014 outbreak. (Doctors Without Borders)
In South America, there has also been a huge uptick in emerging infectious diseases. Among the causes are changes in rainfall as well as massive habitat loss across the continent. In Brazil, where hundreds of millions of trees are being cut down every year to open up farmland, human contact with animals is increasing, leading to the spread of new diseases like Oropouche fever. Meanwhile, secondary impacts like extreme heat exposure have been linked to increases in cardiovascular and kidney diseases, further weakening health in the region.
Recent years have also seen record-breaking epidemics of new vector-borne viruses in Brazil as a result of climate change’s impact on mosquitoes, inundating healthcare systems. Brazil’s Ministry of Health has reported a 38.2% surge in Dengue Fever cases from July 2023 to April 2024 alone, putting the country into a state of emergency and causing a field hospital to be constructed in the capital. Though most patients experience mild symptoms, many will experience swelling and severe headaches as well as serious shock and bleeding. In another example, the Zika virus, a previously little-known pathogen, exploded in 2016, infecting large portions of the population in South America and causing thousands of birth defects.
Elsewhere, in Southeast Asia, climate change has driven disease spread through its impact on weather events. The results of increased flooding and stronger monsoon seasons are already causing damage across the region through direct storm damage. Compounding the issue, each climate disaster brings increased cases of Cholera, which is present in runoff that spreads bacteria to sources of drinking water, where millions of susceptible human hosts await. From there, the disease can spread at an exponential rate. Typically, this means severe but survivable cases of diarrhea. However, if left untreated, it can lead to seizures, shocks, and death within hours.
Deforestation in Brazil has been a large cause of increases in diseases like Dengue Fever, with infected mosquitoes moving into large urban areas from the Amazon Rainforest. (UC San Diego)
US Impact
Despite its relative affluence and location in the global North, the US currently faces the threat of multiple emerging diseases, including West Nile Virus and Valley Fever. Perhaps the most notable example, however, is Lyme Disease, a potentially lethal tick-borne disease now widespread in the Northeastern part of the country. As climate change drives up temperatures, ticks will only be able to access more and more areas. The consequences are already apparent, with almost half a million cases occurring annually across the country.
Climate change has increased the temperatures of many northern areas of the US, making many states a hotbed for disease vectors like ticks and mosquitos. (NOAA)
Taking Action
Climate change is undeniably driving disease spread at an alarming rate. However, as we saw with COVID, tackling health security issues is difficult, especially on a global scale. However, a wide range of actions can still be taken, both in terms of fighting climate change itself and combating the diseases it accelerates. Reducing carbon emissions through the use of public transportation, low energy usage, and avoiding unnecessary purchases are always good ways to curb carbon emissions on an individual level. In terms of preventing diseases, it is always important to stay alert about diseases and follow medical advice when seeking treatment.
Of course, it's still up to governments to do the heavy lifting of implementing regulation that cuts carbon emissions and eliminates habitat loss and deforestation. Simultaneously, they must also work with pharmaceutical companies to improve access to treatment options and preventative tools like vaccines and mosquito notes. For example, Cholera vaccines cost as little as $2.90 per dose, and mosquito nets cost around $2-3 per net, yet both have seen shortages when they were needed most.
Education is also key as climate change enables diseases to infect areas that do not have historical experience fighting them. Governments everywhere should aim to reach vulnerable populations, be it through targeted campaigns or widespread announcements. This is especially vital in the age of social media, where misinformation about new diseases can cause unnecessary panic, turn vulnerable groups against health officials, or cause people to disregard dangerous new outbreaks.
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