Over the last century, the growing global concern around climate change has become part and parcel of modern debates. Yet during news around climate change, there has been a development around another catastrophic threat to humanity, Antimicrobial Resistance (AMR). With both issues being labeled as the biggest potential threats to humanity and the planet, recent research suggests there may be a connection between climate change and AMR.
What is Antimicrobial Resistance (AMR)?
Most of the public are aware of climate change, yet many are still unsure what AMR is, and how it can be considered as big of a threat to our way of life. Despite its low media profile, the World Health Organisation (WHO) has classified AMR as "one of the top global public health and development threats".
Antimicrobials – like antibiotics, antivirals, etc, have been the go-to medicine to treat and prevent infections across society (humans, animals, plants) for over a century. These medicines work by disrupting or even destroying the growth of microorganisms, especially pathogenic ones, creating an inhospitable environment for the unwanted bacteria (which causes bacterial infections like Whooping Cough, Tuberculosis, etc). Meaning antimicrobials have become the cornerstone of modern medicine. However, the overuse and misuse of these medicines have led to the evolution of drug-resistant pathogens, known as "superbugs." These superbugs no longer respond to modern treatments, posing a global threat.
As these superbugs no longer respond to our modern medicines, it has become a problem for all countries across the globe. In 2019 AMR was directly responsible for for 1.27 million global deaths and contributed to the deaths of 4.95 million people. And if the current issue is not addressed quickly, it has been forecasted by 2050 these superbugs could cause more deaths than cancer.
AMR Links to Climate Change
The evolution of superbugs is clearly linked to the misuse and overuse of antimicrobial medication. Yet, recent research has also identified a connection between rising AMR and climate change. Whilst both issues are exacerbated by human actions, and failing to address the climate crisis is seen as adding fuel to the AMR crisis.
Rising Temperatures
The greenhouse effect has caused global temperatures to rise, creating warmer and more humid conditions that facilitate the growth, multiplication, and horizontal gene transfer of bacteria. These factors contribute to increasing rates of antibiotic-resistant infections, such as salmonellosis. Additionally, global warming is helping bacteria spread to new regions, including higher altitudes and latitudes. Diseases typically found in tropical areas, such as Zika and Chagas disease, are now migrating to countries experiencing warmer temperatures, even during winter months.
Soil
Warmer climates and heavier rainfalls accelerate the migration of heavy metals in soils. These heavy metals impact the abundance and dissemination of mobile genetic elements (MGEs) and antimicrobial resistance genes (ARGs), which play a key role in the spread of AMR through co-resistance mechanisms. Thawing permafrost (frozen soil) due to warming climates can revive frozen bacteria and antibiotic-resistance genes. For example, in 2016, thawed soil in Northwest Siberia exhumed infectious Bacillus anthracis endospores, causing an anthrax outbreak that killed 2649 reindeer, and sickened 36 people.
Water
Melting icebergs and extreme weather events have led to increased flooding, causing mass migration and displacement. Overcrowded areas during such crises heighten the risk of waterborne infections, as seen with the cholera outbreaks in Haiti and Nepal after earthquakes. Disastrous weather can also damage wastewater and sewerage infrastructure, leading to floodwater contamination with antibiotic-resistant bacteria.
Livestock and Farming
Climate change-induced overcrowding and overheating of livestock have led many agriculturalists to rely heavily on antibiotics to meet growing demands and improve production. Additionally, deforestation of agricultural plots (a driver of climate change) has facilitated closer contact between humans and zoonotic diseases, increasing the risk of disease transmission.
Conclusion
Despite both issues being originally driven by human activities, we are now at a stage where one crisis is aiding the acceleration of the other. Climate change exacerbates AMR in various ways, from rising temperatures, soil contamination, water pollution, and the impacts on livestock and farming practices, meaning we must address the issue of AMR with a broader perspective.
To safeguard public health and the environment, we need to not only look at the root causes of AMR but the external variables that are promoting its growth. Regardless of an individual's stance on environmentalism, there is an undeniable link between climate change and the increase of AMR, which needs urgent, thorough action. Reducing the effects of climate change will limit the variables that fuel AMR, thereby helping us to combat the direct drivers of AMR more effectively.
