Why did the virus SARS-CoV-2, which caused the COVID-19 pandemic, start infecting people? There is evidence that our interactions with the natural environment are creating perfect conditions for pathogens to move from wild animals to people, as population growth, urbanization and climate change bring us into closer contact with wildlife. Medical News Today looks at the connections between health, sustainability, and the environment, and the lessons we must learn from the pandemic.
Share on PinterestWhat has COVID-19 has taught us about sustainability and health? Image credit: DAVID GRAY/AFP via Getty Images.
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The Paris agreement, signed in 2015, was a global commitment to work toward net-zero emissions and the United Nations’ (U.N.) sustainable development goals.
As many as 192 countries, plus the European Union — a further 27 countries — joined the agreement, which came into force in November 2016. Details for its implementation were finalized in 2018 at the U.N. Climate Change Conference in Katowice, Poland, and in 2021 at the U.N. Climate Conference in Glasgow, UK.
Climate change and sustainability were constantly in the news. Despite a few dissenting voices, most experts recognized that people are largely responsible for climate change and that measures must be implemented rapidly to combat climate change.
Then, in December 2019, COVID-19 struck. Suddenly, there was a more urgent concern for governments to deal with. Climate change rapidly became a problem for the future. People were dying now from this new disease.
But what many began to realize was that the two issues were inextricably linked. The population growth that drives climate change also increases the likelihood of disease transfer from animals to humans.
COVID-19 is not the first zoonotic diseaseTrusted Source — a disease that is naturally transmissible from some animals to humans. The World Health Organization (WHO) records more than 200 such diseases, and unless we react to it in the right way, COVID-19 will not be the last.
Health and environment
“The major determinants of global health and sustainable development are poverty, population, and pollution — all of these are linked to both COVID-19 and the climate crisis.”
– Dr. Jagdish Khubchandani, professor of public health, New Mexico State University
The WHO estimates that more than 13 millionTrusted Source deaths each year are due to avoidable environmental causes, and it names the climate crisis as “the single biggest health threat facing humanity.” So climate and health must be addressed in parallel.
But how is climate linked to COVID-19? The prevalent theory is that COVID-19 moved to humans from bats via an unknown animal vector that was sold in, or had an association with, a wet market in Wuhan, China. And it is not the first disease to move in this way.
According to Amanda McClelland, senior vice president of Prevent Epidemics at Resolve to Save Lives, a global health organization that aims to prevent cardiovascular disease and epidemics:
“There is a strong link between climate change and infectious disease outbreaks. With greater global connectivity and urbanization, habitat loss, and changing environmental conditions, the potential for novel pathogens to become pandemic threats has significantly increased.”
Interactions with wildlife
People are accelerating climate change in many ways — population growth, burning fossil fuels, deforestation, urbanization, and environmental degradation are all adding to the problem. And as populations increase, people need more land, so they move into and use new areas.
They, or their domesticated animals, come into contact with wild animals. Many wild animals carry pathogensTrusted Source: Bats, for example, as well as being prime suspects for COVID-19, harbor several other viruses that cause disease in humans, such as rabies, Ebola, and SARS.
Dr. Kunjana Mavunda, board-certified pediatric pulmonologist and expert in travel medicine and global pandemics, told Medical News Today that “[t]he bat can hold several viruses that can be deadly to humans at the same time and not have a problem.”
However, passed to domestic animals and then to people, pathogens that are harmless to their original host often result in disease. The Centers for Disease Control and Prevention (CDC) estimate that three in every fourTrusted Source emerging diseases spread to humans from animals.
Dr. Mavunda added: “Societies that have markets where different species of wild animals are kept together in crowded conditions with poor hygiene — there is a high risk of the pathogens these animals having being transmitted, mutating and then transmitting to humans.”
And it is in developing countries that these conditions are most likely, as Dr. Khubchandani explained to MNT:
“The demand for resources like food cause greater animal husbandry, higher dependence on animals, and interactions with pests and pets without safety and sanitation. […] In such scenarios, we always notice that emerging infectious diseases originate from developing countries.”