OPINION ARTICLE – Is the COVID-19 pandemic linked to climate change?

Is the COVID-19 pandemic linked to climate change?


Is the COVID-19 pandemic linked to climate change?




Human evolution from “Australopithecus” to “Homo Sapiens” was rambling. Substantial alterations in the African and Eurasian climate played a key role in this process.  Environmental changes and re-shaping of the ecosystems compelled “Homo Sapiens” to expand across the Globe, leading “Neanderthals” simultaneously to total extinction.1 Available records suggest that it took hundreds of thousands of years for the genus “Homo” to emerge, stand upright and finally give birth to a new species; the “Homo Universalis”, or, the “Renaissance Man”.1 An Italian polymath, Leonardo Da Vinci, brilliantly illustrates the essence of the “Renaissance Man”. Even today, his enigmatic works of Art have not been fully decoded by modern scientists. One of those is the legendary “Vitruvian Man”. Various are the interpretations of this masterpiece but according to Mark D. Williams, the “Vitruvian Man” represents a metaphor for the “compleat physician”, one who possesses three essential elements:  science (the square), humanitarianism (the circle), and artistry (the triangle between the pubis and feet).2 Impressively, in this drawing and about 530 years ago, Leonardo da Vinci has well-presented the qualities that physicians should possess nowadays, when human evolution continues to unfold in a changing climate.

            Scientific knowledge is an increasingly important asset for the modern clinician who must now become familiar with concepts outside the medical field, like terms from the climate science. The National Aeronautics and Space Administration (NASA) reported the year 2016 as the hottest year of the last decade, followed by the year 2019, when global temperature was 0.98 degrees Celsius higher than the mean.3 Undoubtedly, global warming will have tremendous effects on human health. Actually, on every aspect of it. The incidence of infectious diseases, chronic kidney disease of unknown origin, heart attacks, heat strokes, respiratory diseases like asthma or chronic obstructive respiratory disease4and ecological stress5 is expected to expand in the near future.

In December 2019, physicians in Wuhan, the capital city of Hubei province in China, noted a surge in patients presenting with a pneumonia of unknown cause and a wide clinical spectrum from asymptomatic infection to severe acute respiratory failure and death.6 Scientists soon isolated a novel coronavirus related to the coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003. This novel coronavirus was named Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and the disease it causes has been named Coronavirus Disease – 2019 (COVID-19).7 Until today, 81,048 cases of COVID-19 and 3,204 deaths have been confirmed in China, with the disease spreading rapidly and exponentially all over the world.8

More recently, the World Health Organization eventually declared the COVID-19 a pandemic and set the alarm for a public health emergency of international concern as the global mortality rate escalated up to 3.4%. Conspiracy theories that link the outbreak of COVID-19 to a new, powerful bioweapon have emerged worldwide.9 After all, one of the most frequently encountered human behavior pattern is to shift responsibility to exogenous factors to reduce inner stress, isn’t it? Citizens having being terrified follow experts’ instructions and choose social distancing and self-quarantine that deluges them by anxiety and depression.10 While much regarding the virus remains to be understood, a recess over the global financial markets already follows the humanitarian crisis with losses that are likely non-recoverable and with consequences even worse than those triggered by the global financial crisis in 2008. Our generation has never faced such a pandemic and we are living in an era of unprecedented change.

However, if we look back in time, we’ll notice that in 1918 the world faced the deadliest pandemic in history, the Influenza pandemic or the “Spanish flu” which spread rapidly and killed people indiscriminately.11 Moreover, similar outbreaks have been noted even earlier, like in the case of plague (also known as the “Black death”), malaria and cholera that have also affected the rise and fall of nations. A search of literature reveals that a common link between pandemic outbreaks is their coincidence with severe climate phenomena like the El Niño events.12 Paraphrasing a quote of Sir Ronald Ross – the pioneer researcher for malaria – “as physicians, we are not familiar with terms from the climate science and when confronted with disease pandemics we don’t view phenomena from a sufficiently high climate-related standpoint”.12 The example of the most recent COVID-19 pandemic clearly inaugurates the era of Climate Medicine. Let’s take a closer look.

The National Oceanic and Atmospheric Administration of the United States, defines the El Niño/Southern Oscillation (ENSO) as a natural climate phenomenon that causes anomalous interannual climate variability patterns driven by changes in wind and surface ocean temperatures across the Equatorial Pacific Ocean, affecting mostly the areas of the tropics and the subtropics. Events have proven that the ENSO has a significant impact not only on the earth’s ecosystems but also on human societies. Two major components of this phenomenon are the El Niño and the La Niña weather patterns, representing each one its extreme warming phase and its extreme cooling phase of the sea surface temperature over the Pacific Ocean, respectively.13 During El Nino events severe droughts, floods and even deadly wildfires like the ones raged over the Amazon, occur all over the world. Interestingly, the origin of the name “El Niño” dates back to the 1800’s and was introduced by the fishermen of Peru and Ecuador who observed that every few years, a warm marine stream appeared on their shores around Christmastime and lasted for several months. El Niño, in Spanish, means baby, and because of Christmas it can also be referred to as “the Divine Infant”. Due to the hot water the fish were scarce at this time and the fishermen had the opportunity to take a break during which they were engaged in the maintenance of their equipment.13 Ironically, the new pandemic burst out in December when climate variations are occurring in the Equatorial Pacific, naturally!

As we already highlighted, 2019 was one of the last decade’s hottest years spurred by an extreme El Niño event which resulted in an increase in rainfall patterns, threatened rice crops and intensified air pollution in China.14 According to available data from National Chinese Authorities, up to 55 days of precipitation (which equal to 15 days more than the seasonal average) were recorded in some cities in the southern part of the country, from December to February 22nd 2019. The El Niño phenomenon also contributed to the reappearance of smog around Beijing and the neighboring Hubei province in northern China. This meteorological phenomenon, through the generation of weak winds, facilitated the transfer of moisture from southern to northern China. Besides, it is known that a very humid atmosphere enhances the retention of polluting particles in the atmosphere, which may have “carried” the virus and contributed to its airborne transmission.14

Global warming drives extreme El- Niño phenomena that lead to hydrological alterations which in turn give rise to various waterborne and vector-borne diseases as the growth of pathogens is promoted.15 It is considered that during droughts, stagnant water remnants allow insect vectors to increase their populations whereas flooding and soil moisture extend their reproduction periods.16 Therefore, humans may become infected either directly through infected animals’(zoonotic transmission) bites or saliva, or indirectly via vectors (which serve as an intermediate host) that carry the disease pathogen and transmit it via biting to humans.17 In the case of COVID-19, scientists suggest that the outbreak of the pandemic occurred through zoonotic transmission associated with a large seafood market in Wuhan which was followed then by human-to-human transmission.18 And therefore, we suddenly realize how climatic phenomena can trigger pandemic diseases affecting various aspects of humans’ life like their health, the practice of medicine, politics, economy and even their evolution.

Humans’ life has changed drastically worldwide. First China, then Italy and now the whole Europe, the United States of America, Australia and even Africa feel the sequelae of the spread of the COVID-19. People remain confined to their homes, constantly washing their hands while the streets are empty. In rare instances, some people walk around in distance, wearing protective masks, buying antiseptics, seeking “purification”… Scientists are now in the quest of a novel vaccine and effective treatment regimens against the SARS-CoV-2. In this era, Goya’s black paintings, and especially “Saturn devouring his son” seems so timely. It could reflect not only the painter’s fear of insanity and his bleak outlook on humanity, but also ours…

At the same time, scientists have noticed that the novel coronavirus outbreak, has caused a dip to global greenhouse-gas emissions that drive climate change. More specifically, available data suggest that the coronavirus has reduced China’s CO2 emissions by a quarter and has lead improvements in air quality that could finally save more lives than the virus has killed. But, what will happen eventually after this global recession? Greenhouse gas emissions are expected to counter-increase whereas climate advocates will come to face the real problems. Al Gore, the former Vice-President of the United States and a Nobel Peace Prize laureate claims that “No one person or party can stop our momentum to solve the climate crisis, but those who try will be remembered for their complacency, complicity, and mendacity in attempting to sacrifice the planet for their greed.”

By any means, viruses will always find a way to survive. Especially, RNA viruses that have very high mutation rates that allow them to evolve rapidly and adapt quickly. The same applies to our planet, Earth who in the last half-billion years has witnessed five mass extinctions. But what about humans? How, our evolution will unfold in a changing climate? Will modern scientists find ways to protect humanity and prevent the sixth major mass extinction that is according to their theories already taking place? Climate medicine may have the answers. As all humans, physicians, too, have a generational mission. We need to act immediately and make known to our peers and the public the health effects of climate crisis that “may be more insidious and more tremendous than we have ever imagined”.19



We received no funding for this work.


Conflict of Interest




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