key: cord-0801358-rdg75pj0 authors: Joshi, Manish; Caceres, Jose; Ko, Steven; Epps, Sarenthia M.; Bartter, Thaddeus title: Unprecedented: the toxic synergism of Covid-19 and climate change date: 2020-12-25 journal: Curr Opin Pulm Med DOI: 10.1097/mcp.0000000000000756 sha: 850a9fd67f854b2154f900ab06be457d7bacdbc0 doc_id: 801358 cord_uid: rdg75pj0 PURPOSE OF REVIEW: To review and compare the constellations of causes and consequences of the two current pandemics, Covid-19 and climate change. RECENT FINDINGS: There has been a transient counterbalancing, in which the response to Covid-19 has briefly mitigated pollution and greenhouse gasses. This divergence belies multiple commonalities of cause and effect. SUMMARY: The convergence of these two pandemics is unprecedented. Although at first glance, they appear to be completely unrelated, they share striking commonalities. Both are caused by human behaviors, and some of those behaviors contribute to both pandemics at the same time. Both illustrate the fact that isolation is not an option; these are global issues that inescapably affect all persons and all nations. Both incur prodigious current and anticipated costs. Both have similar societal impacts, and disproportionately harm those with lesser resources, widening the gap between the ‘haves and the have-nots.’ One can only hope that the devastation caused by these unprecedented pandemics will lead to increased awareness of how human beings have helped to create them and how our responses can and will shape our future. With the concurrence of climate change and Covid-19, human beings are witnessing two simultaneous cataclysmic pandemics for the first time in modern history. Both are existential threats not just to human beings but to the collective species that inhabit our planet. As of October 2020, COVID-19 has killed over one million people worldwide. (The United States has at the time of writing the sad distinction of being the nation with the greatest death toll.) Global economies have been devastated. At the same time, the earth's climate is changing at an unprecedented rate [1,2 && ,3 && ]. Global warming and its consequences are visibly apparent -as of October, 2020, California was burning with unprecedented wildfires and the United States had seen in 2020 an unprecedented hurricane season [4, 5] . For those whose opinions are based on evidence and data, there is now ample evidence that both climate change and the Covid-19 pandemic are caused by human activities and that they are inextricably intertwined [ ]. In addition to being a petri dish for pathogens, animal agriculture is the second largest anthropogenic cause of greenhouse gas emissions (fossil fuel use being the largest) [1,2 && ,3 && ]. Globalization and international travel are possible (at present) only because of the extensive use of fossil fuels. There is also a commonality of consequences. Both COVID-19 and climate change are creating social impairment, with social isolation, place and sex inequality, and food and shelter insecurity occurring disproportionately in vulnerable populations, especially women and children [ (Fig. 1) . The economic impacts of these two crises, such as unprecedented job losses, shrinkage in the world's gross domestic project (GDP), and income inequality, have created sharp conflicts at regional, national and global levels . Both economic losses and the future costs of medical care and containment will add dramatically to this initial total. The costs of climate change are sometimes blatant, as with increased forest fires, and sometimes more insidious, as with the slow rise in ocean levels and the accompanying destruction. Recent models suggest that the cost of climate change for the year 2030 will likely be roughly 1% of America's GDP per year. Meanwhile, current estimates for the cost of Covid-19 to the United States this year range between 7 and 10% of GDP. Thus, over the next 10 years, the two pandemics will have similar costs. If the increasing incidence of zoonotic infections translates into a new disruption similar to Covid-19 once every 10 years, then the economic burdens could be equal on an ongoing basis [25] . Both pandemics have dramatic death tolls. Once again, the deaths from Covid-19 are acute, whereas those from climate change can be both acute (as in death from flooding) and insidious (increasing death rates related to pollution and direct and indirect impacts of global warming). The estimated global death projection is 2.5 million from Covid-19 in 2020 [26] [27] [28] . The climate change crisis is estimated to cause a similar number of deaths over the next decade [22 25, 29] . Furthermore, climate change could be responsible for 73 deaths per 100,000 people (several times more deadly than COVID-19) by the end of the century if emissions continue to increase at current rates [25] . Air pollution caused is not only the major anthropogenic driver for global warming and climate change but also poses the greatest environmental risk to human health [ ]. According to the WHO, air pollution kills an estimated seven million people worldwide every year [31] . https://www.who.int/health-topics/air-pollution#-tab=tab_1] WHO data show that, worldwide, 9 out of 10 people breathe air that exceeds WHO guideline limits for pollutants, with low-and middle-income countries suffering from the highest exposures [31] . For the first time in the history, the earth has been beset by two pandemics, climate change and Covid-19. Both climate change and Covid-19 have anthropogenic roots, some of which overlap. Although there has been a brief period during which the response to Covid-19 has had a beneficial environmental impact, Covid-19 and climate change have massive and overlapping present and future impacts upon global health and the global economy. Unprecedented Joshi et al. Air pollution is one area in which the two pandemics have had a transient divergence in effects. Air pollution can be broken down into two major components; the amount of particulate matter in the air and the concentrations of deleterious gasses The burning of fossil fuels generates both of these -in addition to gasses, burning generates very small particles less than 2.5 microns in diameter (concentration measured as 'PM 2.5 ') that can remain suspended in the air for extended periods and that ] (an international team of researchers), global estimates of daily, sector-specific, country-level CO 2 emissions from January 1st, 2019 to June 30th, 2020, were reported based primarily from near-real-time activity data. The study found that the Covid-19 pandemic led to an 8.8% (1551 million ton) CO 2 decrease in global CO 2 emissions in the first half of 2020 compared to the same period in 2019 (Fig. 2 a,b) . The results were astonishing; authors concluded that the 1551 million ton decrease in CO 2 was the largest ever decline in emissions over a 6-month interval, larger than for any recent economic downturn and larger than the annual decrease (790 million ton CO 2 ) during World War II, although mean emissions are much larger than now at that time (Fig. 2c) . The study also found, not surprisingly, a rapid increase in CO 2 levels in most countries by the end of June -except in the United States, Brazil and India, where the number of Covid-19 cases continued to remain high. In fact, they observed a complete rebound of emissions to above 2019 levels in China as early as the beginning of May, 2020. The Covid-19 crisis has caused unprecedented global disruption. The whole world came to standstill from massive lockdowns and the closing of national and international borders. The global economy took a major hit due not only to loss of income caused by shutdown of large and small businesses and other economic activities but also to massive spending on healthcare systems, including personal protective equipment and other resources to fight Covid- 19 ] examined the temperature response of a direct recovery to pre-Covid-19 national policies and emission levels and also explored models for which the economic recovery to Covid-19 is driven by a green stimulus package versus an increase in fossil fuel use. Their study results showed a negligible long-term climate effect of immediate Covid-19-related lockdowns and restrictions. However, a strong green stimulus recovery with reductions in fossil fuel investments would have the potential not only to avoid future warming of 0.38C by 2050 but also of limiting the temperature rise to 1.58C above the preindustrial era. The data to date have led to a redundancy of both findings and conclusions. Le Quéré et al. 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Part 1: The damaging effects of air pollution A comprehensive article on air pollution-related morbidity and mortality -5287 Copyright ß 2020 Wolters Kluwer Health, Inc. All rights reserved Impact of coronavirus outbreak on NO2 pollution assessed using TROPOMI and OMI observations Study based on high-resolution spaceborne data to show unprecedented decreases in NO 2 columns over widespread areas in China, Europe, South Korea and the United Sates in Airborne Particle Levels Plummet in Northern India The NASA satellite pictures showed dramatic decline in airborne particles in Northern India Airborne Nitrogen Dioxide Plummets Over China Impact of the COVID-19 pandemic lockdown on air pollution in 20 major cities around the world Current and future global climate impacts resulting from COVID-19 Temporary reduction in daily global CO 2 emissions during the COVID-19 forced confinement We would like to thank Leslie Norris, Media Services, University of Arkansas for Medical Sciences, for assistance in graphic design for Fig. 1 . None. There are no conflicts of interest. 8.