Climate of Despair or Hope? It’s Up to Us.

"To be truly radical is to make hope possible rather than despair convincing."

Raymond Williams, Welsh writer

"Action is the antidote to despair."

Joan Baez, American singer-song writer

Climate change (aka global warming) is the single biggest threat to human health. (See, “Microbes and Climate Change: Threats and Solutions,” Germ Gems, December 13, 2023). As The Lancet has consistently reported, most populations are “woefully unprepared for the climate crisis.” (See, “Countdown on health and climate change,” published annually by The Lancet; see also, “Climate Change Is Fueling New Threats—and We’re Not Ready,” Medscape News, March 25, 2025). Yet, our species may face extinction if we fail to act.

In this week’s Germ Gems post, I provide a brief review of the connections between climate change and infectious diseases. I then end on a note of hope: all is not lost if we act.

Rising temperatures. Heat is the leading threat to human health. For the past decade, global temperature records have been shattered every year. Horrendous wildfires are taking an enormous toll on human health and wellbeing all over the world. (See, “Fire Forged Humanity, Now It Threatens Everything,” Scientific American, April 16, 2024). Air pollution and megadroughts pose major threats not only to our species but to that of many other animal and plant species as well.

Climate change and infectious diseases (recap). “Over half of known human pathogenic diseases can be aggravated by climate change.” (See, id., Nature Climate Change, August 22, 2022). The main diseases we’re talking about are vector-borne and water-borne diseases, and two diseases caused by fungi that love warm environments, that is, Candida auris and Coccidioides immitis.

On March 24, 2024, the Centers for Disease Control and Prevention updated its website on “Vector-Borne Diseases.” The vectors that carry and transmit pathogens to humans have not changed; they are mosquitoes, ticks, and fleas. All of these vectors enjoy global warming as it fosters a longer breeding season and an expanded geography.

Malaria is caused by the parasite Plasmodium carried and transmitted by mosquitoes. Globally, malaria is the most important climate change-fueled infectious disease causing an estimated 600,000 deaths per year.

In the U.S., diseases caused by pathogens carried by ticks (Lyme disease, Rocky Mountain spotted fever, anaplasmosis, and tularemia), mosquitoes (dengue fever and West Nile virus), and fleas (plague) are flourishing because of global warming. (I have discussed each of these diseases in previous Germ Gems posts.) Dengue fever, in particular, is experiencing a concerning global increase, with 2023 the worst year on record for cases, and 2024 showing a continuing rise in the Americas.

Politicization of climate change. On December 2, 1970, President Richard Nixon established the U.S. Environmental Protection Agency (EPA) to protect human health and the environment.  In 1988, the nation learned of climate change. Testifying before the Senate’s Energy and Natural Resources Committee on June 23, 1988, NASA climate scientist James Hansen stated that the greenhouse effect had been detected and that the climate was in fact changing.

Nonetheless, climate change wasn’t on most of our radar screens for years. In fact, I was oblivious of the enormous threats of climate change to human health until 2015 when I attended for the first time a lecture on the topic of climate science.

Fortunately, recognition of the importance of climate change to human health as well as to the health of our environment has steadily increased over the past decade. Yet, to date, many Americans do not think there is a climate crisis. A 2023 poll found that only 18% of Republicans compared to 79% of Democrats and 50% of Independents considered climate change “a very important issue.”

Climate of hope. When I first became aware of the climate crisis, I was optimistic; I believed that scientists and governments were making and would continue to make headway in ameliorating the consequences of greenhouse gases—the main cause of climate change. But, progress in countering global warming depends on research and science. It depends on international collaborations and on the development of innovative technologies, including the use of microbes.

When the current administration came into office, it proceeded to ransack the EPA and to gut most, if not all, medical science and public health agencies. I am therefore less optimistic than I was ten years ago but, nonetheless. remain hopeful.

The current administration’s policies are having a major chilling effect on climate activism. (See “Drill, baby drill? Trump policies will hurt climate—but US green transition is under way,” MedPage Today, February 4, 2025; “Public Health, Environmental Experts Decry EPA Rule Rollbacks,” MedPage Today March 21, 2025.) But, as New York Times reporter Alexis Soloski suggests, there is a “time for screaming” and there’s also “room for dreaming.” (See, “Climate Doom Is Out. ‘Apocalyptic Optimism’ Is In,” New York Times, April 21, 2024.) Today, more than ever, there is a need for activism—activism that includes both “screaming” and “dreaming.”

In 2021, environmentalist Bill McKibben founded  “Third Act,” a nonprofit organization “to mobilize people over 60 to take on climate change.” In 2022, actress and activist Jane Fonda founded the “Jane Fonda Climate PAC.” And young people get credit for energizing people, both young and old, to address the climate change crisis.

But, if we want to effect change, we all need to become activists; we all must speak up. This is especially true for anyone in science and/or medicine. As Virginia Commonwealth University School of Medicine Professor Steven Woolf, MD, MPH commented, “[T]he responsibility of the profession is to speak out when the science is clear that it will threaten health or safety. Silence is not an option.” (See “How Should Health Care and Public Health Respond to the new US Administration?,” Journal of American Medical Association, January 31, 2025.)