As global leaders gear up for a major climate change summit in Scotland next month, researchers from 43 academic institutions and United Nations agencies warn that the world is missing its shot to address the public health impacts of the climate crisis and prepare for future warming. 

For the past six years, the medical journal the Lancet has published its annual Countdown report, a comprehensive analysis of the preceding year’s scientific literature on climate change and public health. Last year, the journal’s report said that rising temperatures and emissions threaten to undo 50 years of public health gains from interventions like banning trans fats and restricting cigarette smoking. This year’s major takeaways are no less grim. 

The Lancet tracked 44 health indicators that are directly linked to climate change for this year’s report. Three of those indicators — mental wellbeing, the influence of heat on safe physical activity, and pollution related to the consumption of goods and services — are new this year. The report found that the world’s senior citizens collectively experienced 3.1 billion more days of heatwave exposure in 2020 than average, particularly in China, India, Indonesia, Japan, and the United States. (The annual averages used in the report are based on data collected between 1986 and 2005.) Children under 1 year old experienced 626 million more heatwave days than average. 

The report notes that, in addition to physical risks, heat exposure poses diverse risks to mental health globally. But the way mental health conditions are diagnosed, tracked, and treated varies wildly from country to country, so the authors aim to figure out how to better quantify and document this indicator in future reports.

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One of the Countdown report’s starkest takeaways is that during any given month in 2020, 19 percent of the land surface of the entire planet was affected by extreme drought. Drought and heat combined are putting the world’s major staple crops — corn, wheat, soybeans, and rice — at risk, which means food insecurity will continue to rise in the absence of global leadership on climate change. 

The report’s authors note that the recovery from the COVID-19 pandemic was a golden opportunity for nations to invest in public health by using recovery dollars to transition away from fossil fuels  and create new climate, health, and equity programs. But world leaders in most countries didn’t take advantage of it. 

“Less than one dollar in five being spent on the COVID recovery is expected to reduce greenhouse gas emissions,” Marina Romanello, lead author of the report, said in a statement. “We are recovering from a health crisis in a way that is putting our health at risk.”

Ruth McDermott Levy, co-director of Villanova University’s Mid-Atlantic Center for Children’s Health and the Environment, who was not involved in the Lancet report, told Grist that she was struck by the tone of this year’s report. “The Lancet Countdown’s assertions and pleas for action to protect life are much stronger than past Countdown reports,” Levy said. 

In a brief for U.S. policymakers, public health experts involved in the Lancet report along with some independent doctors and researchers highlighted the way the health impacts tracked in the Countdown report are playing out in America. They specifically focused on heatwaves, drought, and wildfires, three interrelated issues that are undermining public health across the nation. 

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U.S. seniors experienced nearly 300 million more days of heatwave exposure compared to the 1986 to 2005 baseline average, and babies under 1 year old experienced roughly 22 million more heatwave days. The brief notes that particulate matter, tiny particles that infiltrate the lungs and bloodstream and can cause extensive health problems in humans, is up to 10 times more harmful when it comes from wildfire smoke as opposed to other sources. The researchers also pointed to early evidence that wildfire smoke becomes more toxic as it moves further away from its source and interacts with oxygen. And drought compounds all of these issues by worsening water quality, the effects of heat, and even mental health issues in rural areas. 

“The data in this report are more than just alarming statistics and trends,” Renee N. Salas, a practicing emergency medicine doctor at Harvard Medical School and Massachusetts General Hospital and lead author of the policy brief, said in a statement. “I took an oath to protect health and prevent harm, and I can’t do that unless we address climate change.”

The Lancet Countdown points out that there are solutions to the myriad health impacts caused by climate change, and nearly all of them require significantly reducing global reliance on fossil fuels. Sixty-five of the 84 most polluting countries in the world reviewed by the report’s authors continue to subsidize fossil fuels to the tune of $1 billion per year on average. Redirecting those subsidies to national health budgets would be a win-win for the planet and public health, the report says. 

And while world leaders have been slow to understand the negative health consequences of a warming planet, they have been equally slow to grasp the potential health benefits of keeping warming in check. Using COVID-19 recovery funds in a way that helps countries meet the goals of the Paris Agreement — by protecting natural ecosystems, transitioning to renewable energy, and investing in climate-resilient infrastructure — could prevent millions of deaths every year. 

“This pivotal moment of economic stimulus represents a historical opportunity to secure the health of present and future generations,” the report says. If the world lets this moment slip, however, “climate change will become the defining narrative of human health.”