Photo by: Mel Melcon / AP PhotoLos Angeles Times
2021 Lancet Countdown on Health and Climate Change: U.S. Policy Report
10/21/2021 | 2021 Lancet Countdown
Related: Lancet Countdown 2019 | 2020
Fact sheets
- Executive Summary
- Summary for the General Public
- Information for Medical Professionals
- New Science
- Regional Summaries
The United States must rapidly implement an all-encompassing, evidence-informed response to climate change that prioritizes and optimizes health and equity, according to new research published in The Lancet from Dr. Renee Salas, lead author of the Lancet Countdown U.S. Policy Brief and Yerby Fellow at Harvard Chan C-CHANGE. The 2021 Lancet Countdown on Health and Climate Change is a comprehensive yearly analysis tracking the impact of climate change on human health across 44 indicators around the world.
This year, the U.S. Policy Brief highlights opportunities to improve health through climate actions and reducing the use of fossil fuels. It examines three interrelated hazards—heatwaves, drought, and wildfires—to demonstrate the complexities and nuances of climate change and show how health risks vary, can be unexpectedly broad, and have far-reaching consequences. The U.S. Brief accompanies the global report and uses country-specific indicator data to expose the inequitable health risks of climate change.
“The data in this report are more than just alarming statistics and trends,” said Dr. Renee Salas. “These numbers represent patients that I care for, such as those with worsening asthma attacks, Lyme Disease, or life-threatening illnesses from extreme heat. I took an oath to protect health and prevent harm, and I can’t do that unless we address climate change. Acting on climate change is, first and foremost, a way for us to improve health in the U.S. and advance equity.”
Key Takeaways
Extreme Heat
- In 2020, adults over the age of 65 experienced a total of nearly 300 million more days of heatwave exposure in the U.S. compared to the 1986-2005 average baseline, making it the second highest year of exposure recorded since 1986.
- Infants under one year experienced a total of nearly 22 million more days of heatwave exposure in 2020 with respect to that same baseline.
- Policy failures — such as historic redlining or lack of OSHA regulations — disproportionately expose specific groups (such as people of color, outdoor workers, incarcerated persons, and those living below the poverty line) to extreme heat.
Wildfires & Smoke
- Wildfires in the Western U.S. correlate with hotter temperatures, and the wildfire season has been lengthening. By September 2020, the maximum annual wildfire incidence peaked at approximately 80,000 wildfires, which is 8 times greater than the total incidence in 2001.
- There is emerging evidence that PM2.5 from wildfire smoke may be up to 10 times more harmful to human health than PM2.5 from other sources, with increased respiratory harm for children.
- Early evidence also suggests that smoke-related health impacts may be greater farther from the origin of the fire. This could be due, in part, to smoke becoming more toxic over time through a process called oxidation, as well as people not recognizing dangerous air quality and failing to change their behavior.
- PM2.5 from climate-intensified wildfire smoke has been shown to increase susceptibility of contracting and dying from COVID-19, possibly by allowing the virus to travel greater distances and cause more lung inflammation.
Droughts
- Drought harms health in indirect and under-recognized ways by compounding exposure to heat, increasing respiratory and infectious disease risks, worsening water quality, and exacerbating mental health issues — particularly in rural areas.

Infectious Disease
- The likelihood of dengue spreading through the Aedes aegypti mosquito in the U.S. has steadily increased since the 1950s.
- In the past 5 years (2016-2020), the transmission potential was on average 55.6% higher than in baseline years (1950-1954) and briefly rose above the threshold of one for the first time in 2017. (A transmission potential above one means that one case of dengue can cause more than one additional infection, potentially leading to an outbreak in the right conditions.)
U.S. Policy Recommendations
Mitigation
Urgent and equitable economy-wide greenhouse gas emission reductions: Rapidly reduce economy-wide GHG emissions to 57-63% of 2005 levels by 2030, consistent with a 1.5°C national emissions pathway, with at least 40% of investments directed towards improving air quality in under-resourced communities, and a near zero-emission economy by mid-century.
Economics & Finance
Incorporate health-related costs of fossil fuels into the social cost of carbon: U.S. calculations must include these health-related costs to accurately analyze the costs and benefits of policies that contribute to the release of carbon dioxide.
Adaptation
Rapidly increase funding for health protections: Local, climate-specific health research conducted through multi-sectoral partnerships can directly inform the development, implementation, and evaluation of equitable health-protective actions.
Links
“We MUST respect this earth - it is all we have
Claudio Dametto - South Australia
“I will always Vote to Preserve Our World.
Liam McGregor - Western Australia
“A simple message that even a politician can understand
Felicity Crombach - Victoria
“Please show you care about our future generations!!
Phil Harmer - New South Wales
“Save our world , Life & health before profits.
Kerry Lillian - New South Wales
“Close down all coal mines and Do not mine gas . Make these Companies
Daniel Johnson - New South Wales
“We want carbon free energy!
Edan Clarke - New South Wales
“Feels good to be taking a voter action step
Beaver Hudson - New South Wales
“Great Initiative. Let’s Hold elected officials Accountable to their bosses, us!
John Paul Posada - New South Wales
“We need actions not words we need honest democratic govt We need a pm
Bob Pearce - South Australia
“Thank you for this great resource. I was feeling helpless. Even this small step
Silvia Anderson - Victoria
“If political parties continue receiving political donations, we will rarely have politicians working for
Dan Chicos - New South Wales
“I only vote for people who will take urgent action to restore a safe
Susie Burke - Victoria
“Current government is not representing the opinion of the majority of Australian to meet
Neil Price - Tasmania
“We are fighting to rescue our kids' future from those who seek to steal
Vanessa Norimi - Queensland
“No time to waste Now or Never My vote is for NOW
Rosalie White - Victoria
“I am only 9 but I already care
Ava Bell - New South Wales
“From New Lambton Uniting Church - Caring for our world is a moral imperative.
Niall McKay - New South Wales
“Our federal govt is an International climate Embarrassment - its about time they stepped
Oriana Tolo - Victoria
“Vote earth this time!
Sue Cooke - Queensland
“We are in one on the wealthiest countries in the world. we have the
rowan huxtable - New South Wales
“The climate Emergency is the public health opportunity and urgent priority of the 21st
Mike Forrester - Victoria
“If they want my vote they better act now
Barbara McNiff - New South Wales
“We need to act locally now for the earth. Our only home. Vote Earth
Anne Miller - New South Wales
“I often look at the places I've known all my life and see how
Jim Baird - New South Wales
“Strike one For people power!!! Democracy might prevail outside the current cronyism that faces
Lorraine Bridger - New South Wales
“Our federal politicians Are Afraid to make action on climate change a major election
Jennifer Martin - New South Wales
“climate election, let's go!
Fahimah Badrulhisham - New South Wales
“Great to see this website that is a focus on action for climate change
Lynette Sinclair - New South Wales
“Let’s show politicians and the Murdoch media that climate change is by far the
Jane Aitken - Australian Capital Territory
“If you want to stay in power You need to take action to stop
Jane Bulter - New South Wales
“We are all that stands between terminal climate change and the vulnerable. We are
Carol Khan - Queensland
“We need a Government that Believes this is real and not taking money from
Ken Gray - New South Wales
“I'm voting for my childrens future
Anneliese Alexander - New South Wales