The world’s energy choices between now and 2050 will determine so much about the future. Climate change, natural ecosystems, and economic development are all on the line. Add to that list 181 million years of healthy human life — annually.
That’s how many years can be saved from death or disability by quickly ramping up renewable energy and dialing back fossil fuels, according to a new assessment published on Friday, from the nonprofit World Wildlife Fund and the Boston Consulting Group.
The report compares two futures: one in which the world rapidly transitions to renewable energy sources like solar, wind, and bioenergy; and one in which the world continues business as usual by relying largely on fossil fuels.
“The rapid-transition future is not only essential to mitigating climate change, but it’s also quantifiably better for ecosystems, wildlife, and our well-being,” Stephanie Roe, WWF’s lead scientist on climate and energy, and a lead author of the report, told Insider.
Millions of people’s lives are on the line
Disability-adjusted life years, or DALYs, capture years of life affected by disability and years lost to premature death. The metric allows scientists to do a global, lifetime assessment of health risks due to air pollution or climate change, for example.
That’s what the WWF and BCG used to calculate the toll of the two futures on the table.
If the world rapidly transitions to renewables, they found, the energy system will still hurt human health enough in 2050 to lead to early death and disability that affects 30 million years of human life.
Those health impacts would mostly come from air pollution and climate change, but also from other toxicity and radiation associated with nuclear energy.
In the fossil-fuel future, though, the researchers estimate that in 2050 alone the energy system would cause 211 million years of human life to either be lost or lived with a disability. That’s 181 million more years than the green-energy scenario for 2050.
Fossil fuels are terrible for human health
Fossil fuels like gasoline, coal, or diesel are so deadly because burning them releases heat-trapping gases like carbon dioxide into the atmosphere. That’s raising average global temperatures and driving increasingly extreme weather.
Fossil fuels also release toxic gases and particulate matter — minuscule, toxic flakes that can increase the risk of asthma, lung cancer, heart disease, and stroke.
Car exhaust and gas stoves are day-to-day sources of exposure to these pollutants, according to the American Lung Association. Mines, coal-burning plants, and other fossil-fuel facilities also emit poisonous substances.
In 2018 alone, more than 8.7 million premature deaths could be attributed to air pollution from burning fossil fuels, according to Harvard scientists. That’s one in five deaths worldwide.
“We knew this, but it’s nice to have some numbers on it,” Jonathan Buonocore, an assistant professor of environmental health at Boston University School of Public Health, told Insider.
The report also assessed 2022, and concluded that the current energy system already enacts a heavy toll, to the tune of 159 million healthy life-years with each year that passes.
How researchers measure years affected by disability or early death
The researchers made their projections based on groundwork laid in a 2017 study, which had calculated DALYs per kilowatt-hour of energy from solar, wind, coal, and more.
The WWF and BCG researchers applied those DALYs-per-kilowatt-hour calculations to the energy profiles of both scenarios for 2050.
This may even be an underestimate of the human life and health that’s at stake, Buonocore said, since the calculations in the 2017 study didn’t include the impacts of the smallest particulate matter in the air.
What global green energy means
As of 2019 , 80.9% of the world was powered by fossil fuels, 5% of the world was powered by nuclear energy, and 14.1% of the world was powered by renewables, according to the International Energy Agency. To meet the projections laid out in the WWF report, we’d need to reduce global dependency on fossil fuels to 15% and scale up our renewable energy use to 85%.
“I think it’s important to think about energy as a determinant of health,” Buonocore said. “People need energy to do everything.”
That means building solar panel fields and wind farms, ramping up mining rare earth minerals to make more batteries, and shutting down coal mines and fracking operations.
So a shift into a green future would require a massive investment, upending many corners of our current operating system, from individual kitchens to national power grids. In 2022, Stanford scientists estimated that the transition could require $61.5 trillion in funds.
But, the researchers who ran the report say that the investment would be worth the returns. “A fossil-fuel future is just so many orders of magnitude worse than this transition,” Roe said.