A child born in 2021 will live on average through seven times as many heat waves, twice as many wildfires and nearly three times as many droughts, crop failures and river floods as their grandparents, according to a study released Sunday that looks at how different generations will be affected by climate change.

The results, published in the journal Science, found that global warming will disproportionately affect the lives of young people and children, particularly when it comes to extreme events worsened by climate change. The research is the first to extensively model extreme events and future climate scenarios and to apply the projections across demographic groups to quantify how people in different age groups around the world will experience climate disasters across their lifetimes.

The outlook is troubling if the pace of global warming continues unchecked, said Wim Thiery, a climate scientist at Vrije Universiteit Brussel in Belgium, who led the research.

“We found that everyone under 40 today will live an unprecedented life in terms of their lifetime exposure to heat waves, droughts and floods,” Thiery said. “This is true even under the most conservative scenarios.”

The study shows stark intergenerational inequities across the board, but the researchers said climate change will affect children in developing countries even more acutely. The burden will remain disproportionate even with cuts in greenhouse gas emissions that countries have pledged under the Paris Agreement, a global climate pact signed by more than 190 countries.

With what has currently been pledged, 172 million children in sub-Saharan Africa could live through 50 times more heat waves and a sixfold increase in extreme events over their lifetimes, compared to 53 million children in the same age group in Europe and Central Asia, the researchers said.

While the results are already worrisome, Thiery said it’s likely that impacts on people’s lives will be even greater than the study estimates. That’s because the researchers focused only on the frequency of extreme events, which doesn’t take into account how long and severe they are.

Studies have shown that climate change is making events like heat waves, droughts and wildfires not only more likely to occur, but also more intense.

“We don’t account for the fact that a bad heat wave might last twice as long in the future as it does today,” Thiery said.

He added that the researchers also considered extreme events in isolation, which means the study didn’t cover how the impacts of such disasters could be amplified if they coincide.

“There’s a tendency for these things to occur at the same time,” Thiery said. “Think about heat waves and droughts or river flooding and tropical cyclones.”

But, Thiery said, there’s reason for hope. If countries can make aggressive cuts in their greenhouse gas emissions and limit the effects of global warming, some of the study’s most dire scenarios can be avoided, he said.

Young people have been at the forefront of climate activism, with movements like the “Fridays for Future” protests demanding action from governments. The discussions will be particularly important in the coming weeks as world leaders are scheduled to convene from Oct. 31 to Nov. 12 in Glasgow, Scotland, for the 2021 U.N. Climate Change Conference, where countries are expected to set forth ambitious targets to reduce emissions by 2030.

“This should be a call for action,” Thiery said. “We have it in our hands to avoid the worst of global warming. For all of us alive today, we need to combat climate change.”