With tens of thousands of people displaced by floods, wildfires and hurricanes this summer, researchers warn that the majority of untapped fossil fuels must remain in the ground to avoid even more extreme weather.

Fossil fuel producers should avoid extracting at least 90% of coal reserves and 60% of oil and gas reserves by 2050, according to a study published in Nature, to limit global temperature rise to 2.7 degrees Fahrenheit. Even then, that gives the planet only a 50% chance of avoiding a climate hotter than that.

Global temperatures have already warmed about 2 degrees Fahrenheit since the late 1800s, due in large part to the burning of fossil fuels, which releases gases that trap heat in the atmosphere. As a result of the warming, droughts, storms and heat waves are becoming more extreme, causing a cascade of disasters.

The study finds that global coal and oil use would need to peak almost immediately and begin declining 3% annually until 2050. Even that rate is likely an underestimate of what's needed to avoid the worst impacts of climate change, the study's authors say.

"We're a long way from the types of production decline implied by the paper in this analysis," says Steve Pye, associate professor of energy systems at the University College London and an author on the study. "Fossil fuel producers and investors need to recognize that in the main, further investment in fossil fuel combustion is not compatible."

Worldwide, countries are on track to use about double the amount of fossil fuels in 2030 than is needed to limit warming to 2.7 degrees Fahrenheit, according to a report from the United Nations Environment Programme. Global coal use is projected to rebound this year after a lag due to the COVID-19 pandemic downturn.

In the U.S., coal power is already on the decline because both natural gas and renewable energy have become significantly cheaper. The Biden administration just released a roadmap showing how solar energy could potentially power 40% of the nation's electricity grid by 2035.

While some European energy companies are increasing their investments in renewable energy, U.S. companies are sticking with fossil fuels in the hope that carbon capture technology, which traps emissions from burning coal or natural gas, will develop to a point where it becomes economical.

Democrats in Congress are currently working to include a "clean electricity standard" in a multitrillion-dollar budget package, which could zero-out greenhouse gas emissions from power plants by 2035. With a slim political majority on Capitol Hill, Democrats face an uphill battle in passing the proposal, which is one of the core tenets of the Biden administration's climate policy.

Globally, the Biden administration will join world leaders in November for the next round of climate negotiations at the COP26 conference, where scientists say nations will need to commit to much steeper reductions in emissions for any hope of avoiding more catastrophic disasters in the future.