A new study has come to an alarming conclusion about where humanity is headed, and where we will end up as soon as 2100. The study, put out by researchers at the University of Hawaii at Manoa, finds that 74 percent of the world’s population will be hit with deadly heat waves by 2100 if the carbon dioxide levels in the environment continue to rise at their present pace.

And even if we managed to slash emissions, the heat waves would still impact a staggering 48 percent of the world’s human population, an indication that we are quickly running out of time to get a handle on global warming, scientists say. Right now, researchers say we are stuck with choosing between bad or terrible, and time is running out for us to even have that choice.

The human body is fragile when it comes to global temperatures, and heat waves can create a huge risk ot human life by raising the body temperature and causing life threatening conditions. Scientists based their findings on 1,900 cases of high ambient temperatures killing people since 1980.

“We are running out of choices for the future,” said Camilo Mora, associate professor of Geography in the College of Social Sciences at the University of Hawaii at Manoa and lead author of the study. “For heatwaves, our options are now between bad or terrible. Many people around the world are already paying the ultimate price of heatwaves, and while models suggest that this is likely to continue, it could be much worse if emissions are not considerably reduced. The human body can only function within a narrow range of core body temperatures around 37oC. Heatwaves pose a considerable risk to human life because hot weather, aggravated with high humidity, can raise body temperature, leading to life threatening conditions.”