June 20, 2017 3:25 am Study: Earth's Killer Heat Waves Will Only Get Worse A new global study says deadly heat waves will grow in frequency, intensity and duration, affecting 75 percent of the world’s population if greenhouse emissions are not reduced. US & World Videos 2:48 Taylor Swift fans react to Jake Gyllenhaal and Sabrina Carpenter's ‘SNL' appearance 3:11 Ryan Gosling skips darker film roles because of Eva Mendes and daughters 1:07 Britney Spears spotted as authorities respond to alleged hotel incident 2:15 Prince William and Kate Middleton ‘going through hell,' friend claims (report) 8:01 Lady Gaga's outfit changes, Rihanna's bold looks and more iconic Met Gala moments