Obama suggests that trace amounts of CO2 cause a measurable amount of lost lives

Obama mocks skeptics of climate change as ‘flat-Earth society’ - The Hill's Blog Briefing Room

Earlier in his remarks, Obama said the "overwhelming judgement of science, of chemistry, of physics, and millions of measurements" put "to rest" questions about pollution affecting the environment.

"The planet is warming. Human activity is contributing to it," Obama said.

"We know that the costs of these events can be measured in lost lives and lost livelihoods."