Here are the EPA's projections for the future of CO2 concentrations in four different scenarios. Conveniently, the red line (RCP 2.6) shows what happens if global climate emissions peak during Hillary Clinton's first term. By the way, nothing like this is on the table in Clinton's agenda. Her stated goal is merely to "reduce greenhouse gas emissions [in the US] by up to 30 percent in 2025 relative to 2005 levels and put the country on a path to cut emissions more than 80 percent by 2050."
So what happens if emissions don't peak by 2020? The science is straightforward on that, too:
Again: the bottom line, RCP 2.6, shows what happens if emissions peak during Clinton's first term. The others show what happens if they don't. Every alternative has us at or near a 2 degree Celcius rise in temperature in the next 84 years.
Two degrees, remember, is the infamous tipping point in climate science where everything starts really going to hell. Two degrees is where warming processes start triggering other warming processes and the cycle becomes irreversible. Two degrees is where significant coastal areas (particularly in east Asia) start drowning beneath rising tides. Two degrees is where food production in populous nations like India and China begins to drop precipitously. Two degrees, as Gwynne Dyer writes, is where the geopolitical situation becomes so unstable that there is "a probability of wars, including even nuclear wars...Once that happens, all hope of international cooperation to curb emissions and stop global warming goes out the window."
Climate centrists may smugly claim the scientific high ground over radicals like the Kochs, but if they aren't even trying to peak global emissions within the next four years, they haven't actually accepted the science.