My opinion: The untoward effects of increases in greenhouse gasses are due to the geometric increase in the Earth's human population. Those problems are very real, but so far distant. The current alternatives to fossil fuel use, i.e.: wind, solar, nuclear, clustered housing, semi-primitive lifestyles, etc are insufficient to "keep the lights on, the heater and AC running, two cars in the garage" and other goodies. Thus, because humans rapaciously want/demand such benefits of fossil fuel based energy, the planet will be in " A Heap of Trouble" probably sometime around 2050 ce., (Jay Forrester, MIT study in the 60's). I don't have any solutions for our "driving down the road where the bridge is out". But I perceive from history that Nature and Evolution will eventually have a solution which will be to no ones liking. In the interim, politics will have an opportunity albeit contentious.