It doesn't take much of an intellectual leap, Dave, to see the vast effects 7 1/2 billion humans are having on the earth's environment. We have been altering the surface, air and oceans for thousands of years. Many of these effects are accumulative. In the last 150 years, since the beginning of the industrial revolution, we have employed energy and pollution intensive force magnifiers in the form of hundreds of millions of cars, trains, trucks, buses, planes,construction equipment and factories. As this isn't enough to cause climate change, we add vast and expending heat islands around our ever expanding cities. We also divert major rivers, create huge lakes in the desert and remove hundreds of mountain tops in pursuit of coal and other minerals. We haven't been "puny man" for many generations now. We have become a significant force of nature and we are altering the climate, as inconvenient as that may be for you and President Trump.