Powder River in Wyoming is the source of coal for the Gateway Pacific coal export terminal. I believe we must not export coal to China to burn in power plants that raise planetary carbon dioxide levels. Take a basketball and balloon just large enough to stretch tightly over the basketball. The thickness of rubber stretched around the ball is similar in its relative thickness to the ball as earth's atmosphere is in relation to our earth. Wherever coal is burned, it is in the same shared atmosphere.
It's not about air pollution, like smog from the burning coal and dust of coal trains. More importantly it is about carbon dioxide levels rising at exponentially accelerating rates. Carbon dioxide, one of the primary greenhouse gasses, trap solar rays from escaping back into space, keeping our planet in some semblanceof environmental balance.
As earth temperature increases, the majority of climatologists and other scientific experts worldwide have come to a position that this global warming is almost entirely caused by humans, with many types of weather patterns on our planet and those patterns being complex.
There is consensus that as the major ice sheets melt, and sea levels rise, there will also begin an accelerated release of methane gas from newly melting permafrost. Methane, being far more dangerous greenhouse gas than carbon dioxide, I believe will tip us over the edge into a global environmental catastrophe of unspeakable proportions.