Re: exporting gas
I dont know why any country would export fossil fuel.
First of all, the US isn't trying to produce as much natural gas as we do. It is a byproduct of the fracking for oil. The US is now the world's largest oil producer, and based on the trends in production growth from 2008-2018 within the next year or two will produce more oil than it consumes.
If there was no alternative to fossil fuels then I'd agree with you that exporting it would be short sighted for a country like the US but we can't get the oil out without getting gas as a byproduct so we can either let it go waste (burn it off) find ways to use it (difficult since you can't just flip a switch and replace coal or oil burning generators with natural gas overnight) or sell it. You can't leave it in the ground and you sure can't store the volumes we're producing.
For countries like Russia and Saudi Arabia who derive much of their GDP from oil and gas production, leaving it in the ground and using only what you need is only an alternative if you want your government overthrown.
At the rate wind and solar is dropping in price, that natural gas may be worth much less in a decade. Coal is already more expensive - even the pollution regulation cuts Trump's cronies have pushed through won't cure the "problem". Coal is finished in the US, no new plants will be built and the existing ones are being retired before their full life span is reached. Gas is still needed for base load, but as better battery technology (flow batteries etc.) comes online over the next decade, it will become practical to store excess wind/solar and eat into natural gas's baseload role.
It will take decades to replace natural gas's baseload role completely, but once wind/solar is cheaper with storage (it is already nearly equivalent for peak power use) new natural gas plants won't be built and gas utilization will slowly drop as existing plants are retired and replaced by wind and solar.