Rockman, I'm guessing none of these are in dispute:
1. Coal is bad for the environment
2. Lower production & consumption of coal is better for the environment
3. Under Obama coal production & consumption fell sharply
4. Under Obama harmful emissions from power plants fell sharply
Seems like you are now saying the fall of US coal production/consumption and reduction in harmful emissions had nothing to do with Obama's actions? That seems highly unlikely IMHO. Mercury emissions alone fell 86% thanks to Obama's MATS regulation:
Industry aggressively fought the Mercury and Air Toxics Standards (MATS) when the Obama administration proposed it in 2011 and finalized it in February 2012, warning it would precipitate the closure of a swathe of coal capacity nationwide. Six years later, the rule appears to have had a sizable impact on the power sector.
The rule imposes first-of-their-kind emissions limits for mercury, arsenic, and heavy metals associated with fuel combustion on power plants larger than 25 MW, and the Environmental Protection Agency (EPA) says it affects about 600 power plants, which include 1,100 existing coal-fired units and 300 oil-fired units. The EPA received close to a million public comments on the MATS proposal alone—substantially more than any prior rule-making—and most comments from industry decried its potentially exorbitant costs associated with compliance and its potential threat to energy reliability.
An Environmental SuccessWhen the EPA published its final MATS rule in February 2012, it released a companion regulatory impact analysis that projected annual incremental private costs of the final MATS to the power sector would be $9.6 billion in 2015 (in 2007 dollars). But it also estimated that the annual benefits of the rule, including the avoidance of up to 11,000 premature deaths annually, would be between $37 billion and $90 billion.
The environmental benefits of the rule are tangible, it said. In a January 2018 report summarizing analysis of its 2016 Toxics Release Inventory, the EPA noted that since 2006, net electricity generation from coal decreased 38%, while the rate of release of mercury to air per GWh of electricity from coal dropped 77%. Electric utilities overall reduced their mercury air emissions 85% (80,000 pounds) between 2006 and 2016. Total mercury emissions, including air releases and land disposal from the sector fell 48% (68,000 pounds) since 2006.

How Did MATS Affect U.S. Coal Generation?Then there were the rules regulating carbon dioxide emissions, the clean power plan, the
new coal mining regulations, etc.
President Obama has been called one of the most anti-energy presidents in U.S. history. As if to put an exclamation point on this perception, last week the Obama Administration intervened to block an easement for the nearly completed $3.8 billion Dakota Access Pipeline (DAPL). This intervention was despite the fact that the U.S. Army Corp of Engineers had previously approved the easement across the Missouri River, and despite the fact that multiple pipelines already cross the river. The Obama Administration has also banned offshore drilling in the Arctic, and placed additional rules and regulations on the fossil fuel industries -- particularly on the coal industry. Thus, it’s clear that there is some substance to the narrative that President Obama is hostile to fossil fuel development. So let’s take a look at what has happened with respect to energy production while President Obama has been in office.
Recent history in the coal industry definitely supports the anti-fossil fuel narrative of President Obama. In 2008, President Bush’s last year in office, the U.S. produced 1.06 billion metric tons of coal -- an all-time high. By 2015 it had fallen to 813 million metric tons. Final data for 2016 won’t be available for several months, but during the first six months of this year the EIA reported that domestic coal production had fallen to an annualized rate of 667 million metric tons. That marks a decline of 37% in coal production during Obama’s presidency.
The bigger story, however, was the explosion of wind and solar power during the Obama Administration. Again, both started to grow during the Bush Administration, but the forced tilt away from coal provided a tremendous boost to wind and solar power. During the last year of the Bush Administration, wind and solar power respectively supplied 56 Terawatt-hours (TWh) and 1.6 TWh. By 2015 those consumption numbers for wind and solar power had grown to 193 TWh and 39 TWh. That translates to a 245% gain in wind power and a whopping 2300% gain in solar power production over the first seven years of the Obama Administration. And these numbers are likely to grow again in 2016.
I'm not saying Obama was the greenest president in history. Nor am I saying the demise of coal was 100% because of his actions, cheap gas was a large factor as well. But IMHO Obama's actions on coal have contributed to both coal's overall decline in production & use in the US and overall cleaner emissions for the coal that remains.
The oil barrel is half-full.