Donald Trump’s policy efforts to rejuvenate the coal industry are unlikely to succeed.

We’ve argued that for some time, of course. But a new report from Columbia University, which shows that regulations have played only a small part in the decline of the coal industry to date, lends extra weight to the thesis.

If you’ve not been paying attention, coal has been taking a tumble recently. In America, its use fell by 30 percent between 2011 and 2016. The new analysis of what accounts for that slump makes for interesting reading: the Columbia team attributes around half of coal’s decline to the affordability of natural gas, 26 percent to reduced electricity demand, and 18 percent to surging renewables.

The Trump administration has strenuously argued that President Obama introduced rules that placed unnecessary burdens on the burning of coal. The study does indeed identify 10 regulations introduced under the Obama administration—from the notorious Clean Power Plan to more obscure Effluent Guidelines—that will have dampened the sector. But it also finds that they would account for just a 3.5 percent decline in coal. And that’s an upper estimate that assumes all 10 rules had an additive effect on the industry.

Trump’s strategy has been to sign a series of executive orders meant to undo those regulations. Modeling by the Columbia team suggests that they won’t be enough to transform the fortunes of the most polluting of the fossil fuels. Its calculations suggest that the best Trump could hope for would be a return to 2013 levels of coal burning, though further decline could occur if natural gas remains cheap and renewable energy continues to prosper.

Either way, it’s by no means enough to get all the ex-miners working their asses off.

(Read more: Can Coal Make a Comeback?, “Trump’s Empty Promise to Coal Country,” “Trump’s Rollback Paves the Way for a New Climate Leader,” “Coal Power Has Taken a Tumble, But Is It the Beginning of the End?”)