Coal is the worst power source for fueling climate change, as burning it causes air pollution that kills millions and mining is also very dangerous. What few have noticed is the devastating cost to our health of just storing coal. A new paper published in the National Bureau of Economic Research puts some astounding figures on the cost coal imposes on society between the mine and the power plant.

The consumption of thermal coal, used for heating and generating electricity, peaked in 2013 and has fallen almost 10 percent since. With renewable energy, or natural gas, now cheaper than electricity from newly built coal-fired power stations across most of the planet, that trend is likely to continue. Nevertheless, coal is still easily the largest source of electric power in the world.

Many studies have been done on the pollution given off by coal-burning power stations and the effects on the people who have to breath this air. Dr Akshaya Jha of Carnegie Mellon University and Professor Nicholas Muller of Middlebury College looked at something different – the tiny particles blown off coal stockpiles while waiting to be burned.

For every 10 percent more coal stored, fine particulate (PM2.5) air pollution within 25 miles (40 kilometers) of the stockpile rose by 0.07 percent, the authors found. This sounds trivial, but the consequences are severe. According to Jha and Muller, a 10 percent increase in PM2.5 levels increases adult death rates by 1.1 percent and infant mortality by 6.6 percent.

Jha and Muller used these estimates, along with the more than 200,000 tonnes of coal stored in America and the numbers living nearby, for their study. Once they added economists' valuations of years of life lost, their calculations brought the cost of a stockpiled ton of coal at $183 ($203 per tonne). If what blows away in transportation and unloading is included, the cost is even higher.

Thermal prices for seaborne coal are currently $86 a ton ($95/tonne), and stations located near mines pay even less. If even a fraction of the author's estimates were incorporated into the price of fuel, every coal-fired power station on the planet would shut, unable to compete with gas or renewables.

“Despite the thicket of environmental regulations relevant to coal, our paper uncovers an as yet unstudied dimension of coal use that we argue requires policy intervention – the environmental consequences of the coal purchase and storage behavior of U.S. power plants," said Jha in a statement.

This paper is a first attempt to estimate something that has previously been neglected, and the figures will probably face challenges. Yet if the true cost is even half this estimate, coal is actually killing the regions that think they depend on it.