coal

That coincided with rising industrialisation, when burning of fossil fuels, particularly coal, began to heat up our atmosphere, but it's hard to disentangle natural and human causes that far back in time.

This saw the south Wales valleys' numerous coal mines close for two weeks in the summer, prompting families to head to the coast for their annual holiday.

It is a quiet town surrounded by World War One memorials and by the tall coal slag heaps that litter this stretch of northern France.

Department of Energy, which also announced this week that it will open 13 million acres of federal lands for coal mining and provide $625 million to recommission or modernize coal-fired power plants.

To understand Arbor’s innovation, start with coal plants, which burn fossil fuels to heat up water and produce steam that turns a turbine to generate electricity.