Donald Trump signed an executive order on Tuesday to undo a slew of Obama-era climate change regulations that his administration says is hobbling oil drillers and coalminers, a move environmental groups have vowed to take to court. The decree’s main target is Barack Obama’s clean power plan that required states to slash carbon emissions from power plants – a critical element in helping the United States meet its commitments to a global climate change accord reached by nearly 200 countries in Paris in 2015

