The New York Times wrote the following in response to the UK committing to ending sales of new petrol and diesel vehicles by 2040:
"Much depends, too, on where the electricity comes from. If it comes from coal-fired plants, there could be a net increase in the greenhouse gases that are warming the planet; if from natural gas plants, a modest net decrease; if from carbon-free sources like wind and solar power, a huge net benefit. President Trump’s antagonism to the Paris climate accord and his affinity for fossil fuels demonstrate the difficulty of making this shift; and despite Volvo’s exciting announcement that it will make only electric or hybrid cars as of 2019, many manufacturers may well resist abandoning the engines they have spent the past century perfecting."
This paragraph makes an important point that often doesn't receive enough attention in the current fanfare around electric vehicles. If the electricity used to power cars is from a non-renewable source, then greenhouse gas emissions are simply being shifted up the electricity supply chain rather than being reduced. A holistic overhaul of the world's electricity supply chain, that ensures power is sourced from renewable energy, is needed. Electric vehicles are ultimately only one component of this modernisation.