Greenhouse gases: See Global warming, climate change. | Paris climate-change talks. | Urea.

‘The world’s policymakers agreed at the Paris climate-change talks [in December 2015] to try to limit greenhouse-gas emissions so global temperatures rise by no more than 2°C from pre-industrial levels. To succeed, they need, among other things, to encourage people to buy cleaner cars and lorries. Around 23% of carbon-dioxide emissions come from transport, of which three-quarters stem from road vehicles, according to the International Energy Agency, (‘Not easy being green’ The Economist 30th July 2016, p.58).