Brexit was a tag that led to a vote for the UK to leave the EU. Now the doggedly persistent climate change deniers have coined their campaign “CLEXIT” which is a catchy tag that they hope will advance their desire to curb concerns about greenhouse gas emissions and anthropgenic global warming and to ‘exit’ from policies designed to ameliorate emissions from fossil fuels generally thought to be responsible for climate disruption. See this link to their dissenting views.
But for a definitive look at the wealth of data and modelled projections see Climate Change 2013: The Physical Science Basis – the International Panel on Climate Change’s compilation of baseline & modelling data. It includes accessible summaries, FAQs and short videos.