A new study by the UK Met Office suggests annual carbon dioxide levels in the atmosphere are set to shatter the symbolic barrier of 400 parts per million ( PM ) this year and will not fall below it in our lifetime . Climate modelling is a complex and delicate science, but confidence in the latest projections is high among the Met Office experts. The report adds that the likelihood of the threshold being breached a year ahead of expectations carries a risk for the future . The UN ’s Intergovernmental Panel on Climate Change ( IPCC ) warns CO2 concentrations must be stabilised at 450ppm if there is to be any chance of avoiding global warming above 2 ° C , which could bring catastrophic consequences . To achieve that it will require a 40 - 70 % cut in emissions by 2050 , compared to 2010 levels , and zero emissions by the end of the century . However , despite the recent Paris Agreement and a boost in renewable energy , the world is still on track to meet this target .
A new study by the UK Met Office suggests annual carbon dioxide levels in the atmosphere are set to shatter the symbolic barrier of 400 parts per million ( PM ) this year and will not fall below it in our lifetime . The report adds that the likelihood of the threshold being breached a year ahead of expectations carries a risk for the future . The UN ’s Intergovernmental Panel on Climate Change ( IPCC ) warns CO2 concentrations must be stabilised at 450ppm if there is to be any chance of avoiding global warming above 2 ° C , which could bring catastrophic consequences . To achieve that it will require a 40 - 70 % cut in emissions by 2050 , compared to 2010 levels , and zero emissions by the end of the century . However , despite the recent Paris Agreement and a boost in renewable energy , the world is still on track to meet this target .