Limiting temperature increase to 1.5C

This briefing paper has also been published individually as a webpage: Limiting temperature increase to 1.5°C above pre-industrial levels

Authors: Professor Joeri Rogelj, Dr Robin Lamboll, Dr Caterina Brandmayr and Jennifer Bird

Media enquiries: grantham.media@imperial.ac.uk  
Policy enquiries: j.bird@imperial.ac.uk   

This background briefing explores current trends in global warming towards 1.5°C above pre-industrial levels in relation to the Paris Agreement.

Key points

• The Paris Agreement 1.5°C target has not yet been missed: in 2023 we experienced some temporary temperature spikes where the daily global average temperature was more than 1.5°C above pre-industrial levels, and also the year as a whole might turn out to be 1.5°C warmer than preindustrial levels. This is of great concern, but the long-term average global temperature increase is currently at around 1.2°C. 
• We are, however, at high risk of exceeding the 1.5°C level; at current emission levels, the remaining global carbon budget will be exhausted within about 6 years. 
• There is still a chance to limit warming to 1.5°C. We therefore need to set out ambitious plans to rapidly move away from fossil fuels and scale up clean alternatives to reduce emissions across all parts of the economy. This will slow down and halt warming, with a possibility that this is below or around 1.5°C.  
• It makes sense to pursue rigorous mitigation efforts – with every fraction of a degree of warming beyond 1.5°C, impacts will become more severe, and the costs of adaptation will be greater.