Media ReleaseFrom: Springer Nature
Sea-level rises under the Paris Agreement
Sea levels will rise between 0.7 and 1.2 metres by 2300, assuming the Paris Agreement targets are fully met, suggests a new modelling study in Nature Communications. Sea levels will ultimately depend on the pathway of emissions during this century, with an increase of 0.2 metres for every five-year delay in mitigating action post 2020, suggest the authors.
Sea-level rise is a response to several factors, such as thermal expansion of the oceans and ice sheet melt, which respond to climate on different timescales. Even if greenhouse gas emissions ceased today, we are already committed to a rise in sea levels in the coming centuries as a result of such processes. The Paris Agreement is set to limit warming below 2 degrees Celsius and ideally below 1.5 degrees Celsius, but how much sea levels will rise in the coming centuries as a result of mitigating action to achieve such targets has not been quantified.
Matthias Mengel and colleagues present model simulations that show if net-zero greenhouse gas emissions are sustained until 2300, sea levels will rise between 0.7 and 1.2 metres depending on the pathway of emissions during this century. Furthermore, it is unlikely that sea levels will stabilize beyond 2300 even if temperatures are kept below 2 degrees Celsius, due to the inertia of the system.
The study also shows that for every five years of delay in reaching a peak in emissions post 2020, sea-level rise projections for 2300 increase by 0.2 metres. The authors conclude that emissions in the following decades will have a strong influence on sea levels in coming centuries, emphasizing the need for near-term mitigating action to limit the risk of sea-level rise.