No guarantees when it comes to overshooting 1.5°C says new research

Exceeding a 1.5°C increase in global temperature comes with irreversible consequences and rapid emission reductions are essential for reducing climate risks , according to a new report from global scientists.
Even if it is possible to reverse the rise of global temperatures after a temporary overshoot of 1.5°C some climate damages, including rising sea levels, will be irreversible, according to a new study published in Nature.
Dr Chris Smith contributed to the study s the culmination of a three-and-a-half-year project, that analysed so-called ‘overshoot’ scenarios, where temperatures temporarily exceed the Paris Agreement’s 1.5°C limit, before descending again by achieving net-negative CO2 emissions.
It matters how high and for how long we let temperatures rise
The research highlights that if we were to exceed 1.5°C there are clear benefits to reversing warming by acting to achieve net negative emissions globally. This could be achieved through removing carbon dioxide from the atmosphere.
Bringing down the global temperature over a long period could lower sea level rise in 2300 by about 40cm compared to a situation in which temperatures merely stopped rising.
Professor Joeri Rogelj, Director of Research at the Grantham Institute at Imperial College London, and co-author of the study said: “Until we get to net zero, warming will continue. The earlier we can get to net zero, the lower peak warming will be, and the smaller the risks of irreversible impacts.
"This underscores the importance of countries submitting ambitious new reduction pledges well ahead of next year’s climate summit in Brazil."
Full carbon dioxide removal capacity needed
The study emphasises that while there are still pathways open to limiting warming to 1.5°C or lower in the long run, there is a need to ‘hedge’ against higher warming outcomes if the climate system warms more than median estimates.
To do this, ambitious emissions reductions need to go hand in hand with scaled and environmentally sustainable carbon dioxide removal technologies. A ‘preventive capacity’ of several hundred gigatonnes of net removals might be required.