A new study shows it is feasible to limit future global temperature rise to less than 1.5 degrees Celsius by 2100, which experts regard as a safer goal than the currently agreed international aim of 2 degrees Celsius. But there is no time to wait and no room for mistake.
Recently published in the journal Nature Climate Change, the study was produced by researchers at the International Institute for Applied Systems Analysis (IIASA), the Potsdam Institute for Climate Impact Research (PIK), and others. It examines the climate policy actions – including energy economy and environment scenarios – that are consistent with limiting climate change to 1.5 degrees Celsius above pre-industrial levels.
The authors found that the actions for returning global warming to below 1.5 degrees Celsius by 2100 are in many ways similar to those limiting warming to below 2 degrees Celsius, says IIASA researcher Joeri Rogelj, one of the lead authors of the study. “However, the more ambitious 1.5 degrees Celsius goal leaves no space to further delay global mitigation action and emission reductions need to scale up swiftly in the next decades.”
One fundamental action identified by the authors is the need to tightly constrain future carbon emissions. “In 1.5 degrees Celsius scenarios, the remaining carbon budget for the 21st century is reduced to almost half compared to 2 degrees Celsius scenarios,” explains PIK researcher Gunnar Luderer, who co-led the study. “As a consequence, deeper emissions cuts are required from all sectors, and global carbon neutrality would need to be reached 10-20 years earlier than projected for 2 degrees Celsius scenarios.”
The study argues that faster improvements in energy efficiency would be a key enabling factor for the 1.5 degrees Celsius target. In addition, carbon emissions would have to become negative at a global scale at some point in the century, which would likely involve using technology such as carbon capture and storage to remove vast amounts of CO2 from the atmosphere.
Over 100 countries worldwide – more than half of the countries that in the United Nations Framework Convention on Climate Change (UNFCCC), including the Alliance of Small Island States (AOSIS) and the Least-Developed Countries (LDCs) – support a 1.5 degrees Celsius target.
Photo credit: UN Photo/Logan Abassi