Seite - 5 - in options, Band summer 2018

research newsiiasa research www.iiasa.ac.at 5summer 2018 ◼ options ‘Modest’ climate benefits from LPG cooking Switching from wood to liquefied petroleum gas (LPG) cooking, could provide modest climate benefits, but these vary based on the extent of sustainable wood use, according to a new analysis focused on India. Young Scientist Summer Program researcher Devyani Singh found that switching to LPG would reduce net emissions by up to 6.73 metric tons of CO2 equivalent, if 30% wood is assumed non- renewably sourced. Switching would also reduce pressure on woodlands. www.iiasa.ac.at/news/LPG-cooking-17 Climate change policy and future wellbeing What is the best mix of mitigation and adaptation when it comes to climate change? Fabian Wagner and his team found that the answer depends on whether we care about the aggregate wellbeing of humanity or the average wellbeing. They also suggest that lowering population growth could save tens of billions of dollars annually and improve overall wellbeing, while a larger population will leave future generations at greater risk from climate-related damage. www.iiasa.ac.at/news/Climate-wellbeing-17 Who pays for climate loss and damage? There is increasing emphasis on adaptation to climate change and the need to address the ‘loss and damage’ that occurs despite mitigation efforts. Reinhard Mechler looked at the debate around who should pay for such costs and found that practical action is needed, rather than just the current political debates. Adaptation limits are already being breached in some areas, highlighting the urgency of fulfilling the Paris Agreement and tackling the problem. www.iiasa.ac.at/events/EGU-18 Sea level rises with peak emission delays Ensuring that global CO2 emissions peak as soon as possible is crucial for limiting sea level rise, even if global warming is limited to well below 2°C. A new study involving IIASA researcher Joeri Rogelj, has now shown that each five-year delay in peak global CO2 emissions will likely increase the median sea-level rise for 2300 by 20cm. Emissions reductions must therefore be implemented as quickly as possible. www.iiasa.ac.at/news/Sea-level-18 According to IIASA researchers, international policymakers need a broader range of scenarios as they seek to limit climate change to below 2°C above pre-industrial levels, and to avoid the potential negative environmental and social consequences of negative emissions technologies. Ecosystems Services and Management Program Director Michael Obersteiner, led research to develop alternative scenarios that place less reliance on negative emissions technologies. “Many currently used emissions pathways assume that we can slowly decrease fossil fuel emissions today and make up for it later with heavy implementation of negative emissions technologies,” says Obersteiner. “This is a problem because it assumes that we can put the burden on future generations, which is neither a realistic assumption, nor morally acceptable.” The largest share of scenarios achieving a 2°C target in the Intergovernmental Panel on Climate Change 5th Assessment Report, rely on late deployment of a single negative emission technology, namely bioenergy with carbon capture and storage (BECCS). Given the highly uncertain nature of technological progress, or the responses of the earth system, this is a more than risky strategy, says coauthor Johannes Bednar. The researchers present four scenarios incorporating a broader range of mitigation options, such as:  Major reliance on future carbon dioxide removal  Rapid decarbonization starting immediately, and halving every decade  Earlier implementation of carbon dioxide removal technologies, and phasing out by the end of the century  Consistent implementation of carbon dioxide removal from now until the end of the century. Coauthor Fabian Wagner says: “As scientists we need to be careful when we communicate to policymakers about how realistic different scenarios might be. When we present scenarios that require the world to convert an amount of land equivalent to all of today’s cropland to energy plantations, alarm bells should go off.” HT Further info Obersteiner M, Bednar J, Wagner F, Gasser T, Ciais P, Forsell N, Havlik P, Valin H, et al. (2018). How to spend a dwindling greenhouse gas budget. Nature Climate Change [pure.iiasa.ac.at/15031] Michael Obersteiner oberstei@iiasa.ac.at Thinking outside the box on climate mitigation