Drivers of peak and decline

摘要

To limit global warming to 2 °C under the Paris Agreement, global emissions need to peak before 2030 and decline rapidly thereafter1. By 2010,49 countries’ emissions have already peaked, and these emissions accounted for 36% of global emissions . Analysing drivers of CO_2 emissions trends in countries where emissions are decreasing, called peak-and-decline countries, could help us to understand whether emission reductions reflect economic fluctuations or successful efforts to improve energy systems. Understanding the reasons behind the peak-and-decline of emissions in these countries can help further explore the solution-space for deep mitigation. Writing in Nature Climate Change, Le Quéré and co-authors investigated the reasons behind the decreases in 18 peak-and-decline industrial countries, which represent 28% of global emissions and whose emissions decreased by 2.4% per year on average during 2005-2015. Their results show that the decrease in emissions in peak-and-decline countries has beenprimarily driven by the increase in the share of renewable energy and decrease in energy use. Although a growing body of evidence shows that economic growth can go hand in hand with efforts to reduce CO_2 emissions, this study revealed that the lower growth in gross domestic product (GDP) in the peak-and-decline countries compared with previous decades that experienced decreases in energy use. This suggests that to allow for both economic growth and emissions reduction, more efforts on energy efficiency improvement are needed.