Shanghai, China New research published by the open access publisher Frontiers inventories greenhouse gas emissions of 167 globally distributed cities. The study shows that just 25 mega-cities produce 52% of the greenhouse gas emissions from the studied cities. In 2015, 170 countries worldwide adopted the Paris Agreement, with the goal limiting the average global temperature increase to 1.5°C. Following the agreement, many countries and cities proposed targets for greenhouse gas mitigation. However, the UNEP Emissions Gap Report 2020 shows that, without drastic and strict actions to mitigate the climate crisis, we are still heading for a temperature increase of more...