Time for geoengineering governance?

For the third year in a row, 2016 set a record for the highest global average surface temperatures. The global mean surface temperature is now 1.1 degrees celsius above pre-industrial levels. The Paris Agreement on climate change, while a breakthrough in international cooperation, is still weak in ambition. Carbon dioxide in the atmosphere — above 400 parts per million (highest in at least the past 800,000 years) – will stay there for a long time. The impacts are likely to be severe: Rising sea levels; heat and water stress affecting health, mortality, agricultural yields and industrial output; and billions of