We can and must govern climate engineering
Last month, the World Meteorological Organization announced a tragic milestone. Average atmospheric carbon dioxide concentrations surpassed 400 parts per million in 2016. That level last occurred 3 million years ago, when temperatures were 2–3 °C warmer and sea levels 10–20 metres higher.
Unless strategies of reduced emissions, cleaner energy and the increased use of carbon capture, utilization and sequestration are taken up immediately, the last-ditch strategy will be climate engineering: ambitious attempts to brighten clouds to reflect more heat back into space or attempts to mimic the cooling caused by large volcanic eruptions. Many fear that, when global leaders finally realize the peril of climate change, they will jump at engineering projects without any evidence base, risking side effects of unknown magnitude.
photo credit: CIFOR