The battle against global warming takes an intriguing turn as scientists propose a bold strategy: reflecting sunlight into space. But this isn't without controversy. The Royal Society, a renowned scientific body, suggests that manipulating sunlight could 'buy time' by reducing the amount of sunlight reaching Earth, potentially mitigating some climate change impacts. However, they caution that this approach is not without risks and could have unintended consequences.
The proposed methods involve two main strategies: pumping reflective particles into the atmosphere and spraying salt into clouds over the sea. While these techniques are technically feasible, the report highlights a critical concern: a 'rogue nation' attempting to dim sunlight in one region could disrupt weather patterns globally, leading to extreme droughts and other climate disturbances.
Professor Keith Shine, chair of the report's working group, acknowledges the potential risks but emphasizes the urgency of the climate crisis. He suggests that solar radiation modification (SRM) might become a necessary measure when other options fall short. The report underscores that current global efforts to reduce greenhouse gas emissions may not be enough to prevent global temperatures from rising above the 1.5C 'safe' limit, with temperatures potentially reaching 3C warmer than pre-industrial levels by 2100.
One promising strategy, according to the report, is stratospheric aerosol injection. This involves planes releasing sulphur dioxide gas at high altitudes, forming particles that reflect sunlight. Historical events, like the 1991 eruption of Mount Pinatubo, provide real-world evidence of this technique's effectiveness, temporarily reducing temperatures by 0.5C. Computer models suggest that annual releases of 8-16 million tonnes of sulphur dioxide could lower global temperatures by 1C.
While the cost of implementing these strategies is significant, estimated at 'low tens of billions of dollars a year,' Professor Shine argues that it's a small price compared to the global economic impact of extreme weather events, wildfires, and other climate-related disasters. For instance, Hurricane Melissa, intensified by global warming, caused up to $52 billion in damage and economic losses across the western Caribbean.
The Royal Society emphasizes that SRM should not be seen as a replacement for reducing emissions but rather as a temporary measure to buy time while carbon dioxide levels peak and begin to fall. This approach could potentially require deployment for 100 years or more, raising complex ethical and environmental questions.
