One technique involves releasing particles of sulphur dioxide high up in the stratosphere. Another involves trying to brighten the clouds over the sea by spraying salt water off the back of ships. Both are potential methods of solar radiation modification (SRM), a type of solar geoengineering aimed at trying to reflect more sunlight away from Earth, thus helping to reverse the effects of global warming.
While SRM has attracted attention and investment in recent years, it remains a controversial – and some argue, dangerous – idea.
