Can we really save the world by spraying salt into the clouds?

Leading scientists are considering solutions to reverse climate change which sound straight out of a sci-fi novel.

Among ideas under consideration are refreezing the polar regions, spraying salt into the clouds to reflect back sunlight, or growing so much algae in the sea that it takes in carbon via photosynthesis.

Cambridge University is setting up a centre for such ‘geoengineering’ solutions, led by scientist Sir David King.

The concept of humans modifying ecosystems or changing the weather on a huge scale is gaining traction. It is a response to concerns that attempts to limit global warming will not be effective enough and that we need drastic measures to prevent it.

For instance, ‘re-greening’ could mean fertilising the sea with iron salts to stimulate the growth of huge blooms of algae on the ocean surface.

Another proposal being considered is spraying salt water high into the atmosphere to ‘whiten’ clouds in the Arctic region in order to reflect heat back into space.

However, there are concerns that such actions could have dangerous and unpredictable outcomes.

Greenpeace chief scientist Doug Parr told Metro.co.uk: ‘The things that give me most worry are the geoengineering of the upper atmosphere to reflect more sunlight.

’Even if it worked so well we kept the overall global temperature the same, there will still be changes to rainfall as a consequence.’

This could even take the form of cyclones elsewhere, causing some of the same problems as climate change itself.

There are also fears that growing so much more algae in the ocean could kill off other species. No longer limited by the amount of iron available, it could use up all the other nutrients such as nitrogen and phosphorus, making it impossible for fish to survive.

He said: ’In the same way when you chop down a forest it changes the ecosystem – the habitat is not going to be fit for the species which were there.’

Mr Parr added that ‘we would have to do it at a very large scale’ and that would involve cooperation and governance on a global scale of a kind never seen before, urging us to concentrate on pushing for further reductions in carbon emissions.

Doug added that trying to reverse climate change via geoengineering without solving the underlying issues first is a ‘sticking plaster’ and could do more harm than good.

He emphasised that it could ‘interfere with political changes that are needed.

‘This is not any kind of substitute for taking sharp and radical action to do something about our climate now.’