BBC: Changing the Earth's climate

It's hard to feel positvie when you hear about climate change, don't you think, Neil?

Yes. According to the UN's COP26 conference, we're heading for a catastrophic global temperature rise of three degrees by the end of this century... Fires are blazing from the Amazon to the Arctic... And even if we stopped burning all fossil tomorrow, it would take decades to feel the effects. It's all very depressing!

Also called 'climate repair', geoengineering is still in the experimental stages. Some technologies are controversial because they interfere with natural climate systems, and others may not even be possible. 

One ingenious idea to cool the planet involves spraying diamond dust in the sky to deflect the Sun's rays. 

Amazing! But before we find out more, I have a question for you, Sam. Spraying diamond dust in the sky sounds futuristic, but in the 1960's there was a band who wrote a song called 'Lucy in the Sky with Diamonds'. But which band? Was it:

a) The Rolling Stones   b) The Beach Boys or  c) The Beatles?

OK, we'll find out the answer later in the programme. Now, throwing diamonds in the sky might sound crazy but it's far from the wildest idea scientists have thought up to decarbonise the planet. 

Oceans hold sixteens times more carbon than the Earth's atmosphere and could hold even more if the fish and plankton living there had more available nutrients- food that animals and plants need to grow. 

But how to provide these nutrients? Believe or not, one answer involves- you guessed it- whale poo.

David King chairs the Center for Climate Repair at Cambridge University. He explained how his unusual idea would work to BBC World Service programme, Discovery:

Imagine now a pod of whales all coming up and pooing in the same area of the ocean. This could be in an eddy current, and it could lead to something like 10,000 to 20,000 square kilometers being covered in nutrients, including iron. And as we know fro observations today, within three months that region is chock-a-block with fish. 

Whales live in groups called pods. They swim up to the oceam surface to poo, and this poo can be spread in an eddy- a large current of water moving in a circular motion, like a giant whirlpool. 

As a result, huge areas of the ocean are covered in nutrients, and become chock-a-block with fish- an informal way to say 'full of fish'.

Another original idea being explored in 'rock weathering'. Carbon is slowly locked into rocks and mountains over thousands of years by natural geological processes. This literally ground-braking idea would speed up the process by locking carbon into rocks that have been dug up through industrial mining. 

listening as geochemist, Professor Rachael James, explains her idea to BBC World Service's, Discovery:

For every tonne of rock that's mined, only a very tiny proportion, a couple of grams of that, is actually diamond. The rest of it is effectively waste. So, mine waste material is potentially a really great source of material that could be repurposed for enchanced rock weathering and I think that's really good because it creates a circular economy.

Mining for diamonds creates tonnes of waste rock which could be used to capture carbon. Professor James wants to repurpose this rock-to find a new for it. 

Not only would this lock more carbon, it also creates a circular economy- an economic model which involves sharing, reusing and recycling products for as long as possible to avoid waste and to reduce levels of carbon.

While these ideas might sound strange, they're all theoretically all possible. And looking to science for positive solutions reminds some people of the early ecological movement which started in the 1960s and now, fifty years later, is being taken seriously.