What's happening?

The team braving temperatures of -45C in the Arctic are "quite insaneA state of mind that prevents normal behaviour." says Professor Julienne Stroeve, a climate scientist from the University of Colorado Boulder.

She is talking about a project to thicken floating Arctic sea ice enough to stop it melting, by drilling a hole and pumping 1,000 litres of water on to its surface.

The water freezes quickly, thickening the ice. But even the team leader says he is not sure the idea is a good one.

The project is a form of geoengineering. This means trying to change Earth's climate to compensateTo give someone something to make up for their loss of something else. for the damage done by humans.

Here are some of the other ideas now being explored:

Guarding glaciers Building underwater walls to protect glaciersA slowly moving mass of ice formed by snow building up on mountains. from warm water. However, protecting the Greenland ice sheet would require a wall 107m high and almost 5km long.

Paint power Scientists have come up with a new type of white paint which reflects 98.1% of sunlight. They say that it could reduce energy use in buildings because people would not need air conditioning.

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Softening sunlight Releasing tiny particles into the atmosphere which reflect the sun's light might also reduce global warming. Some scientists think calcium carbonatea white solid occurring naturally as limestone or chalk rock particles would work well, while others prefer sulphura bright-yellow coloured non-metal material.

An even more ambitious idea is to send particles or mini-spacecraft with reflective umbrellas into orbit around the Earth.

Fabricating forests A professor at Arizona State University has designed a 10m-high "mechanical tree". The metal tree contains filters to take carbon out of the atmosphere. He hopes to create "tree farms" which will capture as much as 1,000 tonnes of carbon a day.

Encouraging algae Pipes in the ocean could bring nutrient-rich water from the bottom to feed algaeA simple plant that grows in or on water. on the surface. These would take in carbon from the atmosphere and then sink down with it to the sea bed.

Do we need more crazy ideas?

Yes! We have no choice. Global warming is increasing, extreme weather is becoming more frequent and governments are not doing nearly enough to fight it. We need radicalExtreme. solutions to make a difference.

No! Trying to tamperto make changes that you shouldn't be making with the environment in this way is incredibly dangerous and could make the situation much worse. Even the people suggesting these ideas are far from certain about the outcome.