Do we need more crazy ideas? Conventional scientists see geoengineering as a highly dangerous response to climate change. But others say desperate times demand desperate measures.
The ‘insane’ plan to save the frozen North
Iced out: Polar bears depend on polar sea ice for their survival, as do seals, their main prey. Glossary
calcium carbonate - a white solid occurring naturally as limestone or chalk rock
sulphur - a bright-yellow coloured non-metal material
Algae - A simple plant that grows in or on water.
veto - An official way of blocking or forbidding something.