carbon dioxide

The organic waste separates into a flammable gas — made of carbon monoxide, carbon dioxide, methane and hydrogen — and a small amount of solid waste.

That is releasing carbon dioxide into the atmosphere, contributing to climate change.

Driving Dr Barstow's V. nat focus is he wants to see microbes used to tackle big sustainability challenges – from producing jet fuel from carbon dioxide and green electricity to mining rare earth metals.

It also covers all greenhouse gases, not just carbon dioxide, and will be measured "from peak levels" of emissions - the timing of which President Xi did not specify.

These are fuels which can be produced from waste oils, from feedstocks such as wood, crops and agricultural waste, or synthesised from captured carbon dioxide and water.