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Carbon Dioxide

Some of the world's top climate scientists have concluded that global warming is likely to reach dangerous levels unless new technologies are developed to remove greenhouse gases from the atmosphere.

The United Nations' Intergovernmental Panel on Climate Change (IPCC) says pledges from the world's governments to reduce greenhouse gases, made in Paris in 2015, aren't enough to keep global warming from rising more than 1.5 degrees Celsius (2.7 degrees F) above pre-industrial temperatures.

Plants need carbon dioxide to live, but its effects on them are complicated.

As the level of carbon dioxide in the air continues to rise because of human activity, scientists are trying to pin down how the plants we eat are being affected.

Mounting evidence suggests that many key plants lose nutritional value at higher CO2 levels, and scientists are running experiments all over the world to try to tease out the effects.