Net zero means not adding to the amount of greenhouse gases in the atmosphere.
Achieving it means reducing emissions as much as possible, and balancing out any that remain by removing an equivalent amount.
Greenhouse gases like carbon dioxide (CO2) are released when we burn oil, gas and coal for our homes, factories and transport. This causes global warming by trapping the sun’s energy.
Under the 2015 Paris Agreement, 197 countries agreed to try to keep temperature rises “well below” 1.5C to avoid the worst impacts of climate change. Experts say that to achieve this net zero must be reached by 2050.
How Can Carbon be Removed From the Atmosphere?
As well as tackling deforestation, almost every country is planting trees as a cheap way of absorbing carbon, although experts question whether there’s enough space for the trees needed.
Technology involving carbon capture and storage has also been suggested.
This involves using machinery to remove carbon from the air, then solidifying it and burying it underground.
However, the technology is still emerging, very expensive and as yet unproven.
There’s controversy about how some countries might try to reach net zero.
For instance, Country A might record lower emissions if it shuts down energy-intensive industries such as steel production.
But if Country A then imports steel from Country B, it’s effectively handed on its carbon emissions to Country B instead of reducing the sum total of greenhouse gases.
There are schemes that enable rich countries to offset their emissions by paying poorer countries to switch to cleaner fuels.
However, these are seen by some as a way to avoid taking more action domestically.
And it’s hard to say that initiatives funded to offset emissions elsewhere would not have happened anyway.