We release 55 gigatons of greenhouse gases into the air every year.

To stop global warming, we have to get our greenhouse gas emissions down to zero.

But for every country to immediately shut down all greenhouse gas-releasing activities would be an enormous challenge,

especially since some countries have built up an economic head start with no restrictions.

So instead, we can use an approach called net zero.

Net zero means that for every molecule of greenhouse gas we put into the air, we also take one out, making our net emissions zero.

Net zero requires us to make big changes today, use less more efficiently, and even bigger technological changes for the future,

like replacing all greenhouse gas-emitting activities with clean ones.

We'll also have to capture greenhouse gases from the air and store them permanently.

And yet, net zero is our best chance for a sustainable future.

Take action on climate change at Countdown.ted.com