Carbon capture

Avoiding emissions has an intrinsic value, but in many cases is simply not possible with existing technologies (for example, transport and manufacturing).

One possible alternative is to offset emissions by taking carbon out of the atmosphere. For instance, planting a tree would capture $C{O}_2$ and store it in itself and the ground.

The biggest challenge is that there are no carbon capture technologies available that can sequester enough gas. The density of $C{O}_2$ in the atmosphere is relatively low, meaning the technologies would need a gigantic footprint.

This is slightly different for capturing at the source. For example, while making cement or steel (see: 202311101921 The biggest problem is making Things). A carbon capture system could be installed directly at the exhaust of chimneys.

There are many companies working on carbon capture.