Why it need both to solve the problem

Earlier (the 18:th and 19:th), I pointed out the inclusion of charcoal (biochar) in soil as a way to sequester carbon dioxide from the atmosphere. The 24:th, I pointed out possible abrupt climate changes as a real threat if our way of conduct is not changed radically.
The problem is that bifurcations and similar climate changes can not be predicted in time. As with the pack of lions, you can only back away from them.
Up to now, our main efforts (if any) has been to reduce the effluents of carbon dioxide. This is certainly not enough (like walking slower into the lion pack, or closing slower to the point of no return, when we get an abrupt climate change), but it is not in vain. Let me explain why.

In the left pile, the currently added --and dangerous -- 475 Gt of carbon (as carbon dioxide) is successively added on with a successively diminishing amount of new carbon (very ambitious, a 90% reduction), but it is leading straight into the zone of system stress where a bifurcation is imminent.
In the right piles, each period (year?) of diminishing emissions is matched by a carbon sequestration of 2 Gton. This is the same as slowing down, and after some time, backing off from the zone of imminent climate flips.
That is why you need both emission decrease and sequestration.
N.b. that the decrease in emissions certainly is very ambitious (90%), as is the rate of carbon sequestration (2Gt/year). It is in the same size as the war efforts in GB during WW II, but globally.
But the threat is larger.