[Lutger]

Yes, it's because the impact of putting greenhouse gas in the atmosphere is not immediate. Temperatures will continue to rise after the fact. Sea level rise is also much slower, meaning that even if we stop emitting, levels continue to rise for hundreds of years.

There's a lot of uncertainty regarding the tipping points. Some scientists fear that if we cross the 2 degrees celcius, we could have a runaway breakdown due to processes such as melted ice heating the ocean much more and permafrost releasing enormous amounts of ghg.

We don't know for sure that will happen, but its extremely risky. Some fear we could lock in devastating processes within 12 years (even if they won't happen immediately).

Some people think that even if we don't know for sure it'll happen, we should follow the precautionary principle and not take the risk of these extreme events.