1.5C hotter, and 2C hotter. These are set out in the Paris climate treaty, where nations agreed to limit temperature rises to "well below" 2C and to 1.5C if at all possible.
The two are not the same futures.
Even if all fossil fuel use ended tomorrow (and 2017 was a record year for global emissions), we have still put so much CO2 into the atmosphere that no one really knows how Earth will react.
1. The world will drastically reduce CO2 emissions
2. We can invent our way out of this mess
Just this weekend, Saudi Arabia threatened to stonewall today's warning over language suggesting CO2 emissions need to fall "well before" 2030
If you have a bottle of something you've been saving for a special occasion, today's now as good as any to open
"Existential" doesn't sound too smart, does it? climateemergencydeclaration.org/wp-content/upl…