James Hansen et al., predict an increase of 2°C by 2040. http://www.columbia.edu/~jeh1/Documents/PipelinePaper.2022.12.22.pdf

Some believe that such change will make the human civilisation collapse, as definition for this question.

Societal collapse in more than three countries from G9 or BRIC, measured by UN and/or WHO and/or IMF, fulfilling ALL of the following:

1. Loss of Social Complexity: A shift in economic structure characterized by a 30% or more reduction in the diversity of industries or occupations, as measured by labor statistics, over the next 15 years. This could be due to climate change impacts on certain sectors, especially agriculture and fisheries.

2. Downfall of Government: A situation in which a government declares a state of emergency for over a year due to climate-related disasters.

3. Rise of Violence: A 50% increase in violent crime or civil unrest incidents directly linked to resource scarcity or displacement caused by climate change over a 5-year period, as reported by law enforcement or international monitoring bodies.

4. Mass Migration: An increase in displacement or emigration rates where 10% or more of the population leaves the country over a 15-year period due to climate-related issues, such as sea level rise, extreme weather events, or agricultural disruption.

5. Infrastructure Failure: Extended failure (more than 6 months) of critical infrastructure like electricity, water supply, or healthcare services, impacting over 30% of the population due to climate change related events.

===

I'm optimistic (naïve?), and I believe much more can be done if people unite and push their elected politicians to ACT to prevent climate change from getting worse and to prepare/mitigate its effects, so humanity prevail.

I'm preoccupied, therefore this question. If the odds go too high, it means a lot of people are very concerned.