Risk of Mass Human Suffering /​ Extinction due to Climate Emergency

The good folks at Extinction Rebellion are working crazy hard to promote the scientific case for impending societal and economic collapse due to climate change.

This is their talk presenting that case: Heading for Extinction and What to Do About It

I’m curious as to whether this (lesswrong /​EA) community finds the case scientifically convincing, and further, whether their strategy for nonviolent direct action (i.e. taking to the streets and not moving until the government respond to demands) is the best plan of action (given the apparently mounting urgency of action on carbon emissions)?