1) It is very clear what impact “business as usual” is having on emissions. We can see that because in this case “business as usual” has been dramatically interrupted and the emission reductions speak for themselves.
2) We can also see what kind of action is required to dramatically reduce emissions. (We have to reduce global emissions by 7.6% per year, every year until 2030 if we are to stand a remote chance of reaching the 1.5°C Paris Agreement temperature goals)
3) We have low hanging “emission reduction fruit” that can be picked globally immediately. This specifically relates to transportation (tailpipe emissions and aviation — we have the technology AND know-how to end the daily commute of hundreds of millions of knowledge workers by enforcing mandatory remote working. We can also fly less. Most conferences and meetings can be done virtually)
4) The Covid-19 response shows us how we can mobilize in an emergency, which science tells us the climate crisis is. We need similar measures for this vastly more deadly crisis too.
5) There will be a resulting economic slowdown as we transition from fossil fuels. However the pain is worth it considering the alternative.