Paywall half way through the article
There's a bit more to it — people figured that the learning curve for solar would stop improving so much
I think the incredible shrinking Rolodex of politicians in general is the reason for many such gaps.
Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.
As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades:
How much each change to the atmosphere has warmed the world:
Recommended actions to cut greenhouse gas emissions in the near future:
Anti-science, inactivism, and unsupported conspiracy theories are not ok here.