Decreasing the total energy exposure of the complete biosphere to reduce temperature rise sounds risky to me.
Yes, it might not become as warm, but especially plants need sunlight for photosynthesis / oxygen production. If we deny the plants that energy the ripple effect throughout the biosphere will be huge.
It might also be the case that we have no choice but to do this. I'd rather the research get done now, before that (potentially) happens.
I think the fact that the scientific community is writing these letters should also be interpreted as a data-point indicating that this point is close, perhaps even behind us.
But it isn't "[the scientific community [...] writing these letters", it's a few scientists. There are a wide spectrum of beliefs within the scientific community, each holding a set of beliefs about where we are, and a separate set of beliefs about what should be done.
Yes, it might not become as warm, but especially plants need sunlight for photosynthesis / oxygen production. If we deny the plants that energy the ripple effect throughout the biosphere will be huge.