Isn't 100 million usd to fix 0.1% of global warming actually a pretty amazing return? I would imagine most solutions cost a lot more than 100 billion in total.
It's $100M to develop tech that would allow carbon to be pulled out of the atmosphere at the price of $100-$500 per ton of CO2. Even if the tech is successful then it would still cost $100B-$500B per year to pull out the 1 bilion tons of CO2 by 2050 that the IPCC has built into their models.
It's not 0.1% of global warming, it's 0.1% out of ~1/60 th of all emissions we need to eliminate.
See figures SPM.5 and SPM.7 of the "Mitigation of Climate Change" IPCC report for a picture of how much needs to be cut to reach a stable state, and how much Carbon Capture is estimated to contribute.
