At first glance, KlimaDAO looks less DeFi and more a protesting collective forcing carbon credit prices higher.
Polluting companies often have an emissions cap; they can either purchase carbon credits to offset excess emissions, or they can invest in efficient production infrastructure to produce more and emit less.
Carbon credits are more affordable and simpler to manage in the short term – but it’s not a long term solution to combat climate change. Therefore the increase in carbon credit prices makes capital investment competitive.
Here’s a useful summary, with access to their manifesto at the bottom.