1. The science is - believe it or not - unsettled. Take this on soil carbon sequestration: https://www.quantamagazine.org/a-soil-science-revolution-upends-plans

1. The science is - believe it or not - unsettled. Take this on soil carbon sequestration: https://www.quantamagazine.org/a-soil-science-revolution-upends-plans-to-fight-climate-change-20210727/ https://www.quantamagazine.org/a-soil-science-revolution-upe... 2. Leakage seems inescapable both physical and in an economic sense as I described above. 3. Because the market is voluntary, it’s extremely vulnerable to cost-cutting. I’d say those are the three main issues which have not been resolved since last time.