Carbon credit market is a billion dollar industry and applying blockchain will be good for both industry.
It might further questionable political agendas and help to grow crypto markets while legitimizing blockchain technology. Aside from that it won't accomplish much.
The reason carbon credits don't work is they fail to address the real factors affecting our climate. Emissions aren't the main concern. The real issue is between 20% and 80% of the world's natural forests being cut down which greatly reduces the earth's capacity to absorb carbon. Trees function as natural carbon sinks, trapping carbon and storing it for many years.
The secondary issue is: drought. Trees absorb water from their roots and evaporate it through their leaves. This evaporated water generates rainfall. Rising occurrence of drought in the world is also linked to deforestation. If you want concrete evidence of this, deforestation of the amazon rainforest in brazil is linked to their drought issues.
The ideal policies to address climate change are: afforestation. Seed bombings. Addressing desertification.
I agree that one of the biggest concern here is deforestation. I have read an article recently that saving the forests and vegetation is as urgent as reducing the global carbon emissions. This is also one of the reasons why carbon credit is important. There are groups that sells carbon credits and uses the funds to protect forests and vegetation.
Have you heard about infinite-earth? One of their projects is the Rimba Raya Reserve. The Reserve provides, preserves and protects 65,000 hectares of peat swamp forest, hundreds of at risk mammal species and providing community development programs for 16 villages. And yes, they provide offset solutions to customers in the developed world while protecting the planet and its resources.
In addition to the issues you mentioned, I will be adding a possible third one: Corruption. Carbon credits are difficult to trade and track. It lacks transparency. At the moment, the only solution I see to resolve this is by using blockchain.
The way policies like carbon credits are issued is also extremely disproportionate. America's business is punished far more severely than business in china, despite chinese business being vastly more polluting and environmentally damaging than american business. In that we could see political angles being revealed in how the establishment chooses to pursue issues relating to climate change.
I can't comment much on this since this is kind of political issues. But to what I see, America is doing way better than China in reducing carbon emissions. I heard that China launched their carbon trading market at the end of 2017. I hope that there will be a decrease on their carbon emissions.