It would probably be more effective if affluent countries levied import taxes on countries that emit too much CO2. That way it feels like "someone else is paying for it", and there would be a real economic incentive for emerging economies to do something about their infrastructure.
One of the more commonly arguments against fighting climate change is that doing so would ruin the economy. If Denmark can maintain its welfare system while cutting costs, then it means others can too.
But yeah, as someone else said, 70% is compared to 1990 levels and it's not really that dramatic since Denmark is considerable less dependant on fossil fuels today compared to 30 years ago.
On the other hand, all the emergent economies have no (internal) political pressure to do much about pollution, much less about CO2 emission. However, what they tend to have in common is that they export a lot products to these affluent countries.
Someone who earns $100k a year is going to pay a combined 55.5% tax rate, 40.6% income tax + 25% consumption tax. Someone making $1m is going to pay 66%, assuming they don't spend it all on cars which attracts an additional 160% excise plus all sorts of other green taxes.
https://nyheder.tv2.dk/samfund/2020-10-01-nu-udbetales-der-1...
By comparison, in the "socialist" and "high tax" state California, taxes are nominally lower, but what you get for it is essentially a dumpster fire. Plus, you have to pay out of pocket for healthcare and retirement.
If the maker of goods is not in good standing for offsetting their impact then the importing state introduces taxes for that deficiency and has it handled in the importing country.
The second is the idea of showing the actual cost of offsetting. Having honest conversations about that will promote local and incentivize R&D to reduce that cost. Fantastic stuff.