> To tackle your argument of "a lot of pain and political capital expended for very small gains in terms of CO2/GDP" - this is I feel a tangent and feels a bit like moving the goalposts

No, this is my point.

Look, this is a political process. Just like the law that caps deficits to be less than 3% of GDP, which is ignored when there is some political desire to have bigger deficits.

These are political things that do respond to pressure as to whether they will be enforced. So when the Yellow vests threatened to bring down the French govt, the government backed off, precisely because they weren't prepared to pay the political cost.

So what matters is not the promise to do X, but actually doing X, right? And X is measured in total emissions. There is little benefit in saying "90% of the economy is subject to the system and we exempt the 10% where it would be too painful to meet."

So after all the promises and exemptions, at the end of the day you have some reduction in CO2. If that reduction ends up being not much different than the same reduction in other large industrial economies that didn't go through the whole cap system, then what reasonable claim can you make about the cap system making a difference?

We expect, just with increasing technology, that CO2 efficiency will increase. Just as you go from burning trees for firewood to coal to oil to natural gas to gas combined with hydro, etc, you are switching to more efficient energy sources. But everyone is doing that, because more efficient energy sources are cheaper.

The difference will be when the allotments really start to bite - at which point it will be political pressure, and not the agreement itself, that will decide whether these caps will be respected or whether they will be like the deficit caps. So the only way to determine what difference you are actually making is to look at total economy emissions and compare that to nations like the US that don't bother with any caps. If those situations are indistinguishable in terms of CO2 reductions, then I don't see the benefit of spending all this money in fees for carbon pricing. Do you? Lots of other economies are not spending these fees and they are getting the same reductions.

The reason why I am saying this is that I don't like these types of micro-management free market solutions for a nation's energy policy. People don't care where their electricity comes from. If the government wants clean electricity, they should build 100 nuclear reactors, and have 100% clean electricity. Then they can give choices to people to use electric cars that are basically free to power or gas cars if they really need the gas car. And you can electrify the rail system and public transit, at a subsidy, but then let people fly planes without subsidies if they want to do that as well. This way you are solving the problem directly and giving people more choices and more freedom. You are not pushing the problems of a nation's power sources onto individual businesses or end consumers and then constantly taxing them to use dim light bulbs or whatnot. There are much simpler ways you can accomplish much more. But there is something in the Euro spirit that wants Germany to buy more gas from Russia and shut down its nuclear plant but have lots of little micromanagement of individual consumer choices by slapping surcharges on everything and banning random things. Maybe this is done so end users can feel like they are saving the planet by participating in the struggle, as opposed to having the government provide the entire economy with clean, abundant electricity at very low cost. The whole thing has an air of theater to me.