This was itself a suspension of normal democratic procedures and conventions. No elections were held in the UK between 1935 and the conclusion of the war in 1945.
The thirties had a succession of mostly weak coalitions in response to the Great Depression.
I would also argue that rationing in general is incompatible with a free country. If necessary add a fair tax that is ear-marked to deal with global warming and which ofsets the damage. No reason to add more bureaucracy.
I don't see how rationing impacts a free country one way or another as it's merely a method of achieving a fair distribution of a limited resource. The US also had rationing in WW2, introduced after Pearl Harbor. Was the US still a free country?
But more to the point: rationing is stupid, since you are strictly better of taxing the good you want to limit, and if necessary spend some of the tax in direct payments to those with the least income. The free market will take care of pricing the use of the taxed commodity correctly and the poor will be better of.
In the case of wartime fuel rationing, and perhaps if we were to end up with a carbon ration, it achieves a fair distribution, without the wealthy simply being able to pay extra not to participate. With enough wealth someone may not care that something carries a punitive tax rate, and they can continue being part of the problem.
In times of crisis, such as wartime or a failing ecosystem, we may find that ability to pay your way out of it unacceptable. Reasonably so in my opinion.
We need a WW2 scale response, perhaps with similar restrictions like rationing - only this time of carbon or flights etc. Once some nations are active, others will join. Perhaps we need to see carbon and environmental impacts baked into import tariffs to "encourage" reluctant others to join.