Whilst it might be true to state that it would reduce overheads and provide easier access to transport, markets etc I find it hard to see that as the determining factor in the adoption of steam power. Steam engines in the UK were first developed for purposes unrelated to the textile industry such as pumping water from mines, they were a solution to a practical problem. By the early decades of the 19th century it became obvious that they were a far more efficient source of power for the textile industry than water mills. I'm not clear if you are positing the possibility of a socialist revolution in pre-industrial ( and pre proletarian) britain bringing to power a regime which would have the power of foresight and stopped the use of steam due to the likelihood of global warming two centuries later??
What about the other applications of steam power? Would a socialist government in the 1820s have put a ban on steam travel? Would Britain have remained a nation of canals and sailing ships?? What impact would a steam free economy have had on productivity? How would it have ensured the production of the necessities of life vital to the material underpinning of a more egalitarian society??
I accept all your points about the global south but your description of an alternative history in the global north seems utopian. To the extent that any economic development in the 19th century would inevitably have involved fossil fuels suggests it is not only capital that is to blame.
Unfortunately I think socialism being achieved in the timeframe required to bring about a zero carbon economy is extremely unlikely ( if it is ever to happen). espousing the view that only under socialism will we achieve this seems a counsel of despair.
Meanwhile Jaguar have announced they will produce electric only cars by 2025.