We're talking about just keeping track of who owns what amounts of a commodity. That part is using terawatt hours per year! I am very doubtful that the "keeping track of who owns what amounts" part of the stock market is anywhere near that.
Determining who has the rights to make changes to what data, auditing changes, auditing ever-changing access control rights, systematically changing these rules to adapt to technological advancements, etc. is the function which Bitcoin accomplishes that you are discounting from your perceived cost of the traditional stock market.
The financial sector is 20% of global GDP. Bitcoin is much less than 20% of world carbon emissions.
Further, fiduciary duty of corporations to maximize shareholder profit has led to almost every environmentally harmful exploit of externalities. I'd argue that the stock market is fundamentally responsible for 99% of all pollution.
Financial sector does not produce 20% of carbon emissions. They are maybe 0.1%. The act of trading on exchanges is significantly more efficient than the act of trading on blockchain. Because there really is no need for an untrusted ledger when there is the USG certifying that the NYSE and NASDAQ will not execute erroneous trades.
Bitcoin does not eliminate the idea of fiduciary duty. Bitcoin holders still expect bitcoin loanees to trade and operate in their financial interest.
for processing/validating transactions? couple hundred MWH. How much do you think the Nasdaq/NYSE mainframes really eat?
bitcoin numbers don't include the off-chain stuff either, lol.
Bitcoin energy is literally expended on a massive, inefficient mainframe that processes a couple hundred transactions a second. That's all - everything else is additional to that.
No, what is the cost of the system which enables the USG to reliably prevent the execution of erroneous trades?
Tens to hundreds of thousands of highly paid bureaucrats, accountants, risk managers, regulators, legislators, clerks, lawyers, law enforcement, judges, etc.
Obviously the purely digital systems consumes more compute, but I think you're discounting many of the true costs of the existing system.