The carbon impacts of most jobs are huge, certainly in finance. The need for perpetual economic growth is by far the largest contributor to climate change.
Even if each person threw only one plastic bag in the Virgin River per year, Zion would suck very soon.
Participating in finance is itself a force multiplier for others to do the same, and with such an energy-hungry practice as finance, that is going to cause worse outcomes. We can't just buy our way out of the problem, because on the whole, the economic activity you generate enables others to help cause worse outcomes (even per-capita, it's a lot of people).