Here is a contrived example:
Suppose you obtained $20k by applying your skills as a consultant where you helped some business make an additional $200k profit by more effectively advertising their products.
Suppose that business has a profit of 20% for each item they sell, so you've actually lifted their revenue by $1m.
Now, suppose these products are essentially useless consumer products that will go out of fashion within 1 year.
I claim without evidence that the environmental impact of producing, advertising, distributing and disposing of $1m of useless products may, in many cases, be well in excess of how much of that impact you could attempt to reverse with a $20k budget.
So, another option is to consider is that the world may be better off if you didn't earn that $20k in the first place. It very much depends on the direct and indirect effects of how you did it.
edit: I am curious if I am copping the odd down-vote because this argument is complete nonsense (in which case please help me modify my beliefs!) or simply because I mention something that is perhaps uncomfortable to reflect upon. I claim no moral high ground here.