As a drug it's actually pretty benign.
But every time I buy coffee, I am feeding the beast of global exploitation and environmental damage.
Compared to drinking coffee, the alternative is: simply don't do that. And if I take the alternative, the carbon footprint, other environmental footprint reduces a bit and reduces the profits of exploitative power structures.
The industry is just a waste of fossil fuels and logistics, really, seeing as it serves no particular purpose because life runs just fine without coffee.
Just Coffee is a worker owned coop where the farmers receive their share of the profits. Additionally if a farmer within the network has a bad year of harvest due to climate change or disease they still get paid because who knows what next year can bring for anyone. The coffee is also very good.
Finally, as far as environmental impact goes coffee is actually a crop that benefits greatly from the preservation of native habitat within the farm. Basically by leaving plots of undisturbed habitat within the coffee fields you'll have higher yield than if you were to clearcut the forest for more Coffee. This is due to native pollinators using the forest as refuge and BEF (biodiversity ecosystem function, increases in biodiversity result in increases in ecosystem functions). That doesn't change the damage that farming in general does or the climate footprint of shipping coffee from around the world, but there are worse crops.
Link to just coffee: https://justcoffee.coop/about/
Link to paper on coffee farms: https://link.springer.com/article/10.1007/s10457-008-9120-y