User blog comment:L4dyj4zz/Ecological Issues Within the Mass Effect Universe/@comment-4953843-20160120185520

ok, i'll bite.

first off, races in the ME universe aren't capitalized except for special cases. Protheans with a P, Collectors with a C, Leviathans, Reapers, quarians, krogan, turians, etc.

as to the main question at hand:
 * 1) Rannoch's codex entry states that the geth mainly kept it clean after their Morning War with their creators. they lived in their space stations for the most part and actually worked on restoring the planet.


 * 1) Tuchanka and the krogan. pre-uplift krogan discovered industrialization, population exploded. warred with each other over diminishing space and resources, nuked themselves to the stone age. salarians gave them high tech in exchange for stomping out the rachni, part of which is the Shroud facility to keep out the worst of the radiation on tuchanka. a few reward planets and colonies later, krogan numbers kept increasing (due to lack of competition) that they began annexing other races' territories (see Garvug, Lusia). of course the lizards didn't care much for sustainability that they invariably ravaged the ecosystems of those planets, so one genophage bomb later they're mostly back on the still blasted world of tuchanka with barely any initiative to rebuild.


 * 1) Rakhana and the drell: textbook Malthusian catastrophe. again, overpopulation and diminishing resources nearly drove the drell extinct except for the few hundred thousand the hanar managed to fly out. planet is a cemetery world with only a few thousand living there. more expats than natives. again, no initiatives to rebuild that i'm aware of. and of course, drell living in environments as humid as Kahje means kepral's syndrome simply because they're not adapted to it.


 * 1) Heshtok and vorcha: tuchanka had a vibrant predatory ecosystem. hestok had a vibrant volcanic geology that discouraged nearly everything except vermin from proliferating.


 * 1) climate change on Earth is real. see the codex entries on the page.


 * 1) Namakli: cue Mad Max with vorcha actors. ancient Leviathan worshipers used to live there, we have only speculative ideas what happened to them. it was barely livable to begin with when discovered in the modern era, but due to economic realities any attempts at developing the planet were put on the backburner and the vorcha brought there naturally proliferated beyond control despite poor resources.


 * 1) the entire galaxy should shepard activate the Crucible. large swathes of Earth and Palaven can be seen burning from orbit, that -has- to have major consequences regardless of the aftermath. well, space magic can always restore things even if it takes a while.


 * 1) if you have lots of time to kill further, Codex/Planets and Locations and Background Races. the planets that used to host the known background races were usually blasted by three guesses what. sometimes barely livable, sometimes completely toxic even eons later. bits and pieces here and there can also be dug up at the Cerberus Daily News archives, like 6 other civs who nuked themselves to extinction before ever joining the galactic stage.