To be honest, I do not really think there are any insurmountable environmental obstacles to human society, despite the plethora of issues facing us today. General trends like increasing inland water salinity or desertification are natural environmental shifts, and I generally only tend to think of the legitimate problems as the anthropogenic ones. Populations might have to migrate but such instances have happened throughout history and have never proven to be too problematic.
Global warming might shift biomes but the main threat it posses are to coastal areas, however those areas always tend to hold the most risk anyway (hurricanes, tectonic fault lines- volcanism, etc.) and with that in mind it really seems like less of an issue. Rising water levels will be a gradual shift and so it is not incredibly difficult to assume local governments will be able to handle the challenge, with perhaps the exception of island nations.
I think one of the greatest issues we face is the availability of fuel, but natural gas should be able to hold us over until renewable become more viable (especially algae that produces fuel.) In terms of local issues I think fracking is the biggest problem that needs more attention because that is an incredibly harmful practices to local environments and it is being swept under the rug currently. However, human perseverance and ingenuity have been able to handle most every problem so far and I an confident that with the right attention even fracking can become a clean(er) practice.