20-Year Prospect
The good news is that as long as there's an environment to protect, you'll have a job. The bad news is, we're kind of running out of environment.
See, we've really done a number on poor planet Earth. Arctic sea ice is disappearing at a rate of 11.5 percent per decade, sea levels are rising at a rate of a couple of millimeters per year...and, well, all of the other indicators are pretty dismal, too.
You and many of your fellow environmental scientists are doing everything in your power to ensure that nature doesn't go the way of the dinosaurs. There are, however, a few of your colleagues who work for the Dark Side.
That's right: There are environmental scientists who actually work for (gulp) the oil and gas industry. Oh, sure, these turncoats are supposed to "ensure the safe, reliable, and compliant operation of our sites"...because that worked out so well in 2010, when the Deepwater Horizon rig blew up in the Gulf of Mexico and leaked 4.9 million barrels of oil all over Louisiana.
Where were you then, oil-and-gas-industry environmental scientists? Where were you then?
At any rate, environmental scientists will be employed for at least a few more decades in a probably fruitless scramble to save the world. You might be able to buy your career a bit more time, however, if you can convince those traitors in O&G to do a little less on-the-job rubber-stamping.