20-Year Prospect
You're going to be so busy for the next few decades. Climate change is fundamentally altering our environment, and you're the poor soul in the middle of the crowded room, screaming that the end is nigh. (Okay, there are actually a lot of people screaming with you.)
Take the Audubon Birds and Climate Report, which is the kind of thing you'll churn out on a regular basis as an ecologist. It predicts that 314 of North America's 588 bird species are going to be up the creek without a paddle come 2080, because climate change will have forced them to give up more than half of their territorial ranges.
As for the 2014 National Climate Assessment, it projects that, under certain scenarios, nearly half of trout habitats in the western United States could be gone by 2080...which would be terrible, because trout are delicious.
So, yes, your job will be around in twenty years. What's more, you're going to be booked solid with writing reports and conducting studies. Make sure you're emotionally prepared, though, since the information you'll be putting out probably won't be terribly upbeat.