I don't need a study to say that what's growing today will often be what wasn't growing 20 years ago- and what probably won't be growing 20 years from now either.
I've seen one buzzword after another turn into a bust. Biotech, hydrogen, the "information society", nanotechnology- not that all of those buzzwords don't represent areas of human endeavor that many people are employed in now and may be in future, but none of them ended up being the unmitigated growth engine that sopped up all the engineers they could find for twenty years and kept wanting more. None of them had a hope of living up to the hype.
Booms don't last. They inevitably end in a bust. You might be able to catch one early enough to profit from it, but just realise that the end will come when nobody expects it.
Build versatile skills across a number of industries, keep sharp, don't get complascent, and avoid being pidgeon-holed, and be willing to move where the work is or choose to live in an urban centre with a widely diversified economy- these are the keys to staying employed as an engineer over the long term.