Environmental research is a continuously expanding discipline.
This is a good thing.
Ecologists are often exhorted to leave their academic silos and they often have, making important contributions to understanding the functioning of our planet and society.
But the discipline expands faster than it grows leaving its core thin.
I would be less worried about the trend, if we had a quantitative assessment of how many environmental researchers we need in different areas.
Academic search committees are not the best determinant of this. State and federal legislators seem to take the 5% approach. Increasing budgets by 5% in good years, decreasing it by 5% in bad years until something seems to break.
Somehow, we can determine how many military members we need. How many police officers and firefighters are required. How many teachers should be in the classroom.
Why not environmental science?
To some it would seem self-serving for one group to make these recommendations about themselves...
Police chiefs often set their own assessments of how many officers are required.
The Association of American Medical Colleges makes assessments of how many doctors will be required in the future.
These recommendations are made in every quasi-public arena...
not ours, though.
If we are going to meet the challenges of solving present environmental problems, no less future ones, we are going to need a lot more people.
How many researchers are working on the environmental consequences of novel compounds? How many are documenting changes in global biogeochemistry? How many are working to integrate ecological understanding into political or corporate decision making? How many research the population biology of our wildlife? Or the spread of invasive plants?
My back of the envelope assessment is that the base force of environmental researchers would need to at least quadruple to begin to answer the problems we face.
How many researchers does it take to work on a topic? How many topics should we be working on?
Determining the precise metrics to back this up would take time, but it is a lot more effective than relying on shifting around the relatively few researchers we have by exhortation.