Parallels

Psychology is all about human behavior.

For a long time, it had been focused on pathologies.
Rather recently, "positive psychology" has been developed to point out
that it was actually the aim (also) to research what made for a good life, for happiness.

Ecology is all about "the economy of nature."

A part of that is how human beings are a part of nature, too,
and would need to live within the limits of Earth's ecosystem
– what we typically mean by "sustainability" (or, at least a part of that).

Ecology, as science and as environmentalism, has been focused
on analyzing and  decrying the problems.

For motivation, it would need to pay more attention to how this is both
necessary for the survival of humanity, good for the individual,
and opening up possibilities for progress…