In order to answer such a question we should first define terms.
Moral often is equated to ethical. However, I sense in the word moral unusefully implies some inherent and universal good exists. Moral relativism highlights the weakness of chasing absolutism. As such, I prefer the term ethical if only to downplay any measure against a slippery, imaginary absolute.
Divorced from an implied absolute ethical assessment can proceed. The paradigm of goodness can be fluid, but more importantly requires explicit explanation. As examples Christian ethics, secular humanist ethics, and global biodiversity ethics name different ideologies that connect to specific paradigms of goodness, sometimes at conflict with each other as well as internally.
To act is easier to define, though still with its subjective side. An action exercises ones agency with intent of effecting a change of some kind. Willful inaction arguably is acting at times, though any one person or organization can not possibly act on all concerns. Thus, to say that an entity failed to act can meaningfully be challenged.
Putting the two together, the question "what is a moral act?" is unhelpful rhetoric. If we phrase "what is an ethical act?" is better phrased, but needs to be connected to a specific ideology or world stance. Still, as with so much in life, this means we need to have an extended conversation to discuss the particulars. Only then can we evaluate whether individual or communities action conforms to the associated ethical standards.
The challenge, of course, is to find the best, trade-off actions that pursues positive short-term and long-term outcomes. In other words, the ends justify the means AND the means justify the ends.
If we are successful at this challenge, then shared ethical progress has a chance.