Some damage now sustains itself, so removing the cause does not remove the effect

The argument

A second argument offered for this position concerns damage that has become self maintaining. Proponents argue that the assumption behind stepping back is that a system will return along the path it came, and that many degraded systems do not. Once a threshold has been passed, the degraded condition is held in place by its own feedbacks, and the original pressure no longer needs to be present for the damage to persist. The argument points to the mechanisms by which this happens. Soil stripped of vegetation loses the structure that held water and seed, so the ground becomes drier and barer than regrowth requires, which keeps it bare. A forest opened at its edges dries and becomes flammable, and fire prevents the regeneration that would close it again. A shallow lake pushed into turbidity keeps itself turbid, because the sediment movement and nutrient cycling that follow the loss of rooted plants prevent those plants returning. An introduced species that has become established is not maintained by human activity at all, and may exclude returning natives indefinitely. Proponents emphasise that in none of these cases does walking away help, because what is now doing the damage is the system itself. Holders of the view conclude that intervention is not an optional supplement to natural recovery but the thing that makes recovery possible. A system held in a degraded state has to be pushed back across the threshold it crossed, by stabilising ground, restoring the movement of water, removing what has established itself, or replanting what can no longer arrive on its own. Proponents argue that this is why the honest answer to the question is no, since left alone such systems do not recover, and the capacity the other positions describe applies to damage that has not yet gone this far.

Premises

Counter-arguments

Opponents argue that the mechanism is real and the conclusion overstated. Thresholds of this kind are documented in particular systems rather than being general, many degraded sites do recover slowly without help, and the periods over which proponents judge a system stuck are often shorter than recovery takes. They also note that the interventions recommended have a poor record of their own, since ground works, replanting and the removal of established species frequently fail, sometimes make matters worse, and produce systems needing maintenance indefinitely. Several add that intervention competes for resources with simply ending the pressure, which is cheaper and works on all the damage that has not yet become self sustaining.

Rejecting the premises

[Rejecting P1] Self reinforcing degraded states are documented in particular systems rather than being a general property, and many sites judged stuck recover slowly once observed for longer. [Rejecting P3] Interventions intended to move a system back across a threshold frequently fail or produce systems requiring indefinite maintenance, so the proposed remedy does not reliably follow from the diagnosis.