Avoiding Collapse (but not controversy)

A paper by Safa Motesharrei, Jorge Rivas, and Eugenia Kalnay explores the implications of a mathematical model referred to as HANDY (Human And Nature DYnamical).  A number of scenarios are presented showing the dynamic interactions of populations of elites and commoners along with the value of natural resources and accumulated wealth.  The authors identify two common features among societies that have collapsed--ecological strain and economic stratification.  The model leads them to the conclusion that

Collapse can be avoided, and population can reach steady state at the maximum carrying capacity, if the rate of depletion of nature is reduced to a sustainable level, and if resources are distributed equitably.

Otherwise, historical examples suggest that elites can be oblivious to the coming disaster and continue to thrive (in the near term) while everything falls apart.

Update (March 17):  The authors point out that over-exploitation of natural resources or strong economic stratification can independently cause collapse.  (Scarcity of resources or Type II collapse versus scarcity of workers or Type I collapse.)  Yet, under conditions of inequality, it was found that collapse became very hard to avoid.

Also, Annie Leonard says it's a false choice to address ecological issues or the problem of inequality.  She calls solutions to both inseparable.

Update (March 24):  I'll leave the original post intact, but there are now serious questions about the research presented.  Joseph Tainter, author of The Collapse of Complex Societies, said

I found the paper to be trivial and deeply flawed.

The Guardian article says the paper has been accepted for publication.  I actually printed the paper, read it, and shared it with a colleague.  I believe I understood the gist of the mathematics, though I'm not an expert. I didn't question the assumptions.  I understood it is a simple model, but the results seemed plausible.  It looks now like one of those cases of blindness caused by one's political views.

Update (March 29):  Seeking to follow up on the controversy, I discovered that Nafeez Ahmed of the Guardian posted a pretty quick response to Keith Kloor.  I think it's worth pointing out that Ahmed does have science credentials unlike Kloor.  Kloor is also apparently no stranger to controversies of his own.

The most recent version of the paper is available.  Tainter's criticism is acknowledged, but others in the field see merit to the HANDY model.  Rodrigo Castro of the Swiss Federal Institute of Technology in Zurich (ETH Zurich) explains that

[t]he model is a very strong simplification of the human-nature system, which results in many limitations. Despite its simplicity, such a model is easy to understand and offers a more intuitive grasp of underlying dynamical phenomena compared to more complex and less aggregated models.

And I think that's the whole point of the effort.  It's not the last word on the issue and there's no hard and fast prediction for collapse.  We're looking to gain some insight.  And the implications are clear.  That may cause me to be uncritical of the study while the right-wing CNS News lashes out against the "Socialism or Extinction" study.

Posts at Azimuth and Planet3.0 give their take.

Update (April 27, 2017):  A BBC report refers to the HANDY research and examines "how Western civilisation could collapse".