Thursday, June 7, 2012

Expecting the unexpected

A  new study published study in Nature alerts to impending catastrophic developments - this time not mainly based on climate change impacts but on wider developments caused by resource use. Here is the abstract:
Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale ‘tipping point’ highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes.

Interestingly, the argument is not based on the climate change tipping points and associated alarm but on more general problems produced by the Anthropocene. I wonder what readers with a knowledge of the field make of it. At the moment of writing there is a working link to the paper here.

The paper concludes as follows:

Diminishing the range of biological surprises resulting from bottom-up (local-to-global) and top-down (global-to-local) forcings, postponing their effects and, in the optimal case, averting a planetary-scale critical transition demands global cooperation to stem current global-scale anthropogenic forcings315161719. This will require reducing world population growth31 and per-capita resource use; rapidly increasing the proportion of the world’s energy budget that is supplied by sources other than fossil fuels while also becoming more efficient in using fossil fuels when they provide the only option79; increasing the efficiency of existing means of food production and distribution instead of converting new areas34 or relying on wild species39 to feed people; and enhancing efforts to manage as reservoirs of biodiversity and ecosystem services, both in the terrestrial80 and marine realms39, the parts of Earth’s surface that are not already dominated by humans. These are admittedly huge tasks, but are vital if the goal of science and society is to steer the biosphere towards conditions we desire, rather than those that are thrust upon us unwittingly. 


Dennis Bray said...

What is it they say - a change is as good as a rest (one scary story for another so to speak).

This line is quite interessting: 'goal of science and society is to steer the biosphere towards conditions we desire, rather than those that are thrust upon us unwittingly.' Who are the "we"?

plazaeme said...

A better link (full paper):

Hans von Storch said...

This is an idea which came up in the 19070s, or so - thew interesting and inspiring performance of low-dimensional non-linear systems. I rememberer it was called then "catastrophe"-theory; I guess it came up in the aftermath of Lorenz' butterfly-observation.

The problem with this system is that it is low-dimensional; there are some cases, when this is an appropriate description of a real system; mostly it is not - in most cases there are ziggilions of butterflys and many degrees of freedom, which makes the system effectively stochastic.

A famous case was the break down of the gulf stream, which works fine in simplified systems; in case of "full" GCMs this phenomeon has not been observed (even though the overturning is changing when the earth warms up).

In short - a nice toy of ("ecological") mathematicians, which mostly melts away with increasing realism when describing the considered system. In our 1999-book, Storch/Guess/Heimann, Das Klimasystem und seine Modellierung, we have an example of the effect of stochasticity on a non-linear system, Chapter 4.6.2 with Figure 4.8 on page 98.

DeNihilist said...

And again, where does this huge ego come from, that insists that whatever humankind achieves, somehow is not of or for nature?Whatever the outcome, massive disruption or a benign warmth, the result will be all within the parameters of the potentiallity of nature.

We do NOT walk outside of nature! What we do is as natural as snow melting in the sun.

Reiner Grundmann said...

The Guardian has published an other long interview with Jim Lovelock which is worth a read

Hans von Storch said...

In the interview, Jim Lovelock says: "Germany is a great country and has always been a natural leader of Europe, and so many great ideas, music, art, etc, come out of it, but they have this fatal flaw that they always fall for an ideologue, and Europe has suffered intensely from the last two episodes of that. It looks to me as if the green ideas they have picked up now could be just as damaging. They are burning lignite now to try to make up for switching off nuclear. They call themselves green, but to me this is utter madness."
While I am not opposing this view - even if I am not sure which the second episode is supposed to be - I find it remarkable how righteous Lovelock seems to be. He admits errors, which is fine, but he seems not to learn from these errors.
This was also how I experienced him then back when we had the joint BBC event. He was a real ideologue at that time (and I was the token contrarian). I think he still is an ideologue but combined with a strong feeling that he knows better - even if he chooses to reverse his opinion. In that sense he is a great entertainer, but that is it. Given his quote on Germany, we should invite him as a leader.