Un altre cop, el mestre Ugo Bardi (http://cassandralegacy.blogspot.com.es/2014/12/seneca-cliffs-of-third-kind-how.html), ens recorda quan fàcil i ràpid és el col·lapse en la part final de l’explotació d’un recurs respecte a la part inicial. De fet, com ja hem vist en l’anterior article on posava l’exemple de l’oli de balena, tots segueixen en la seva part d’explotació inicial el model de corba de Hubbert i en la seva part final adopten una forma més pendent….. de penya segat. Se suposa que això hauria de servir per què els nostres governants – i molts economistes acòlits que els serveixen – prenguessin les decisions més encertades. Però no cal que us expliqui que pel general sempre tracten de mantenir el model BAU actual amb les conseqüències que anem veient dia a dia…..
Monday, December 15, 2014
Seneca cliffs of the third kind: how technological progress can generate a faster collapse
The collapse of the North Atlantic cod fishery industry gives us a good example of the abrupt collapse in the production of resources – even resources which are theoretically renewable. The shape of the production curve landings shows some similarity with the “Seneca curve“, a general term that I proposed to apply to all cases in which we observe a rapid decline of the production of a non renewable, or slowly renewable, resource. Here is the typical shape of the Seneca Curve:
The similarity with the cod landings curve is only approximate, but clearly, in both cases we have a very rapid decline after a slow growth that, for the cod fishery, had lasted for more than a century. What caused this behavior?
The Seneca curve is a special case of the “Hubbert Curve” which describes the exploitation of a non renewable (or slowly renewable) resource in a free market environment. The Hubbert curve is “bell shaped” and symmetric (and it is the origin of the well known concept of “peak oil). The Seneca curve is similar, but it is skewed forward. In general, the forward skewness can be explained in terms of the attempt of producers to keep producing at all costs a disappearing resource.
There are several mechanisms which can affect the curve. In my first note on this subject, I noted how the Seneca behavior could be generated by growing pollution and, later on, how it could be the result of the application of more capital resources to production as a consequence of increasing market prices. However, in the case of the cod fishery, neither factor seems to be fundamental. Pollution in the form of climate change may have played a role, but it doesn’t explain the upward spike of the 1960s in fish landings. Also, we have no evidence of cod prices increasing sharply during this phase of the production cycle. Instead, there is clear evidence that the spike and the subsequent collapse was generated by technological improvements.
The effect of new and better fishing technologies is clearly described by Hamilton et al. (2003)
Fishing changed as new technology for catching cod and shrimp developed, and boats became larger. A handful of fishermen shifted to trawling or “dragger” gear. The federal government played a decisive role introducing newtechnology and providing financial resources to fishermen who were willing to take the risk of investing in new gear and larger boats.
Fishermen in open boats and some long-liners continued to fish cod, lobster and seal inshore. Meanwhile draggers and other long-liners moved onto the open ocean, pursuing cod and shrimp nearly year round. At the height of the boom,dragger captains made $350,000–600,000 a year from cod alone. … The federal government helped finance boat improvements, providing grants covering 30–40% of their cost.
By the late 1980s, some fishermen recognized signs of decline. Open boats and long-liners could rarely reach their quotas. To find the remaining cod, fishermen traveled farther north, deployed more gear and intensified their efforts. A few began shifting to alternative species such as crab. Cheating fisheries regulation—by selling unreported catches at night, lining nets with small mesh and dumping bycatch at sea—was said to be commonplace. Large illegal catches on top of too-high legal quotas drew down the resource. Some say they saw trouble coming, but felt powerless to halt it.
So, we don’t really need complicated models (but see below) to understand how human greed and incompetence – and help from the government – generated the cod disaster. Cods were killed faster than they could reproduce and the result was their destruction. Note also that in the case of whaling in the 19th century, the collapse of the fishery was not so abrupt as it was for cods, most likely because, in the 19th century, fishing technology could not “progress” could not be so radical as it was in the 20th century.
The Seneca collapse of the Atlantic cod fishery is just one of the many cases in which humans “push the levers in the wrong directions“, directly generating the problem they try to avoid. If there is some hope that, someday, the cod fishery may recover, the situation is even clearer with fully non-renewable resources, such as oil and most minerals. Also here, technological progress is touted as the way to solve the depletion problems. Nobody seems to worry about the fact that the faster you extract it, the faster you deplete it: that’s the whole concept of the Seneca curve.
So take care: there is a Seneca cliff ahead also for oil!