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Archive for Junho, 2014

ANTÓNIO TURIEL

 

¿Qué pasaría si por un momento dejáramos nuestro diario quehacer y echásemos un vistazo a la salud ecosistémica de nuestro planeta, de nuestro hábitat? Todo el mundo es consciente de que hay muchos problemas, pero posiblemente no todo el mundo se hace una idea clara de cuántos llegan a ser y cómo de graves son, y no digo ya para las otras especies sino para la nuestra propia. Quizá son tantos estos problemas, y tan graves, que deberían de ocupar las primeras páginas de los diarios, en vez de estar relegados, y aún eso de tanto en tanto, a las de Ciencia y Sociedad. Quizá Vd. piense que no hay para tanto, que se exagera con estos temas. Con un cierto conocimiento de algunos de los problemas clave de la Humanidad hoy por hoy, algunos minutos de paciencia en un buscador y seleccionando sólo las fuentes más razonables se dibuja ante nosotros un panorama ciertamente desolador…

El daño a la Gran Barrera de Coral es irreversible si no se toman acciones radicales.


Las estrellas de mar se deshacen en una materia gelatinosa y nadie sabe por qué.


Mortandad masiva de ostras y festones en la costa Noroccidental de los EE.UU. – Millones de mariscos se mueren – Nunca se había visto una cosa así – En Julio la mortandad llegará al 95%.

Mortandad masiva de la vida marina en la Costa Oeste de los EE.UU., ¿radiación de Fukushima… o algo más? 

Las zonas muertas del océano (zonas pobres en oxígeno donde no hay vida) han incrementado su área 10 veces durante el último siglo.

 

El Mediterráneo se calienta y se acidifica a un ritmo sin precedentes.

El cambio climático y la cantidad decreciente de peces permiten prever un nivel de capturas estancado.

 
La contaminación hace hermafroditas a unos peces en el Mediterráneo.

  El hielo marino ártico está contaminado con microplásticos.

  Los microplásticos amenazan la salud de los ecosistemas y de los humanos en el Nordeste de Ohio.

Cómo los microplásticos domésticos comunes amenazan la fertilidad.

Las medusas se están haciendo con los mares, y puede ser demasiado tarde para pararlas.

El máximo anual de extensión de hielo ártico es la quinta menor desde que hay registros.

La Armada americana predice un Ártico sin hielo en 2016.

(mais…)

Anúncios

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At the Age of Limits Conference, I gave a talk called Converging Crises (PDF), talking about the crises facing us as we reach energy limits. In this post, I discuss some highlights from a fairly long talk.

A related topic is how our current situation is different from past collapses. John Michael Greer talked about prior collapses, but because both of our talks were late in the conference and because I was leaving to catch a plane, we never had a chance to discuss how “this time is different.” To fill this gap, I have included some comments on this subject at the end of this post.

The Nature of our Current Crisis

Figure 1

The first three crises are the basic ones: population growth, resource depletion, and environmental degradation. The other crises are not as basic, but still may act to bring the system down.

Figure 2

Humans have found a series of ways to keep deaths down, each adding more control of external energy.

  • Control of fire, starting over 1 million years ago. This allowed humans to cook their food, making it possible for more energy to go to develop the brain, and less to developing teeth and digestive apparatus. Humans could also extend their range into colder areas.
  • Agriculture, starting about 10,000 years ago. We grew desirable plants and animals and excluded other species, thus increasing the amount of food produced.
  • Coal, starting around 1800 C. E. With coal, we could make metals in quantity since we didn’t need to cut down trees for smelting. We could also make concrete and glass in quantity. With these, we could build hydroelectric power plants, and build electric transmission lines.
  • Oil, ramping up after World War II. Oil allowed the use of cars for personal transport, plus trucks to deliver goods precisely where they were needed. It also improved agricultural productivity through irrigation, refrigeration, herbicides, pesticides. The ability to use airplanes enabled globalization.

As humans’ control of energy improved, human population grew and the population of other species fell. According to Niles Eldredge, the Sixth Mass Extinction began 100,000 years ago, when there were fewer than 100,000 people on the planet, back in the days of hunter-gatherers. The extent of die-off of other species has grown as we added agriculture, and later added coal and oil use.

Humans are not doing anything “wrong.” Humans are reacting to the same instinct that all species have, namely to make use of available energy to allow more of the species to live to maturity. Population growth stops when a species reaches a limit of some sort–lack of food because the species eats too much of its would-be food supply; too much pollution; epidemics (related to crowding and poor nutrition); or limits associated with gathering external energy.

Individuals can change their personal actions, but built-in instincts tend to guide the direction of civilizations as a whole. Thus the population of civilizations tend to rise until bottlenecks are reached.

[…]

How This Time is Different

Greer, in his talk, mentioned several points about prior collapses:

  • Typically 95% of the population died off.
  • The time between civilizations tended to be about 500 years.
  • The 5% who survived were able to go about doing things, pretty much as had been done in the past.
  • The downslopes often had jogs and bumps in them, and could be slow.

The question arises as to how helpful this information is with respect to what is ahead. As I see the situation, civilizations that failed in the past were not fossil fuel dependent or electricity dependent. While there was specialization of labor, there was much less specialization than there is today. While there was some trade, the majority of food and clothing was locally produced. The biggest problems were

  • Growing population
  • Arable farmland that did not expand to meet growing population
  • Soil problems (loss of fertility, erosion, salinity)
  • Deforestation
  • Competition from neighboring civilizations
  • Government collapse
  • Debt problems

I view the 500 year gap between civilizations as including what I show as the “inter cycle” period between civilizations in Figure 6, above. This is the gap that took place before new growth could occur.

The big problem in the past with civilizations that collapsed was that humans were using renewable resources faster than they could renew. Population continued to expand as well. The combination of rising population and depleting soil and forest resources led to diminishing returns, lower wages for many workers, and difficulty funding governments. A 500 year gap between civilizations took the population pressure off an area. Forests were able to regrow, and soil was able to renew (at least partly through regeneration of soil by erosion of base rock).

Today, we sill have the problems we had in the past, but we have some new ones as well:

  • We are depleting aquifers much more rapidly than they regenerate. In many cases, the water table is far below what can be reached with simple tools. It will take thousands of years for these aquifers to regenerate.
  • We are depleting minerals of all kinds, so that we now need “high tech” methods to extract the low ore concentrations. These minerals will be out of reach, without the use of electricity and fossil fuels. In fact, the vast majority of fossil fuel energy supplies will also be out of reach, without today’s high tech methods. Eventually this may change, with new fossil fuel formation and with earthquakes, but the timeframe is likely to be millions of years.
  • Most people today do not know how to live without fossil fuels and electricity. If fossil fusel and electricity disappeared, most of us would not know how to produce our own food, water, and other basic necessities.
  • Most of us could not just “pick up and do as we did before,” with respect to our current jobs, if the government and 95% of the population disappeared. Our jobs are often supported by global supply chains that would disappear, as well as direct use of fossil fuels and electricity.
  • The world is sufficiently networked that most of it is likely to be drawn into a world-wide collapse. In the past, areas that did not collapse continued to function. These areas could act as a back-up, if functions were lost.

In the past, the 500 year gap was enough to allow regeneration of forests and soil, once population pressures were reduced. If that were our only problem now, we could expect the same pattern again. Such a regeneration would allow a reasonably large group of people (say 500 million people) to get back to a non-fossil fuel based civilization in 500 years, with new governments, roads and other services.

In such a new civilization, we would likely have difficulty using much metals, because ores are now quite depleted. Even reprocessing of existing metals is likely to require more heat energy than is easily available from renewables sources.

We are now so dependent on fossil fuels and electricity that any collapse that does take place seems likely to be faster than prior collapses. If the electric grid goes down in an area, and cannot be repaired, most business functions will be lost–practically immediately. If oil supply is interrupted, it also will bring a halt to most business in an area, because workers can’t get to work and raw materials cannot be transported.

We are bing told, “Renewables will save us,” but this is basically a lie. Wind and solar PV are just as much a part of our current fossil fuel system as any other source of electricity. They will only last as long as the weakest link–inverters that need replacing, batteries that need replacing, or the electric grid that needs fixing. We are being told that these are our salvation, because politicians need to have something to point to as a solution–not because they really will work.

(Para ler o resto: Our Finite Planet)

tverberg-estimate-of-future-energy-production

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