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søndag 22. mai 2011

Ingen utvei?



via kommentator "pri-de" på TOD (som virkelig burde skaffe seg et annet nick, jeg ser ham for meg som en stolt-av-det homofil tysker (ikke det at jeg har noe imot verken homser eller tyskere, men jeg tror ikke det er effekten nickets innehaver ønsker å oppnå ;-)):

No way out? The double-bind in seeking global prosperity along with mitigated climate change (T. J. Garrett / EGU.eu)

Om prosjektet:
Modern IAMs [Integrated Assesment Models] are based on neo-classical economic models that, unlike EaSMs [Earth System Models], do
not explicitly represent physical flows. Here, a different approach is taken, which is to
make a comprehensive appeal to thermodynamic laws in order to make deterministic
forecasts of the coupled evolution of the global economy and greenhouse warming.
Civilization is as much a part of the universe as is the atmosphere. Therefore, the
25 intent of this article is not to focus on evaluation of the merits of any potential policy
actions. Rather, the aim is provide a range of physically constrained trajectories for
how we might expect the atmospheric composition and the global economy to evolve
over the coming century.

Det er ikke nødvendig å gjøre det komplisert:
This combination of theoretical and observational support is the key result that
serves as a basis for assuming that civilization is financially well-mixed and that wealth
is derived most fundamentally from a capacity to enable a flow of potential energy. If
it is generally correct, it enables an enormous simplification of what is required to accurately
model the global economy and its waste products. At least at a global scale,
a sophisticated IAM approach that explicitly considers people and their lifestyles is not
necessary in order to forecast future rates of energy consumption. People do not need
to be thermodynamically resolved in order to calculate global scale flows.

Viktig resultat:
Thus, what we normally term “economic growth” [...] is a consequence of an
acceleration in the growth rate of the rate of energy consumption[.]

Oooog....
It is counter-intuitive, but comparing two scenarios with very low resilience to climate
change, energy consumption rates rise about twice as fast with rapid decarbonization
as with no decarbonization. The reason is that decarbonization aids society health,
and this means greater energy consumption, which then leads to a partial offset of any
environmental gains from decarbonizing in the first place.

Garret har også en hjemmeside hvor han har skrevet litt om disse tingene: Thermodynamics of civilization growth

Tar med denne når vi først er i gang:

Energy Limits Global Economic Growth, Study Finds (ScienceDaily)

The research leads the study's authors to infer that energy use limits economic activity directly. They conclude that an "enormous" increase in energy supply will be required to meet the demands of projected world population growth and lift the developing world out of poverty without jeopardizing standards of living in most developed countries.

The study, which used a macroecological approach, was based on data from the International Energy Agency and the World Resources Institute. It was conducted by a team of ecologists led by James H. Brown of the University of New Mexico. The team found the same sort of relationship between energy consumption per person and gross domestic product per person as is found between metabolism and body weight in animals. Brown's group suggests the similarity is real: cities and countries, like animals, have metabolisms that must burn fuel to sustain themselves and grow. This analogy, together with the data and theory, persuades the BioScience authors that the linkage between energy use and economic activity is causal, although other factors must also be in play to explain the variability in the data.

Kanskje også verd å ta en titt på boken Into the Cool: Energy Flow, Thermodynamics and Life av Eric Schneider og Dorion Sagan. (Kurt Cobbs omtale av boken)

søndag 14. februar 2010

Staniford om mat



Stuart Staniford kommenterer på Food Security: The Challenge of Feeding 9 Billion People.

Jeg hadde skannet den noen dager før og funnet den uinteressant -- den er holdt i svært generelle termer, så generelle at det hele blir nærmest meningsløst. Men Stanifords kommentarer er interessante; det er også hans to år gamle TOD-essay The Fallacy of Reversibility (som han linker til i en kommentar).

"Food Security:..." refererer til Forecasting Agriculturally Driven Global Environmental Change (Science / Tilman et al.)
som har litt mer kjøtt på beina...

During the first 35 years of the Green Revolution, global grain production doubled, greatly reducing food shortages, but at high environmental cost (1-5). In addition to its effects on greenhouse gases (1, 6, 7), agriculture affects ecosystems by the use and release of limiting resources that influence ecosystem functioning (nitrogen, phosphorus, and water), release of pesticides, and conversion of natural ecosystems to agriculture. These sources of global change may rival climate change in environmental and societal impacts (2, 8). Population size and per capita consumption are assumed to be the two greatest drivers of global environmental change. Humans currently appropriate more than a third of the production of terrestrial ecosystems and about half of usable freshwaters, have doubled terrestrial nitrogen supply and phosphorus liberation, have manufactured and released globally significant quantities of pesticides, and have initiated a major extinction event (2-4, 8-10).

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