4 ms·

https://www.ncbi.nlm.nih.gov/pubmed/12178986 https://www.ncbi.nlm.nih.gov/pubmed/12178986

Animats 10y ago
That's from 1993. Needs an update. Agriculture has been reducing their inputs in recent decades. With precision farming and a lot more data collection, farms use less of everything. Using lots of water and fertilizer is out. It looks like we're not going to run out of energy. Solar and wind have now become Big Solar and Big Wind, and fight it out with Big Oil and Big Gas. (Big Coal went bust.[1]) Electric cars aren't a joke any more. We can still do nuclear if we have to. We're more likely to have metal shortages than energy shortages. [1] https://www.washingtonpost.com/news/energy-environment/wp/2016/04/13/coal-titan-peabody-energy-files-for-bankruptcy/?utm_term=.003968a26f35 https://www.washingtonpost.com/news/energy-environment/wp/20...
- dredmorbius 10y ago
  The trends over the 20th century generally fit the narrative of exponential growth in energy consumption. Major drivers have been fertiliser (especially nitrogen fixation via Haber-Bosch), farm equipment (especially considering both embodied energy of manufacture plus fuel use), and irrigation costs. Two additional factors are the growth in consumption of both animal products (eggs, dairy, poultry, port, and beef, roughly in that order of increasing feed:food conversion cost), and in the consumption of non-staple foods: fuits and vegetables are vastly less energy dense than corn, wheat, rice, and soybeans, and hence have a higher energy cost:calorie ratio. Vaclav Smil's 1994 Energy in World History has an excellent exposition of these trends generally, though ending 22 years ago. Manfred Weissenbacher's Sources of Power updates the story to 2009. It's also helpful to realise that sub-Saharan Africa still has very little mechanised agriculture (fewer tha 1 million tractors per Weissenbacher), and little fertiliser or pesticide use. Even in the US and Europe, nitrogen fertiliser use didn't take off until the 1950s -- for the first 30 years or so, Haber-Bosch were largely in the munitions business. Since ~1990, energy productivity of ag seems to be increasing (that is, less input energy to output crop) in the US and EU (USDA and DOE have several reports). Global data and graphics are much harder to find, I don't know what the situation is.
vonmoltke 10y ago
That abstract mentions nothing about exponentially-growing energy requirements. It's also an abstract for a paper from a forum sponsored by Negative Population Growth, a non-profit devoted to encouraging a reduction of the world's population for sustainability reasons. I am talking this with the same salt I take a climate change paper put out by energy company scientists.

That's from 1993. Needs an update. Agriculture has been reducing their inputs in recent decades. With precision farming and a lot more data collection, farms use less of everything. Using lots of water and fertilizer is out. It looks like we're not going to run out of energy. Solar and wind have now become Big Solar and Big Wind, and fight it out with Big Oil and Big Gas. (Big Coal went bust.[1]) Electric cars aren't a joke any more. We can still do nuclear if we have to. We're more likely to have metal shortages than energy shortages. [1] https://www.washingtonpost.com/news/energy-environment/wp/2016/04/13/coal-titan-peabody-energy-files-for-bankruptcy/?utm_term=.003968a26f35 https://www.washingtonpost.com/news/energy-environment/wp/20...

dredmorbius 10y ago
The trends over the 20th century generally fit the narrative of exponential growth in energy consumption. Major drivers have been fertiliser (especially nitrogen fixation via Haber-Bosch), farm equipment (especially considering both embodied energy of manufacture plus fuel use), and irrigation costs. Two additional factors are the growth in consumption of both animal products (eggs, dairy, poultry, port, and beef, roughly in that order of increasing feed:food conversion cost), and in the consumption of non-staple foods: fuits and vegetables are vastly less energy dense than corn, wheat, rice, and soybeans, and hence have a higher energy cost:calorie ratio. Vaclav Smil's 1994 Energy in World History has an excellent exposition of these trends generally, though ending 22 years ago. Manfred Weissenbacher's Sources of Power updates the story to 2009. It's also helpful to realise that sub-Saharan Africa still has very little mechanised agriculture (fewer tha 1 million tractors per Weissenbacher), and little fertiliser or pesticide use. Even in the US and Europe, nitrogen fertiliser use didn't take off until the 1950s -- for the first 30 years or so, Haber-Bosch were largely in the munitions business. Since ~1990, energy productivity of ag seems to be increasing (that is, less input energy to output crop) in the US and EU (USDA and DOE have several reports). Global data and graphics are much harder to find, I don't know what the situation is.

vonmoltke 10y ago

That abstract mentions nothing about exponentially-growing energy requirements. It's also an abstract for a paper from a forum sponsored by Negative Population Growth, a non-profit devoted to encouraging a reduction of the world's population for sustainability reasons. I am talking this with the same salt I take a climate change paper put out by energy company scientists.