The model to be used is the population model - exponential growth constrained by carrying capacity. We are human - we have obviously increased the carrying capacity for ourselves a 1000 fold or more and we are only just at the beginning of bigger, better and many more technological advances. Thorium in fast neutron reactors would seem to be an obvious candidate for a fuel of the coming centuries. Let’s solve one problem at a time. Just when we should be confident - you want to throw in the towel?
There are billions of people now in the direst poverty. We are nowhere near filling the universe with wheat. At any rate - economic growth is not necessarily about physical resource inputs. It includes medicine, education, art, poetry, music, philosophy, mathematics and technological innovation. On Dec 28, 5:29 pm, Phil Hays <[email protected]> wrote: > On Sun, 2009-12-27 at 13:22 -0800, Robbo wrote: > > 'Limits to growth' ideas are dangerous bullshit > > Really. > > Energy use (or anything else) that grows at 3% a year doubles roughly > every 24 years. > > Every hear of the chessboard and the prince? > > The prince agreed to pay one grain of wheat on the first square of the > chessboard, and two grains on the next square, and four grains on the > third square, and continue doubling for all the squares of the chess > board. As soon as he agreed to this, the prince was bankrupt. > > Is there enough wheat on the Earth today to pay for the 64th square? Do > calculate. > > Let us change the problem a little bit, to four chessboards. Is there > enough wheat in the universe to pay the 256th square? > > Let me help you out. 2^256 is about 10^77. The Universe has somewhere > around 10^80 atoms. A grain of wheat has about 10^23 atoms in it. So a > Universe that was nothing but wheat would have have about 10^57 grains > of wheat. A lot, to be sure, but not enough. Not even close to enough. > Even if the universe is all wheat. > > Staying within known physics, (meaning no direct mass to energy > conversion or faster than light transportation), but allowing for fusion > energy, how many doublings of energy use before all the hydrogen in the > oceans has been converted to helium? Ignore the little problem of > getting rid of the waste heat. > > Extracting uranium from ocean water might well be practical. If so, > nuclear energy could support current total energy usage for about 5 > billion years, much longer than the Earth will be habitable. If energy > production from nuclear grew at 1%, how long would this amount of energy > last. Do ignore the little problem of the ocean needing time to be > recharged uranium content by rivers, and the other little problem of > getting rid of the waste heat. > > Agree that there are limits? > > Then let us get a little closer in time. Oil is somewhere between 1/4 > and 1/2 drilled, pumped and burnt. We almost surely can't do another > doubling of oil production. What replaces oil? How? > > -- > Phil Hays <[email protected]> -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
