Lust4Life, thanks for your contribution in which you say (inter alia):
The best authority on this subject is the UN Food and Agriculture Organization’s GAEZ (Global Agro Ecological Zones) study.
Among other things, the study showed:
There is more unused rainfed cropland in South America than all of the cropland farmed in North America.
There is more unused rainfed cropland in Africa than all of the cropland farmed in Europe and Russia.
There is enough unused rainfed cropland in the Sudan alone to feed all of Africa.In other words, although your concern about the increasing population is valid and does you credit … we don’t have to cook the algae any time soon.
intention, good to see you contributing to this thread. However, the above sounds like a strangely optimistic view of our ability to find new non-fossil fuel sources of energy that seems to be at odds with your view (in this post) that any attempt to regulate greenhouse gas emissions will “impoverish the world”. Since about the worst that can possibly happen from regulating greenhouse gas emissions is that we have to wean ourselves from fossil fuels (and we don’t even have to do this if we find that sequestering CO2 is a cost-effective option), I find these two views you have hard to reconcile. Could you explain to me how they fit together for you?
The difference is the time scales. brazil84 had asked
In the question, I was looking a long way into the future.
This of course is very different from wasting money today. If we waste billions today on anything you might care to name, that will impoverish the world of today, regardless of whether we discover a new energy source in the year 2065.
intention: So, am I to understand that you are saying that the theoretical limits are a long way off…but we might run into practical limits far before that because, for example, we will use up our energy resources too fast before we are able to discover new forms of energy? In other words, your talk about the theoretical limits being far off really does not have any practical value, and for all practical purposes, the limits may be much closer to being reached?
jshore, we were talking about a theoretical question, which was, is there a physical limit to how much food the world can provide? brazil84 had said “Our current understanding of physics says that we will hit a limit eventually. Granted the theoretical limits are a long way off.”
I was pointing out that our current understanding of physics says no such thing about a theoretical limit. I said nothing about practical limits.
In the event, the practical limits are generally issues that relate to the distribution of the food, rather than how much we can produce. As the GAEZ study shows, we are a long way from maximum food production.
Just out of curiosity, given climate changes predicted due to global warming, with shifts in weather patterns, will these areas of Africa remain sufficiently rain fed to perform as expected? I know that this sort of prediction is not necessarily reliable (or may be downright controversial), but is there some consensus about what might happen climatewise and how it would impact these regions?
Here we are in some murky waters. The recent study by Wentz pointed out significant shortcomings in the models’ ability to forecast rainfall patterns.
We can make some general statements, however. One is that a warmer world is a wetter world, and as Wentz has showed, wetter than the models predict.
Another is that IF the world does warm, one effect will be a slight shifting of the desert belts polewards. A major feature of world climate is the existence of the so-called “Hadley Cells”. These huge circulating masses of air rise at the Equator, and move outwards towards the Poles after they reach altitude. The water is precipitated out, and the air masses move to about 30°N and S of the Equator. There, the (now) dry air drops back to the surface and returns to the equatorial area.
One result of the Hadley circulation, then, are the great desert belts at about 30°N (Sonora, Sahara, and Gobi deserts) and at 30°S (Atacama, Kalahari, and Australian deserts). IF the world warms in the upcoming decades (it has no , the Hadley circulation will be increased, and these desert belts are slated to move slightly polewards.
The cropland in Sudan is south (towards the Equator) of the Sahara. Accordingly, it will likely receive more rather than less rain in a warming climate.
Finally, although the IPCC gives plenty of warnings about how the GCMs don’t do well in forecasting regional changes, people still do it … the TAR said “The IPCC has concluded that climate models at present provide useful predictions at the global and continental scale, but as yet allow little confidence at subcontinental scales (IPCC 1996, WG I, Section 6.6.3; Annex B of this report).”
The AR4 says “Nevertheless, important deficiencies remain in the simulation of clouds and tropical precipitation (with their important regional and global impacts),” and “These exceptions to the overall good agreement illustrate a general characteristic of current climate models: the largest-scale features of climate are simulated more accurately than regional- and smaller-scale features.”
I don’t trust any of the GCMs, either globally or regionally. I have researched them extensively, and have not found any that have been tested, validated, or verified even as much as the software that runs a modern high-rise elevator or a subway system. Regarding the current question, for example, the numbers that they give for the size of the Hadley Cell circulation are way out of whack. Nor do they give results that could be considered “lifelike” regarding things like the variations in surface temperatures.
jshore seems to think that this lack of V&V and SQA (Software Quality Assurance) testing of the models is fine, and I respect his opinion … but me, I’m much more cautious. Call me crazy, but the idea of making multibillion dollar decisions based on untested, unverified, unvalidated software seems … mmm … let me call it “less than prudent”.
As has been pointed out, the shortage of food has more to do with foolish government, than actual scarcity. For example, the New York Times carried and article about a Japanese rice farmer, who has a warhouse full of unsold rice-this is because the cost of producing rice in Japan is about 4 times the world cost. So this guy grows his rice, and gets a subsidy-to grow stuff that he can’t sell. In the same vein, fertile cropland in Zimbabwe stands idle-because Mugabe’s goons have chased the farmers away!