Thanks, Willis (Willis Eschenbach (11:48:48)). My BS alarm began going off as soon as I read 40% too. Looks like a phony number to me as well.

What do you think the difference is between cropland and irrigated? They both sound like cropland to me. It isn’t that important though because with urban at 0.2%, cropland at 8.3% and irrigated at 3% humanity’s footprint on this planet is pretty damned small at 11 1/2%.

Both are cropland, and the GAEZ report distinguishes between rainfed cropland and irrigated cropland. It is of interest because there is more cropland which is not currently being used, and to determine how much, it is necessary to distinguish between potential rainfed cropland and potential irrigated cropland. Part of this is involves analyzing currently used rainfed and irrigated cropland.

The GAEZ study should be required reading for people who are interested in resources and how they are used.

What do you think the difference is between cropland and irrigated? They both sound like cropland to me. It isn’t that important though because with urban at 0.2%, cropland at 8.3% and irrigated at 3% humanity’s footprint on this planet is pretty damned small at 11 1/2%.

there was a really good article recently in energy and environment its in the november journal yearly round up and in it an articl claims that we have converted 40 percent of the worlds ice free land for agricultural puproses when this is though about in conjunction with the above article then it easy to see how inflated temps are less likely than ever before to be associated with carbon dioxide.

Numbers, dear friends, numbers … think about them. Tune up your bad number detectors, mine starting ringing like crazy when I read this. Is there any possible way that 40% of the ice free land is dedicated to agriculture when we have the Amazon forest and the Sahara desert and all the rest of the unused land on the planet?

The premier resource for this question is the GAEZ study done by the UN FAO. Going back to it, I find that it gives the following numbers:

Forest 21.2%
Desert and barren 20.9%
Woodland 14.5%
Grassland 13.6%
Mosaics 8.5%
Cropland 8.3%
Ice and cold desert 5.9%
Lakes and rivers 3.3%
Irrigated 3.0%
Wetland 0.7%
Urban 0.2%

Cropland, including both irrigated and unirrigated and assuming that the mosaics are 50% cropland, is about 15% of the ice-free land area of the planet.

I urge everyone to read the study. Among other things, it shows that:

• There is more unused potential rain-fed cropland in Africa than cropland being used in Europe.

• There is more unused potential potential rain-fed cropland in South America than cropland being used in North America.

• There is enough unused potential potential rain-fed cropland in the Sudan to feed every person in Africa.

Numbers …

——————————————————————————–
Science 16 October 1998:
Vol. 282. no. 5388, pp. 442 – 446
DOI: 10.1126/science.282.5388.442
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Reports

A Large Terrestrial Carbon Sink in North America Implied by Atmospheric and Oceanic Carbon Dioxide Data and Models
S. Fan, M. Gloor, J. Mahlman, S. Pacala, J. Sarmiento, T. Takahashi, P. Tans “”"
So check out this paper; and then tell me that the USA is the world’s biggest polluter.

I believe it has been long established that there are vastly more trees in the USA than there were here when the pilgrims first stepped ashore on Plymouth Rock; or wherever it is that history says they did.

But hey; I’m all in favor of planting trees; I just think people should put them up or take them down wherever that seems feasible and desirable to do.

I noticed in that MaCintyre Lindzen piece with the flick about Finland; there was a shot of somebody extracting a bored core from a tree.

What an image that was; a perfect illustration of how a failure to observe the Nyquist Sampling Theorem, leads to flse information being gathered.

That tree core sample was a puny representation of what the entire volume of that mass of wood looks like inside ; but it will go down in the record books, as being quite typical of what the rest of the tree looks like; let alone the rest of the forest. Yes it truly is analagous to putting a finger up in the air to sense which way the wind is blowing.

With the result being that people who understand the system, will cut down their 5.5″ trees.

The land use change question is: what were the atmospheric changes that resulted from global land use change from 1850 to present. There was wide expansion of agriculture, both extensively and intensively. Forests overall retracted. Urban heat islands were created. An area the size of Texas was paved (all the worlds building footprints, parking lots, patios and the global road network which is about 20 million miles long)

Perhaps half of the change in temp from 1850 to present can be attributed to these land use changes, but the effect in the next 100 years may be quite different.

In 2010, the net stock of global forests may be increasing, cropland area is about the same as additional food is being provided by increased productivity. Pasture and rangeland is retracting as more animals are fed crop grains and improved pasture grasses. Paved land is still increasing, recently in China with extensive city and road buidling.

Or, most of the land use change impact from 2010-2100 will be found outside the USA.

And, reforestation and increase in overall vegetation has already started and does not need any public policy intervention.

The USA exurban pattern is interesting, but the impact is an open discussion. The non-urban part of metropolitan areas (or the 600,000 square miles of metropolitan area that is not part of the area of 100,000 square miles of urban land), has about 30 million people that are scattered in small clusters of houses on large lots, typically from 1 to 5 acres.

As most of these residents work in cities and do not farm, they might be expected to be rather passive with what they do with their property. Lots of grass managed with riding mower, trees planted to outline their lots, some gardening. Heat island effect limited, given the house footprint and driveways at most pave about five to ten percent of the lots. Probably comparing the environmental impact of large lawns versus pastured grass, corn or soybean fields. Overall, probably nowhere near as significant as urban heat islands created in downtowns, suburban employment centers, airports, etc.

Church bells to ring out warning on climate change