2.4.4 Implementation

2.4.4.1 Modeling

Before any surface coverage is attempted, computer simulations of the proposed changes in surface albedo on climate must be performed. Because climate models have poor resolution and require data points on the order of 250 x 250 Km, they are generally only useful for modeling global climate.

Adverse climate changes in the covered area and in surrounding regions may be detected by the modeling. Previous modeling found that a hypothetical replacement of the boreal forest of Canada and Russia with bare land caused a cooling of most of North America in the spring of 2-3?C with 1?C cooling for areas near the equator and as much as 12?C above 60?N. Changes on this scale might be disastrous. However, this was based on an instantaneous change in surface albedo, whereas we are proposing incremental changes, so that the coverage could be stopped or reversed if necessary.

Possible problems resulting from surface albedo enhancement of the deserts that might be detected by modeling include an expansion of the Sahara into the neighboring Sahel due to increased subsidence heating and in general, an increase in the size of the deserts covered. Reduction of atmospheric dust from deserts could also be detected. This could impact global ecology as some of this dust carried by the trade winds provides iron for N. Atlantic phytoplankton and phosphorous for the Amazon.

A recently advanced theory that changes in land albedo have a greater impact on climate than radiative heating due to GHGs could also be evaluated by the climate modeling.

2.4.4.2 Selection and Installation of Cover Material

The best choice for a surface cover material is white linear low-density polyethylene plastic film. The white color comes from titanium dioxide either added during the extrusion process or coated on the surface. Antioxidants, UV inhibitors and thermal stabilizers are also included in the plastic to increase its longevity in the sun. Exposure to UV radiation eventually causes the plastic to become brittle and disintegrate. Conventional films are stated to have a lifetime of 2-3-years, with some studies suggesting a 10-year lifetime is possible.

A specially engineered plastic will be required for this project, since the cover may need to remain in place for up to 150 years. A 10-year life cycle would result in 15 replacements. A 4-mil (0.004 inch) thick white construction film costs 1.5-cents/square foot (SF) in lots of 2000 SF. We believe that the plastic cost can be reduced to 0.5 cents/SF, even if thicker and more custom engineered material is required.

Installation will require special plastic laying machines, grading of the surface to level it and removal of soil and rocks that could puncture the plastic. It will have to be secured in place with natural soil cover or by other means.