In these cost estimates it is assumed that the cover must remain in place for 150 years from the date of the first year’s coverage. This means that the first year’s coverage will remain in place for 150 years and the last coverage applied 60 years later, for 90 years. The 150-year time period was chosen because 90 years after the last coverage is applied more than two thirds of the carbon dioxide emitted during the 60-year period of application should have been reabsorbed by the oceans and plants. Most of the methane and other GHGs emitted during this time period should have also have gone away except for the halocarbons. The exact time period that the coverage should be maintained to result in 100% removal of the GHGs emitted during its application is beyond the scope of this research plan and will require better estimates of GHG longevity in the atmosphere than are available today. A 150-year period of coverage should also be long enough for the transition to GHG free energy production and use and GHG free food production technologies to have been made globally.

Assuming the cover must be maintained for 150 years (2010-2160), the total cost/sq. mi. accrued for the first square mile installed in 2010 (year 1) by 2160 would be as follows (see Appendix B for details):

Plastic 2,100,000

Installation 525,000

Monitoring 678,125

Maintenance 1,672,500

Total 4,975,625

The same cost breakdown for plastic installed in year 30 would total $4,171,500, while the cost for plastic installed in year 60 would only be $2,985,375. The lower cost in the later years is due to fewer replacements of plastic and equipment and less years of maintenance. The average cost per square mile over the life of the project based on averaging the costs for year 1 and 60 is $3,980,500. The overall cost calculated this way is $15.9 trillion or $106 billion per year. This level of spending would not show up until after several cycles of replacement have occurred and much of the plastic is in place. For example, the cost in year 1 would be $14.3 billion and in year 12, $37 billion.

These cost estimates do not take into account inflation and are only presented as rough estimates of what the project might cost. They also do not take into consideration much lower costs that might result if ways can be found to maintain the plastic cover for longer than 10 years before replacement, nor do they consider lower costs that might result if the plastic

can be recycled. The possible impact on much higher prices for crude oil (the raw material for the plastic) relative to inflation decades from now has also not been considered.