GEO-ENGINEERING

 Deserts occupies an area of approximately 2% on the Earth's surface. Alvia Gaskill who wrote 'Global Albedo Enhancement Project' said that "Making Reflecting plate made​of polyethylene aluminum and desert albedo is raised to 0.36 to 0.8, cooling effect globally will appear as -2.75W/m²." But you can not be used desert for other purposes and desert ecosystem will changes. Changes in the local radiative force may lead to change a wide range of atmospheric circulation. For example, the monsoon of East Africa will bring rain in the Sahara in Africa. In addition, the installation of reflectors per 1m2 per year is estimated to be $ 0.3. If you are installing reflectors on approximately 10% of the crust surface (10 trillion m²), a $ 1 trillion per year will required.

 So far this method does not have been considered as geoengineering because it does not require any special skills, but can be run immediately and a lot of good products regarded as a beneficial way on geoengineering. Meanwhile, to raise various crops reflecting more sunlight into the atmosphere, the earth's average temperature could be reduced. Andy J. Ridgwell, the university of Riverside professor, found that if raise crops appropriate to these hypothesis, it will reduce summer temperature about 1°C in some area and can he big help to protect drought. Plants have different reflection capacity depending on leaves degree of hairs, shine and arrangement. If possible, there is way that transforms the plants' gene to reflect well. This way has the advantage that you do not need to have a lot of money and it does not require international cooperation.

Chemical weathering of rocks absorbs carbon dioxide in the air. The annual amount of carbon being absorbed in the rocks is about 100 million t. Compared the amount of fossil fuels emits, it is not enough. In addition, all the silicates and carbonates react with just one carbon dioxide. But more than two times the weight of the carbon dioxide molecules. In other words, to eliminate 1 t CO2 then these minerals need 2 t. If we have sown silicates in the farming soil to eliminate the emissions of carbon dioxide, we have to dig silicate corresponding to the 7km³ each year. It is huge amount corresponding to the twice amount of coal produced.

Air capture is the device to absorb carbon dioxide in the atmosphere. This device is different with carbon capture and storage (CCS) technology. CCS capture the carbon dioxide emitted from coal-fired power plant and permanently preserves it in underground. In contrast, air-trapping devices such as air capture, wherever, can be used to capture carbon dioxide. Therefore, air capture is regarded as the only way that can absorb carbon dioxide emitted from cars and airplanes. However, it is not easy task that the concentration of only 0.4% of carbon dioxide in the atmosphere immediately absorbed. It is difficult to absorb thermodynamically because of low concentrations and it is expensive to move. In spite of that, David Keith, the university Calgary in Canada, has shown nearly commercialized technique through researches on collection CO₂ from air. The team removed CO₂ from air directly, by using the electricity under 100 kWh. If we use 1 m² CO₂ separation material, this technique can remove 20 t CO₂/year. If it applies to coal-fired steam plant, it can collect 10 times CO₂ emitted from same amount of electricity.

The mean earth albedo is 0.15. If 118W/m² comes into the earth, 30W is gone back. To reduce 4W/m², Albedo has to increase from 0.15 to 0.17. You may think 0.02 doesn't matter. But because most of earth is covered by the ocean and we can't increase albedo of all the surfaces, it's difficult to raise albedo. So if the area possible to increase albedo must enhance until 1.0, it will be effective. In 2009, Dr. Hashem Akbari of Lawrence- Berkeley Laboratory announced that if you increase the reflectivity of roofs and roads, the albedo of the city will rise 0.1. This method is particularly good in the middle of summer so that cooling costs had reduced. However, if they repeated to paint a house in every 10 years , in the United States alone would cost $ 0.3 per 1m² per year. Painting the 1% of surface white will be $ 300 billion per year