In this section, we analyzed the case where the distance of a city from the sea is fixed, and the elevation is varied to determine the specific height to which LCCO2 emissions can be reduced. For example, the average elevation in the Sahara Desert, the largest desert in Africa, is about 300 m. Still, the maximum height of the present study is set to 2000 m to analyze alpine cities. Since all cities with a population of 1 million or more are below 2000 m except for the top 10 cities in the world, , the elevation up to 2000 m is sufficient to evaluate cities in high altitude areas.