how does greenhouse regulate light water and CO2?
The covers that are used in greenhouse are either of glass or plastic which are transparent. So light can easily enter inside. Water is supplied to the plants inside. Ventilation is the most important factor for a greenhouse. Ventilator allows limited amount of fresh air to enter which contains atmospheric carbon dioxide for photosynthesis.
Over 97% of all greenhouse gases are natural and there is nothing we can do about them. For example, India's population of one billion people produces more carbon dioxide just by breathing than is produced by all the coal-burning power plants in the United States. Moreover, termites are said to produce more carbon dioxide each year than all other living organisms combined.
Environmentalists would have you believe that the greenhouse effect originated in the 20th century. The greenhouse effect is essential to the survival of life on Earth. If there were no greenhouse gases, the temperature of the air would be about 32°F (18°C) colder than it is. In other words, the world would be frozen most of the time.*
The two predominant greenhouse gases are water vapor and carbon dioxide. You produce both of these gases when you exhale. Between 94½ and 96½ percent of atmospheric carbon dioxide comes from natural sources.* Between 94 and 98 percent of the warming effect is due to ordinary water vapor, which comes from the oceans and lakes.
Please note that volcanos produce more carbon dioxide than all the activities of man. So even if all industrial activity is outlawed (in order to "save the earth"), the volcanos will still keep pumping CO2 into the atmosphere, and the air will remain just as it is.
It is also claimed that cows and termites produce more CO2 than people (and cars and trucks) do.
The subject of unstoppable coal fires is something I have just recently (and briefly) explored. The Centralia, Pennsylvania coal mine fire has been burning since 1962,* and there are 38 of these fires in Pennsylvania alone.* There's another such fire in Jharia, India, that has been burning for almost a century,* one in Glenwood Springs, Colorado, that has been burning since 1910,* and there are hundreds of coal fires buring in China.* Australia's Burning Mountain, the oldest known coal fire, has burned for 6,000 years.* And of course every air-breathing animal in the world emits carbon dioxide, a little at a time, so the idea of curtailing carbon dioxide emissions completely — as some have suggested* — is futile.