as CO2 levels go up , global temps go up too . this has happened many times in earths history . earths hottest period was the 100 million year carboniferous epoch , when even the arctic was tropical and oil and coal were formed , atmospheric CO2 levels were as high as 362 ppm .
on 12 21 12 atmospheric CO2 hit 400 ppm *. many climate models predict that at that level ( and still going up fast ) that the earth will go into a runaway , irreversible , permanent greenhouse effect . to give you an idea of how earth will look and a rough timetable of when this will happen , watch the move " soylent green " ( 1975 ) charlton heston , edward g robinson ( youtube ) . the movie is set in the year 2023 , it was fiction in 1975 , but it is becoming all to true .
Carbon in the atmosphere is virtually all in the form of CO2.
CO2 is, like H2O, a greenhouse gas.
What that means is that it tends to reduce the amount of heat / energy, that the earth radiates into space.
Here's how that happens:
http://www.rkm.com.au/ANIMATIONS/carbon-...
If there's more CO2, then more infrared radiation is prevented from escaping back into space.
SO, the earth gets the same amount of energy from the sun,
But, less of that energy gets radiated back to space.
Just like a pot of water on your stove, you add energy to it and it warms.
When you turn the gas off, then the pot of water loses energy and cools.
It's the balance between energy added, and energy lost, that determines the temperature.
That's why you turn the heat down on something you want to keep warm, but not overheat.
The earth is the same way. It gets energy from the sun and radiates energy away. That balance has been changed by additional CO2 in the atmosphere, and the earth is now warming.
Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. In 2011, CO2 accounted for about 84% of all U.S. greenhouse gas emissions from human activities. Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle (the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals). Human activities are altering the carbon cycle―both by adding more CO2 to the atmosphere and by influencing the ability of natural sinks, like forests, to remove CO2 from the atmosphere. While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution. [1]
U.S. Carbon Dioxide Emissions, By Source
Pie chart that shows emissions by use. 38 percent is electricity, 31 percent is transportation, 14 percent is industry, 10 percent is residential and commercial, and 6 percent is other (non-fossil fuel combustion).
Note: All emission estimates from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011.
The main human activity that emits CO2 is the combustion of fossil fuels (coal, natural gas, and oil) for energy and transportation, although certain industrial processes and land-use changes also emit CO2. The main sources of CO2 emissions in the United States are described below.
Electricity. Electricity is a significant source of energy in the United States and is used to power homes, business, and industry. The combustion of fossil fuels to generate electricity is the largest single source of CO2 emissions in the nation, accounting for about 38% of total U.S. CO2 emissions and 32% of total U.S. greenhouse gas emissions in 2011. The type of fossil fuel used to generate electricity will emit different amounts of CO2. To produce a given amount of electricity, burning coal will produce more CO2 than oil or natural gas.
Transportation. The combustion of fossil fuels such as gasoline and diesel to transport people and goods is the second largest source of CO2 emissions, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. greenhouse gas emissions in 2011. This category includes transportation sources such as highway vehicles, air travel, marine transportation, and rail.
Industry. Many industrial processes emit CO2 through fossil fuel combustion. Several processes also produce CO2 emissions through chemical reactions that do not involve combustion, for example, the production and consumption of mineral products such as cement, the production of metals such as iron and steel, and the production of chemicals. Fossil fuel combustion from various industrial processes accounted for about 14% of total U.S. CO2 emissions and 12% of total U.S. greenhouse gas emissions in 2011. Note that many industrial processes also use electricity and therefore indirectly cause the emissions from the electricity production.
Carbon dioxide is constantly being exchanged among the atmosphere, ocean, and land surface as it is both produced and absorbed by many microorganisms, plants, and animals. However, emissions and removal of CO2 by these natural processes tend to balance. Since the Industrial Revolution began around 1750, human activities have contributed substantially to climate change by adding CO2 and other heat-trapping gases to the atmosphere.
In the United States, since 1990, the management of forests and non-agricultural land has acted as a net sink of CO2, which means that more CO2 is removed from the atmosphere, and stored in plants and trees, than is emitted. This sink offset about 14% of total emissions in 2011 and is discussed in more detail in the Land Use, Land-Use Change, and Forestry section.
To find out more about the role of CO2 warming the atmosphere and its sources, visit the Causes of Climate Change page and the Greenhouse Gas Indicators page in the Science section.
look up the greenhouse effect. it lets in but not out. causes all mannr or problems. that is why venus is inhospitable
This video helps to explain the process quite well, in layman terms.
