![]() ![]() It takes a lot of energy to warm all the oceans, the atmosphere and the land by almost 2 degrees. Since 1880, the global annual temperature has increased 1.9 degrees, with the majority of the warming occurring since 1975.Ī 1.9 degree increase isn't that much, is it? That means the blanket around the Earth has gotten thicker and it's having an effect. The difference between 280 parts per million and 418 might not seem like a lot, but it means humans have generated an estimated 1.5 trillion tons of carbon dioxide pollution in the last 150 years. How can such a tiny amount of CO 2 cause so much trouble? According to NASA, half of the increase in atmospheric carbon dioxide concentrations in the last 300 years has occurred since 1980, and one-quarter of it since 2000. Today, it's risen to 418 parts per million, the highest it's been in 3.6 million years.Īs people began burning more fossil fuels, the amounts have increased. In 1750 the amount of CO 2 in the atmosphere was estimated to be about 280 ppm. Here's how much the balance has changed: For the last 400,000 years, the amount of CO 2 in the atmosphere fluctuated between 200 and 280 parts per million, according to NASA. This added new carbon dioxide to the atmosphere from fossil fuels that had been buried deep underground for millions of years. That's when the Industrial Revolution began in England and factories started burning coal to power machines. Humans began to change the balance of greenhouse gases in the atmosphere around 1750. Natural CO 2 comes from outgassing from the ocean, decomposing plants, wildfires and volcanoes. It's a cycle, humans and other animals exhale CO 2 but it's the same carbon that was "inhaled" by the plants we eat, so it doesn't contribute to global warming.Ĭarbon dioxide in the atmosphere comes from two primary sources, natural and human activities. But that's balanced by the plants we eat, so humans and animals aren't affecting the balance of atmospheric CO 2. Note that CO 2 is the greenhouse gas that's most discussed because, although it's less powerful than some such as methane (natural gas), it stays in the atmosphere for hundreds and even thousands of years.Ĭarbon dioxide is what people and animals breathe out after breathing in oxygen. Too much and the temperature starts to rise. Too little CO 2 and the Earth wouldn't stay at a temperature suitable for life. So the more CO 2 molecules in the atmosphere, the more heat they can trap. The more complex geometry of CO 2 molecules means they can absorb a much wider range of light waves, including the infrared waves that carry heat. That geometry means they only interact with a narrow wavelength of light. ![]() They are each composed of two, not three, linked atoms, two nitrogens or two oxygens. How does carbon dioxide work as a greenhouse gas?ĬO 2 is great at holding in heat partly because it's a bigger molecule than the nitrogen (78%) and oxygen (21%) that make up most of Earth's atmosphere. In chemical texts it's written this way: CO 2 where the subscript numeral two means there are two oxygen atoms. That simply means it's a molecule that contains one carbon and two oxygen atoms. You'll often see carbon dioxide written with its chemical formula name, CO 2. In terms of US greenhouse gases emissions, here's a list by amounts from the Environmental Protection Agency: Greenhouse gases are among those "other things."Ĭarbon dioxide is a greenhouse gas, one of the four main ones. That natural process, however, has begun to change due to humans burning fossil fuels.Įarth's atmosphere is made up of 78% nitrogen and 21% oxygen, with just 1% other things. "It's really lucky for us that we have air." Without it, the Earth would just be a white frozen ball hanging in space-uninhabitable. ![]() The greenhouse effect is a natural process, said Denning. That "blanket" is made up of several gases nicknamed " greenhouse gases" because they hold in heat, just like the glass panes of a greenhouse hold in the sun's heat. For that we need the Earth's atmosphere, which acts like a blanket holding in some of the heat, said Scott Denning, a professor of atmospheric science at Colorado State University. The energy that comes in from the sun alone is not enough to keep the Earth warm. Why does carbon dioxide cause global warming?Įarth is heated by the sun-About 71% of the solar energy that arrives is absorbed by the atmosphere and surface and 29% is reflected back into space, according to NASA. So how is something so necessary to life also so harmful? Here's what to know: That gas is critical to life on earth because plants use sunlight and carbon dioxide to create energy through the process of photosynthesis.īut carbon dioxide is also the primary reason the climate is warming, a long-term shift in temperature that threatens the delicately balanced ecosystems humans depend upon.
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