why do we need carbon dioxide in the atmosphere

We hear a lot about carbon dioxide when we talk about, but sometimes it's important to go back and examine why too much CO2 in the atmosphere is a bad thing. CO2 в a naturally occurring gas that is also emitted at great levels by human activity в is one of several in our atmosphere. Other greenhouse gases include water vapor, methane, ozone, nitrous oxide and halocarbons. To understand the impact of these gases, we first start with the sun, which sends solar radiation in the form of light to Earth. The atmosphere deflects some of this radiation, while the rest hits the planetary surface and warms the land and oceans. The Earth then radiates its own heat back up in the form of infrared rays.

Some of those rays escape the atmosphere, while others are absorbed and then re-emitted by the atmospheric gases. These gases в the greenhouses gases в then help to keep the planet at its normal temperature. For millions of years, the production of greenhouses gases was regulated by the natural systems of the planet. Gases would be absorbed and emitted at a fairly steady rate. Temperatures, meanwhile, were maintained at a level that supported life around the world. The Environmental Protection Agency characterizes this as
Humans changed the balancing act beginning in the second half of the 1700s, at the start of the Industrial Revolution.

Since that time we have been adding greenhouse gases, primarily CO2, to the atmosphere at a steadily increasing rate, trapping that heat and warming the planet. Although there are several greenhouse gases в some are more potent than others в CO2 currently represents about, totaling about 30 billion tons a year. Most of this comes from burning fossil fuels for and transportation, although industrial processes and forestry also contribute heavily. Before the Industrial Revolution, CO2 levels were about 270 parts per million (ppm). CO2 levels were at about 313 ppm in 1960. They reached earlier this year. Many climate scientists say levels need to be to avoid the effects of climate change. isn't only affecting the atmosphere.

It has also made the oceans about 30 percent more, affecting a wide variety of sea organisms. That percentage is also expected to rise in the coming years. Obviously all of this carbon we have added to the atmosphere will not go away overnight. Its effects will be destructive and long-felt. But by understanding the impact of CO2, hopefully we can make steps toward reducing our emissions and, if we're really lucky, avoid the worse effects of climate change yet to come. Related on MNN: The Earths early atmosphere is believed to have been mainly carbon dioxide with little or no oxygen gas.

The Earths atmosphere today contains around 21 percent oxygen and about 0. 04 percent carbon dioxide. So how did the proportion of carbon dioxide in the atmosphere go down, and the proportion of oxygen go up? photosynthesis The chemical change that occurs in the leaves of green plants. It uses light energy to convert carbon dioxide and water into glucose. Oxygen is produced as a by-product of photosynthesis. This process uses carbon dioxide from the atmosphere (with water and sunlight) to produce oxygen (and glucose). The appearance of plants and algae caused the production of oxygen, which is why the proportion of oxygen went up. Photosynthesis by plants and algae used carbon dioxide from the atmosphere, but this is not the only reason why the proportion of carbon dioxide went down.

These processes also absorb carbon dioxide from the atmosphere: Today, the burning of fossil fuels (coal and oil) is adding carbon dioxide to the atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing, contributing to global warming. It also means that the oceans are becoming more acidic as they dissolve increasing amounts of carbon dioxide. This has an impact on the marine environment, for example making the shells of sea creatures thinner than normal. Now try a.