Since 1958 scientist Charles Keeling and others have measured the amount of carbon dioxide in the atmosphere in Hawaii. The yearly fluctuations in carbon dioxide are due to seasonal plant growth, while the overall rise in carbon dioxide over many years is due to a combination of fossil fuel burning, deforestation, and cement production.
Click on image for full size
Windows to the Universe based on data from NOAA and UCSD
The Carbon Cycle Changes
Carbon moves naturally to and from various parts of the Earth. This
is called the carbon
cycle. Today, however, scientists have found that
more carbon is moving into the atmosphere from other parts of the Earth. It
moves into the atmosphere when fossil fuels, like coal and oil, are burned.
It moves into the atmosphere when forests burn.
The carbon in the atmosphere is in molecules of carbon
dioxide (CO2). Carbon
dioxide is a greenhouse gas. Greenhouse gases trap heat in the atmosphere. By
increasing the amount of carbon dioxide in the atmosphere, Earth
is becoming warmer.
Even if people stopped adding carbon dioxide to the atmosphere now, Earth
would continue to warm for a long time. Carbon dioxide does not
leave the atmosphere quickly; it can spend many centuries up there. Over time,
carbon can move slowly out of the atmosphere and into plants. The plants take
the carbon dioxide out of the atmosphere as they make their food from the Sun’s
energy by photosynthesis. Carbon can also move into ocean
water or be
stored in rocks. We are currently adding carbon to the atmosphere faster than
all the plants on Earth can take it out. Scientists are studying ways to move
some of the carbon out of the atmosphere.
This isn’t the first time that there have been high amounts of carbon dioxide
in the Earth’s atmosphere. The carbon cycle has changed throughout
the billions of years of Earth’s history. However, prehistoric changes
happened for different reasons. During the Paleozoic
, tons of volcanic
spewed lava, ash, and gases like carbon dioxide into the atmosphere. The lava
fell to the ground right away. Most of the ash fell to the ground within
a few days to weeks. But the carbon dioxide stayed in the atmosphere for hundreds
of years! Today, the amount of volcanic eruptions is very low compared
with other times in the past, yet the amount of carbon dioxide in the atmosphere
is high because of burning forests and fossil fuels.
Last modified October 26, 2007 by Lisa Gardiner.
Shop Windows to the Universe Science Store!Cool It!
is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store
You might also be interested in:
Carbon dioxide (CO2) is a kind of gas. There isn't that much carbon dioxide in Earth's atmosphere, but it is still very important. Carbon dioxide is a greenhouse gas. That means it helps trap heat coming...more
Over 100 years ago, people worldwide began burning more coal and oil for homes, factories, and transportation. Burning these fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere....more
Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water, carbon dioxide, and solar energy into sugars and oxygen. It is a complex chemical process by which plants and...more
Leaders from 192 countries are meeting in Copenhagen, Denmark December 7-18, 2009 to decide how the world will deal with climate change. They are trying to decide how to limit the amount of greenhouse...more
The climate where you live is called regional climate. It is the average weather in a place over more than thirty years. To describe the regional climate of a place, people often tell what the temperatures...more
Even though only a tiny amount of the gases in Earth’s atmosphere are greenhouse gases, they have a huge effect on climate. There are several different types of greenhouse gases. The major ones are carbon...more
Satellites that orbit Earth help us study Earth's atmosphere, weather, and climate. Here are a few of the many spacecraft that study our atmosphere. Aura was launched in July 2004. It is studying pollution,...more