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United States Department of Agriculture

Agricultural Research Service

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Climate Change to Plants: “Ready, Set….GROW!”

When a camp fire burns, oxygen feeds the flames until there is no wood left. While it is burning, a campfire also gives off--emits--other substances into the Earth’s atmosphere, like carbon dioxide, methane, carbon monoxide and soot particles.

Animals, including humans, also need oxygen to produce energy for moving muscles, digesting food, growing bones…and everything else they do! So, like a camp fire, they breathe in oxygen and breathe out carbon dioxide, which is just a leftover waste product after all the oxygen has been used up.

But most plants are ready to take in that carbon dioxide. They use sunlight and carbon dioxide to make sugar, which they use to grow and reproduce. They also give off oxygen, which is the waste product from their energy production.

The Earth’s atmosphere has a very small amount of carbon dioxide, a gas that is becoming famous--but not in a good way. Scientists say carbon dioxide is a “greenhouse gas” that helps hold heat in the atmosphere, and its levels are rising.

There are all kinds of reasons for this. Cars, like camp fires, burn fuel and emit carbon dioxide and other gases. Forest fires emit the same gases that campfires emit, only a lot more of them. Burning coal or other fuel to make electricity emits tons and tons of carbon dioxide into the atmosphere.

Many plants can use that new carbon dioxide to “bulk up.” Scientists have found that this can be a good thing and a bad thing.

For instance, soybeans grow more when there is more carbon dioxide around for them to take in. So do some kinds of rice.

But so does poison ivy, a plant that produces a nasty oil. People who get some of that oil on their skin can develop an itchy rash that lasts for days and days. When more carbon dioxide is available for poison ivy to breathe in, the plant grows even more. And to make matters worse, the oil that causes the rash also becomes more potent. That means that it takes a smaller amount of the oil to cause the same amount of itching!

Another “problem plant” is ragweed, which increases its growth and pollen production when more carbon dioxide is available. Ragweed pollen can make you sneeze and sniffle for days. And the pollen may also become stronger, so you could end up sneezing and sniffling even more.
The relationship between plant growth and rising carbon dioxide levels is just one aspect of global climate change that Agricultural Research Service (ARS) scientists are studying. They want to help farmers find ways to produce crops and livestock as the temperature of the Earth’s atmosphere rises and as ecosystems change.

And when they’re out in the field, scientists repeat the rhyme they use to identify poison ivy: “Leaves of three, let it be!” They know tangling with even a wimpy poison ivy plant can leave them itching and scratching for days!

By Ann Perry, Agricultural Research Service, Information Staff

Oxygen: A colorless, odorless, and tasteless gas that makes up about 21 percent of the planet's atmosphere. Return to Top.

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Last Modified: 8/12/2016
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