The concentration of carbon dioxide in Earth’s atmosphere is currently at nearly 412 parts per million and rising. This represents a 47 percent increase since the beginning of the Industrial Age, when the concentration was near 280 ppm, and an 11 percent increase since 2000, when it was near 370 ppm.* We know from the carbon cycle that carbon compounds are continuously recycled through the Earth’s systems. Photosynthesis uses carbon dioxide from the atmosphere to produce glucose, while cellular respiration* in living organisms produces carbon dioxide as a byproduct that is released back into the atmosphere. Effects of agricultural activities impact the carbon dioxide balance as well. During summer in the U.S. farming communities are seeing an intense absorption of carbon dioxide associated with agricultural activities. The same thing is being observed in Eastern and Southern Asia. When photosynthesis decreases due to activities such as deforestation* and clear-cutting, this will disrupt the balance of CO2 production and use, causing an increase in the amount of atmospheric carbon dioxide. Not only does deforestation decrease plants which serve as carbon reservoirs, but also increases CO2 emissions from burning. Although more rare, volcanic eruptions* also release carbon dioxide into the atmosphere. It is widely known that human actions, has the greatest impact on atmospheric carbon dioxide levels. Scientists know that increases in atmospheric carbon dioxide are caused primarily by burning fossil fuels.* Carbon produced by burning fossil fuels has a different ratio of heavy-to-light carbon atoms, so it leaves a distinct “fingerprint” that instruments can measure. A relative decline in the amount of heavy carbon-13 isotopes in the atmosphere points to fossil fuel sources.* So, what are the effects of increasing atmospheric carbon dioxide? Carbon dioxide is a greenhouse gas that traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But since the start of the Industrial Revolution about 150 years ago humans have burned so much fuel and released so much carbon dioxide into the air that global climate has risen over one degree Fahrenheit. According to data from ice cores, the atmosphere has not held this much carbon for at least 420,000 years. The recent increase in amounts of greenhouse gases such as carbon dioxide is having a significant impact on the warming of our planet. However, that’s not all. About 30 percent of the carbon dioxide that people have put into the atmosphere has diffused into the ocean through direct chemical exchange. Dissolving carbon dioxide in the ocean creates carbonic acid, which increases the acidity of the water. This is affecting ocean life as is the warming of ocean waters. Human actions are contributing significant amounts of carbon dioxide to the atmosphere which is not only affecting Earth’s climate, but it’s oceans and land as well.*
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Question 1
Excess carbon dioxide is harmful to the oceans because
Responses
A they product carbonic acid form the atmospheric carbonthey product carbonic acid form the atmospheric carbon
B it removes most of the dissolved oxygenit removes most of the dissolved oxygen
C it decreases the rate of evaporationit decreases the rate of evaporation
Question 2
Which of these has the greatest impact on increased levels of atmospheric carbon dioxide?
Responses
A volcanoesvolcanoes
B burning fossil fuelsburning fossil fuels
C agricultureagriculture
Question 3
What is used as a "fingerprint" to distinguish the carbon dioxide produced from fossil fuels?
Responses
A heavy carbon-13heavy carbon-13
B ozoneozone
C carbon monoxide
C heavy carbon-13
Answer all 3 questions
Question 1: Excess carbon dioxide is harmful to the oceans because it creates carbonic acid, which increases the acidity of the water.
Question 2: Burning fossil fuels has the greatest impact on increased levels of atmospheric carbon dioxide.
Question 3: Heavy carbon-13 is used as a "fingerprint" to distinguish the carbon dioxide produced from fossil fuels.