Global Climate Change

Introduction:

Carbon dioxide (CO₂) is a greenhouse gas that has a significant impact on climate. Human activities, such as the combustion of fossil fuels and deforestation, have inadvertently put more CO₂ into the atmosphere than was present before these activities became widespread. Because matter cannot be destroyed, it must be cycled out of the atmosphere and it was long thought that the oceans and vegetation would have the capacity to do so. Regular measurements of atmospheric CO₂ levels have been taken at Mauna Loa, Hawaii since the end of the 1950’s, providing a substantial amount of historical data with which we can track the concentration of CO₂ in the atmosphere over time.

CO₂ Concentrations

CO₂(ppm)

Data from the NOAA Earth System Research Laboratory (ESRL)

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Question

Carbon dioxide concentrations in the atmosphere are measured in parts per million (ppm). To see how these concentrations have been rising or falling in recent times, create a graph showing the monthly average of carbon dioxide concentration in parts per million (ppm) between January of 2012 and January of 2014. Using the drop down menus, you can select the time frame for the data set you would like to display.

1. During what month of 2013 does the CO₂ concentration reach its highest point for 2013?

April

May

June

September

Correct.

Incorrect.

Question

2. The highest concentration for the year is reached in May and then declines for several months. Yet we have learned that there is strong evidence for increasing atmospheric carbon dioxide concentrations. Does this data contradict the trend?

Yes. The concentration seems to rise and fall on this graph and there is no indication that it is steadily increasing.

Yes. This is an indication that the concentration of carbon dioxide is actually decreasing.

No. Although it appears that there may be an decreasing trend in this limited view, we need more long term data to establish this with certainty.

No. It indicates that although carbon dioxide concentration has been increasing historically, it has stabilized in recent years.

Correct.

Incorrect.

Question

3. Between January and December of 2013, what is the percent change in carbon dioxide concentration between the highest and lowest points? (Hint: To calculate percent change, find the difference (increase or decrease) between the two numbers you are comparing. Next, divide the difference by the original number and multiply the answer by 100. The equation looks like this: ((y2-y1)/y1)*100).

1.6%

4.3%

-3.3%

-1.6%

Correct.

Incorrect.

Question

4. What does this percent change suggest in terms of overall atmospheric carbon dioxide concentration?

That CO₂ concentration is decreasing by 1.6% annually.

CO₂ concentration fluctuates within the course of a year.

CO₂ concentration oscillates but appear to be relatively stable.

CO₂ concentration is steadily declining.

Correct.

Incorrect.

Question

Now create a graph showing the monthly average of carbon dioxide in parts per million (ppm) between January of 1970 and January of 1972.

5. During what months of 1971 was the carbon dioxide level at its lowest and highest, respectively?

September and May

September and February

June and December

August and November

Correct.

Incorrect.

Question

6. What is the percent change in carbon dioxide level between the highest and lowest points in 1971?

3.5%

-2.6%

-1.7%

-5.0%

Correct.

Incorrect.

Question

7. How does this percent change compare with the percent change calculated in the previous section?

It is greater, so it appears that annual fluctuations are decreasing with time.

They are very similar, which suggests that CO₂ concentrations fluctuate annually at predicable times and by similar amounts.

They are very similar numbers which suggests that CO₂ concentrations are in fact stable.

Both numbers are negative which suggests that CO₂ concentrations in the atmosphere are decreasing.

Correct.

Incorrect.

Question

8. Now create a graph with the entire data set from 1958 to 2015. What is the percent change between the highest carbon dioxide level in 1959 and the highest concentration recorded in 2015? (Hint: It may be helpful to zoom in to the individual years to determine which value is highest. You can do this by manipulating the time frame parameters on the graph controls)

45%

27%

12%

Correct.

Incorrect.

Question

9. Why does the lowest concentration of CO₂ in each year occur at the same time of year?

These measurements are taken at the end of the summer months, suggesting that hot weather burns off carbon dioxide.

The lowest concentrations are measured in the winter months, suggesting that the annual increase in arctic sea ice absorbs carbon dioxide from the atmosphere.

It coincides with the end of the growing season in the Northern Hemisphere, when vegetation has absorbed a maximum amount of carbon dioxide through photosynthesis.

You cannot tell from the graph if this trend is seen annually.

Correct.

Incorrect.

Question

10. In 1997, nations began ratifying the Kyoto Protocol with the objective of reducing greenhouse gas emissions below 1990 levels. Compare the highest concentration measured in 1990 with that measured in 2015. What can we conclude from this data?

The Kyoto Protocol fell short of its objective.

Future international agreements will need stronger provisions or more adherence to be successful.

The objectives of the Kyoto Protocol were met, showing the effectiveness of early action to combat climate change.

Both the first and second responses are correct.

Correct.

Incorrect.

true

Chapter 14. Global Climate Change