Topic 4.4: Climate Change
Key facts
1. Common examples of nutrient recycling include the carbon cycle, the water cycle, the
nitrogen cycle and the carbon cycle.
2. The carbon cycle is a major factor in the greenhouse effect.
3. The carbon cycle represents the interaction of living organisms and the biosphere through
the processes of photosynthesis, cell respiration, fossilization and combustion.
4. Photosynthesis allows the fixation of carbon dioxide from the atmosphere. Combustion
results in the release of and accumulation of more carbon dioxide in the atmosphere.
Respiration results in the release of carbon dioxide and accumulation in the atmosphere.
5. Decomposers, saprotrophs and detritivores, result in release of carbon dioxide into the
atmosphere, and therefore, the recycling of carbon.
6. Data presently being collected in our atmosphere is showing an increase in atmospheric
carbon dioxide levels. This increase is thought to be adding to the greenhouse effect we
are presently witnessing on our planet.
7. Antarctic ice shows a steady atmospheric level of carbon dioxide for two thousand years
until 1880. From 1880 onwards the level of carbon dioxide has been steadily increasing.
This finding is confirmed by readings from Mauna Loa, Hawaii. Both areas confirm an
increase of carbon dioxide in the atmosphere of nearly 100 ppm.
8. Besides carbon dioxide there are other atmospheric gases contributed to the greenhouse
effect. These gases include methane, oxides of nitrogen, and sulfur dioxide.
9. Greenhouse gases in the atmosphere trap some of the long-wave radiation of the sun,
causing the Earth to be warmer than if the radiation escaped. This long-wave radiation
comes from the short wavelengths of the sun’s rays that can pass easily through the
atmosphere. The trapping of the long-wave radiation is thought to be a major cause of
the global warming we are recording at present.
10. The effects of global warming on the Arctic ecosystems include increased rates of
decomposition of detritus previously trapped in permafrost, expansion of the range of
habitats available to temperate species, loss of ice habitat, changes in distribution of prey
species affecting trophic levels, and increased success of pest species, including
pathogens.
11. These changes in the Arctic ecosystems would affect the whole world because of rising
oceans, increased carbon dioxide release into the atmosphere, altered food chains and
webs in the Arctic and associated areas, increased world pathogens, and extreme weather
events.
12. Carbon dioxide and water vapor are the most significant greenhouse gases.
13. Other gases including methane and nitrogen oxides have less impact.
14. The impact of a gas depends on its ability to absorb long-wave radiation as well as on its
concentration in the atmosphere.
15. The warmed Earth emits longer-wave radiation (heat).
16. Longer-wave radiation is reabsorbed by by greenhouse gases which retains the heat in the
atmosphere.
17. Global temperatures and climate patterns are influenced by concentrations of green house
gases.
18. There is a correlation between rising atmospheric concentrations of carbon dioxide since
the start of the industrial revolution two hundred years ago and average global
temperatures.
19. Recent increases in atmospheric carbon dioxide are largely due to increases in the
combustion of fossilized organic matter.
Be able to complete the following.
20. . List three sources of carbon dioxide in our atmosphere.
21. . What major biological process allows a decrease in atmospheric carbon dioxide
levels?_____________________
22. Present some reasons for the increase in carbon dioxide levels in the Earth’s atmosphere
since the 1800s.
23. Besides carbon dioxide, what are some other gases that may be contributing to the
greenhouse effect?
24. Explain why carbon dioxide levels seem to increase in areas during the winter but
decrease in those same areas during the summer.
25. What wavelengths of light pass through the Earth’s atmosphere relatively
easily?___________________ Which wavelengths of light do not so easily pass through
the atmosphere?____________________
26. How does the Earth’s atmosphere compare to a greenhouse?
27. Why is the Earth’s atmosphere warmer than outer space
28. What impact is global warming having on ocean ecosystems?
29. How might this impact affect ecosystems throughout the world?
30. Describe threats to coral reefs from increasing concentrations of dissolved carbon
dioxide.
31. Evaluate claims that human activities are not causing climate change.