Carbon dioxide and global warming: the greenhouse effect
4 marks · NormalThe table shows estimated global carbon dioxide (CO2) levels and average surface temperatures at two different years:
| Year | CO2 concentration / ppm | Average temperature / °C |
|---|---|---|
| 1850 | 285 | 13.6 |
| 2020 | 415 | 14.9 |
Describe the trend shown by the data.
Suggest a possible link between the CO2 levels and average surface temperature.
Explain one environmental consequence of this link.
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(a) Both CO2 concentration and average temperature increased from 1850 to 2020.
(b) As CO2 levels increased, the average surface temperature also increased; higher CO2 may contribute to warming.
(c) A possible consequence is melting of polar ice caps, leading to rising sea levels.
Common mistakes: Stating only one variable changed; Giving effect without environmental consequence
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Marking points
B1 (a) · 1 mark · Trend described: both CO2 and temperature increase.
M1 (b) · 1 mark · Possible link identified: higher CO2 may cause higher temperature/global warming.
M2 (c) · 1 mark · States one consequence (e.g., melting ice caps, rising sea levels, extreme weather).
A1 (c) · 1 mark · Links consequence to increased CO2/global warming.
Worked solution
a) The data shows both CO2 concentration and average surface temperature have increased from 1850 to 2020.
b) Higher CO2 levels may have caused an increase in temperature, suggesting a link between CO2 and global warming.
c) An environmental consequence of this is melting of the polar ice caps, leading to rising sea levels.