The atmospheric concentration of carbon dioxide (CO2\text{CO}_2CO2) has been rising steadily due to anthropogenic emissions. Many climatologists and ecologists point to this rise as a principal driver of increasing global air temperatures.
The table below records measurements of atmospheric CO2\text{CO}_2CO2 concentration (in parts per million, ppm) and the global average temperature anomaly (in ∘C^\circ\text{C}∘C, relative to the 1951–1980 baseline) recorded at ten-year intervals from 1970 to 2020.
| Year | Average CO2\text{CO}_2CO2 concentration (ppm) | Global average temperature change (∘C^\circ\text{C}∘C) |
|---|---|---|
| 1970 | 325 | +0.03+0.03+0.03 |
| 1980 | 338 | +0.18+0.18+0.18 |
| 1990 | 354 | +0.33+0.33+0.33 |
| 2000 | 369 | +0.40+0.40+0.40 |
| 2010 | 389 | +0.72+0.72+0.72 |
| 2020 | 414 | +1.02+1.02+1.02 |
Using the data in the table: (i) Describe the overall trend in atmospheric CO2\text{CO}_2CO2 concentration from 1970 to 2020.
Describe the overall trend in global average temperature change from 1970 to 2020.
Explain how an increase in the concentration of carbon dioxide in the atmosphere causes an increase in global air temperature.
Some critics argue that because global temperatures fluctuate from year to year, carbon dioxide is not causing global warming. Evaluate this objection by using the table's data and explaining why a long-term trend is more scientifically valid than single-year fluctuations.
State one biological process that decreases carbon dioxide concentration in the atmosphere.
Give two potential negative consequences of an increase in global air temperature on ecosystems or living organisms.
49 exam-style questions on AQA GCSE Biology 7.3 Biodiversity and the effect of human interaction on ecosystems, covering 7.3.1 Biodiversity, 7.3.2 Waste management, 7.3.3 Land use, 7.3.4 Deforestation, 7.3.5 Global warming, and 7.3.6 Maintaining biodiversity. Each one has a worked solution and a mark scheme showing where the marks go.