The concentration of carbon dioxide (CO2\text{CO}_2CO2) in the atmosphere has risen continuously over the past several decades, heavily influencing global marine and terrestrial systems. The table below displays measurements of atmospheric CO2\text{CO}_2CO2 concentration (in parts per million, ppm) at a high-altitude research station alongside the mean Sea Surface Temperature (SST) anomaly (in ∘C^\circ\text{C}∘C, relative to a 20th-century baseline) recorded every eight years from 1980 to 2020.
| Year | Average atmospheric CO2\text{CO}_2CO2 concentration (ppm) | Mean Sea Surface Temperature (SST) anomaly (∘C^\circ\text{C}∘C) |
|---|---|---|
| 1980 | 339 | +0.12 |
| 1988 | 352 | +0.21 |
| 1996 | 363 | +0.18 |
| 2004 | 378 | +0.36 |
| 2012 | 394 | +0.45 |
| 2020 | 414 | +0.69 |
Using the data in the table:
(i) Describe the overall trend in atmospheric CO2\text{CO}_2CO2 concentration from 1980 to 2020.
(ii) Describe the overall trend in the mean Sea Surface Temperature (SST) anomaly from 1980 to 2020.
Explain how an increase in the concentration of carbon dioxide in the atmosphere causes an increase in sea surface temperatures.
Some critics argue that because ocean temperatures fluctuate (such as the decrease in the SST anomaly observed in 1996), greenhouse gases like carbon dioxide are not driving ocean warming. Evaluate this objection by using the table's data and explaining why a long-term trend is more scientifically valid than short-term fluctuations.
(i) State one biological process that acts as a carbon sink in marine ecosystems.
(ii) Give two potential negative consequences of rising sea surface temperatures on marine ecosystems or living organisms.