Sea ice and carbon dioxide

• Main Authors: Hambler, C, Henderson, PA
• Format: Report
• Language: English
• Published: 2020
• Subjects: Antarctic; Arctic; Palmer Station; Palmer-Station; South Pole; Antarc*; Barrow; Point Barrow; Sea ice; South pole; Alaska
• Online Access: https://ora.ox.ac.uk/objects/uuid:640a0c7e-6b55-4aff-a9cc-f47f6b490254

1) The annual cycles of atmospheric CO₂ at Mauna Loa and Point Barrow (Alaska) are statistically almost completely explained by changes in Arctic sea ice volume and extent. 2) The annual cycles of atmospheric CO₂ at the South Pole and at Palmer Station are statistically largely explained by changes in Antarctic sea ice extent. 3) Results are consistent with a monthly CO₂ flux dependent on the distance from equilibrium of a temperature dependent process. Degassing and calcium carbonate crystal formation during the sea ice freeze likely contribute to the peak net monthly emission rate of CO₂. High solubility of gas in cold sea ice meltwater and dissolution of calcium carbonate likely contribute to the peak net monthly sink rate of CO₂. 4) The global annual mean Lower Tropospheric temperature anomaly has high predictive value for annual CO₂ changes, consistent with marine outgassing (and possibly vertical transport mediated by sea ice). 5) The global carbon cycle is poorly understood, with abiotic factors likely dominating biotic fluxes - and little scope for substantive human involvement in the annual cycle. 6) A new investigative paradigm is required in which atmospheric CO₂ level is a response variable of temperature or an unknown covariate. 7) Climate predictions and attributions must be revisited. 8) The policy implications are as significant as the relationship between sea ice and CO₂ rates.