Key knowledge gaps amidst dramatic changes in the polar regions
30 October 2023
Key knowledge gaps amidst dramatic changes in the polar regions
30 October 2023
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30 October 2023
There are dramatic ongoing changes in the polar regions. Polar oceans are warming, and sea ice is becoming thinner and more ephemeral than before. But to observe these changes over time and through seasons is not easy in remote areas covered by sea ice.
A newly published article in the journal Elementa: Science of the Anthropocene highlights that the polar seas remain understudied despite major and expensive international efforts. Key knowledge gaps prevent meaningful prediction of climate-driven changes in sea-ice environments, according to the writers among which are several CRiceS-researchers. There is a “need not only for improved observational coverage across seasons and heterogenous sea-ice environments but also for better connection of observations with models across scales”.
The writers conclude that “only with a broader understanding of the system across seasons and icescapes will we be able to predict the impacts of warming and changes in the icescape on sea-ice biogeochemistry, air–sea fluxes of greenhouse gases, particles and aerosol precursors, and resulting implications for the atmosphere”.
Willis, MD, Lannuzel, D, Else, B, Angot, H, Campbell, K, Crabeck, O, Delille, B, Hayashida, H, Lizotte, M, Loose, B, Meiners, KM, Miller, L, Moreau, S, Nomura, D, Prytherch, J, Schmale, J, Steiner, N, Tedesco, L, Thomas, J. 2023. Polar oceans and sea ice in a changing climate. Elementa: Science of the Anthropocene 11(1). DOI: https://doi.org/10.1525/elementa.2023.00056
Schematic representation of coupled processes in the ocean–sea ice–atmosphere system. Similar to other regions of the global ocean, spring blooms in polar regions are initiated when the water column stabilizes and enough light becomes available to drive increases in photosynthesis (Section 2.1 and 2.2). The end of the algal bloom is marked by nutrient exhaustion, consumption by marine grazers, and in the case of ice algae, melting of their sea-ice habitat. Light availability within and under the ice is controlled by snow and sea-ice thicknesses (Section 2.1). Nutrient concentrations are controlled in the upper ocean by the degree of stratification, and in sea ice by brine transport and exchange with the underlying seawater (Section 2.1). The polar seas and sea ice are overall a sink for CO2. Primary production in sea ice (ice algae) and seawater (phytoplankton) followed by particle export to depth contributes to this CO2 sink. Air–sea exchange in the presence of sea ice occurs through direct exchange between ocean and atmosphere (i.e., in leads, polynyas, marginal ice zones; Section 3.2), transport within sea ice, and exchange across the atmosphere–ice interface (Section 3.1). Sea ice, frost flowers, and saline snow are potential sources of reactive halogen species (Section 4.1), which can control mercury (Hg) depletion and atmospheric oxidizing capacity (i.e., the sum of HOx radicals, hydrogen peroxide (H2O2), ozone (O3), and XO radicals where X is Cl, Br or I). Polar oceans and sea ice regulate the uptake and emission of both aerosol, such as sea spray particles (Section 4.2) and associated biological material, and climate-active gases (Section 4.2–4.3), such as dimethyl sulfide (DMS) and reactive organic carbon (ROC) gases. These interactions can lead to emission and formation of aerosols that act as cloud nuclei (i.e., both cloud condensation nuclei [CCN] and ice nucleating particles [INP]).
Source: https://online.ucpress.edu/elementa/article/11/1/00056/197494/Polar-oceans-and-sea-ice-in-a-changing-climate
Source: https://online.ucpress.edu/elementa/article/11/1/00056/197494/Polar-oceans-and-sea-ice-in-a-changing-climate
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