A study trip to Greenland
One of our objectives was to study CO2 fluxes between the ocean and atmosphere. CO2 flux refers to the amount of CO2 (measured in moles) moving through unit square meter area per second. We analysed data collected from a measurement station located in a fjord ‘Young Sound’ in the high arctic. (For the experts: the data was measured using Eddy Covariance method.)
The ocean is a significant sink for atmospheric CO2. The uptake rates of atmospheric CO2 in Nordic seas are among the highest in the world’s oceans. Studies indicate the coastal area including fjords of Greenland take up approximately 5% of the CO2 taken up by the world’s coastal area (Sørensen et al. 2015).
The amount of CO2 absorbed by the ocean depends on the water temperature, pressure, salinity (solubility pump) and biological processes (biological pump). Colder, saltier water absorbs more CO2.
The ocean also releases CO2 through different pathways. Gases may cross the air-sea interface through three routes: by the interfacial exchange that is controlled by molecular processes, by spray-mediated exchange controlled by microphysical processes at the surface of sea spray droplets and by the bubble-mediated exchange. These are found to increase with an increase in wind speed due to greater mixing at the surface.
Relevance of these studies
The global temperature depends on the presence of greenhouse gases in the atmosphere which is heavily influenced by human activities. This, in turn, has an impact on the global carbon cycle.
Ice cover has an influence over uptake rates. There is an increase in flux events when there is less or no ice cover as compared to the when there is full ice cover. CO2 uptake in future climate depends mainly on the changes in sea-ice cover and the wind climate. It is essential to understand these processes in order to predict the further evolution of the amount of carbon in the atmosphere. Studies by Krause-Jensen et al. (2012) show that the open-water (water surface is ice-free) period in Young Sound has been increasing over the years 1950-2011.
A fisherman´s perspective?
The Arctic is warming twice as fast as the rest of the world. During our stay, we also got the chance to speak with local fishermen to understand their views on the current environmental conditions and to hear how local communities in Greenland are adapting? We noticed that climate change is far from their main concern. Many spoke about the regulations, policies and certifications that are now required by authorities regarding the fishing business. This is seen by some as a disruption to their traditional fishing ways.
In recent years glacial meltwater has become a source for generating lower-cost hydropower in Greenland. Moreover, oil and minerals have been discovered and many see this as a positive evolution which can help the country become economically self-sufficient.
In the wake of globalisation and socio-cultural and economic changes, the problem of climate change seems to be overshadowed; at least this is the impression I got after hearing what the locals had to say.
While scientists and researchers around the world are busy studying the atmosphere-ocean gas exchange and climate changes, the results may not reach out to populations in a way that is intended. I find this a more important task at the moment, to get the message across to the general public in a way they understand and help them be aware so that everyone as a community can be a part of the solution.
Written by Nandita Rajan, who studies atmospheric sciences at the University of Helsinki. As part of her course «Effects of climate change on Arctic ecosystems and societies», she travelled to Nuuk, Greenland.
Posted on 19 August 2016