The ESS and Grade 10 geography classes recently had the pleasure of Skyping with Dr. Jennifer King of the Norwegian Polar Institute about her work studying sea ice thickness in the arctic. We are really grateful to Dr. King for taking the time to speak with us. So many of the things she discussed reinforced things we’ve learned about in our curriculum and we learned many new things as well.

We’ve learned about positive feedback mechanisms in class and Dr. King provided a powerful example of one in action. The sea ice at the poles is decreasing because the earth’s temperature is increasing due to global warming. If the ice melts, the Albedo effect (the amount of solar radiation reflected) decreases, causing the ocean temperature to rise. This leads to more snowfall and less ice formation.

Dr. King discussed the many different methods of measuring sea ice thickness and how new technologies have increased our ability to verify sea ice measurements. She is able to track the location of older sea ice and measure its decline over time. Older sea ice is more effective at limiting the transfer of energy from solar radiation to the ocean below, and can better withstand melting due to increased temperatures, because it is thicker. However, the amount of older sea ice is quickly diminishing. Her discussion on the new technologies she uses to measure these changes helped us better understand the global context element for this year’s MYP eAssessment. We’re exploring how systems, models, methods, products, and solutions help us understand the world in which we live. Dr. King uses satellite data, thermal infrared cameras, ice cores, snow probes, electromagnetic sensors, and even helicopters(!) to survey the ice thickness. It was interesting to learn that there are so many methods used which lead to greater confidence in the data.

We had many questions for Dr. King; more than could be answered in a class period. She was very kind to continue the conversation with us on our blog. Below are some of the questions we covered during the Skype session along with some additional questions she answered for us later. For more interesting information and pictures of the work being done at the Norwegian Polar Institute, check out their Instagram page!

Melina: At which ice thickness would the environment be in critical condition as well as the species living on it?

Dr. King: There is not a defined ice thickness at which one should be concerned; rather the combined effect of the loss in extent and thickness is already very worrying. One example of the impact on the species that rely on the sea ice for their habitat is about how the sea ice cover in Barents Sea has an effect on polar bear denning. This is not my specialization but work done by the environmental management section here at NPI. They found that:

• The number of days when the sea ice cover in the Barents Sea exceeds 60% has a strong influence on the number of females that den
• Few days with sufficient ice cover leads to few females entering dens.
• Since 1979, when sea ice monitoring started, there has been a marked decrease in the number of days with sea ice cover.
• Since the den counts started in the 1990s, there has been decrease in the number of dens

There is more info on this website.

Matea: Is there a correlation between sea ice thickness and global temperature? If so, if there is a decrease in thickness, what will happen in regards to climate change? ​

Dr. King: Yes these are absolutely linked via what we call feedback mechanisms. The decrease in ice thickness changes the energy balance so the energy from the sun is more easily transferred through the ice to the ocean below, while the decrease in ice extent allows the ‘dark’ ocean to directly absorb more energy from the sun, which in turn will accelerate warming of the ocean and melting of the sea-ice that remains.

Lauren: How will you be able to track the younger ice throughout this process?

Dr. King: In the field we can investigate ice age by drilling an ice core and measuring the salinity. There is a process called brine rejection that means that MYI is less salty than FYI because the brine is no longer trapped in pockets but has drained out. Also if you find very clear ice in the top of a core this can be evidence of a former melt pond, this is a clear sign that the ice has survived at least one summer. Relative ice age can be identified on scatterometer data from satellite remote sensing because young, salty ice gives a much less strong return than low salinity, well drained (lots of air pockets and structures for the incoming signal to bounce back from) Multi year ice.

Lea: How do you know what Ice Berg or Ice Volume to look at and gather the most reliable data from?

Dr. King: We try to gather information on as many different ice types as possible, or to make a spatial survey of a large region so that the sample we have is representative of the area.

Lea: Why did you choose the Fram Strait and to what extent does it enable you to reach the goal of theoretical discovery in your research? (does analysing and gathering data from the Fram Strait help you establish theories in the long-term?)

Dr. King: The Fram Strait is an important region because it is the main export channel from the Arctic Basin. Ice is carried in the transpolar drift across from Siberia and exits through the Fram Strait. So monitoring changes in the condition of the ice in Fram Strait can tell us something about changes to conditions in the Arctic. Monitoring of the sea ice thickness in Fram Strait by NPI since 1990 showed:

• Reduction of old level ice thickness by 32%
• Amount of ice > 5 m thick (ridges) reduced by about 50%
• Annual mean thickness of 3 m (1990s) down to 2.2 m (2008-11)
• Substantial part of the change after 2005/2006

(From the paper Hansen, E., S. Gerland, M. A. Granskog, O. Pavlova, A. H. H. Renner, J. Haapala, T. B. Løyning, and M. Tschudi (2013), Thinning of Arctic sea ice observed in Fram Strait: 1990–2011, J. Geophys. Res. Oceans, 118, 5202–5221, doi:10.1002/jgrc.20393.)

Lea: You mentioned using satellites to gather data and record the movement of ice volumes; have you sensed a major improvement in technology which enables you to gather better or more sophisticated data in your research?

Dr. King: The ice extent on a whole arctic scale has been  well known since 1979 from passive microwave remote sensing – this is measuring the energy emitted by the earth at different wavelengths, the energy emitted by sea ice depends on its physical temperature and on geophysical quantities such as salinity, roughness, porosity, and air content, and is very different to the signal from the ocean so the two can easily be told apart.

The sea ice extent and concentration can also be identified using ‘active’ remote sensing techniques called scatterometry  and synthetic aperture radar (also in the microwave part of the spectrum)  that send a pulse to interact with the earth’s surface and then measure the return.

Sea Ice drift tracking from consecutive pair of images is also quite well established, using a method called cross-correlation which is a computer algorithm that matches patterns from one image to the next.

Sea ice THICKNESS from remote sensing is where we really made a big leap just recently, with the launch of CryoSat2 in 2010. This a radar altimetry mission with an orbit that reaches far enough to only leave a really small hole up at the North pole – previous altimetry missions had quite a large hole. Radar altimetry gives the height of the ice surface above the ocean surface, known as ‘freeboard’. The freeboard can be converted to sea ice thickness using the assumption of isostatic balance of the ice floes in the water, using the density of the ice and snow. The density of first year ice is different to the density of multiyear ice, so to use this technique one also needs to know something about the age of the ice.

Lauren: Whilst doing this experiment, are you making sure that you are not setting up the experiment to get the results you want?​

Dr. King: There is a system called the ‘peer review process’ where if you want to publish your results in a paper in a scientific journal, the journal will send it to at least two other researchers and ask them to provide an anonymous review of the quality of the paper. This process should go a long way towards preventing invalid research from being published. What you may not realize is that the peer review process also applies to funding applications. A lot of research is funded by what we call ‘soft money’, that is research grants from for example national Research Councils, or EU initiatives such as Horison2020, and to apply for funding a researcher has to prepare a grant proposal with a really detailed description of the question they would like to address and the methods they plan to use. These grant proposals are also peer reviewed, which acts to control badly designed research, because if the method is not applicable to the question the project will find it impossible to get funding.

Matea: What are the stakeholders present in your projects and investigation?

Dr. King: At the moment I work for a government institute, we have a remit to supply the government with information about the state of the environment, for example the extent of the sea ice in the Barents Sea region, which can relate to fisheries, or to oil exploration. Over in the environmental management section they have responsibility for counting animals, for example, Polar Bears and Seals to monitor the populations of these animals for the purpose of environmental management and conservation.

Spencer: What do you find to be the best course of action to promote a better future, in regards to what you have been studying, and what do you think that we can do ourselves to help out?

Dr. King: I’m not sure I have a clear-cut answer to this one. It seems obvious now that what is happening in the Arctic will affect us all, whether via sea level rise (melting of land ice & expansion of warmer oceans when sea ice cover is lost) or by changes to synoptic scale weather patterns bring more winter storms to Europe, or just by the amplification of climate warming due to the feedback mechanisms we discussed in the lesson. Reducing emission of greenhouse gasses is still the main goal if we would like to slow climate warming. What we can do as individuals probably falls into two categories: on the small everyday scale we can try to reduce energy use, for example take the bike instead of car, eat less meat, turn the light out when you leave the room. On the bigger scale the best thing is probably to be politically active and to take the message to your politicians that climate change matters to you, the population, and that they should be taking tougher steps at government level towards reducing emissions.

Spencer & Matea: How does tracking the sea ice better help us understand the ways in which we are affecting it? In your opinion how will “furthering the understanding of sea ice motion” contribute to improving ocean conservation methods?

Dr. King: Can we combine and reword these two to ‘What is the main reason for tracking sea-ice motion?

From a research perspective tracking sea-ice motion can give us information about the two forces that drive sea ice motion: winds, and ocean currents. On a short time scale (day to day) the wind will have the bigger impact, but over a longer time scale (~years) the currents will be the dominant force, for example moving ice across from Siberia towards the Norwegian Arctic and out of the Arctic Basin via Fram Strait. From an operational perspective boats or oil rigs trying to operate in ice infested waters are interested in knowing the drift direction to know whether a lot of ice is coming towards them in near real time, and whether the ice is converging (likely to trap a boat) or diverging (easier to push through).