When the eternally frozen ground thaws, researchers must know the consequences

At a remote place in northern Norway, researchers deploy mini-greenhouses, solar panels and automated instruments to investigate how the tundra ecosystem responds to climate warming.
 


By Andreas R. Graven

Renee McDonald, Bachelor student from St. Francis-Xavier University in Canada, came to help set up automated sampling of carbon dioxide and methane for the FEEDBACK project.


The researchers’ field trip this summer was carried out on Finnmarksvidda, meaning lots of hard work, heavy rain, mosquito swarms, and – luckily – some glimpses of the sun.

If you are not very excited about what happens when permafrost thaws – then there are probably many other places you would rather want to be. Unless you are a son of the wilderness.

The campaign was part of the FEEDBACK project (Full project title: Advancing permafrost carbon climate feedback – improvements and evaluations of the Norwegian Earth System Model with observations)

At the field site outside Karasjok in Finnmark, an international team of researchers, led by Hanna Lee from Uni Research in Bergen, set up automated instruments that sample carbon dioxide (CO2) and methane (CH4).

The FEEDBACK project aims to build accurate predictions of future climate feedbacks from thawing permafrost - and permafrost carbon release by gaining process level understanding from field observations.

– The heavy rain did not prevent us from working with sensitive equipment. Like in Bergen, there is no such thing as bad weather up here - it is just a matter of being properly prepared - or, as in this case, making the best of what you have available nearby, researcher Casper Christiansen at Uni Research says.   
 

The FEEDBACK project aims to build accurate predictions of future climate feedbacks from thawing permafrost - and permafrost carbon release by gaining process level understanding from field observations.


Today’s data technology makes it possible to monitor field data being collected in Finnmark from Bergen in real-time. The instruments were set up and tuned during the fieldwork campaigns.


– We measure surface CO2 fluxes using the fully automated Forced Diffusion chambers, powered by small solar panels, says climate researcher Hanna Lee at Uni Research, and the Bjerknes Centre for Climate Research. 

– The longer thawing persists the wetter it gets due to land surface subsidence. We use a pentagonal-shaped plastic construction, in other words mini-greenhouses, to passively warm the environment. This experimental climate manipulation allows us to investigate how the tundra ecosystem responds to climate warming, Lee adds. 

Lee and her colleagues hope to discover how much CO2 and CH4 is emitted from permafrost soils because of thawing, the latter being a much more powerful greenhouse gas than CO2.

– One unique thing about permafrost is that it preserves large amounts of organic matter (old plant remains) in the ground, and therefore contains a lot of carbon. At the same time permafrost prevents an increase in ice-melting and risk of land surface subsidence on a very large scale, sometimes as large as the size of a football field, Lee says.  
 

Six transects were established that represent permafrost thaw chronosequence and subsequent moisture gradient, the longer thawing persists the wetting it gets due to land surface subsidence. Mini-greenhouses are used to passively warm the environment. This experimental warming allows us to understand how ecosystem responds to warming. Here, we measure surface CO2 fluxes using the fully automated forced diffusion chambers powered by small solar panels.


Methane is a far more “powerful” greenhouse gas compared to CO2, but luckily, the process involved in soil organic matter decomposition is much slower when it is favorable condition in producing CH4 than CO2.

– Under anaerobic conditions, soil organic matter decomposition results in emissions of both CO2 and CH4, where CH4 being more powerful greenhouse gas than CO”. Methane gas does not evolve slowly, it is the decomposition process that emits methane which is slower. Under aerobic conditions, when a mire becomes dryer, decomposition of organic matter occurs at a faster rate than under anaerobic conditions, where things are completely inundated, Christiansen explains.

The fieldwork took place near the Iškoras mountain, a half an hour drive and an hour hike from the cabin in Karasjok that the researchers use as basecamp.

– A big advantage of working far north during the summertime is that the sun never sets –definitely helpful when days in the field are limited, and lots of new equipment is waiting to be installed, and samples and measurements need to be obtained, says Casper Christiansen.

Whereas the Karasjok summer can get relatively ‘hot’ (average July air temperature is +13 °C), the winter on Finnmarksvidda is still so cold that some areas have permafrost, while other thawing areas nearby have turned into wetlands.

 

Dr. Casper Christiansen, Uni Research Climate and FEEDBACK researcher, is manually sampling carbon dioxide emitted from the surface. This measurement will allow us to understand the rate of carbon dioxide emissions from ecosystem to the atmosphere.



Finnmark is now one of many discontinuous permafrost regions where the average annual soil temperature is approaching 0 °C. That means thawing, and at worst, the permafrost might degrade fast.

­– In several places in Norway the permafrost is about to reach 0 °C.  We see that half the moor areas at Finnmarksvidda, the so called pals mire have disappeared over the last 50 years, Sebastian Westermann, associate professor at the department of Geosciences, University of Oslo, told forskning.no

Department of Geosciences at UiO is one of the partners of the project.

The landscape on Finnmarksvidda, filled with contrasts, therefore provides a good starting point for the researchers to investigate what happens when permafrost thaws. In other words, how will thawing affect emissions of greenhouse gases, and what are the consequences for our future climate. 

 

Dr. Sebastian Westermann, University of Oslo and partner of FEEDBACK project, is showing gas bubbling from one of the permafrost thaw ponds. Even under anaerobic conditions under water with lack of oxygen, soil organic matter decomposes. The gas produced as a result can contain large amounts of carbon dioxide and methane, powerful greenhouse gases.
 


Lee, Christiansen and colleagues would like to find out more about these emissions – both from within the soil and from the expanding thaw ponds.

During some of their field campaigns, they also invited climate-modelling experts that are more used to sitting comfortably inside their offices, in front of the computer. 

–Occasionally, at lunchtime, some of our people ate their sandwiches while still wearing their bug net. In such situations, one could easily distinguish between people used to working in the wild, and people who are not, Casper says with a grin.

However, working in the field provides – even for people not doing it very frequently – an important contribution to tighten the gap between observations and modelling in climate research. 

–The FEEDBACK project will give us a better overview, higher data quality and improved predictions from the modelling. Also, findings from Finnmark are applicable to the development in the greater Arctic region, says Hanna Lee.

Eating lunch in the field was difficult at times because of mosquitoes. We had to eat our sandwiches wearing the head net. The only two who are not wearing the head net are the two students from Canada. They were toughies!

 

With their new sensor based system, and power from solar panels, the researchers can collect data continuously without being in Finnmark almost the whole year round.

Christiansen says that even though they now have automated measurements, they still have to collect many data manually, and be at the field site to maintain the equipment as well:

–Installing automated systems in all our plots would be too costly for us now, but it is something that we dream of doing one day, he says.

The 3-year FEEDBACK project receives 7 MNOK from the Research Council of Norway. FEEDBACK is led by Uni Research Climate and The Bjerknes Centre for Climate Research, with other leading research institutions in Norway and abroad as partners.

Norwegian partners are University of Oslo, Department of Geosciences, IRIS-Energy, and NILU, while international partners include St. Francis-Xavier University, Canada, and the National Center for Atmospheric Research (NCAR), USA.


Jan. 17, 2018, 10:32 a.m.

People involved

cp: 2018-05-21 11:15:25