The Arctic is a hostile and unforgiving place, with a harsh climate and extremes of light and temperature. It is hardly conducive to human life, yet its secrets may well hold the key to understanding the effects of global warming, over the proceeding decades of this century. Sam Illingworth describes a current project aiming to uncover them.
In days gone by, miners would take canaries down into the mineshafts with them, not as pets but as biological detectors of harmful gases that may be present underground. Signs of distress from the bird indicated that concentrations of these gases were too high, and that conditions had become unsafe.
Because of a series of positive feedbacks - for example, a loss of sea ice leads to an increase in the amount of sunlight that is absorbed by the sea, which is darker and less reflective, melting still more ice - the Arctic feels the effects of global warming more strongly than other areas of the globe. So it can be thought of as the Earth's canary: signs of distress indicating that we are approaching unsafe conditions.
The Arctic is also home to large reservoirs of methane, in the form of permafrost soils on the land and methane hydrates beneath the seabed - a hydrate is a substance that contains water. A warming climate may destabilize both of these. Methane in the Earth's atmosphere is an important greenhouse gas; over 100 years, its comparative impact on climate change is over 20 times greater than that of carbon dioxide.
The melting of these large Arctic reservoirs and their subsequent release into the atmosphere could therefore have potentially catastrophic implications for Earth's climate; this means it is crucial that we to try to understand the relative strengths of these potential sources of methane.
As part of the NERC Arctic Research Programme, the 'Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling' (MAMM) campaign aims to address this issue, by improving our knowledge of the sources and atmospheric concentrations of Arctic methane and other greenhouse gases.
As well as ground-level measurements of how much methane is emitted and absorbed over both the land and sea, a significant part of the campaign involves measuring atmospheric composition using the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 Atmospheric Research Aircraft (ARA).
The ARA is a commercial jet that has been modified to carry a large suite of scientific instrumentation, enabling it to make precise measurements of greenhouse gases including methane, carbon dioxide, water vapour, carbon monoxide, and nitrous oxide. It has a range of over 2000 miles, can reach heights of about 6 ¿ miles, and can fly for more than five and a half hours carrying three crew members and up to 18 scientists.
The first phase of MAMM consisted of surface measurements in the field and the deployment of the aircraft out of Kiruna airport, Sweden, in July 2012. We made many successful measurements of atmospheric methane concentrations, and by comparing these to a highly resolved land cover map could then calculate methane fluxes over Arctic wetlands, thereby giving us a better understanding of the relative strength of these potentially large sources of Arctic methane.
The next two phases of the campaign are to take place in mid-late August and September of this year. In this part of the world making measurements that are accurate and precise enough for rigorous scientific investigation is no mean feat. On the ground, even in mainland Finland during the summer, temperatures can reach below freezing.
And the lack of easy access to many of the sites means lugging about delicate, often extremely heavy equipment can quickly become an arduous task - we often favour pristine conditions far away from any settlement to avoid contamination by any manmade local emissions. In the aircraft we face a whole host of different challenges, from equipment maintenance and in-flight calibrations to evade approaching weather fronts while avoiding restricted air space, but the knowledge and expertise of both the flight crew and the scientists on board mean that we are always in safe hands.
During the August and September flights, members of the MAMM team plan on publishing a daily written blog, with the aim of communicating different aspects of the science that is being done, whilst giving a first-hand account of what it's like to be a research scientist operating in testing conditions at the end of the world. The blog can be found at http://arcticmethane.wordpress.com/, where as well as written updates from the MAMM team and pictures of the expedition, there will also be a series of audio clips hosted by the Barometer podcast (http://thebarometer.podbean.com/), hopefully giving further insight into the MAMM project and the people behind it.
The measurements that we make throughout the MAMM campaign will allow us to characterise the possible Arctic sources of methane and other greenhouse gases. This will enable us to better understand the present and future effects on Earth's climate as a result of global warming, hopefully before Earth's canary stops singing forever.
Dr Sam Illingworth is a post-doctoral research assistant in the Centre for Atmospheric Science at the University of Manchester. Email: firstname.lastname@example.org. The MAMM project is led by Professor John Pyle of the University of Cambridge.
The orginal article can be found at Planet Earth Online.
Image credit: FAAM.