On Thin Ice

Through early explorations of arctic environments, expeditions to reach the North Pole, and stories narrated by novelists and filmmakers, the polar north has become engrained as much in popular culture as scientific study. Over recent years, images of starving polar bears marooned on increasingly fragmented sea ice and cascading glacial collapses along retreating ice sheets have captured the demise of the Arctic as an emblem of human-induced climate change. What's more, satellite images of declining minimum sea ice extent have set in motion geopolitical feuds over the governance of Arctic regions with the aim of exploiting natural resources and developing new shipping routes.

Stranded polar bear

Fragmenting ice sheets

Alongside such images, the monthly updates on Arctic sea ice extent provided by the National Snow and Ice Data Centre are frequently discussed by scientists and the media to put forward both sobering statistics, as well as optimistic hopes drawing from exaggerated predictions. In this blog, I aim to discover what really is happening in the Arctic with regards to climate change, why this is important and what it means for the future of the region and globally.

Why the Arctic?

The Arctic is the northernmost region of the Earth, located north of the Arctic Circle (66° 33’N) and far removed from the polluting industrial centres inhabited by much of the world's population. So why is the climate change recorded in arctic environments so important for the rest of the planet?

The amount of carbon in the atmosphere continues to rise through the burning of fossil fuels, warming our planet and pushing Earth systems beyond critical tipping points. As a regulator of the Earth's climate, the Arctic 'acts as an early warning system for the entire planet' (Dr. Chip Miller, NASA).

'Arctic amplification' means that the regional climate of the Arctic is altering at a dramatic rate with the surface air temperature rising twice as fast as the global average in the last few decades (Najalfi et al., 2015). Previously, rapid growth of sea ice during autumn produced a negative feedback and initiated cooling. However, the loss of sea ice (particularly old ice) has been staggering. A combination of the surface albedo feedback and ice insulation feedback (due to a warmer ocean in areas that were previously under ice cover) has accelerated Arctic warming (IPCC, 2013). In addition, melting permafrost, changes in sea level, alterations in atmospheric and ocean circulation, and modifications to plant ecotonal boundaries are also all positive feedbacks, amplifying warming in the Arctic (Miller et al., 2010).

What's been happening in the Arctic this year?

This year the seasonal minimum sea ice extent was reached on September 2010 (4.14 million km²), tying with 2007 as the second lowest extent in the 37-year satellite record. All in all, this was 2.56 million km² lower than the 1979-2000 average (that’s equivalent to over 10 times the area of the UK).

Daily Arctic sea ice extent for 2012-2016 against the 1981-2010 average (NSIDC, 2016)

Monthly September ice extent from 1979-2016 (NSIDC, 2016)

What’s even more worrying is the significant decline in Arctic sea ice thickness, which relates to the age of the ice (Tschudi et al., 2016). Thicker 4+ year-old ice made up only 3.1% of the total extent this year (compared to 33% in the mid-1980s!). Not only does this reveal how extensive ice melting has become, it also denotes worrying trends in the future. Young, thin ice is far more prone to melting at the end of the summer and a growing proportion of it brings us closer and closer to experiencing a ‘Blue Ocean Event’ where the Arctic is devoid of ice.

It is clear that the Arctic has undergone considerable change in the past few decades. As the blog progresses, I hope to look beyond changes in sea ice extent and understand more about this altering environment by studying the following questions:

What is the evidence for climate change in the Arctic?

In what ways is increased atmospheric CO2 impacting arctic environments?
To what extent do confounding factors play a role?

What does the future look like for the Arctic and the rest of the world?

My next few posts will explore in further detail the evidence for climate change in the Arctic before investigating the impacts at varying spatial and temporal scales. In the meantime, the video below is a nice illustration of changing ice age and cover in the Arctic through a week to week time lapse since 1990: