The New Arctic: Leaving the Fridge Door Open

Professor Jeff Obbard, Ph.D.

The U.S. National Oceanographic and Atmospheric Administration (NOAA) published its annual ‘Report Card’ on the state of the Arctic in December 2017[1]. NOAA is the premier scientific agency in the U.S. that focuses on the condition of our global oceans and atmosphere. Released every year since 2006, the Arctic Report Card is a peer-reviewed source for reliable scientific information on the current state of the Arctic ecosystem.

The 2017 Report Card stresses the perilous state of the Arctic’s ice or ‘cryosphere’. According to the latest NOAA data, a warmer Arctic climate is the ‘new normal’, thanks to continued global warming that is closely associated with climate change. According to Dr Jeremy Mathis, director of NOAA’s Arctic Researcher Program, the Arctic is now changing faster than at any rate in at least the last 1,500 years. The speed of change is rapidly becoming a survival challenge to the Arctic’s ecosystem and its indigenous communities that are struggling to adapt. Arctic trends of note in the 2017 Report Card include:

• Warmer air: The average annual air temperature in 2017 over Arctic land was the second highest on record (after 2016) with a temperature 1.6^oC above average. It is worth noting that the 2015 Paris Climate Agreement includes a target for limiting mean global surface temperatures to no more than 1.5^oC compared to a pre-industrial level.
• Declining sea ice: The maximum winter sea-ice area, measured each March, was the lowest ever observed in 2017. The Arctic ice cover continues to be relatively young and thin with older, thicker ice now only comprising only 21% of the ice cover compared to 45% in 1985.
• A warmer ocean: Sea surface temperatures in August 2017 were 4^oC above the average in the Arctic seas. Warmer seas not only hold less carbon dioxide, but also contribute to coastal melting of land-based ice further south on Greenland.
• Changing snow cover: For the eleventh year in the past twelve, snow cover in the North American Arctic was below average.

Not all data from the Arctic for 2017 was necessarily negative. NOAA reported that the Eurasian part of the Arctic had above average snow cover this year – although this is the first time that has happened since 2005. The Arctic land tundra ecosystem is also becoming greener for longer due to increased cover by grasslands and shrubs in response to warmer seasonal temperatures. Although more plant growth draws down excess atmospheric carbon dioxide, this can be a ‘double-edged sword’ as distorted seasonal temperatures upset the delicate ecological balance in the Arctic for plants, animals and the indigenous Inuit communities.  NOAA also reported that the vast frozen ice-sheet on Greenland, located between the Arctic and Atlantic Oceans, experienced less ice-melt was less this year compared to 2016. Although seasonal melting began early on Greenland in 2017, it slowed during the cooler summer, resulting in below-average melting compared to the previous nine years. However, Greenland’s ice-sheet, a major contributor to sea-level rise, continues to show an overall strong downward trend in ice mass loss since 2002, when satellite measurements began.

Why are changes in the global cryosphere of any relevance to warm and tropical SQ? Well, there are two key reasons as to why we should be paying attention. The first is because of the potential for an accelerated release of the greenhouse gases that drive global warming. SQ is predicted to be amongst the first countries in the world to experience so-called ‘Climate Departure’ i.e. the point in time when the average temperature of coolest years at a given location become warmer than the average temperature of its hottest year between a base period of between 1960 and 2005[2]. In other words, when the climate of a location experiences a paradigm shift to permanently warmer temperatures. According to a scientific report in the journal ‘Nature’ this could happen as soon as 2028 for Singapore under a ‘business as usual’ scenario of global greenhouse gas emissions, mainly because of continued burning of fossil fuels. As well as anthropogenic (human-sourced) emissions, greenhouse gases are also emitted from impacted natural ecosystems, such as those in the Arctic, where warmer soils under the tundra, known as ‘permafrost’, begin to melt and release their stores of frozen carbon as carbon dioxide (CO₂) and methane (CH₄) to the atmosphere. According to the 2017 Arctic Report Card, the Arctic is now experiencing record permafrost warming, and its stores of carbon are vast: several times bigger than that of the atmosphere. Melting permafrost is a potent source of CH₄ – a particularly strong greenhouse gas that captures up to 36 times as much atmospheric heat over a 100year period as CO₂. Therefore, a warmer Arctic risks accelerating global warming and even earlier (and more severe) climate change impacts for Singapore.

A warmer atmosphere also means a warmer ocean, and both mean less ice on -the planet. Ice in the Arctic is mostly floating on the sea, meaning that when it melts it does not contribute to global rise sea levels. However, the loss of sea-ice does reveal a darker ocean surface that then absorbs more heat from the atmosphere, thus making the ocean warmer. A warmer ocean not only holds less CO₂, but it also exacerbates the melting of coastal ice-sheets further south around Greenland, which are also melting from the warmer air above. A similar process is also happening at the other end of the world, particularly around the Western Antarctic ice-sheet which, like Greenland, is losing ice mass over time due to global warming. Loss of this land-based ice, together with a thermally expanded ocean, has the potential to dramatically increase the pace of sea level rise this century. Indeed, the Intergovernmental Panel on Climate Change (IPCC) has specifically warned of the risk of abrupt warming impacts on the global cryosphere, as well as the associated risks to low-lying islands and coastal areas from sea level rise, and inundation[3]. Indeed, the last time global average ‘equilibrium’ temperatures were like those of today – during the Eemian interglacial period 126,000 years ago – sea levels were between 6 and 9 meters higher[4].

The warming Arctic has now been described by NOAA as the ‘new normal’ and there is no sign of it returning to its previous stable and frozen state anytime soon. With the Earth now out of energy balance due to excess greenhouse gases in our atmosphere[5], the importance of achieving the Paris Climate Agreement goals cannot be underestimated. The situation was aptly summed up by Dr Mathis of NOAA who said that the Arctic has, up until recently, provided a great service to the planet by acting as a ‘refrigerator’ – effectively regulating a global climate that is conducive to human prosperity, but now “We’ve left that refrigerator door open”.