Revisiting the Arctic

This blog, in essence, is attempting to discuss whether anthropogenic forcing has pushed the Arctic environment to a non-recoverable point, one where it will continually decrease or as a result of reaching a tipping point will succumb to a variety of positive feedback mechanisms and begin to rapidly collapse.

Addressing the situation in the Arctic we identified 4 systems within the Arctic as a whole: Sea Ice, the Greenland Ice Sheet, the Thermohaline Circulation, and the Polar Vortex. In reality only the Sea Ice faced any sort of threat from positive feedback mechanisms.

When first addressed the Sea Ice presented a strong case for succumbing to feedback mechanisms as its daily rate of formation was significantly lower than every previously experienced and resulted in the Sea Ice extent being 400,000km2 lower the previous lowest October formation. However, during December an anomalous rate occurred once again only in the opposite direction, ice was forming at 90,000km2 per day meaning by the close of the year there wasn’t a significant gap between the 2016 and 2017 opening extent, only the expected decrease was observed. This prompted the question of true nature of tipping points within the system and whether they in fact existed. However, before we could answer this question we first needed to understand the feedback mechanisms at play within the system, the major one being the albedo effect. Later on in the blog we visited geoengineering projects that would utilise albedo in order to regain sea ice and lower global temperature, in this instance we can refer to said blog post to validate the albedo effect. It was modelled that by increasing the reflectivity of the local ocean, between 70-90 degrees it will cause cooling such that sea ice would reform and stabilise, this comes as a result of its capacity to function sustainably within different climate settings. The albedo effect then plays a vital function in the stability of the sea ice, the continued loss of sea ice as a result of anthropogenic forcing and global warming causes the increased absorption of energy into the local ocean which is significant enough to cause subsequent melt through rising temperatures. In terms of the further interactions and feedbacks they are all rather negligible in terms of affecting the future situation.

The Greenland Ice Sheet

Perhaps with the greatest potential to incite rapid climate change we examined whether it was being impacted by global warming as severely as the media spreads. Upon discover we found there were areas to be concerned, the functioning of millennial scale process on a decadal once causes slight alarm, however, the sheer mass and volume of the ice sheet insulates itself from any major rapid change instead it will be a continual decrease over the next several hundred years that could well accelerate and flood over 50% of Asia’s population as a result of sea level rise. Apart from this the only cause for concern is that of major icebergs detaching and becoming highly influential in the Arctic Meridional Circulation but that will be discussed in due course. The formation of supraglacial lakes on the Antarctic Ice Sheet is a mirror of the effects felt similarly on the Greenland Ice Sheet, only at a much slower pace. The more rapid pace in the Northern hemisphere could lead to earlier destabilisation of the sheet and encourage the aforementioned ice bergs to break from the main body.

The Polar Vortex

Before we address the complexities of the Thermohaline Circulation lets first revisit the Polar Vortex. Perhaps the most significant in terms of impacting the daily lives of the population, the weakening of the polar vortex causes localised climate change as it lowers the colder temperatures on the Pacific mid-west as well as potentially over Northern Europe. Although this is not necessarily a significant and demanding consequence it is an early example of how warming the Arctic can begin to affect day to day lives.