Elsa Saunders, Wyedean School, reports on Arctic Climate Change talk

Ella Saunders (Y12, Wyedean School, near Chepstow) reports below on the GA Autumn lecture by Dr. Harry West, University of the West of England.

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On Thursday 14th November, nearly 70 students from across the region attended a GA lecture by Dr Harry West that linked to their A-level Geography courses and satisfied their wider geographical curiosity. It was titled – ‘Climate Change in the Arctic; from regional warming to global impacts’.

Dr West began by demonstrating the context for this relevant issue, defining climate change as “a change in the state of the climate that can be identified by changes in the mean and/or variability of its properties and that persists for an extended period, typically decades or longer.” (IPCC, 2021). We were presented with evidence that it is now undoubtedly clear that climate change is real, and occurring today.

Yet, we know that climate change is not a new phenomenon. Dr. West illustrated the pattern of climate change in the recent geological past – of hundreds of thousands of years of interglacial and glacial periods, which are linked by step-wise cooling. However, he pointed out there have been disruptions to this broadly smooth pattern, with several periods of dramatic and abrupt change. The extent of our changing climate was shown by a representation of how Bristol might have appeared during the peak of the Devensian glacial period, about 21,000 years ago. Scenes of rocky, mountainous tundra, and sub-artic meadows in our region in the past reinforced to me the extent and possible impact of climate change and the value of our arctic ecosystems.

But, how does natural climate change occur? Dr West explained the theory of the Croll-Milankovitch cycles – caused by changes in orbital eccentricity, the axial tilt, and precession. These cycles cause changes in solar insolation resulting in interglacial and glacial periods, and define our very presence on our planet. However, they are now being disrupted, by unnatural, anthropogenic climate change. To relate to the beginning of the lecture, Dr West reminded the audience of the abrupt or non-linear periods of climate change that stuck out from the trend of glacial periods. These seemingly innocent anomalies are a real result of enhanced feedback loops and can have major impacts. To demonstrate this, Dr West put forward the idea of a higher intensity of solar insolation due to changes on the Croll-Milankovitch cycles. This would have many ‘knock-on effects’; a retreat of continental ice sheets, decreased reflection through an albedo effect, and then further warming and retreat of ice sheets. These cycles of positive feedback are dangerously significant for what can be ‘delicate’ components of the Earth system, as Dr West explained they can reach a ‘tipping point’, and cause abrupt changes to our Arctic systems.

We explored the already-occurring geopolitical implications of ice sheet retreats. We know that the Arctic is rich in minerals, oil, and gas. No-one knows this better than Arctic nations, who are reinforcing their territorial claims, and expanding their military presences. Dr Harry West commented on Russia’s modernisation of its Arctic fleet. The US and other NATO countries are also enhancing their Arctic capabilities. Dr West highlighted raised concerns about the potential for military confrontations in these resource-rich regions and disputed waters.

Finally, Dr West introduced us to a concept that he considered to be potentially the most ‘scariest impact’ of climate change – and I found myself agreeing. The Atlantic Meridional Overturning Circulation, or AMOC, as it’s known, is a negative feedback role performed by the oceans. Circulation of water around the globe reduces the enhanced heating effect we see in the equatorial, and redistributes heat around the Earth’s surface. Surface water is sinks in Arctic waters to the deep ocean, and results in colder, North Atlantic Deep Water travelling southwards. Dr West proved its significance to us, as it is a key contributor to both NW European climate. The catch though is that in the last 20 years we have seen a loss of mass from the Greenland Ice Sheet. This has, in turn, caused a freshwater input of ablation waters into the AMOC system – named a ‘freshening effect.’ This has the potential to dramatically change our climate. Some scientists believe they are already seeing a decreasing trend in the AMOC’s stability.

As the University’s bell chimed eight o’clock in the evening, Dr West concluded the lecture by underlining the consensus view that it is highly likely we will see significant impacts in the UK within the next century.

In conclusion, this trip highlighted to me the very real concerns faced by humankind. I realised the increasing importance of finding a solution to climate change, in which we are all responsible for, as a real future, that can and must be achieved. I would like to thank Dr Harry West for this incredible lecture and for demonstrating the significance of our actions, as well as highlighting the consequences of them, on this dark winter evening in Bristol.

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The slides and some links used in this lecture are available in Resources (students)