Cascading effects of polar warming: a call for coherent policy responses across borders

The Arctic and Antarctica regions are experiencing much faster warming (up to four times the global average) than the rest of the world. Arctic climate change is evident through reduced sea ice, thawing permafrost, increased wildfires, and ecosystem shifts. In the Antarctic, accelerated ice sheet melt and disruptions to marine ecosystems are among the significant observed changes. The Arctic region, home to nearly 4 million people and pristine ecosystems, is already experiencing the profound impacts of local warming. However, Arctic warming is not merely a regional issue. The environmental changes occurring in the Arctic can exacerbate global warming and may affect weather patterns at lower latitudes through climate feedback mechanisms and teleconnections. The local consequences of climate change in the Arctic can also propagate through economic, biophysical, and social pathways, potentially triggering significant global risks. This highlights the urgent need for increased and better targeted international mitigation and adaptation efforts. While scientific advancements continue to shed light on these issues, critical knowledge gaps persist. Ongoing research on polar regions and their global impacts is essential for informing EU policymakers and the international community. To develop effective adaptation and mitigation strategies that safeguard both people and nature, it is imperative that policy processes remain responsive to scientific findings and integrate new information as it emerges. The CRiceS project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 101003826. The work reflects only the authors’ view; the European Commission and its executive agency are not responsible for any use that may be made of the information the work contains. Policy brief No 1 January 2023 Cascading effects of polar warming: a call for coherent policy responses across borders CRiceS Policy brief, October 2024 Summary of the research Warming in the polar regions gives rise to climate effects and environmental change with wide-reaching consequences for nature and society, both near to, and far from the poles. Polar climate change with global Earth System implications Thawing permafrost, sea ice loss and more open ocean, as well as ecosystem changes can enhance global warming through changes in uptake and release of greenhouse gases and energy. Such climate feedbacks can in turn exacerbate climate risk and hamper efforts to mitigate humaninduced climate change. A more direct effect of polar warming on lowerlatitude climate and weather occurs through the link between loss of sea ice and changes in atmospheric circulation, so-called polar teleconnections. Current research supports, through multiple lines of evidence, that such teleconnections exist – at both poles: • In the Arctic, there is strong evidence that warming can lead to weakened mid-latitude storm tracks and jet streams in the summer months. It can also contribute to a shift in location of the jet and may contribute to a higher chance of stationary weather patterns. However, science is not yet conclusive on the two latter mechanisms. Similarly, Arctic warming and sea ice loss have been proposed to lead to wintertime cooling and cold spells over the Northern Hemisphere mid-latitude continents, but the strengths and mechanisms behind this effect are still debated. • In the Antarctic, which is still less studied than the Arctic, literature points to teleconnections between Antarctic sea ice loss and Southern Hemisphere lower latitude weather. It is, however, unclear how widespread the effects are, with some studies suggesting an influence extending as far as to the Arctic. While many details remain uncertain, polar teleconnections do have the potential to pose significant climate risks to lower latitude societies, as illustrated in Figure 1. Examples include shifts in the latitude and directions of storms moving in over Europe and changes in the duration and frequency of stable weather conditions and associated heatwaves, cold spells, and dry periods. Moreover, these risks combine with those arising from underlying humaninduced global warming and other non-climatic drivers. A good knowledge of the links between warming and risk is therefore a prerequisite for adapting to the climate of the coming decades. CRiceS Policy Brief 2024 Winter Potential impacts of a warming Arctic on mid-latitude regions Summer Coldwaves Heatwaves Drought Floods Weaker Storms Floods Arctic sea ice loss Weakening of polar vortex Amplified and more stationary planetary waves Shifting position of jet stream Weakening of storm tracks Figure 1 Illustration of the mechanisms through which Arctic warming and sea ice loss can potentially affect weather and climate in mid-latitudes. Cascading impacts with cross-border risks involving many international actors Sea ice retreat, permafrost thaw or glacier and ice sheet melt are some of the initial impacts that can propagate across borders, leading to further impacts such as increased economic activities (shipping, tourism or mining), sea level rise, or damage to infrastructure. This propagation of impacts creates risks and opportunities far beyond the Arctic region, see figure 2. For instance, when global warming leads to sea ice retreat which opens the waters for shipping. Increased shipping encourages changes in global trade patterns, especially between Asia and Europe. Increased trade is thus one opportunity that emerges, linked with the development of new economic activities such as shipping, tourism, commercial fishing or mining. But this opportunity is linked with many potential negative impacts on ecosystems and local population. The propagation of impacts also creates risks and opportunities for financial systems. Indeed, the development of new activities and the associated need for infrastructure create investment possibilities. Investments and infrastructure are necessary to help local adaptation for populations who are impacted negatively by changes in the Arctic environment. Security risks are also present as the opening of the Arctic Ocean intensifies geopolitical tensions over sovereignty rights and resource protection with increased military presence in the region. Finally, impacts on ecosystems and the social consequences of the changes in the Arctic environment, landscape and economy cause many risks to the livelihood and social rights of local communities. Social, economic, technological, and geopolitical drivers play and will continue to play a significant role in the changes of the polar regions, and they can in turn also be influenced by climate change. For example, mining for critical raw materials in the Arctic is becoming increasingly possible due to Arctic warming. Technological shifts to renewable energy and electronic vehicles make demand for this type of materials remarkably high and may influence the responses to Arctic warming. The war in Ukraine has also been an important geopolitical driver in the region, shifting priorities away from advancing mitigation and adaptation towards finding new sources of energy for Europe to replace Russian gas. The war has also greatly impeded indigenous communities, scientific collaboration and knowledge sharing with Russia. The various risks and opportunities impact a broad spectrum of stakeholders, ranging from local populations and indigenous communities to national and international entities. Key players include the Arctic Council, Arctic nations, and external nations utilizing Arctic resources, such as the EU. Private enterprises, including mining and tourism companies, along with international organizations like NATO, also play crucial roles in addressing the challenges and prospects emerging from changes in the Arctic. CRiceS Policy Brief 2024 Definitions Polar teleconnection The influence that a more rapid polar warming, or loss of ice, can have on climate and weather nearer the equator – or in the opposite hemisphere. Climate impact drivers Physical climate system conditions (e.g., mean changes, events, or extremes of e.g. temperature, precipitation, storminess) that affect an element of society or ecosystems. Non-climatic drivers An agent or process outside the climate system that influences a human or natural system. Climate feedback An interaction mechanism between processes in the climate system where the result of an initial process triggers changes in a second process that in turn influences the initial one. Positive feedback intensifies the original process, and negative feedback reduces it. Cascading impacts A chain of events triggered by an initial climate impact driver, where one event is propagated to cause another, leading to a series of interconnected impacts, sometimes crossing borders. These effects can amplify the consequences of the original event. Adapted from: IPCC, 2022: Annex II: Glossary. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. CRiceS Policy Brief 2024 Climate trigger POLAR WARMING F e e d b a c k P r o c e s s e s Sea ice retreat Fishing & Marine Ecosystems Trade Mining Geopolitical INITIAL IMPACTS PROPAGATED IMPACTS CROSSBORDER RISKS Tourism & Shipping Infrastructure Permafrost thaw Coastal Erosion & Flooding Human Security & Social Justice Glacier & sea ice melt Altered species distribution & abundance Figure 2 Illustration of transmission of cross-border climate change impacts originating in the Arctic. Adapted from Mosoni et al. 2024. Policy recommendations Adapting to the multitude and cascading impacts of Arctic change, within and beyond the region, requires coherent policy responses and cross-border cooperation. • Enable comprehensive adaptation strategies through improved understanding about climate risk arising from polar change The climate impact drivers and subsequent risk to low-latitude regions associated with polar teleconnections are insufficiently understood. This may pose a blind spot in climate adaptation strategies at regional and national levels. Addressing this knowledge gap requires support for continued research efforts, including for Earth observational infrastructures and coordinated modelling, and the incorporation of new knowledge into climate risk assessment. • Encourage multi-level perspective on already known global risks Understanding how impacts are transmitted across borders, between climate impact drivers and socio-economic risks, can bring new insights on how to mitigate already known global risks such as sea level rise or changes in the yield of important fisheries. In this case, understanding the transmission of impacts can influence what should be prioritized in the perceived investment opportunities in the Arctic, and understanding both the physical and economic risks involved. • Increase policy coherence between different levels of governance The European Union policies and strategies concerning the Arctic region may be coherent with the objectives of the EU, but incoherent from an Arctic perspective. This highlights the need for better coordination across governance levels. Many studies emphasize the need for incorporating traditional knowledge and addressing economic inequities. • Incorporate an understanding that the Arctic matters to everybody Adaptation risks to indigenous livelihoods in the Arctic threaten cultural heritage and pose broader concerns for human security and social justice. To frame these adaptations within the context of global responsibility is important to prevent maladaptation and enhance coherence of policy responses. Adaptation challenges in the Arctic is a matter of concern for the global community. • Prioritise adaptation interventions: Tradeoffs between potential benefits and risks Addressing cross-border climate impacts requires balancing adaptation with other societal goals. For instance, limiting resource extraction and transport could improve local resilience in the Arctic, but expanding Arctic raw material extraction (which promotes more shipping) is crucial to EU climate policies for reducing carbon emissions. It is crucial to identify compromises that enhance overall resilience, considering the likelihood, magnitude, and timing of impacts and responses. Timing is especially important. Some impacts are already felt while others, like global shipping growth, may not materialize until after the 2030s. • Mitigation efforts must be scaled up The global ramifications outlined in this policy brief underscore the urgent need for ongoing and intensified mitigation strategies. These efforts are essential to curtail further degradation of Arctic ecosystems and to mitigate their farreaching consequences on a worldwide scale. CRiceS Policy Brief 2024 Contributors: Claire Mosoni, Stefan Fronzek, Marianne Tronstad Lund, Heidi Katrine Bang, Eilif Ursin Reed, Carley Iles, Bjørn H. Samset, Adeline Suppo, Jennie L. Thomas This policy brief is based on: Mosoni, C., Hildén, M., Fronzek, S., Reyer, C. P. O., & Carter, T. R. (2024). Cross-border dimensions of Arctic climate change impacts and implications for Europe. WIREs Climate Change, 15(5), e905. https://doi. org/10.1002/wcc.905 Doblas-Reyes, F. J., Sörensson, A. A., Almazroui, M., Dosio, A., Gutowski, W. J., Haarsma, R., et al. (2021). “Linking Global to Regional Climate Change,” in Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, eds. V. Masson-Delmotte, P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, et al. (Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press), 1363–1512. doi:10.1017/9781009157896.012. The CRiceS project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 101003826. The work reflects only the authors’ view; the European Commission and its executive agency are not responsible for any use that may be made of the information the work contains CRiceS Policy Brief 2024 www.crices-h2020.eu