Train Where You Expect to Fight: Why Military Exercises Have Increased in the High North

The new Arctic Military Exercise (ArcMilEx) dataset, which I introduce in this article, demonstrates that since 2006, Western-led military exercises have increased in the ‘High North’ (European Arctic), and that involvement in such exercises is not limited to Arctic states (26 European countries from beyond the Arctic have participated in at least one of these exercises). What the increased number of military exercises shows is that Western states (including both Arctic and non-Arctic countries) are keen to demonstrate that they have the capabilities, competence and resolve to project force in the northern high latitudes to deter potential adversaries. This paper examines the reasons behind this activity. First, it highlights the calls made by small Arctic states, especially Norway and Iceland, for their non-Arctic allies to increase their military presence in the High North. Second, it points to the renewal of NATO’s commitment to deterrence and territorial defence in Europe, including the High North, as it has sought to improve Alliance cohesion and enhance interoperability. Both developments have emerged in response to concerns growing in the West about Russia’s military ambitions in the Arctic, North Atlantic and Europe, especially since President Vladimir Putin’s re-election in 2012. The paper concludes that the material increase in Western military exercises weakens claims that cooperation is the dominant trend in the Arctic and reinforces recent scholarly analyses that paint a more complex picture of the contemporary regional security environment where conflict and cooperation go hand in hand. Using the new ArcMilEx dataset to monitor military exercises in the Arctic (and who is participating in them) is shown to be a valuable barometer of both Arctic and non-Arctic states’ concern about regional stability and security.


Introduction
Military activity in and around the Arctic is growing. It has been well documented that all eight Arctic states (A8) 1 have been restructuring and upgrading their military forces over the past decade (Wezeman 2012(Wezeman , 2016. However, what tends to be overlooked is that the armed forces of countries from far beyond the Arctic, including leading European military powers, have also increased their military activity in the region, especially in the 'High North'. 2 This growing involvement of non-Arctic states in military activities in and around the High North since 2006 is captured by a new dataset on 'Arctic Military Exercises' (ArcMilEx), which I introduce in this paper.
The growing military involvement of non-Arctic states in the High North is a development which, along with the overall intensification of (expensive) military exercises in and around the High North, is rendered all the more striking by the fact that for much of the past two decades, A8 diplomats have downplayed any potential for armed conflict in the region (Centre for International Law 2008; Jacobsen 2018). Yet the material changes in military activity in and around the Arctic -including the significant increase in Western-led Depledge: Train Where You Expect to Fight 290 eration in the region have stood in stark contrast to the emergence of primarily media-driven narratives, warning of impending armed conflict over territory, resources and trade routes. Hence, there has been considerable speculation and debate from 2007 onwards as to whether the Arctic would remain a region of cooperation or become a zone of (armed) conflict (Young 2009(Young , 2011. While some warned that the Arctic was being re-militarised, especially by Russia, others emphasised that in places where military activity was rising, it was generally in keeping with the expectations of changing national security requirements brought about by climate change (Borgerson 2008;Åtland 2011;Wezeman 2012Wezeman , 2016. In addition, the continuation of joint military exercises between former Cold War adversaries, the cooperative efforts to address 'soft' transboundary security challenges (such as search and rescue) and the emergence of new fora -such as the Arctic Security Forces Roundtable and the Arctic Chiefs of Defence Staff Conference where military staff could discuss the evolving security environment -suggested that even with increasing military activity, the Arctic was still characterised more by cooperation than by conflict.
Meanwhile, the resumption in 2006 and the subsequent intensification of Western-led military exercises (especially those involving non-Arctic states) that were implicitly, if not explicitly, at least in part directed towards Russia (such as those shown below) have been largely ignored in the scholarly literature -despite the fact that such exercises remind us that the Arctic security and defence complex is not just an A8 concern, but has long been of consequence for others from well beyond the region. 5 Even when these Western-led exercises have been mentioned by scholars, their significance was only hinted at (see, for example, Huebert 2010), perhaps because military exercises interfered with the consensus that had emerged after the Cold War, and yet again after 2008, that the prospect of conflict in the Arctic was exceptionally low. Perhaps, too, it was because some were still hopeful that rising Russian Arctic military activity should, and could indeed, still be regarded as defensive and, in fact, necessary given the effects of climate change. Naturally, this approach also neatly side-stepped the fact that the contribution by Western military exercises to increasing the overall level of military activity in the Arctic certainly antagonised and worried Russia.
Either way, the post-Cold War Arctic security environment has always been more complicated than the conflict-cooperation dichotomy would suggest. Even immediately after the Cold War, when there was good reason to think that the Arctic might actually become a permanent zone of peace and cooperation for the Arctic states, inclusive of post-Soviet Russia, the potential for conflict remained (Åtland 2008). This was true despite the period of institution-building that culminated in the creation of the Arctic Council in 1996. During that time, military concerns seemed less pressing. The A8 had appeared more interested in exploring circumpolar approaches to tackling shared 'human security' challenges in the region (Exner-Pirot 2012). Soviet/post-Soviet Russian and NATO military activity was scaled-back, and some cooperative ventures were initiated, such as the joint Norway-Russia Norwegian/Barents Sea Exercise 'POMOR' in 1994 (Łuszczuk 2016). Military cooperation in the Arctic between the West and Russia also increased within the area of environmental security, with initiatives such as the 1996 Arctic Military Environmental Cooperation.
Yet, while the Arctic clearly witnessed a higher level of peace and stability after the Cold War ended, not all residual military activity in the region was cooperative in spirit. As its economy collapsed and its armed forces deteriorated, Russia still put in place measures to concentrate and maintain its sea-based nuclear forces under the protection of a 'Strategic Northern Bastion' centred in the Kola Peninsula (Åtland 2011). Russian naval patrols in the High North continued until the end of the twentieth century (Tamnes 2017). During this period, some NATO countries also remained cautious, even though the region received little attention from the Alliance (Heininen 2010). While Alliance concepts and command structures were rearranged to support the 'War on Terror' and NATO-led training and exercises in the Arctic declined, several non-Arctic NATO members (the United Kingdom, most notably) continued to send troops -albeit in smaller numbers -to train and exercise in northern Norway, as they had done throughout much of the Cold War (Depledge 2018).
So, despite a substantial fall in military activity in the Arctic and a surge in circumpolar cooperation among the A8, it was clear that the ghosts of the Cold War were never completely exorcised (Palosaari & Möller 2004). However, this interpretation has only recently regained traction within the Arctic security studies community, thus demonstrating the extent to which much of the scholarly work that followed the geopolitical intrigue of 2007/8 was focused on trying to debunk notions of an imminent conflict in the Arctic and, particularly, that Russia posed any sort of threat to Western interests. At the same time, the US-Russia 'reset' in 2009 pointed towards an easing of the broader geopolitical tensions sparked by NATO enlargement and the Russia-Georgia War. Thus, in this period, there was perhaps less interest in the potential for a strategic spill-over effect in the Arctic than what emerged after West-Russia relations worsened again in the wake of the latter's military interventions in Ukraine and Syria. Even then, only limited attention was paid to the Western-led military exercises (especially those involving non-Arctic states) which, as the data presented below shows, were continuing to grow in number. 6 This was the case in spite of the potential for the growing number of military exercises since 2006 to highlight the contribution by Western states to the broader rise in military activity in the Arctic, destabilise the claim that the Arctic remains a region of low tension and cooperation, and reinforce more recent attempts to nuance our understanding of the region's conflict potential.

The Arctic Military Exercise Dataset (ArcMilEx)
I created the Arctic Military Exercise (ArcMilEx) dataset to shine a light on the increasing number of Western-led military exercises involving non-Arctic states taking place in and around the Arctic. 7 These exercises involving non-Arctic states matter because they implicate the Arctic in a wider strategic competition between the West and Russia that also encompasses adjacent areas, such as the North Atlantic and the Baltic. Exercises involving fewer than three countries (i.e. bilateral as opposed to multilateral exercises) or in which only Arctic states participated, have been excluded from the ArcMilEx because they tend to be more regional in focus. Unfortunately, Russian exercises involving non-Arctic states cannot be presented due to a lack of open source data on the extent of non-Arctic state participation, known to have included Collective Security Treaty Organisation countries (Buchanan & Boulègue 2019).
The dataset begins in 2006, when Norway invited its non-Arctic allies to take part in a major joint military exercise, led by its own national defence forces: 'Cold Response' (EXCR). Since then, two other military exercise series have been developed that also take place in and around the High North: Dynamic Mongoose (DYMON) and Arctic Challenge (ACE). I discuss the reasons behind the emergence and evolution of these exercises in the section below. The ArcMilEx also accounts for several exercises that have taken place since 2006 in and around other parts of the Arctic. Thus, the ArcMilEx highlights the varied geography of Western military interest and activity in the Arctic, reinforcing the need to be cautious about defining the entire region by any single trend towards cooperation or conflict (Østhagen, Sharp & Hilde 2019).
Some may find my definition of Arctic-related military exercises problematic. However, the definition of the Arctic and its sub-regions (like the High North) is notoriously difficult (Tamnes & Offerdal 2014). For the purposes of this paper, the crucial factor underlying all of the exercises considered is that they -either partly or fully -took place above the Arctic Circle (at 66°33'47.8 North) or are otherwise consequential for the region. For example, the area of operations for the anti-submarine warfare exercise DYMON has only occasionally crossed to north of the Arctic Circle. Nevertheless, fundamentally, DYMON is oriented toward preparations for a potential threat coming from the Arctic, reflecting the core principle of military exercises that you train where you expect to fight or, at the very least, aim to deter potential adversaries. Overall, the effect in the case of each exercise is to increase the involvement of non-Arctic states in military activity in the region.
According to my more expansive definition, non-Arctic countries participated in at least 24 multinational exercises in and around the Arctic between 2006 and 2019. These exercises are listed in Table 1. The non-Arctic countries involved are shown in Figure 1. The number of exercises per year is shown in Figure 2. The number of exercises each non-Arctic state has participated in is shown in Figure 3. No assessment has been made of the actual numbers of participating troops or assets contributed by each country as this data was not consistently available. What the data does reveal is that while the overall number of non-Arctic states that have participated in military exercises in and around the Arctic has grown since 2006, the number of states participating in any given year has varied, with one exception: All NATO countries participated in the northern-focussed Trident Juncture (TRJE) in 2018. This variation is partly explained by the fact that, excluding TRJE (which was a one-off exercise in the north), the largest exercise considered here, EXCR, is held biennially, bringing a surge of non-Arctic countries to the High North every two years. 8 In spite of the variation from year to year, some countries have participated regularly (most notably the UK, which has participated in all but one of the exercises listed), while others have participated on a more sporadic basis. Given the size, geographical reach, operational history and strategic ambitions of their respective armed forces, it is perhaps unsurprising that France, Germany and the Netherlands are the other non-Arctic countries that have participated in more than half of the exercises. For other countries, with smaller armed forces and more constrained defence budgets, participation has been more ad hoc. Nevertheless, even irregular participation signals a willingness amongst other European nations to demonstrate solidarity with their northernmost allies. That was particularly important in a NATO context when it came to TRJE 2018: For ten of the countries 9 identified here, this was the only exercise in and around the Arctic which they participated in during the period in question.    Arguably, the most important revelation in the ArcMilEx is that the intensity of exercises in and around the High North has increased since 2006: from one exercise every one-two years to two or three exercises each year, peaking with four in 2019. While this may not look dramatic, it implies an increased military presence and a higher tempo of activities involving non-Arctic states, which not only raises the costs for those involved, but also ties up capabilities that might be needed for military operations elsewhere in the world. As I explained earlier, it is reasonable to suggest that the more military exercises there are in the region, the greater the potential for accidents, misunderstandings and miscalculations that might inadvertently raise the risk of conflict. Increasing military exercises might also provoke rather than deter potential adversaries, especially in a region like the High North where Russia strongly opposes Western-led military activity. These greater economic, political and strategic risks are unlikely to be tolerated unless the perceived benefits of exercising (which may relate, for example, to strategic communication, the strengthening of alliances, the testing of capabilities and so on) outweigh the costs.
Comparatively, hardly any multilateral exercises in the North American Arctic have involved non-Arctic states until 2019 when Canada invited France to participate in Operation Nanook-Nunalivut. This reflects the fact that, historically, under the 1940 'Ogdensburg Agreement', Canada and the United States have opted for a bilateral approach to defence and security in the North American Arctic. By contrast, in the High North, NATO has been the main guarantor of security for most of the Nordic states (Østhagen, Sharp & Hilde 2019). However, given the decline of NATO interest in the High North after the Cold War, the fact that the Alliance had a historical interest in the High North does not explain why military exercise activity, especially activity involving non-Arctic states (most of which are members of NATO), has been increasing again since 2006.

The High North Calling
Several connected occurrences help to explain why Western-led military exercises involving non-Arctic states are happening more often in and around the High North than a decade or so ago. The first is that two small Arctic states, Norway and Iceland, have urged their non-Arctic allies to increase their awareness of how the High North is being transformed because of climate change and provide assurances that they are still willing and able to operate militarily in the area. The second is that after years of being bogged down in ' out-of-area' operations in Afghanistan and Iraq, NATO recognised that, as part of its 'return' to Europe, there were good reasons to resume exercising in and around the High North, if only to rebuild key capabilities and increase inter-operability. This was a useful compromise from Norway and Iceland's perspective as it encouraged a general increase in Alliance activity in and around the High North without being directed explicitly towards Russia. It was not until Russia's illegal annexation of Crimea in 2014 and its more overt hostility towards the West -especially NATO -in the years after that Nordic and Alliance exercise planning in and around the High North became more urgent. Together, these developments gave rise to three new military exercise series: EXCR, DYMON and ACE as well as several other military developments and ad-hoc activities.

Iceland and Norway: Alone in the High North
Despite the significant decline in the threat Russia posed to Norway after the Cold War, Oslo always remained mindful that it relied on its NATO allies for national defence and deterrence (Hilde & Widerberg 2014). Still, military exercises in the High North became less frequent and more modest in scope (Heier 2018). However, in the early 2000s, after '9/11' and the start of the US-led operations in Afghanistan and Iraq, some within the Norwegian Ministry of Defence began to question whether NATO could still be relied upon to come to Norway's defence, especially since the 'Northern Flank' was barely receiving any attention in Alliance circles (Tamnes 2017). More broadly, the Alliance had also ceased to conduct collective defence exercises after the new NATO-Russia partnership was confirmed in 2002, leaving smaller members like Norway particularly exposed (Heuser & Palmer 2018). Oslo's concerns grew more serious as Russia's economic and strategic resurgence in the early-to mid-2000s began to take hold and growing evidence of Arctic climate change promised significant transformation of the region, especially in terms of access to territory, resources and trade routes (Hilde & Widerberg 2014).
By the mid-2000s, Norway was close to losing confidence in NATO's new command structure and exercise programme. 11 Both had undergone significant changes in response to NATO's shift in focus to ' out-of-area' operations. Norway's own national defence forces had also been restructured in a way which arguably made the country more dependent on rapid allied reinforcement in the event of a crisis (Heier 2018). This worried Norwegian defence officials, because if multinational exercises in northern Norway ceased altogether, Oslo's allies would lose the capabilities and competence to operate effectively in the climate and topography there, even if their resolve remained intact (Depledge & Dodds 2012;Heier 2018). The potential loss of this key pillar of deterrence was particularly concerning because the recent uptick in Russian military activity in the region increased the possibility of minor disputes that might not cross the threshold needed to produce an immediate and decisive response from Norway's allies, leaving Oslo vulnerable to pressure from Moscow (Heier 2018). Several diplomatic incidents between Oslo and Moscow over Norway's administration of a Fisheries Protection Zone around Svalbard, although carefully managed by both sides through non-military channels, had already served as a reminder of Norway's unsettled disputes with Russia in the Barents Sea (Åtland & Ven Bruusgaard 2009). Elsewhere, Russia was squaring off with Ukraine over gas supplies , thus seemingly confirming Oslo's concerns that Moscow was prepared to flex its returning geopolitical muscle (Hilde & Widerberg 2014).
In 2006, Oslo responded to NATO's apparent ambivalence concerning the High North by announcing a new multinational military exercise to be held there: EXCR. The exercise would be Norwegian-led, but invitations were issued to all NATO allies and partners. To encourage participation, EXCR would focus on a crisis response scenario that reflected NATO's growing focus on collective security ' out-of-area' as opposed to collective defence 'in area'. For Oslo's immediate purposes, the focus of the exercise mattered less than the very act of exercising in northern Norway. Also, Oslo's long history of being cautious of Russia, and not unnecessarily antagonistic, meant that overt exercises of collective defence against a hostile power (which many would have assumed to be Russia) would have made little sense at the time (Østhagen, Sharp & Hilde 2019). Oslo's main priority with EXCR was to show the world that Norway still had military allies with the capabilities, competence and resolve to come to its defence in the High North and deter aggression from potential adversaries.
Norwegian calls for NATO allies not to lose sight of the High North were echoed by Iceland that same year. Washington's sudden decision in 2006 to unilaterally withdraw US forces from the Keflavik Naval Air Station after more than five decades of continuous operations had forced Reykjavik to rethink its approach to national security and defence (Ingimundarson 2007). With new defence responsibilities to take on, and in the absence of any national defence forces, Iceland pursued a more active role in NATO. As part of this, Reykjavik echoed Oslo's calls (which also provided considerable support to Iceland as it adjusted to the withdrawal of US forces) for the Alliance to pay more attention to emerging challenges in the High North. Like Oslo, Reykjavik was concerned about NATO's apparent loss of interest in the North Atlantic and High North at a time when the Arctic was attracting greater attention internationally.
Norway and Iceland's efforts between 2006 and 2009 were at least partly successful. Although many of their allies were focussed on operations in Afghanistan and Iraq, several countries, including leading European military powers such as the UK and France, accepted Norway's invitation to participate in EXCR 2006. Despite the diminished significance of the 'Northern Flank' for these countries, the resumption of military exercises in the Arctic coincided with the growing concern in the West about Russia's ambitions under President Vladimir Putin, as exemplified by his claim a year earlier that the collapse of the Soviet Union was the 'greatest geopolitical catastrophe' of the 20 th Century. For EXCR 2007, the number of non-Arctic participants rose from seven to eleven, the most notable other addition being Germany. Eleven countries, this time including Turkey, participated in EXCR 2009. These figures suggest that for several non-Arctic NATO members, even in the absence of any immediate security concerns in the High North, participating in EXCR was regarded as a valuable opportunity to practice interoperability and test personnel and capabilities under extreme conditions (including mountains and cold weather environment, which might be beneficial in other places such as Afghanistan), at the same time demonstrating their commitment to their northernmost allies. Meanwhile, in Iceland, in 2007, NATO acquiesced to Reykjavik's request for the Alliance to provide a 'light' air policing mission to protect Icelandic airspace (Ingimundarson 2009). Then, in 2009, NATO's North Atlantic Council took part in a joint Iceland-NATO Seminar in Reykjavik on 'Security Challenges in the High North', exploring future challenges arising from Arctic ice melt (Holtsmark & Smith-Windsor 2009).
However, Norway and Iceland's efforts to bring their allies back to the north were ultimately blunted by disagreements within NATO -also among some of the NATO Arctic states -over whether increasing NATO's military presence in the High North would cause more problems than it would solve (Haftendorn 2011). Here, it is important to note that even the presence of non-Arctic NATO members was potentially problematic, particularly since Russia tends not to distinguish between activities led by NATO (such as the seminar in Reykjavik and, later, military exercises such as Dynamic Mongoose) and activities not led by NATO, but involving key members like the UK (such as the Norwegian-led EXCR). At any rate, relations between the West and Russia were showing signs of improvement after Washington and Moscow reset their relations in 2009, following several years of tension over NATO enlargement and Russian aggression towards Europe. While stories swirled in the international news media about an impending conflict in the Arctic, many in the West -including Norway and Iceland -preferred to focus on the prospects for closer cooperation with Russia in the region. Thus, any increase in military exercises -and especially the presence of non-Arctic allies -was kept at a relatively low level (see, for example, Holtsmark & Smith-Windsor 2009).

Renewing Commitments and Capabilities in the High North
The creation, three years later, of a new NATO exercise series -Dynamic Mongoose (DYMON) -focussed on antisubmarine activity in the North Atlantic and the High North and was only partially connected to Norway and Iceland's earlier calls for NATO to pay more attention to the Arctic. Of greater influence within NATO was the way that Oslo's concern about a lack of activity in the High North was linked to a broader concern about the Alliance's shift in focus towards ' out-of-area' operations, and the extent to which this detracted from its core task of providing territorial defence in Europe (Efjestad 2017;Heier 2018). In 2008, Norway put forward for consideration by its allies a 'Core Area Initiative' to redirect NATO's focus to Europe. This reflected Oslo's growing apprehension about Russia and Norway's determination to ensure that its allies were ready to come to its defence. The proposal gained support from other allies in the Alliance's peripheries as well as the US and the UK (which had initially been sceptical because of the ongoing operations in Iraq and Afghanistan) (Hilde & Widerberg 2014). Further efforts to enhance Alliance solidarity around ' collective defence' were eventually manifested in NATO's 2010 Strategic Concept. At the Chicago Summit in May 2012, Alliance leaders were emphasising the need to ' expand' training and exercises across Europe to improve the interoperability of NATO forces (NATO 2012).
It was in the context of these broader efforts (as opposed to Norway and Iceland's independent concerns about the Arctic) to redirect the Alliance's focus to the collective defence in Europe that the costs of neglecting the North Atlantic and the High North in the early 2000s started to become apparent to several NATO allies. The need to address this inattention had taken on greater urgency as Russia's military exercises, including in and near the Arctic, had begun to intensify (Heuser & Palmer 2018). A key area of concern for NATO was the degradation of the Alliance's ability to conduct anti-submarine warfare in the North Atlantic and High North, following years of declining training and exercise activity (Gade & Hilde 2015). This capability had long been seen as critical to protecting the Trans-Atlantic Sea Lines of Communication between Europe and North America, but after the Cold War ended, the North Atlantic was no longer considered to be ' contested waters' (Olsen 2017). The need for NATO to pay greater attention to the North Atlantic was further compounded by the relative lack of naval assets at the Alliance's disposal following two decades of post-Cold War cuts to national capabilities among member states, right at a time when Russia was investing heavily in modernising its undersea capabilities. 12 Starting in 2012, NATO responded by reinvigorating its maritime exercise programme in the North Atlantic and High North. It did so by amalgamating what remained of national and small group training and exercises into a single NATO exercise involving undersea, surface and airborne assets: DYMON. 13 The new NATO-led exercise allowed the Alliance to begin regenerating its joint anti-submarine warfare capabilities in the North Atlantic and High North (that had perished significantly since the beginning of the century 14 ). Aside from the Icelandic Air Policing mission, this was arguably the most significant NATO-led military exercise activity in the proximity of the High North since the Alliance had stopped exercising there in 2005. As such, DYMON marked the return of NATO to the North Atlantic and High North, although any link to changes unfolding in the Arctic could only be inferred by its proximity to the Greenland-Iceland-UK Gap and the focus on antisubmarine warfare. All of this was happening against the backdrop of emerging concern within NATO -and among leading members of the Alliance, including the UK and France -about Russian's growing undersea capacities, many of which were being deployed from bases in the Arctic (Hudson & Roberts 2017).

Russia, the Ukraine Crisis and the High North
Despite the substantial evolution of Russia's military posture in the Arctic since the beginning of the century, up until 2013, the strategic imperative for NATO allies and partners to exercise in the High North had remained limited. As already noted, many in the West were still focussed on improving relations with Russia.
The Norwegian defence establishment clearly had concerns about Russia which was the impetus behind Oslo's calls for its allies to not neglect the High North in the 2000s. At the same time, however, reflecting Norway's longstanding approach to defence, Oslo was cautious not to provoke Russia unnecessarily, especially given the importance of their bilateral relationship regarding economic activity in the High North. At any rate, despite growing concerns about Russia's plans to upgrade its Arctic military structures and the challenges posed by its renewed submarine activity in the North Atlantic, military competition in the High North still looked a distant prospect. After all, as suggested by the US-Russia reset in 2009, the 2010 Norway-Russia agreement settling a forty-year old dispute over their maritime border in the Barents Sea and the 2011 treaty on search and rescue cooperation signed by the A8, there were many positive projections. The establishment of the Arctic Security Forces Roundtable, a US-led initiative in 2011, and the Northern Chiefs of Defence Conference, a Canadian-led initiative in 2012, had furthermore for the first time created formal spaces for military chiefs to meet and build trust with respect to military activity in the northern high latitudes. All this was reflected in the relatively limited increase in Western military exercises involving non-Arctic states between 2006 and 2013.
In 2013, that picture changed rapidly. Relations between the West and Russia had already taken a turn for the worse after a series of disagreements following President Vladimir Putin's return to office a year earlier. Russia also began to stage 'no-notice' snap-alert exercises, including in the Arctic (Heuser & Palmer 2018). Sweden became particularly concerned after Russian planes simulated an airstrike on Stockholm and surrounding areas which, as later revealed, had included a nuclear component (The Local 2016). Sweden responded by pushing for an expansion of air defence cooperation in the High North. For several years already, the defence cooperation between the Nordic states had been deepening, leading to regular joint air training and exercises (Efjestad 2018). However, in 2013, the US, the UK and NATO AWACS were invited to become training partners in a new exercise series called Arctic Challenge (ACE) that would take place on a biennial basis. 15 While ostensibly focussed on improving interoperability among participating air forces, ACE also sent a firm signal that the Nordic countries, their allies and their partners were willing and able to protect northern European airspace.
However, the biggest shift in the West's pattern of military exercise activity in and around the High North was still to come. Relations between the West and Russia virtually collapsed after Russia's illegal annexation of Crimea in 2014, Moscow's subsequent efforts to destabilise eastern Ukraine and the subsequent implementation of Western sanctions. The first sign of a shift in tone with respect to Western military exercises emerged when DYMON became an annual exercise, reflecting growing concerns about Russian submarine activity in the North Atlantic and High North. A year later, the 2015 iteration of ACE was expanded to include more non-Arctic states (from one in 2013 to five in 2015), and the exercise is now one of the largest and most complex air exercises in Western Europe (Efjestad 2018). Perhaps the most significant development of all though was that the planning for EXCR 2016 was openly shifted from crisis response to collective defence, with the clear purpose of sending a message that Norway and its allies were prepared to defend their interests in the High North (Heier 2018). Two years later, Norway further demonstrated its resolve by hosting NATO's massive Trident Juncture Exercise (TRJE). 16 This Alliance-led exercise, which stretched into the High North, saw NATO and partner nations training and operating together in an Article 5 scenario, in what was by far the largest exercise to take place in Norway since the Cold War.
While another exercise in the magnitude of TRJE may not be expected for several years (unless there is further deterioration of the strategic environment in the North Atlantic and High North), EXCR is likely to stay focussed on the collective defence for the foreseeable future (unless there is a significant improvement in relations with Russia). Meanwhile, DYMON will continue to provide the basis for exercising NATO's antisubmarine warfare capability in the High North and North Atlantic, while ACE will continue to test air force capabilities in the skies over Scandinavia. Even if the initial impetus for all three exercises was precautionary and ostensibly inward-focussed, the scaling up of this activity since 2014 both reflects and addresses the worsening of West-Russian relations and the subsequent imperative, particularly among the smaller Arctic states (Norway, Iceland, Sweden and Finland), to ensure that their non-Arctic allies have the capabilities, competence and resolve to provide military support, if necessary, and to communicate this to potential adversaries.

Conclusion
This paper began by questioning why Western-led military exercises in and around the High North have increased since 2006, hereunder the substantial involvement of non-Arctic countries. The most notable feature of the analysis of the ArcMilEx is to confirm the increasing tempo of these Western-led military manoeuvres. As the ArcMilEx reveals, we have witnessed an escalation from one exercise every one-two years to two or three exercises each year, peaking with four in 2019. This increase is explained by several linked developments. Calls from small states feeling vulnerable in the High North, demands for NATO to 'return' to Europe and improve Alliance cohesion and growing concerns about Russia all appear to have been key considerations as military exercises in and around the High North became more frequent, complex and important in order to signal that the West had the capabilities, competence and resolve to defend its allies and interests. As shown by ArcMilEx, there are now three regular joint exercise series involving non-Arctic states, relating to the High North: EXCR, DYMON and ACE. Besides, there have been other irregular exercises involving extra-regional countries.
The rising number of military exercises involving non-Arctic states makes it clear that the High North and the Arctic are once again emerging as an integral part of European and North Atlantic security and defence planning. After all, you train where you expect to fight or, at the very least, where you aim to deter. Significantly, military exercises -as opposed to base-building or permanent deployment of non-Arctic forces above the Arctic Circle -appear to have become the instrument of choice in the West for building cohesion and expressing solidarity among allies whilst pushing back against (or perhaps catching up with) Russia's attempts to strengthen its military position in the Arctic. An advantage of military exercises is that they can be quickly scaled up or down in terms of size and ambition -and advanced or withdrawn -in order to force a shift in an opponent's strategic calculations, or respond to changes in relations. This gives Western states greater flexibility when it comes to managing the economic, political and strategic costs associated with military exercises in an extreme environment as the High North. Such flexibility is particularly useful for the small Nordic states which are constantly faced with the challenge of balancing deterrence and confidencebuilding in relation to Russia. Naturally, the danger is that efforts to use exercises to deter potential adversaries are misjudged and actually increase the likelihood of conflict by contributing to the build-up of military forces in and around the High North, at the same time adding to the risk of provocation, miscalculation and misunderstanding. This is why it is important to keep updating the ArcMilEx and ensure that Western military exercises in the Arctic, and indeed their effects in the regional security environment and adjacent areas such as the North Atlantic and the Baltic, receive greater attention and scrutiny.
At the same time, more research is needed to understand the various motives of different non-Arctic states for engaging militarily. 17 In the United Kingdom, for example, participation in High North exercises has been useful in building closer defence relations with Norway, Sweden, Finland and the US. UK involvement also reflects its particular concerns about Russia's submarine activity in the North Sea and the North Atlantic, expanding military activity in the Arctic, and geopolitical ambitions in Europe (Depledge, Dodds & Kennedy-Pipe 2019). For other states, it may be that they mainly participate because it is an opportunity to train on a larger scale than they are capable of nationally and because they want to demonstrate commitment to allies.
Ultimately, the ArcMilEx contributes to the wider academic debate by reinforcing recent efforts to dispel any notion that the Arctic is a region of ' exceptional' peace and stability. That is not to say that cooperative endeavours are failing, or that the region is now defined by conflict. Rather -as Heier (2018) has argued specifically in the case of Norwegian military exercises -any change in the tempo of military exercises in the region and the extent of non-Arctic state involvement is perhaps best regarded as a useful barometer of Western sentiment towards the stability of the region and, more broadly, West-Russia relations. Thus, continuing to use tools like the ArcMilEx to monitor the intensity of Western military exercises in the Arctic, the extent of non-Arctic states' participation and the geographies involved, will be valuable in assessingalongside other trends -how the regional security environment is evolving in the years ahead.
would further like to thank Caroline Kennedy-Pipe, Andrew Foxall, Paal Sigurd Hilde and Dmitriy Tulupov for their helpful comments during the drafting process. All errors remain my own.