Crowded Skies and Turbulent Seas: Assessing the Full Scope of NATO-Russian Military Incidents

August 19, 2021
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In June, Russian forces threatened to fire on a British destroyer, HMS Defender, while it was sailing in the Black Sea near Crimea. Russia accused the warship of violating its territorial sovereignty, while the British government insisted that it was operating, legally, in international waters. Over 20 Russian aircraft shadowed the Defender, while coast guard vessels tried to force it off course. These actions posed a serious threat to the British ship, and constituted one of the most harrowing military incidents between London and Moscow since the Cold War. While the tensions that day in the Black Sea did not spin out of control, Russia’s subsequent threat to escalate on future such occasions was particularly ominous.

As dramatic as it was, the Defender incident was not a one-off. Indeed, the more compelling issue here is that the frequency of these dangerous encounters has risen significantly over the last several years. According to a database we compiled using official and open-source data, from January 2013 through December 2020, there were some 2,900 reported events of NATO allies and Russia conducting missions that brought them into proximity with one another. Further, within this period, annual numbers have trended upward, making the challenge of managing these occurrences now considerably more daunting than before. Although incident rates were highest around the Baltic, Black, and Norwegian Seas, these events take place all around the world — spanning the NATO-Russian border — making the problem truly global rather than regional.

Behind the Numbers 

Our database incorporates as many incidents between NATO and Russian forces as possible from official and secondary sources to appreciate the scale, chronology, and geographic scope of this larger problem. We gathered available aggregate annual activity summaries from U.S., NATO, and Russian military commands to get a sense of how often, where, and why these events occur. Then we added details on as many of these specific incidents as we could find from the respective sides’ command web sites, media stories, citizen investigative work, and online reporting (such as the Russian Military Incident Tracker) to illuminate the circumstances behind the aggregate totals.



We found detailed accounts of individual incidents in about 20 percent of the estimated total number of cases, enough to arrive at guarded conclusions about events by type, including air intercepts, show of force demonstrations (such as bomber deployments or naval task force patrols), and freedom of navigation operations (intended to challenge excessive maritime claims). With the database, these incidents can be probed for any other information that might be relevant, such as dangerous, unprofessional maneuvering or failure to comply with established procedures for collision avoidance (i.e., filing flight plans and utilizing transponders). Formal, regularly scheduled military exercises were excluded because they are anticipated and connote less immediate operational risk of problematic encounters. Ad hoc operations that are sometimes referred to as “exercises” are included. Because 2013 was the last year before the transformative Russian seizure of Crimea and invasion of eastern Ukraine — a major turning point in relations between Russia and the West — we use it here as our baseline.

Every incident was cross-checked by date, location, and detail to avoid double counting. In the case of air intercepts, which are far and away the most common events, we counted scrambles. For show of force activity, we counted only the overall mission and not individual sorties over several days. Where such information is available, the types and numbers of aircraft and naval vessels involved were noted as those particulars are indicative of the purpose of the missions involved.

There are, without doubt, unavoidable issues with our sourcing. It is difficult to find complete official, annual U.S./NATO and Russian time series data on incidents. Accordingly, we had to make estimates for some years using fragmentary reporting and averages to fill in gaps. This was the case specifically for U.S./NATO operations in Europe for 2013 and 2014, and for Russian data for 2013 to 2016. We were able to check our estimates with occasional official statements about trends (usually upticks) in activity. We also compared these estimates with our incident database, the assumption being that tendencies we see there should roughly reflect the aggregate figures, and the fit here seems good. If error was incorporated in this process, we believe it to be on the downside — that is, if more detailed data become available, they will almost certainly drive the total event numbers still higher. Consequently, although we are confident that our findings are certainly suggestive of the overall operational and strategic dynamic, we acknowledge that they are not, strictly speaking, dispositive.

What the Numbers Say 

There were some 2,900 incidents between NATO and Russian forces between 2013 and 2020. The three-year moving average increased by more than 60 percent over this eight-year timespan.

Figure 1

Source: Generated by authors using U.S, Russian, and NATO documents.

The most common incidents between NATO and Russian forces in this period (around 85 percent of all occurrences) involved air-to-air intercepts. Some of these were responses to show of force missions, particularly involving strategic air assets (such as U.S. Air Force bomber deployments) and others in response to naval freedom of navigation operations. Pervasive airborne intelligence, surveillance, and reconnaissance missions also drew a large number of air intercepts. During some of these, Russian fighters have performed unprofessional maneuvers with a high risk of mid-air collision. However, many intelligence collection missions do not show up in our numbers because they did not generate a reported air defense fighter response. According to Russian sources, there were more than 2,600 “foreign” intelligence gathering missions around Russia’s frontiers between 2019 and 2020 alone, an average of over three daily. Russian Ministry of Defense activity reports show 491 Russian fighter scrambles during that period. In all likelihood most of these were in response to U.S. and NATO intelligence aircraft. 

Where’s the Action?

The events enumerated above occur worldwide but, when geolocated, they reveal heavy activity concentrations in the Baltic, Black, and Norwegian Seas and in the Northeast Pacific region. The Baltic Sea and its littoral, accounting for close to 40 percent of all U.S./NATO-Russian encounters, is by far the most problematic when it comes to deconfliction between NATO and Russia. When the Baltic states (Estonia, Latvia, and Lithuania) joined NATO in 2004, the alliance quickly established the Baltic air policing mission to provide airspace security over their territory. Quick reaction alert fighters drawn in rotation from other NATO members began responding to purported Russian airspace violations or to identify aircraft, typically Russian, flying without flight plans and/or active transponders. Enhancements made to NATO radar coverage, command and control of its air assets, and greater operational tempo on the Russian side — including numerous intelligence gathering sorties of their own — led to much higher air intercept figures. Available NATO data show that, between 2015 and 2020, its fighters conducted over 750 Baltic air policing scrambles. Our estimate for 2013 to 2020 is just over 900.

The next most significant area for military activities that draw U.S./NATO and Russian forces into proximity is the North Sea-Norwegian Sea-Barents Sea sector, which accounts for about a fifth of our geolocated data points. This is a region that has increased significantly in terms of its geostrategic importance over the last decade and, accordingly, both NATO and Russian activity there has ramped up. Most of the events occurring in this area are also air intercepts, especially those conducted by the Norwegian and British air forces in response to Russian long-range aviation patrols rounding the North Cape and continuing southward towards, and sometimes beyond, the British Isles. Additionally, U.S./NATO forces have markedly increased their show of force activity in this region, both in terms of operational tempo and geographic extent that, in turn, prompts a more vigorous Russian response.

Two other regions, the Black Sea and the Northeast Pacific, each account for 10 percent of our locatable events. The Black Sea, another critical strategic nexus, has been the scene of rapidly increasing military activity since Russia occupied and annexed Ukraine’s Crimea region in 2014. With their huge naval complex at Sevastopol and enhanced forces in the adjoining Southern Military District, Russia has the capability to employ considerable strength in defending its interests in this vital area and has shown a willingness to confront U.S./NATO forces operating there. On the other hand, the allies have pushed back by creating a new air policing mission based out of Romania and Bulgaria, and by conducting naval freedom of navigation operations to demonstrate solidarity with NATO member states in southeastern Europe. Yet again, Russian aircraft routinely intercept U.S. and allied airborne intelligence collection missions over the Black Sea, often in a provocative manner.

The Northeast Pacific and the Chukchi and Beaufort Seas account for another 10 percent of U.S./NATO-Russian contacts, almost entirely composed of air intercepts of Russian strategic bombers approaching Alaska and northern Canada. The North American Aerospace Defense Command detects and coordinates these intercepts by U.S. and Canadian fighters. The number of such intercepts each year has trended up from low single digits early in our study period to over 20 in 2020. More recently, an inbound Russian aviation package might include escort fighters and airborne early warning and control aircraft, suggesting that the Russian Air Force is maturing its operational training by conducting more complex missions in this area.

Events in other regions, although less numerous than those above, are by no means insignificant. Russian air intercepts of allied surveillance sorties in the eastern Mediterranean in connection with Russia’s war in Syria have risen in numbers. Show of force missions by the Russian navy in this area likewise are notable. U.S. airborne intelligence and bomber missions over the Sea of Okhotsk have drawn strong responses from Russians forces and, in one particularly concerning incident, a Russian destroyer threatened to ram the USS John S. McCain as it was conducting a freedom of navigation operation in the Sea of Japan. Finally, on four occasions between 2013 and 2015, Russian Tu-95 (Bear) strategic bombers conducted long-range missions from the Russian Far East to Guam, which hosts a key U.S. military complex, as a dramatic show of force.

Why Is This Happening?

The increasing number of U.S./NATO-Russian military encounters and the locations where they take place are due to the need for both sides to demonstrate their ability to project power and also to show that they can protect their respective homelands. First, the show of force and freedom of navigation missions conducted by the alliance and Russia signal their interest in demonstrating operational capability in regions that each considers strategically significant. Although there are certainly training and interoperability benefits to such undertakings, the assurance and deterrence messaging and the desired demonstration effect of the missions themselves are usually highlighted by the initiating side. As Michael Mazarr has argued in these pages, such efforts may no longer be as relevant in light of the realities of distance and technological change. However, they have actually become more frequent and on a larger scale through the period of this study.

The second imperative, defense of the homeland, is more complicated for the NATO alliance given the dozens of state actors involved, some of which have little capacity to defend themselves. But those members that have air defense capabilities share in the alliance-wide airspace defense mission. For example, to date, 17 different national air forces have taken on the Baltic air policing alert mission. Russia plays up airspace vigilance through frequent press releases from its Ministry of Defense and on state-controlled media. Indeed, maintaining a strong national defense has long been a cornerstone of Russian President Vladimir Putin’s political survival strategy. As evidenced by the latest Russian national security strategy, any backing away from this posture is unlikely.

Our event database illustrates both the offensive and defensive sides of the geopolitical equation. Show of force and freedom of navigation activities, especially by the United States and NATO, have pushed aircraft and naval operations into areas that hitherto had seen little, if any, probing by the opposing sides since the height of the Cold War. Take, for example, the deployment of U.S. strategic air assets from bases in the United States to the European theater. Over the last three years, these bomber task force deployments have steadily increased the U.S. presence in northern Europe, especially in Norway and its adjoining seas, with B-1, B-2, and B-52 missions above the Arctic Circle and over the Barents Sea. U.S. and allied navies have also extended their show of force and freedom of navigation operations into the same area — including a carrier strike group — for the first time since the end of the Cold War. These naval demonstrations are highly visible and demonstrate significant offensive capability. At least three allied multinational task forces have conducted patrols into the Barents Sea which, given the vast Russian military establishment there centered on the Northern Fleet, drew considerable attention from Moscow.

A growing number of U.S. and NATO warships have entered the Black Sea since 2014. Russian surface ships and aircraft frequently shadow NATO vessels during their transit, at times acting aggressively to convey territorial sensitivities. In 2018, HMS Duncan approached closer to Crimea than Moscow desired and was met with a flurry of Russian aircraft activity around the vessel, some at very close quarters. This incident, in that it was very similar to that experienced in 2021 by HMS Defender, illustrates how the basic scenarios involved have not changed fundamentally even as they have become more frequent.

Looking Ahead 

NATO and Russia are engaged in an ongoing geopolitical drama, one in which the actors are willing and perhaps driven to increase the tempo and expand the arena in which it plays out. This makes dangerous military interactions, both at sea and in the air, much more commonplace and virtually guarantees more of the same all along the NATO-Russian frontier. One of the authors, in an earlier piece in this forum, argued that deconfliction and risk reduction measures should be a high priority for national security policymakers. Seemingly mundane steps like sharing flight and maritime routing and employing transponders could reduce the uncertainty inherent in no-notice encounters. The alliance and Russia should expand the agenda for the strategic stability dialogue that began in Geneva in July to include such deconfliction protocols for ongoing military activities, with an aim to reduce the risk inherent in the trends we have described here. Otherwise, the law of unintended consequences may be proven once again.



Ralph Clem is a senior fellow at the Steven J. Green School of International and Public Affairs at Florida International University. He also served as an Air Force Reserve intelligence officer in a fighter squadron and wing, and at the national agency level before retiring as a major general.

Ray Finch is a Eurasian military analyst for the Foreign Military Studies Office at Fort Leavenworth, Kansas. He served 20 years in the U.S. Army in field artillery and as a foreign area officer, and has spent the past 20 working in business, academia, and as a contractor for the U.S. government. 

The authors acknowledge valuable contributions from Kent D’Angelo and Mason Hussong in compiling and managing the database of events for this study, and extend thanks to an anonymous reviewer for comments on a draft of this piece. Any shortcomings remaining are solely the authors’ responsibility.

Image: North American Aerospace Defense Command