An earlier edition of this article was selected as the Naval Submarine League award-winning paper from the Naval War College. —Ed.
INTRODUCTION
Since the 20th century, the undersea has become an increasingly contested and strategically important domain, fueled by the exponential advancement of undersea technology. This domain first became a key area of contention with the advent of large-scale submarine operations over the two World Wars, where Allied forces employed anti-submarine convoys to counter German U-boats in Europe and the Atlantic, and turned the tables to engage in unrestricted submarine warfare to cripple the Japanese war effort in the Pacific.1 The devastating effect of adver- sarial submarine fleets against surface ships during both wars provided stark evidence that undersea superiority had become critical in ensuring the freedom of movement on the sea, and a lack thereof, particularly when facing a formidable adversary, could ultimately pose an existen- tial threat for maritime nations. Therefore, the undersea continued to be highly contested during the Cold War where the United States devel- oped an array of anti-submarine forces to mitigate the Soviet submarine threat. Beyond the security realm, this domain has also surged in eco- nomic importance. As land resources grow scarce and deep-sea explora- tion technology continues to advance, countries are turning towards un- dersea resources to meet rising energy and rare mineral demands.2 More crucially, the ocean floor is presently home to about 3EE transoceanic submarine cables through which more than $D trillion worth of financial transactions and 95 percent of the world’s voice and internet traffic flow.3 Hence, while the undersea today is not as fiercely contested as in the 2Eth century, the strategic importance of achieving and maintaining undersea superiority has indeed burgeoned with potential adversaries being better equipped to exploit the domain for one’s security and economy.
Having built significant submarine forces and anti-submarine capa- bilities to counter the Soviet submarine fleet during the Cold War, the United States eventually gained dominance of the undersea following the Soviet Union’s dissolution in 1991. To find, track, and hold-at-risk Soviet submarines around the globe, the United States deployed 184 ASW-capable destroyers and frigates, 102 nuclear attack submarines, and 450 P-3C maritime patrol aircraft by the 1980s.4 The United States also developed passive and active sonar systems, including the Sound Surveillance System (SOSUS) which was established at strategic under- sea locations worldwide as well as the Surveillance Towed Array Sensor System (SURTASS) which enabled the U.S. Navy to track Soviet nucle- ar submarines.5 Thus, after the Soviet Union’s demise, the United States became the sole proprietor of undersea supremacy and has hitherto been able to operate with “near-impunity throughout the world’s oceans and littoral waters” and maintain awareness of submarine activities along strategically important waterways.6 There is, however, an emerging challenge to U.S. undersea dominance particularly in the Indo-Pacific region with China rapidly building up its submarine forces, ASW capa- bilities, and naval logistics support in order to strengthen its maritime defenses and influence within its “near” and “far” seas, which portends far-reaching implications for U.S. regional influence and position.1
CHINA’S GROWING UNDERSEA WARFARE CAPABILITIES
China’s Naval Objectives: “Near Seas” Defense & “Far Seas” Protection Since 2013, China’s naval objectives have primarily become two- fold – “near seas” defense and “far seas” protection. Severely scarred from its century of humiliation during which Western powers and Impe- rial Japan mounted numerous invasions from the South and East China Seas, the People’s Republic of China, following its founding in 1949, charged its navy to strengthen its coastal defenses to prevent further sea- borne infiltrations.7 Yet, China lacked a robust overarching naval strat- egy until it finally adopted then-Commander of the PLA Navy (PLAN) Admiral Liu Huaqing’s “offshore waters defense” strategy in 1987 which premised on exerting control and defending China’s near seas to protect its territorial sovereignty, safeguard its immediate sea lines
1 China’s “near seas” refers to the waters within its first island chain which includes the Yellow Sea, and South and East China Seas, while the “far seas” refers to the waters beyond East Asia. of communications, and facilitate a forceful reunification with Taiwan through military means if required.8 Given China’s longstanding percep- tion of U.S. regional presence as a key security threat, China has con- tinued to pursue the strengthening of its near sea defenses with Chinese President Xi Jinping reasserting in 2014 the need for “an impregnable wall for border and ocean defense.”9
With growing overseas maritime interests where more than 60 per- cent of its trade and 80 percent of its oil imports travels by sea, China has since 2013 stressed the need to become a maritime power to ensure its economic prosperity and national development.10 At the 18th Chinese Communist Party Congress, outgoing President Hu Jintao declared that “China should enhance its capacity for exploiting marine resources… resolutely safeguard its maritime rights and interests, and build Chi- na into a maritime power.”11 President Xi has expectedly continued to champion the cause, stating in a subsequent party meeting that “China should do more to promote its efforts to become a maritime power.”12 In accordance with China’s 2015 defense white paper which stated the need to protect China’s maritime interests and sea lines of communi- cations in the far seas, the PLAN intends to shift its objectives from “offshore waters defense” to the “combination of offshore waters de- fense with open seas protection,” and enhance its strategic deterrence, counterattack, and maritime maneuver capabilities.13
China’s Courses of Action: Anti-Access/Area Denial and Power Projection
To achieve its near- and far sea objectives, China turned towards active strategic counterattacks on exterior lines (ASCEL), analogous to the Western concept of anti-access/area denial (A2/AD), and blue-wa- ter power-projection respectively. Through the establishment of A2/ AD defenses in its near seas, China could deny potential adversaries the freedom of maneuver within the first island chain and prevent them from intervening in a potential China-Taiwan conflict or attacking the Chinese mainland.14 China could thereby preclude a repeat of the 1995- 96 Taiwan Straits crisis where the United States deployed two U.S. car- riers off China’s coasts to deter Chinese aggression against Taiwan. In addition, to enable the protection of its growing maritime interests in the far seas, China could strengthen its blue-water power-projection ca- pabilities in order to sustain naval missions for prolonged periods and at greater distances from Chinese shores. Such missions could include collecting intelligence, protecting sea lines of communications, and pro- viding support to combat missions, which allow China to exert greater regional influence and better safeguard its maritime assets, rights, and interests.15
However, U.S. dominance of the undersea could turn this domain to be a critical vulnerability and weakness in China’s A2/AD and pow- er-projection ambitions. Nevertheless, recent developments in undersea technology, coupled with the unique characteristics of the undersea do- main, have presented opportunities for China to mitigate its comparative disadvantages. For instance, the development of Air-Independent Pro- pulsion (AIP) capability which increases diesel submarines’ submerged endurance as well as new noise-cancelling technology could enable Chinese attack submarines to narrow their capability gap vis-à-vis U.S. Virginia-class submarines. With littoral waters creating challenges for both submarine detection and submarine operations, China could also establish advanced sensor networks to seize the advantage in its near seas. Furthermore, the recent emergence of unmanned underwater vehi- cles could yet provide another avenue for China to mitigate its undersea weaknesses. Hence, buttressed by strategic imperatives and significant economic resources, China is developing several undersea warfare ca- pabilities to challenge U.S. undersea dominance and fortify its A2/AD defenses and blue-water power-projection capabilities.
China’s Means to Grow its Undersea Warfare Capabilities
First, China is rapidly building and modernizing its submarine force. The PLAN currently operates more than 60 submarines, including 4 new Jin-class nuclear ballistic missile submarines (SSBNs), 5 Shang-class nuclear attack submarines (SSNs), 12 new Yuan-class AIP-equipped diesel submarines (SSPs), and 12 Russian-built Kilo-class diesel sub- marines (SSKs).16 In particular, the Kilo- and Yuan-class submarines are widely-recognized as two of the world’s premier diesel attack subma- rines due to their quieting and AIP technologies respectively, and both classes can be equipped with Chinese anti-ship cruise missiles which have effective ranges of about 290 nautical miles.17 With China indig- enously building about two new submarines each year, its submarine force is expected to reach 74 boats by 2020, and 100 by 2030. This would include the new Type-095 SSNs that are currently under devel- opment as well as the potentially quieter SSPs given China’s forays into electric-driven propulsion systems and electrically-powered, rim-driven propellers which would further reduce the acoustic signature of their submarines.18 Besides capability development, the PLAN has also sought to expand the operational reach of its submarines by deploying them to the Indian Ocean region regularly, extending beyond their tradi- tional operating areas within China’s near seas.19
Given their aggressive buildup, China’s attack submarines would severely outnumber that of the United States within a decade and could pose a credible threat to U.S. maritime interests in the event of a Si- no-American conflict. Despite raising the production rates of Virgin- ia-class submarines, the U.S. Navy is facing a dearth of attack subma- rines with its inventory projected to fall to just 41 boats in 2029 following the decommissioning of the aging Los Angeles-class submarines.20 Fur- thermore, unlike China, the United States would need to divide its forces between the Pacific and Atlantic theaters, portending that there would only be 25 U.S. attack submarines deployed to the Indo-Pacific which – according to Commander U.S. Pacific Command Admiral Harry Harris
– would only meet half of the region’s peacetime requirements.21 While analysts have argued that U.S. submarines could leverage their highly superior ASW capabilities to mitigate their numerical disadvantage, the PLAN submarines’ progressive quieting technology could allow them to evade U.S. submarine detection as well as submarine-on-submarine confrontation completely.22 Indeed, with the PLAN submarines likely to be augmented with land attack capabilities, they would then be able to exploit their stealth and numerical advantage to project operational fires effectively against U.S. seaborne assets and land-based interests. Therefore, while PLAN submarines might not threaten U.S. submarines directly on a technological level, they could nevertheless affect decisive strategic and operational outcomes.
Second, having recognized ASW to be a longstanding critical weak- ness, the PLAN is making significant investments to strengthen its ASW capabilities. The PLAN’s newer surface combatants such as the Jiang- kai-II-class destroyers have been augmented with a variable depth so- nar, a hangar to embark a Z-9 or Z-18 ASW helicopter equipped with a dipping sonar and ASW torpedoes, as well as the newly developed Yu-8 ASW missile which has a flight range of DE nautical miles.23 The PLAN has also built 26 ASW-capable Jiangdao-class corvettes, with 60 more currently in production.24 Equipped with a towed array sonar, these cor- vettes are able to conduct ASW operations in littoral waters and provide limited ASW protection to the PLAN carriers. For ASW aircraft, the PLAN has sought to replicate the U.S. P-3 Orion maritime patrol air- craft and SH-60 helicopters through their Gaoxin-6s and Z-20s respec- tively. In particular, the Gaoxin-6 maritime patrol aircraft would house an array of ASW sensors and weapons including a maritime search ra- dar, a magnetic anomaly detector (MAD), sonobuoys, and air-launched torpedoes.25 Thus, through these acquisitions, the PLAN is developing a nascent “distributed ASW lethality” capability where it could deploy a preponderance of airborne and surface assets to conduct ASW opera- tions within its littoral waters.
Like the United States, China is also investing extensive resourc- es into developing unmanned underwater vehicle (UUV) technology, which is widely perceived to be a potential gamechanger and key force multiplier in undersea warfare. Yet, in recent years, China has surged ahead in the UUV race by setting the record for the deepest and longest dives as well as achieving significant technological breakthroughs with its state-of-the-art “Haiyi” unmanned underwater gliders.26 More impor- tantly, in July 2017, a swarm of 12 Haiyi gliders was deployed to collect and relay underwater data instantaneously to a land-based laboratory
– a command and control feat yet to be achieved even by the United States.27 With China expected to eventually employ UUVs for military purposes, this successfully demonstrates that it could soon develop the ability to remotely direct and control a swarm of underwater drones to execute undersea missions. These could include ASW operations and disruption of dual-use undersea infrastructure, which would provide the PLAN with an asymmetric tool to contest undersea dominance.28 As ac- centuated by its seizure of a U.S. underwater glider in December 2016, China values UUV technology highly and is willing to bear significant risk to seize the advantage in this potentially disruptive capability.
Beyond hardware development, the PLAN is also strengthening its operational ASW proficiencies. To this end, the PLAN has conducted increasingly advanced ASW drills and has participated in bilateral ASW exercises with the Russian and Pakistani navies.29 Particularly, the PLAN conducted an internal two-sided ASW exercise in 2016 which persisted without interruption for 24 hours under “actual combat conditions” and saw highly coordinated ship-aircraft maneuvers and aggressive subma- rine prosecutions.30 The evident advances in realism and complexity of PLAN’s exercises suggest that its ASW capabilities are improving, prompting analysts to predict that the PLAN would be able to conduct effective ASW operations within its littoral waters by 2020.31 This has significant implications for the U.S. Navy as they have identified the PLAN’s traditionally weak ASW capabilities to be the proverbial Achil- les heel of China’s A2/AD defenses which U.S. submarines could ex- ploit. With the PLAN ostensibly gaining headway in mitigating its ASW weakness, the United States could soon be divested of an important sil- ver bullet against China’s A2/AD strategy. Moreover, by its improving ASW competencies, the PLAN could also provide increasingly robust operational ASW protection to its carriers, thereby enhancing its overall blue-water power-projection capability.
Third, China is establishing an underwater surveillance network in the South China Sea to improve its ability to detect and monitor sub- marine operations within its near seas. Aptly named the ‘Underwater Great Wall,’ the network involves a web of surface ships, sonar systems, underwater security equipment, and unmanned submersibles to gather, process, and transmit precise and real-time information regarding under- water targets and the maritime environment.32 The ‘Underwater Great Wall’ – with its incorporation of supercomputers – would be a highly upgraded version of the SOSUS network which the United States em- ployed extensively during the Cold War to counter Soviet submarines. Then, SOSUS was reportedly able to track a U.S. Navy SSBN contin- uously across the Atlantic Ocean and detect Soviet nuclear submarines entering the Greenland-Iceland-U.K gap.33 Given its strategic utility, China is likely to eventually deploy its ‘Underwater Great Wall’ in all areas of interest including “the depths of the far seas, around islands bordering the far seas, as well as in strategic passages.”34 Indeed, China has already trialed the network around its own submarine bases since 2010 and has, in the meantime, deployed two independent cutting-edge acoustic sensor systems in the international waters off Guam.35 In par- ticular, the latter allows the localization of submarines by detecting and intercepting their acoustic communications with undersea cables and sonobuoys.36 With these two technologies, China possesses the ability to monitor submarine activities and operations in strategic locations.
With China expected to undertake a large-scale implementation of its ‘Underwater Great Wall’ in the near future, the PLAN is set to gain a significant boost in its undersea capabilities while mitigating its tradi- tional ASW weakness. By monitoring and analyzing foreign submarine activities over time, the PLAN would be able to ascertain the operational and deployment profiles of potentially adversarial submarine fleets in- cluding the U.S. Pacific Fleet Submarine Force. This information could then be exploited as operational and tactical intelligence in the event of a Sino-American conflict. Moreover, there is a possibility that the PLAN could “weaponize” its ‘Underwater Great Wall’ following its procurement of the ‘Reef Defense’ system which aims to incorporate anti-frogman sonar and interception systems as well as short-range air defenses into the surveillance infrastructure.37 Should this upgrade ma- terialize, the PLAN could potentially locate, track, and prosecute under- water threats remotely, further tilting the balance of undersea warfare capabilities vis-à-vis the U.S. Navy.
IMPLICATIONS OF CHINA’S GROWING UNDERSEA WARFARE CAPABILITIES
With its growing undersea warfare capabilities, China could pose a credible challenge to the U.S. undersea dominance in the near future. Following the demise of the Soviet Union, the United States has main- tained dominance of the undersea with no other country able to rival its submarine force and undersea capabilities. The U.S. Navy could thereby deploy its submarines around the world largely unopposed, whilst lever- aging its undersea surveillance systems to maintain awareness of under- sea activities along strategic waterways. Moving forward, this status quo is set to change with the PLAN projected to operate a stronger subma-rine fleet and establish its ‘Undersea Great Wall’ surveillance network within its near seas. Although the U.S. Navy need not regard the PLAN as a threat to its submarines in this current environment, it could avoid deploying them to China’s near seas to prevent compromising their op- erational and deployment profiles. In other words, with its submarines and surveillance systems, PLAN could potentially restrict the freedom of maneuver of U.S. submarines through deterrence, thereby eroding
U.S. undersea dominance.
On a separate note, China’s advancing undersea warfare capabili- ties would also buttress its A2/AD defenses and blue-water power pro- jection capabilities. With its expanding submarine force and improving ASW capabilities, the PLAN would be able to strengthen the undersea component of China’s A2/AD, first deterring entry of adversarial sub- marine and if this fails, bringing to bear substantial firepower against the enemy. These capabilities could also contribute towards PLAN ef- forts to achieve sea control, for instance, along the Taiwan Straits in order to facilitate a hostile reunification with Taiwan if reBuired. Further afield, China’s undersea growing warfare capabilities would strength- en the PLAN’s blue-water power-projection by conducting submarine operations and supporting carrier operations in the far seas. This could therefore bring about a shift in balance of maritime power in the Western Pacific with China able to exert effective deterrence and defense against the United States.
Beyond kinetic implications, China’s growing undersea warfare ca- pabilities could also portend implications in the non-kinetic realm. To- day, more than 95% of the world’s voice and data traffic, including tele- phone calls, financial transactions, social media posts, and military and diplomatic transmissions, flow through transoceanic undersea fiber-op- tic cables. Countries therefore have a growing dependency on undersea connectivity for their economic output and health, as well as to execute military operations and coordinate diplomatic missions. Recognizing the increasing value of undersea cables, China has in recent years drasti- cally increased its market share of cable construction projects. Between 2012 and 2015, Chinese companies were only involved in 7 percent of global undersea cable projects and dealt exclusively with projects re- lated to China and Taiwan. Between 2016 and 2019, however, Chinese companies surged its market share to 20 percent of global undersea ca- ble construction projects, with over half taking place outside the South China Sea. China’s increasing submarine cable ownership and construc- tion and its growing undersea warfare capabilities therefore make for an ominous combination.
Despite the importance of undersea cables, they are only protected by a rubber sheath and can be tapped into and disrupted. Indeed, im- provements to undersea exploration equipment and UUVs have made the finding of particular undersea cables even easier and faster. Real- izing the vulnerability of the undersea cables, China imposed undersea cable protection measures during key events such as the Belt and Road Summit in May 2017 to prevent the disruption of live telecasts and inter- national communications. With its growing undersea capabilities, China would be able to better protect and maintain its undersea cables. On the other hand, these same capabilities could also enable China to disrupt a potential adversary’s economy and diplomatic and military missions where a loss of communications for even seconds could have disastrous effects. As Sun Tzu asserted, “to subdue the enemy without fighting is the acme of skill.” Given its overall technical knowledge and undersea capabilities, undersea cables could potentially an area China could ex- ploit in the event of a conflict.
Despite its growing undersea warfare capabilities, critics have as- serted that China would not be able to mount a sustained challenge nor eventually seize dominance of the undersea from the United States due to the PLA’s systemic challenges and lack of operational experience, as well as other strategic issues. The PLA continues to be riddled with corruption and prioritizes the learning of communist dogma over more important keys such as military training due to its main objective of sus- taining the political power of the Chinese Communist Party. Moreover, the PLA lacks modern combat experience with its experience in armed conflicts limited to the Korean War in the 195Es and border scuffles with India and Vietnam in the 1960s and 1970s respectively. Despite its progress in submarine technology, China’s submarine capability re- mains about two decades behind the United States, by which time the
U.S. Navy would have recovered its submarine capacity. Most of its attack submarines in its inventory are also excessively noisy, with China still lacking the necessary quieting and propulsion technologies to build submarines which can challenge U.S. or even Russian submarines. Its Jin-class SSBNs are reportedly noisier than the Russian Delta III SSBNs built in the 1970s, while the forthcoming Type-095 SSBNs are expected to only be comparable with the Russian Akula submarines made in the 1980s. Additionally, China’s UUVs are still in their nascent develop- mental stages and are yet to be proven in military operations.
At the strategic-level, given its slowing economy and other social is- sues, China may need to re-prioritize and re-allocate its resources away from the PLA going forward. Moreover, with its economy fundamen- tally dependent on international and the existing world order, China is unlikely to risk escalating tensions or conflict with the United States. In- deed, China is reportedly refraining from surging its SSBN inventory in order not to unnecessarily antagonize the United States. China also lacks the network of allies and partners of the United States and is becoming increasingly isolated in the region due to its maritime assertions in the South and East China Seas. Given this host of issues at the strategic and operational levels, it is unlikely that its challenge to U.S. undersea dom- inance would come to fruition.
Nevertheless, while China remains to be plagued by organizational structure and cultural challenges, China has managed to address other key issues in the PLA. In China’s Military Power: Assessing Current and Future Capabilities, Roger Cliff asserts that “by 2020, the quality of China’s military doctrine, equipment, personnel, and training will likely be approaching, to varying degrees, those of the United States and other western militaries.” Cliff also adds that “the 2020s are likely to be a time of power transition in Asia where China would have the capability to, at a minimum, contest control of the seas and airspace and where an attempt to oppose a Chinese use of force will be dangerous and costly for any country, including the United States.” RAND’s recent ‘The US China Military Scorecard’ supports Cliff’s assertions, stating that China is catching up to the United States, has geography on its side, and ‘is narrowing the military gap in almost every area and even move ahead in some’ due to the speed of change in the PLA. Moreover, despite China’s slowing economy, its defense budgets have continued to increase over the years and, unlike the United States, are not undermined by grow-ing sovereignty debt, destructive political partisanship, or an inefficient military industrial complex. In fact, investments into the PLA’s abilities could set to grow even further given the strategic priority of the Chinese leadership.
Since coming to power in 2012, President Xi has made the ‘Chi- nese Dream’ – which involves “restoring China to its historical position of global preeminence” – emblematic to his leadership. The Chinese leadership is therefore driven to develop its various instruments of na- tional power on the domestic front, whilst resolving its sovereignty is- sues with regard to Taiwan and in the South and East China Seas on the external front. In all of these cases, a stronger, more capable, and better equipped military would contribute towards achieving China’s strategic objectives. With regard to the strategic isolation of China, its massive ‘Belt and Road Initiative’ will certainly promote interdependency be- tween China and countries stretching across Europe, Asia, and Africa. Moreover, China’s seemingly ‘no-strings-attached’ investments into its developing neighbors are likely to influence their strategic calculus. In- deed, in the coming years, we could even see countries which are keen to ensure China’s continued largesse choose to leave the U.S. strategic orbit to join China’s, buttressing China’s ability to reshape the region- al political, economic, and security order at the U.S. expense. Taking account of these strategic and operational potentialities, it is clear that China remains in good stead to challenge U.S. undersea dominance in the near future.
RECOMMENDATIONS FOR THE UNITED STATES
To ensure that it can maintain its dominance of the undersea do- main, the United States should certainly follow through with President Trump’s proposal to build a 350-ship Navy. A 350-ship Navy would not only increase the strategic depth but also the surge capacity of the U.S. Navy to generate an incremental increase in forward-deployed capacity in the Indo-Pacific Region. However, further measures are reBuired to mitigate the capacity shortfall within the next decade.
First, the United States should seek to build an Indo-Asia-Pacific Region coalition of submarine forces. The United States maintains trea- ty alliances with Japan, South Korea, Australia, and New Zealand and has worked with them to develop undersea information-sharing mecha- nisms and common training and operating relationships. It should there- fore continue to develop this working relationship and cooperation to institute a coalition USW charter to have its allies commit more resourc- es and capacity to mitigate the rising Chinese influence in the region.
Second, the United States should work with its allies and partners to foster coalition research, development, and acquisition of affordable technologies to increase coalition USW capacity. The United States is investing in the research and development of numerous technologies such as USVs, UUVs, and distributed, network undersea surveillance technologies that may present low cost solutions for coalition partners to strengthen their distributed undersea awareness capacity. The United States should invite coalition partners to participate in the development and research strategies to increase the economies of scale and improve their affordability for partners.
Last, the United States should demonstrate conventional deterrence in the undersea domain through hold at risk USW operations. This would cast doubts in the minds of PLAN naval commanders that their subma- rine force would survive in the event of conflict and could subseBuently question their utility.
CONCLUSIONS
After the demise of the Soviet Union, the United States became the sole proprietor of undersea supremacy and has been able to operate with near-impunity throughout the world’s oceans and littoral waters and maintain awareness of submarine activities along strategically important waterways. However, with a rapid buildup of its submarine forces, ASW capabilities, and naval logistics support, China is posing a strong chal- lenge to U.S. undersea dominance. The United States needs to ensure it resists the Chinese challenge and retains dominance of the undersea do- main, because as seen during the two World Wars, succumbing control of the undersea to the adversary would lead to disastrous results. This is pertinent for the United States going forward, given that one cannot preclude a Sino-American conflict from taking place. Moreover, should China succeed in seizing dominance of a domain which has hitherto been a traditional U.S. stronghold, China could be emboldened to chal-lenge U.S. leadership in other arenas such as in the international order, which could portend a highly uncertain and volatile world.
Endnotes
1 Bryan Clark, “The Emerging Era in Undersea Warfare,” Center for Strategic and Budgetary Assessments, January 22, 2015, http://cs- baonline.org/uploads/documents/CSBA6292_%28Undersea_Warfare_ Reprint%29_ web.pdf.
2 Michael Lodge, “Deep sea mining: the new frontier in the struggle for resources?” World Economic Forum, November 10, 2014, https:// www.weforum.org/agenda/2014/11/deep-sea-mining-the-new-frontier- in-the-struggle-for-resources.
3 Bryan Clark, “Undersea cables and the future of submarine com- petition,” Bulletin of the Atomic Scientists, June 15, 2016, https://tand- fonline.com/doi/pdf/10.1080/00963402.2016.1195636?needAccess= true.
4 Sean R. Liedman, “Taming Sea Dragons: Maintaining Undersea Superiority in the Indo-Asia-Pacific Region,” Center for a New Ameri- can Security, October 2017, https://www.cnas.org/publications/reports/ taming-sea-dragons.
5 Bryan Clark, “Game Changers – Undersea Warfare,” Statement before the House Armed Services Seapower and Projection Forces Sub- committee, October 27, 2015, http://csbaonline.org/research/publica- tions/undersea-warfare-game-changers
6 Ibid.
7 Office of Naval Intelligence, The PLA Navy: New Capabilities and Missions for the 21st Century, January 2015, http://www.dtic.mil/ dtic/tr/fulltext/u2/a616040.pdf.
8 Ibid.
9 Bill Hayton, “What the West doesn’t get about China,” Nikkei Asian Review, April 6, 2017, https://asia. nikkei.com/Politics/Bill-Hay- ton-What-the-West-doesn-t-get-about-China.
10 “How much trade transits the South China Sea?” China Power Project, Center for Strategic and International Studies, accessed April 30, 2018, https://chinapower.csis.org/much-trade- transits-south- chi- na-sea.
11 Office of Naval Intelligence, The PLA Navy: New Capabilities and Missions for the 21st Century.
12 Ibid.
13 China’s Military Strategy, The State Council Information Office of the People’s Republic of China, May 26, 2015, https://jamestown. org/wp-content/uploads/2016/07/China%E2%80%99s-Military-Strate- gy-2015.pdf.
14 Charles Koch Institute, “What is A2/AD and why does it matter to the United States,” undated, https://www. charleskochinstitute.org/ blog/what-is-a2ad-and-why-does-it-matter-to-the-united-states.
15 Office of Naval Intelligence, The PLA Navy: New Capabilities and Missions for the 21st Century.
16 Ibid.
17 Ronald O’Rourke, “China Naval Modernization: Implications for U.S. Navy Capabilities – Background and Issues for Congress,” Congressional Research Service, April 25, 2018, https://www.every- crsreport.com/ reports/RL33153.html.
18 Ibid.
19 Sean R. Liedman, “Taming Sea Dragons: Maintaining Undersea Superiority in the Indo-Asia-Pacific Region.”
20 Ibid.
21 Christopher Woody, “China’s subs worrying region and US,” Business Insider, March 20, 2018, http://www. businessinsider.com/chi- na-growing-submarine-force-worrying-pacific-us-2E18-3
22 Lyle Goldstein, “The US-China Naval Balance in the Asia-Pa- cific: An Overview,” The China Quarterly, Vol 232, December 2E17: 904-931.
23 Ibid.
24 Ibid.
25 Stratfor Worldview, China: Closing the Gap in Anti-Submarine Warfare, July 20, 2015, https://worldview. stratfor.com/article/chi- na-closing-gap-anti-submarine-warfare.
26 Tom O’Connor, “China’s military could leave U.S. Navy dead in the water with new sea drones,” Newsweek, July 26, 2017, http:// www.newsweek.com/china-military-leave-us-navy-dead-water-new- sea-drones-642436.
27 Ibid.
28 Michael S. Chase et al, “Emerging Trends in China’s Develop-ment of Unmanned Systems,” RAND Corporation, 2015, https://www. rand.org/pubs/research_reports/RR990.html.
29 Elsa B. Kania, “The Undersea Dimension of Strategic Competi- tion in the South China Sea,” Center for International Maritime Security, July 28, 2016, http://cimsec.org/undersea-dimension-strategic-compe- tition-south-china-sea-reviewing-plans-intensified-focus-anti-subma- rine-warfare/26858.
30 Ibid.
31 Jesse L. Karotin, “Trends in China’s Naval Modernization,” US China Economic and Security Review Commission Testimony, January 30, 2014.
32 Richard D. Fisher, “China proposes ‘Underwater Great Wall’ that could erode US, Russian submarine advantages,” IHS Jane’s De- fence Weekly, May 17, 2016, http://www.janes.com/article/60388/chi- na-proposes-underwater-great-wall-that-could-erode-us-russian-subma- rine-advantages.
33 Brian Wang, “Under undersea warfare gamechangers – China building upgraded SOSUS and US upgrading sensor and fielding net- work of undersea robots,” Next Big Future, May 18, 2016, https://www. nextbigfuture. com/2016/05/undersea-warfare-gamechangers-china. html.
34 Lyle J. Goldstein, “China’s ‘Undersea Great Wall’,” The Nation- al Interest, May 16, 2016, http:// nationalinterest.org/feature/chinas-un- dersea-great-wall-16222.
35 Stephen Chen, “Surveillance under the sea: how China is listen- ing in near Guam,” South China Morning Post, January 22, 2018, http:// www.scmp.com/news/china/society/article/2130058/surveillance-un- der-sea-how-china-listening-near-guam.
36 Ibid.
37 Richard D. Fisher, “China proposes ‘Underwater Great Wall’ that could erode US, Russian submarine advantages.”
