19 April 2023

The Global Nuclear Balance: Nuclear Forces and Key Trends in Nuclear Modernization

Anthony H. Cordesman

The CSIS Emeritus Chair is issuing a survey of the trends in the United States, Russian, and Chinese nuclear balance provides an unclassified overview of recent U.S. force planning and intelligence data on U.S. nuclear forces and the Russian and Chinese threats and compares summary estimates of global nuclear and related missile forces by the International Institute for Strategic Studies, the Federation of American Scientists and Bulletin of Atomic Scientists, and CSIS.

It also contains summary data on U.S. force improvement plans taken from the testimony of General Anthony J. Cotton, commander of the U.S. Strategic Command, before the House Armed Services Committee on Strategic Forces on March 8, 2023.

This survey is entitled The Global Nuclear Balance: Nuclear Forces and Key Trends in Nuclear Modernization and is available on the CSIS website at https://csis-website-prod.s3.amazonaws.com/s3fs-public/2023-04/230414_Cordesman_Global_NuclearBalance%202.pdf?VersionId=DOuD0qi0fgNdCrm9RWh_NMN8jyBBqabJ.

Its purpose is to illustrate some of the different ways that experts portray the changes taking place in the nuclear balance between the major powers, the emergence of China as a strategic nuclear great power, and the shifts taking place in other nuclear forces like those of the United Kingdom, France, North Korea, Iran, Israel, India, and Pakistan.

It is a compilation of some of the most respected unclassified resources that have been put together to illustrate the range of data now available, rather than provide a full analysis. It should be stressed that the different estimates of force numbers and weapon types provided in this summary analysis only provide a limited illustration of the many differences in open-source estimates of the size and nature of foreign nuclear-armed forces and national efforts to modernize and expand them.

Readers are encouraged to go back to the original sources as indicated. The work by Hans M. Kristensen. Matt Korda, Robert Norris, and others in the country-by-country Nuclear Notebooks published in the Bulletin of Atomic Scientists are particularly helpful in understanding limits and uncertainties in such data—and the extent to which many estimates are dated, uncertain, or based on uncertain sources.

There are, however, a number of key uncertainties that affect virtually all of the data now available. Many of the data on the type of non-U.S. nuclear weapon—fission, boosted, or thermonuclear—and its yield are uncertain. So are the background data on the level of technical sophistication in designing the weapon, upgrades and serving of weapons over the years, and its reliability in a real-world delivery on target.

Data on each country’s full explosive tests of nuclear weapons are sometimes uncertain, and so is progress in testing weapons designs using simulated weapons with low levels of enrichment remain classified—although both India and Pakistan are reported to have used such methods. The readiness of stored weapons is not assessed, and the ability to use existing weapons assemblies in missiles and other delivery systems that are normally assessed as having conventional warheads is unknown.

Many data on non-U.S. missiles are based on estimates of range based on the type and size of the missile rather than actual flight test data. Estimates of accuracy are often based on the maximum capability of the guidance platform rather than actual missile tests, accuracy is not tied to reliable estimates of nuclear weapons yield, and no reliability data based on actual tests of even the missile system alone are normally available.

Data are lacking on the targeting and retargeting capabilities of given countries, and on their ability to retarget, launch on warning, and accurately detect and characterize nuclear strikes on their own territory and enemy territory, and characterize the difference between counterforce strikes on nuclear and other military forces, and countervalue strikes on civilian populations, key economic and infrastructure targets, and other critical non-military and recovery capabilities.

More broadly, any analysis of national nuclear forces is limited by the fact that the unclassified data now available on nuclear capabilities focus almost exclusively on nuclear delivery systems and weapons rather than on analyzing actual warfighting capabilities. Open-source efforts to analyze the warfighting impact of actual nuclear exchanges largely ended after the collapse of the former Soviet Union, as most tactical and theater nuclear forces were withdrawn from active service and as arms control seemed to create a truly stable balance of strategic nuclear deterrence.

As a result, there are only a handful of credible data on how a nuclear war might now lead to given patterns of counterforce strikes against an opposing side’s nuclear and other military forces, and the impact of fall out and the countervalue impact of counterforce strikes.

There also seems to be virtually no recent unclassified analysis of how a war might lead to countervalue strikes against populations, economies, and recovery capabilities and the levels of damage and casualties that might result. There also has been no meaningful open-source analysis of the shifts taking place in key aspects of vulnerability to nuclear attack like dependence on imports, manufacturing capability, and changes in the economic value of given cities, key infrastructure targets, and key industrial centers.

This lack of analysis of the impact of actual nuclear warfighting seems increasingly dangerous. China is emerging as a major nuclear power and radically changing potential nature of nuclear warfare between the major powers. Past efforts to actually analyze nuclear warfighting ignore the fact that there are now three major groups of nuclear forces: The United States, France, the United Kingdom, Russia, and China. This not only presents major problems in modeling the possible patterns in nuclear warfighting and escalation, but it also presents the problem for the United States that any exchange with only Russia or China would make the power that stayed out of the conflict the de facto winner in a major nuclear exchange.

The war in Ukraine has shown that Russia is willing to make nuclear threats, and much of the arms control effort in Europe and between the United States and Russia have now ended or has an increasingly uncertain future. China has so far refused to engage in arms control negotiations.

Proliferation by smaller nuclear powers has remained a relatively limited global threat, but proliferating states like India, Pakistan, and North Korea are changing and modernizing their forces, and the nuclear efforts of nations like Israel and Iran illustrate the rising risk proliferation may pose in the future.

There are several other major areas of uncertainty that affect the estimates of nuclear forces in this summary analysis:One is proliferation. Key cases involve the steady rise in Indian and Pakistani near force capabilities, the uncertainties surrounding the real-world nuclear capabilities of Israel, North Korean efforts to develop and deploy ICBMs, and the risk of Iran acquiring nuclear weapons and its impact on the development of nuclear forces by Iran’s Arab neighbors.

Another is the ways in which nuclear forces can be used in combat and the extent to which the ability to manage a nuclear war in near-real time is becoming far more dynamic. There has been almost no open-source discussion of the potential impact of space sensors, AI, and big data in radically changing the current and future ability to provide reliable launch-on-warning capability and real-time data on the exact nature of nuclear strikes and their effects. This may well allow the managers of an actual nuclear war to rapidly retarget, shift in near real-time from counterforce to countervalue targets, and fight even the highest levels of nuclear combat dynamically in near real-time. These issues are now being publicly explored in designing forces for advanced forms of conventional Joint All-Domain Operations, but there has been little public discussion of how they might change the modernization of nuclear war fighting.

A third, as the 2023 edition of the ODNI’s Annual Threat Assessment highlights, is the risk that new forms of biological warfare pose a rising strategic threat and one that could be used anonymously and to produce a wide range of lethalities and economic and social effects.

Finally, no reliable unclassified estimates seem to exist of the impact that counterforce strikes launched to destroy an opponent’s nuclear forces would have on the opponent’s civil population, economy, and recovery capabilities. Past studies indicated that the real-world difference between counterforce and counter value could be limited by fall-out and longer-term weapons effects in major counterforce exchange, but they are now seriously outdated.

It should be noted that few nuclear powers other than the United Kingdom provide clear national statements of their nuclear modernization efforts, a full spectrum of current and future nuclear capabilities, and actual war-fighting capabilities. Statements like “no first use” are matters of doctrine that any nation can declare and ignore in a crisis, and no nuclear state has declared possible limits to its uses of nuclear weapons, possible ways in which it might agree to halt nuclear escalation once it begins, and limits to its countervalue targeting.

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