The Foreign Service Journal, December 2009

46 F O R E I G N S E R V I C E J O U R N A L / D E C E M B E R 2 0 0 9 greater with the CTBT in force than without it. Ratification is essential to making short-notice, on-site inspections pos- sible and maintaining long-term political and financial sup- port from other nations for the operation of the CTBT’s International Monitoring System and International Data Center. Over the past decade, national and international monitoring for nuclear weapon test explosions has become so effective that no would-be cheater could be confident that a nuclear explosion sufficient to threaten U.S. security would escape detection. Additional Verification Tools. The CTBT establishes a far-reaching International Monitoring System to detect po- tential nuclear explosions using four technologies: seismic, hydroacoustic, radionuclide and infrasound. Since 1999, many more of these stations have been built and are deliv- ering data. To date, more than 280 of the planned IMS sta- tions have been built, including a new array of highly capable “noble gas” monitoring stations that can detect minute amounts of the radioactive gases emitted by under- ground explosions into the atmosphere. The International Data Center, based in Vienna, collects and analyzes infor- mation from the IMS and disseminates the raw and processed data to member-states for their own evaluation. Under the CTBT, member-states are allowed to monitor compliance with their own satellites and other national in- telligence means. In the U.S., new technologies such as in- terferometric synthetic aperture radar can now provide detailed monitoring of vertical deformations caused by un- derground nuclear test explosions. Thousands of high-qual- ity civilian seismic stations around the world provide further detection capabilities. Detection Capabilities. During the Senate debate on the CTBT in 1999, some critics claimed that the IMS could only monitor for underground explosions at yields at or above the equivalent of one kiloton of TNT. In reality, IMS capabilities were much better even then and have contin- ued to improve; moreover, they are only intended to sup- plement the United States’ very capable national monitor- ing and intelligence capacity. In 2002, a National Academy of Sciences panel deter- mined that “underground nuclear explosions can be reli- ably detected and can be identified as explosions using IMS data down to a yield of 0.1 kilotons (100 tons) in hard rock if conducted anywhere in Europe, Asia, North Africa and North America.” Advances in regional seismology have pro- vided additional confidence. For some locations, such as Russia’s former nuclear test site at Novaya Zemlya, the use of new seismic arrays and regional seismic stations has low- ered the detection threshold to below 0.01 kilotons. Skeptics have also claimed that there is no certain method of detecting very low-yield nuclear explosions, in- cluding so-called hydronuclear tests. However, this argu- ment misses the point on verification: explosions below a few hundred tons in yield — potentially low enough to evade detection — are not very useful in assessing a new nuclear warhead design. High Confidence. CTBT skeptics have also suggested that it may be possible for some states to hide full-scale nu- clear tests. But according to the NAS panel report, “those countries that are best able to successfully conduct such clandestine testing already possess advanced nuclear weapons of a number of types and could add little, with ad- ditional testing, to the threats they already pose to the United States. Countries of lesser nuclear test experience and/or design sophistication would be unable to conceal tests in the numbers and yields required to master weapons more advanced than the ones they could develop and de- ploy without any testing at all.” On-Site Inspections. The CTBT would provide, for the first time, the option of short-notice inspections, an impor- tant form of deterrent against potential clandestine nuclear testing. However, some critics complain that because the treaty requires 30 of 51 nations on its Executive Council to agree to an on-site inspection if there is evidence of a clan- destine test, such inspections could be blocked by states un- friendly to the United States. In reality, the CTBT’s OSI provisions were established to balance the need for rapid re- sponse to a suspected test against the possibility of “frivolous or abusive” inspections. OSIs would be approved as needed, but not by a small minority with questionable motives. Similarly, to protect national security interests unrelated to the OSI, states are allowed to restrict access to parts of the inspection area no larger than four square kilometers each, or a total of no more than 50 square kilometers. How- ever, if an inspected state restricts access it must provide al- ternative ways for the inspection team to carry out its mission. If the bar for OSIs had been set much lower, or if no allowances had been made for unrelated national secu- rity interests, one could imagine that there might be con- cerns in the Senate that CTBT on-site inspections unduly infringe on U.S. (or Israeli) sovereignty. Zero Means Zero. Another misconception that is re- peated by CTBT critics is that some countries, such as Rus- sia, consider hydronuclear experiments (which produce a F O C U S