Until recently, research into science and technology was funded primarily by governments. Today, technological breakthroughs are being driven primarily by private firms funded with venture capital. This change in the R&D landscape is leaving governments and international organizations scrambling to craft oversight tools and policies that will help manage the disruptive impacts—and possible threats—resulting from … Continued

Nuclear power advocates maintain that nuclear power is essential to a low-carbon future because it emits no carbon dioxide and provides large amounts of baseload electrical generation. However, critics point to nuclear power’s costs and accident and proliferation risks as continuing drawbacks to large-scale nuclear reactor construction. With this important policy discussion in mind, the … Continued

Nuclear Notebook: How many nuclear bombs does the U.S. have? At the beginning of 2017, the US Defense Department maintained a stockpile of an estimated 4,480 nuclear warheads for delivery by more than 800 ballistic missiles and aircraft. This figure is unchanged over the last year. Since September 2009, when the United States announced that … Continued

Tens of thousands of people came to the Bulletin of the Atomic Scientists’ website over the last week, looking for answers on what a new Trump administration means for the health and safety of our planet. As Bulletin editor John Mecklin writes, Donald Trump’s positions on serious questions have often ricocheted from side to side: … Continued

An extraordinary global energy transformation will be required for the world to successfully slow and then halt climate change, and that transformation will change the power dynamics among nations. The security arrangements necessary to keep the peace among the powers that vie for an energy advantage in the coming renewables era demand attention now. Here's … Continued

Nuclear Notebook: How many nuclear weapons does Pakistan have? Pakistan continues to expand its nuclear arsenal with more warheads, more delivery systems, and a growing fissile materials production industry. Analysis of a large number of commercial satellite images of Pakistan army garrisons and air force bases shows what appear to be mobile launchers and underground … Continued

On Monday, October 10, Russian President Vladimir Putin withdrew his country from the US-Russia Plutonium Management and Disposition Agreement (PMDA). The PDMA, first signed in 2000 and renewed in 2009, affirmed the intention of each country to dispose of stockpiles of plutonium that could be used to build nuclear warheads. President Putin’s decision to pull … Continued

Today, 71 years later, the world remembers one of the most lethal bomb attacks in world history. In the immediate aftermath of the atomic blast at Nagasaki, anywhere from 45,000 to 75,000 lives were lost. In many ways, Nagasaki is a more realistic – and thus alarming – case study of what a modern nuclear strike might look like. Hiroshima was considered an ideal military target: a medium-size population center that had been untouched by conventional weapons with a sizable troop concentration. Nagasaki, on the other hand, had no major troop concentration. It did have the Mitsubishi industrial complex, but the main reason it was chosen as the target that day was because the primary target – Kyushu – had poor visibility. Nagasaki’s hilly geography, unsuited for a nuclear strike but suitable for surviving one, accounted for the minor difference in the loss of life between the two blasts.

Nuclear Notebook: How many nuclear bombs does China have? The modernization of China’s land-based nuclear-capable missile force has progressed significantly over the past year, with Beijing fielding a new version of an existing nuclear missile and a new dual-capable missile. The country has also reorganized its nuclear missile command structure. The authors estimate that, in … Continued

On Friday, May 27, President Barack Obama will become the first sitting U.S. president to visit Hiroshima, Japan, site of the first atomic bomb detonation in history. Amid the debate over the visit—will he or won’t he go; will he or won’t he meet with the Hibakusha; will he or won’t he apologize—it is clear … Continued

Nuclear Notebook: How many nuclear warheads does Russia have? Russia is in the middle of a broad modernization of its strategic and nonstrategic nuclear forces. While much of this process continues well-known programs that have been underway for many years, some developments are new. The modernizations, combined with an increased number of military exercises and … Continued

Nuclear Notebook: How many nuclear warheads does the U.S. have? At the beginning of 2016, the US Defense Department maintained a stockpile of an estimated 4,670 nuclear warheads for delivery by more than 800 ballistic missiles and aircraft. The stockpile did not shrink significantly over the last year, but has shrunk by roughly 350 warheads … Continued

Nuclear Notebook: How many nuclear weapons did the U.S. have at sea during the Cold War? Newly declassified documents from the US Defense Department show how many nuclear weapons the United States deployed at sea between 1953 and 1991. The documents, which give totals for the Atlantic Ocean, Pacific Ocean, and Mediterranean Sea, show that … Continued

Nuclear Notebook: How many nuclear bombs does Pakistan have? Pakistan continues to expand its nuclear arsenal and is growing its fissile materials production industry. Since our last Nuclear Notebook on the country in 2011 (Kristensen and Norris, 2011), it has deployed two new nuclear-capable short-range ballistic missiles (SRBM) and a new medium-range ballistic missile (MRBM), … Continued

Nuclear Notebook: How many nuclear warheads does India have? India’s drive to develop a nuclear triad reached an important milestone in 2014 with the first nuclear-powered ballistic missile submarine deploying on its initial, brief, sea-trial voyage. Now, with several long-range ballistic missiles in development, the Indian nuclear posture is entering an important and dynamic new … Continued

Nuclear Notebook: How many nuclear bombs does China have? We estimate that China has approximately 260 nuclear warheads in its stockpile for delivery by approximately 160 land-based ballistic missiles as well as aircraft1 and an emerging ballistic submarine fleet. This estimate is 10 warheads higher than last year, primarily due to additional sea-launched ballistic missiles. … Continued

Nuclear Notebook: How many nuclear bombs does Russia have? Russia is in the middle of a broad modernization of its strategic and nonstrategic nuclear forces. While much of this process continues well-known programs that have been under way for many years, some developments are new. Combined, the steps Moscow is taking contribute to growing concern … Continued

Nuclear Notebook: How many nuclear weapons does the US have? At the beginning of 2015, the US Defense Department maintained a stockpile of an estimated 4,760 nuclear warheads for delivery by more than 800 ballistic missiles and aircraft. The stockpile did not shrink significantly over the last year, but has shrunk by roughly 350 warheads … Continued

Nuclear Notebook: How many nuclear weapons exist in the world? Longtime Nuclear Notebook readers know that we typically take an in-depth look at arsenals around the world to reveal, as much as possible, what kind of nuclear weapons are deployed, where they are, and in what numbers. In this issue of the Bulletin of the … Continued

Nuclear Notebook: How many nuclear weapons does Israel have? Although the Israeli government neither confirms nor denies that it possesses nuclear weapons, it is generally accepted by friend and foe alike that Israel is a nuclear-armed state—and has been so for nearly half a century. The basis for this conclusion has been strengthened significantly since … Continued