A report recounting a litany of near-misses in which nuclear weapons came close to being launched by mistake concludes that the risk of potentially catastrophic accidents is higher than previously thought and appears to be rising.

Too Close for Comfort: Cases of Near Nuclear Use and Options for Policy, published on April 29 by Chatham House, the international think-tank based in London, says that “individual decision-making, often in disobedience of protocol and political guidance, has on several occasions saved the day,” preventing the launch of nuclear warheads.

The report lists 13 instances since 1962 when nuclear weapons were nearly used. In several cases the large-scale launch of nuclear weapons was nearly triggered by technical malfunctions or breakdowns in communication causing false alarms, in both the U.S. and Russia. Disaster was averted only by cool-headed individuals gambling that the alert was caused by a glitch and not an actual attack.

The Chatham House authors say the risks appear to be rising. Nuclear weapons are spreading — most recently to North Korea — and disarmament is stalling. Russia and the U.S. still have an estimated 1,800 warheads on high alert, ready to launch between five and 15 minutes after receiving the launch order — a fact that becomes all the more significant with rising tensions over Ukraine.

“The question today is: are these risks worth it?” said Patricia Lewis, Chatham House research director for international security and one of the report’s authors. “You can imagine a situation in which tensions rise and signals come in and people misinterpret what is going on. Will people always have sound enough minds to take the time to make a reasoned decision?”

The report focusses on cases in which nuclear weapons came close to being launched deliberately on the basis of bad or incomplete information.

However, there is an additional risk of accidents inherent in the maintenance of stockpiles of more than 17,000 warheads held by Russia, the U.S. and the other seven nuclear-armed states. Some of those accidents were described in a book published last year, entitled Command and Control . — © Guardian Newspapers Limited, 2014