The peace research institute Sipri has identified a worrying trend in the development of nuclear weapons. Overall, the total number of nuclear warheads continues to decline, the Stockholm-based institute noted in its annual report published Monday. Currently, however, more nuclear weapons are operational than a year ago, it said. The reduction of deployable warheads appears to have stalled. At the same time, comprehensive and expensive modernization programs were underway.

According to the report, the U.S., Russia, the U.K., France, China, India, Pakistan, Israel and North Korea possessed a total of 13,080 nuclear warheads at the beginning of this year. That's 320 fewer than at the start of 2020 and less than one-fifth of what the nuclear powers had in their arsenals at the height of the Cold War in the mid-1980s. The U.S. and Russia continue to have more than 90 percent of these weapons, according to Sipri estimates. The decline is attributed primarily to the disposal of discarded warheads by Russia and the United States. Together, the two countries possess more than 90 percent of all nuclear weapons. The reduction had been agreed in the 2010 bilateral "New Start" disarmament agreement. Shortly before it expired on February 5, it had been extended by five years.

The peace researchers classify the number of nuclear warheads that have already been mounted on missiles or are located on active bases as a cause for concern. These nuclear weapons are considered by Sipri to be ready for deployment. Their number increased from 3720 last year to 3825, and it is estimated that about 2000 of them are kept on high alert. Almost all of them are in the possession of Russia or the USA. These two nuclear powers each added about 50 deployable nuclear weapons last year. Britain and France also have deployable warheads.To be sure, the last-minute extension of New Start was a relief, explains Sipri nuclear weapons researcher Hans M. Kristensen. But the prospects for additional bilateral nuclear arms control between the nuclear superpowers remain poor. Kristensen calls the increase in operationally deployable warheads alone "a worrying sign."

Nuclear weapons appear to play an increasingly weighty role in Russian and U.S. national security, according to Sipri. There are ongoing programs to further develop nuclear weapons systems such as nuclear warheads, missile and aircraft carrier systems, and production facilities, he said. The seven other nuclear powers have much smaller arsenals. But they are also in the process of modernizing or upgrading them.

According to a recent study by the International Campaign to Abolish Nuclear Weapons (Ican), the nine nuclear weapons states spent 72.6 billion U.S. dollars (the equivalent of about 60 billion euros) on expanding their arsenals last year. Adjusted for inflation, that was $1.4 billion more than in 2019. Nobel Peace Prize laureate Ican had overseen the UN agreement to ban nuclear weapons, which was adopted in July 2017. It entered into force in January. The nuclear powers as well as members of the NATO military alliance, which also includes the U.S., Britain and France, have so far rejected the agreement.