Nuclear test ban treaty thrust back into spotlight as tensions rise — and NORSAR plays quiet but crucial role.

 Vienna — In Vienna this week, diplomats are confronting a reality many believed belonged to the past: the possibility that the global moratorium on nuclear testing could come under real strain.

NORSAR, Norway’s national data centre for nuclear test monitoring, is also present, with five experts participating in several of the key technical and policy discussions throughout the meetings.

Officials gathered for meetings related to the Comprehensive Nuclear-Test-Ban Treaty (CTBT) say the deteriorating global security climate — from the war in Ukraine to escalating tensions in the Middle East — has pushed the treaty back into urgent focus. Nearly three decades after it was opened for signature, the CTBT remains one of the most important yet unfinished pillars of nuclear arms control.

And amid the diplomacy, one small Nordic country is playing a disproportionately important role.

Norway’s seismic monitoring institute, NORSAR, is a central component of the global system designed to detect illicit nuclear explosions — a role that diplomats and experts say is becoming increasingly critical as geopolitical trust erodes.

A treaty still waiting to enter into force

Adopted by the United Nations in 1996, the CTBT was intended to end all nuclear test explosions and halt the development of new nuclear weapons. Yet the treaty has never formally entered into force because several key states — including the United States, China, Iran, Israel, India, Pakistan and North Korea — have not ratified it.

Despite that political stalemate, the treaty’s implementing body, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) in Vienna, has spent decades building one of the most sophisticated monitoring networks ever created.

The International Monitoring System spans the globe with seismic, hydroacoustic, infrasound and radionuclide stations capable of detecting nuclear tests even at very low yields.

For many years the system operated largely outside the public spotlight. But diplomats say the shifting geopolitical landscape has changed that.

“The global moratorium on nuclear testing is under more strain than at any time since the 1990s,” one European diplomat attending the Vienna meetings said. “In this environment, the monitoring system becomes indispensable.

Read more: The Comprehensive Nuclear-Test-Ban Treaty (CTBT) | CTBTO

In 2023 Russia revoked its ratification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), while stating it would continue to observe its voluntary moratorium on nuclear testing

The decision came against the backdrop of the war in Ukraine, which has already shattered several long-standing assumptions about stability in Europe.

Arms control analysts warn that even limited or experimental nuclear tests could send destabilising signals in such a tense environment.

“If the political barriers weaken, the technological ability to detect tests becomes even more important,” said one expert involved in CTBT verification efforts.

Iran and rising tensions in the Middle East

At the same time, tensions surrounding Iran’s nuclear programme are expected to shape discussions in Vienna.

Iran signed the CTBT in 1996 but has never ratified it. Western governments have expressed increasing concern over the country’s nuclear activities, while Israel — which has also not ratified the treaty — also  face increased tension.

The combination of regional instability and uncertainty over nuclear intentions is bringing renewed attention to the verification system designed to detect any illicit tests.

Norway’s quiet role in global nuclear monitoring

Among the institutions helping to underpin that system is NORSAR, the Norwegian seismic monitoring centre that has become one of the world’s most respected authorities in detecting underground nuclear explosions.

Operating from Norway but integrated into the CTBTO’s international monitoring network, NORSAR manages several highly sensitive seismic stations capable of detecting extremely small ground vibrations thousands of kilometres away.

The institute’s instruments have previously helped detect nuclear tests conducted by North Korea — events that demonstrated the reach and precision of the global monitoring system.

Diplomats and experts say capabilities like these would be essential if any state attempted to resume nuclear testing.

“Reliable, independent monitoring is crucial in a world where political trust is declining,” one CTBT official said. “Institutions like NORSAR are a fundamental part of that verification architecture.”

What is at stake in Vienna

This week’s meetings in Vienna are unlikely to produce dramatic diplomatic breakthroughs. The structural obstacles preventing the treaty from entering into force remain formidable.

But delegates are focusing on ensuring that the monitoring and verification regime remains strong. Discussions are expected to cover the status of the International Monitoring System, preparations for on-site inspections in the event of suspected tests, and ways to maintain global commitment to the test ban.

Behind those technical discussions lies a broader concern: that weakening arms control norms could eventually lead the world back toward an era of nuclear testing.

For supporters of the treaty, the goal is clear.

“The CTBT was created to stop the nuclear arms race from starting again,” said a Vienna-based arms control expert. “With today’s crises, that mission has never been more important.”

And in the complex machinery designed to enforce that mission, Norway’s quiet seismic arrays — listening for tremors beneath the earth — remain one of the world’s most reliable early warning systems.

Facts:

How many nations participate in the CTBT meetings in Vienna?

At the CTBTO meetings in Vienna (such as the Working Group sessions taking place this week), participation is drawn from all States that have signed the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

• 187 countries have signed the CTBT, and these states are members of the CTBTO Preparatory Commission, which runs the meetings in Vienna.
• Of these, 178 have ratified the treaty, while 9 have signed but not ratified.
• Non-signatory states and international organizations can sometimes attend as observers, but decision-making belongs to the signatory states.

Because delegations vary by meeting, not every one of the 187 states is physically present, but they are all eligible participants in the Vienna sessions.

Key countries participating

In practice, delegations come from most UN member states, including all major nuclear powers and regional actors. Examples include:

Nuclear-armed or nuclear-capable states

• United States
• Russia
• China
• United Kingdom
• France
• India
• Pakistan
• Israel
• North Korea

(Only the United Kingdom and France have ratified the treaty, but others still participate in CTBT-related processes.)

Other influential Annex-2 states (whose ratification is required for the treaty to enter into force)

• Germany
• Japan
• Canada
• Brazil
• South Africa
• South Korea
• Iran
• Egypt
• Turkey
• Ukraine
• Norway
• Sweden
• Switzerland
• Australia
• Argentina
• Mexico
• Netherlands
• Spain
• Poland
• Finland
• Belgium
• Romania
• Indonesia
• Vietnam
  …and others, totaling 44 Annex-2 states that must ratify the treaty before it can legally enter into force.

Summary

• Eligible participants: 187 CTBT signatory states
• Ratified: 178
• Signed but not ratified: 9 (including the U.S., China, Iran, Israel, Egypt, and Russia)