New York, United States - When it comes to nuclear attacks, there is no shortage of nightmare scenarios.
Saboteurs could breach a nuclear power station and start a reactor meltdown. A renegade Pakistani general could seize tactical nuclear weapons and blow up a city. Radioactive materials, which are found in many hospitals, could cause dirty bomb mayhem at an airport.
Against this backdrop, US President Barack Obama will host world leaders for a Nuclear Security Summit on Thursday, in an international effort to stop possible assailants from using radioactive material to outdo the 9/11 attacks on New York and Washington.
The leaders may not be doing enough. Analysts point to big gaps in the global security architecture, dozens of atomic power plants coming online in developing regions and new threats, such as Islamic State of Iraq and the Levant (ISIL also know as ISIS), on the scene.
"The world has drastically improved nuclear security these past 25 years but significant gaps remain and the government structure for nuclear security is a patchwork," former White House science adviser Matthew Bunn told Al Jazeera.
"The key question for this summit is: will leaders take enough action to put the world on a path of continuous improvement and steadily reducing the risk of nuclear terrorism, or will attention turn elsewhere, progress stall, and complacency return?"
A psychological weapon
Fears of attacks with nuclear materials resurfaced after the March 22 bomb attacks at a Brussels airport and on a packed metro, which killed 35 people and injured more than 300, and indications that the ISIL-linked attackers had nuclear ambitions.
The suicide bombers may have originally planned to hit a nuclear site, according to reports. Last year, it emerged that those behind ISIL's November 13 attack on Paris, which killed 130 people, had been video-recording a high-ranking Belgian nuclear official.
These revelations stoked fears that ISIL sought radiological material to wrap around explosives and yield a dirty bomb that, if detonated, would cause alarm, even if the radioactivity itself was not life-threatening.
"It's a psychological weapon that causes economic damage," Kenneth Luongo, president of the Partnership for Global Security, a think-tank, told Al Jazeera.
"If those two bombs in the Brussels airport had any radioactive material in them, you would not be cleaning that airport so it reopens within in a week, you would be building a new airport."
The problem for summit envoys is that a dirty bomb's radiological ingredients are found in many hospitals and industrial sites around the world. Despite efforts to secure them, they go missing at a worrying rate.
"This is not science-fiction. Creating a dirty bomb is not difficult. Every piece of food sold in a supermarket has a barcode on it, but these radioactive sources don't. We don't have a good tracking system," added Luongo.
"All we have is a completely voluntary international system and national regulations. We must improve the way we secure, track and dispose of high-intensity radiological sources."
'An apocalyptic ideology'
Most "insurgents" are content with AK-47s, Semtex and other conventional arms, said Victor Asal of New York State University. In recent years, only about two dozen groups have upped the ante with chemical, biological and other mass-casualty weapons.
According to Bunn, a Harvard University scholar, ISIL's known efforts in the nuclear field fall short of its forebear, al-Qaeda, which sought highly enriched uranium (HEU) and hatched plans for a crude nuclear device akin to those dropped on Japan in 1945.
"There's no public evidence of a focused ISIL nuclear programme, as al-Qaeda had back in the day. But ISIL has an apocalyptic ideology that envisions a total war with crusader forces, including the US, a nuclear-armed superpower," Bunn said.
"If ISIL does turn to nuclear pursuits, they have more money, people, territory and a greater ability to recruit experts globally than al-Qaeda at its strongest ever had. And they've shown an ability to manage and implement long-term projects."
Other dangers are growing too, analysts say. Pakistan has embraced smaller, tactical nuclear weapons that can be deployed on the battlefield. Islamabad insists they are secure; the US and others worry they could fall into the wrong hands.
An uptake in atomic power has seen Northeast Asia become a "thicket of nuclear facilities" in the neighbourhood of North Korea's volatile regime, and where the security of fissile material is imperfect, said Luongo.
Plans for new plutonium-yielding plants in China, India and Japan will increase the global stockpiles of bomb-making fuel, which currently amounts to about 2,000 metric tonnes.
|A Pakistani-made Shaheen-III missile, capable of carrying nuclear warheads, loaded on a trailer during a military parade to mark Pakistan's Republic Day in Islamabad [AP Photo/Anjum Naveed]
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A serious threat
US officials point to improvements since Obama launched the first nuclear security confab in 2010. Stockpiles of HEU and plutonium have been removed or downblended from more than 50 facilities in 30 countries.
Japan and Ukraine are ditching much of their fissile material. Hospitals and industrial plants have stricter rules on radioisotopes nowadays. Borders are better guarded. Nuclear workers are more vetted and better trained, US officials said.
Delegates have made more than 260 pledges over the course of three summits. More are expected at the fourth meeting, which begins in Washington on March 31 - the last in the series, before the UN, Interpol and other multination organs assume the watchdog role.
Some 50 countries will take part, but Russia - a key nuclear power - will stay away.
Governments have shown willingness to act, but not enough for more sweeping controls, said Ben Rhodes, Obama's deputy national security adviser.
"In an ideal world, a treaty, for instance, related to fissile material is something that we have expressed support for in the past, but there is not sufficient international buy-in to advance at this time," Rhodes told Al Jazeera.
Over two days, Obama will meet the leaders of South Korea and Japan to discuss Pyongyang's recent atomic tests, and privately with Chinese President Xi Jinping. Separate sit-downs will cover ISIL and a nuclear deal with Iran.
Carl Robichaud, of the Carnegie Corporation think-tank, warned that leaders may still be complacent.
Governments have resisted tough curbs on plutonium activity, which has commercial uses, and fissile material for weapons, submarine engines and other military uses - which account for 85 percent of global stockpiles, he said.
"It's hard to muster the political will to take steps," Robichaud told Al Jazeera. "It's either going to be a serious incident or a very close call that drives people to take this threat seriously."
Follow James Reinl on Twitter: @jamesreinl
Source: Al Jazeera