Scientist Stephen Hawking is seen during a press conference on the Doomsday Clock, a symbol of the risk of atomic cataclysm. (Lewis Whyld/Associated Press)

The world is now two minutes closer to a destructive nuclear war.

At least that is the view of a group of prominent scientists from Europe and North America who, in January 2007, turned forward the hands of time on the Doomsday Clock.

These scientists believe that such factors as impending climate change, globalization and a revival of nuclear ambitions by smaller nations such as North Korea and Iran will create the conditions for a second unleashing of nuclear weaponry.

Changing the clock is not a step the scientists take lightly. The clock was developed in 1947 by former Manhattan Project scientists who sided against nuclear weapons after creating the world's first atomic bomb.

The prophetic clock premiered during the Cold War to measure how close humankind was to self-destruction via nuclear weapons. When it was established, scientists set the clock at seven minutes to midnight, with 12 a.m. representing the nuclear obliteration of the human race. It has now been set at two minutes closer to the end.

The timepiece hangs at the University of Chicago and has been reset 17 times in the last 60 years to reflect a changing sense of security in a nuclear world. Some frequently asked questions:

Who is responsible for the clock?

In 1945, a group of atomic scientists founded the newsletter Bulletin of Atomic Scientists to promote their concerns about the danger of nuclear technology to politicians and the public.

The newsletter eventually evolved into a magazine that is still in circulation and the group is currently based out of Chicago. The scientists are all important authorities on nuclear technology and the world has relied on the Doomsday Clock to gauge the status of nuclear threat.

The people behind the Bulletin include some of the most prominent scientists and professors in the world. For the most recent change of the minute hand, for example, the Bulletin's board of directors consulted with its board of sponsors, which is composed of 18 Nobel Prize laureates.

One of the notable sponsors was prized physicist and mathematician Stephen Hawking who was part of the January 2007 announcement.

When was the clock closest to midnight?

In 1953, the minute hand rested precariously only two minutes away from midnight and a nuclear-inspired Armageddon. This reflected U.S. development of the hydrogen bomb in October 1952 and its testing on an atoll in the Pacific Ocean. This action provoked the Soviet Union, which nine months later tested its version of the nuclear device. At the time, Bulletin announced: "Only a few more swings of the pendulum and from Moscow to Chicago atomic explosions will strike midnight for Western civilization." The clock ticked back in 1960 to 11:53 when Soviet and U.S. scientists came together to share information at the Pugwash conference. The two superpowers also agreed to avoid any direct confrontations in regional conflicts.

When was the minute hand furthest away?

The Doomsday minute hand sat a comfortable 17 minutes from midnight in 1991, a year after the Cold War ended. At that point, the United States and Russia began the process of disarming through the Strategic Arms Reduction Treaty.

The number of nuclear weapons possessed by each side decreased and talks brought down the ready-to-fire status on much of the weaponry.

Why the recent move to five minutes from midnight?

Add a new crop of countries dazzled by nuclear technology to other global threats such as climate change and environmental degradation and the result, according to the Bulletin of Atomic Scientists, is almost toxic.

"We stand at the brink of a second nuclear age," the board said in a statement.

The move from seven to five minutes from midnight was decided upon after scientists reviewed the current nuclear situation in combination with expected climate change, marking the first time the Doomsday Clock has ever reflected a separate world threat in addition to the bomb.

"As scientists, we understand the dangers of nuclear weapons and their devastating effects, and we are learning how human activities and technologies are affecting climate systems in ways that may forever change life on earth," said board sponsor Stephen Hawking at the Doomsday Clock announcement in London.

The board emphasized that climate change is a slow process but said that in time its lasting effects and the challenges it will bring to peaceful existence may be second only to atomic weapons.

Climate change can upset the delicate ecosystems of the world, leading to the disappearance of animals, land and even whole societies.

Global warming is also likely to turn much of the world toward nuclear power as an environmentally cleaner alternative to fossil fuels. But this would make nuclear material more readily available and perhaps lead to a dependence on the explosive material.

Today's nuclear weapons, the scientists warn, are already much stronger than their predecessors — 50 of the top nuclear weapons available are capable of wiping out 200 million people.

What's more, there are also 26,000 nuclear remnants leftover from the Cold War in the hands of the U.S. and former members of the Soviet Union. Many of this latter group, it is said, don't have the resources to properly safeguard their stash.

Uranium and plutonium, both atomic materials, are also relatively unguarded in power plants and in research and military facilities. That leaves the material accessible to persons or groups bent on creating nuclear havoc.