Nuclear Disarmament is still a long way off as nations continue to invest in new weapons systems, according to a report published on Tuesday. The Stockholm International Peace Research Institute says the modest cuts in US and Russian strategic nuclear forces have made only a small dent in global arsenals.

The Stockholm-based research group, which is better known as SIPRI, says the outlook isn?t all bad.

The good news is that overall arsenals and nuclear weapons have declined in number since the Cold War when there were some 70,000 nuclear weapons in the world.

Now SIPRI says there are probably around 20,000; that decline, it says, was helped by a treaty signed last year between the US and Russia, the Strategic Arms Reduction Treaty or START.

But Shannon Kile, head of SIPRI?s Arms and Non-proliferation Program, says there?s also bad news.

He says all legally recognized nuclear weapons states are committed to retaining nuclear weapons as part of their national security postures for the long term.

"They all have either announced or they have launched forced modernization programs, in the case of the United States the time frame for these are decades into the future. So although total arsenals are coming down, it's pretty clear that nuclear disarmament is going to be quite a distant point in the horizon," said Kile.

The SIPRI report says around the world more than 5,000 nuclear weapons are deployed and ready for use.

The United States and Russia have by far the largest supply of nuclear weapons. As of January 2011, Russia had 11,000 nuclear weapons and the United States 8,500 and each have more than 2,000 deployed.

There are five legally recognized nuclear weapons states: the U.S. and Russia, plus France, Britain and China.

India, Pakistan, and Israel are also thought to have nuclear weapons and possibly North Korea as well.

Kile says these countries are also a worry, especially in south Asia. "India and Pakistan are basically engaged in an accelerating nuclear arms race. They are both increasing their capabilities to produce fissure material for nuclear weapons to expand their weapon stockpiles. And they are also working quite hard to increase the size and diversity of their nuclear weapon delivery systems. So if anything the trend is going the opposite way in south Asia and I think that is something we should be very concerned about," he stated.

Dan Plesch is director of the Center for International Studies and Diplomacy at the School of Oriental and African Studies in London. He too says the situation in south Asia is dangerous.

"It would be disastrous for the planet if there was, for example, India and Pakistan in nuclear war because you would get upwards of 1 billion people dying from starvation because of crop failures as the dust from these explosions blotted out the sun across the planet, the precise opposition of global warming - very rapid global cooling. So these proliferation issues are not about things that are remote from us they would affect us absolutely directly," said Plesch.

He says the vast arsenal of nuclear weapons still held by the United States and Russia makes it difficult for them to dissuade other countries from mounting their own nuclear systems.

But he says if the right political will was in place it would be possible to resolve the situation.

He says at the end of the cold war, tens of thousands of armaments across Europe were regulated and destroyed under treaties, which can be used to control all forms of conventional weapons.

And he says on the nuclear front, the United Nations? inspection regime in Iraq was effective.

"If you combine the inspection regime of weapons of mass destruction in Iraq with the European security structures, one could move to control all weapons down to police functions really in not much more than a decade, because that was the pace that was achieved during the end of the cold war," noted Plesch.

The United States is the only country that?s used nuclear weapons in warfare. Its bombings of Japan?s Hiroshima and Nagasaki during the Second World War killed around 200,000 people.