mantra
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Of course nuclear bombs cause environmental and atmospheric change. Not only is the depleted radiation spread for hundreds of kms on the ground - it also remains in the atmosphere.
Climate threat from nuclear bombs
Alok Jha in San Francisco Tuesday December 12, 2006 Guardian Unlimited
Nuclear weapons pose the single biggest threat to the Earth's environment, scientists have warned.
In a new study of the potential global impacts of nuclear blasts, an American team found even a small-scale war would quickly devastate the world's climate and ecosystems, causing damage that would last for more than a decade.
Speaking at the American Geophysical Union's meeting in San Francisco yesterday, Richard Turco of UCLA said detonating between 50 and 100 bombs - just 0.03% of the world's arsenal - would throw enough soot into the atmosphere to create climactic anomalies unprecedented in human history.
He said the effects would be "much greater than what we're talking about with global warming and anything that's happened in history with regards volcanic eruptions". According to the research, tens of millions of people would die, global temperatures would crash and most of the world would be unable to grow crops for more than five years after a conflict.
In addition, the ozone layer, which protects the surface of the Earth from harmful ultraviolet radiation, would be depleted by 40% over many inhabited areas and up to 70% at the poles.
Alan Robock, the co-author of the study, told Guardian Unlimited: "Nuclear weapons are the greatest environmental danger to the planet from humans, not global warming or ozone depletion."
There are around 30,000 nuclear warheads worldwide, 95% of which are held by the US and Russia.
In addition, there is enough unrefined nuclear material to make a further 100,000 weapons.
Black smoke In the 100 warhead scenario, more than 5m tonnes of sooty black smoke would spew from the resulting firestorms. This smoke would float to the upper atmosphere, get heated by the sun and end up being carried around the world.
The particles would absorb sunlight, preventing it from reaching the surface, which would result in a rapid cooling of the Earth by an average of 1.25C.
"This would be colder than the little ice age, the largest climate change in human history," said Prof Robock.
The model also showed that the smoke would stay in the upper atmosphere far longer than anyone had previously thought.
Older models had assumed that the smoke would linger for around a year, as has been observed with the dust from volcanic eruptions. However, using improved atmospheric data the new study showed that the climate would still be suffering a decade on from the initial conflict.
"Far removed from the conflict, there would be large impacts on agriculture - there would be less precipitation and less sunlight; it would be a huge shock to agriculture everywhere," said Prof Robock.
There is a precedent for this sort of climactic change: major volcanic eruptions in the past have thrown global ecosystems into temporary turmoil.
The eruption of Mount Tambora in 1815 was the biggest such event on record. The resulting cloud of ash spread around the world and caused crops to fail the following year in North America and Europe, resulting in the worst famine of the century.
Shock to the system The scientists said a sudden change to the Earth's ecosystem because of nuclear blasts would be worse than any of the effects predicted by global warming due to greenhouse gases.
"Global warming is a problem and we certainly should address it but in 20 years, the temperature might go up by a few tenths of a degree and it will be gradual," said Prof Robock.
"We'll be able to adapt from some of it. But the climate change from even the small nuclear war we postulated would be instantaneous and such a shock to the system"
He said that the results should act as a warning to the international community.
"Proliferation is very dangerous - even using a couple of weapons is so much worse than anyone can imagine. I think the world should be much more concerned about proliferation than we are."
Prof Turco said that the end of the cold war had taken people's minds focus off the potential dangers of nuclear war.
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