Nuclear war and climate change

By: Dr. Jeff Masters , 5:31 AM GMT on January 29, 2007

In the 1980s and early 1990s, a series of scientific papers published by Soviet scientists and Western scientists (including "rock star" scientists Dr. Carl Sagan, host of the PBS "Cosmos" TV series, and Nobel Prize winner Paul Crutzen) laid out the dire consequences on global climate of a major nuclear exchange between the U.S. and Soviet Union. The nuclear explosions would send massive clouds of dust high into the stratosphere, blocking so much sunlight that a nuclear winter would result. Global temperatures would plunge 20°C to 40°C for several months, and remain 2-6°C lower for 1-3 years. Up to 70% of the Earth's protective stratospheric ozone layer would be destroyed, allowing huge doses of ultraviolet light to reach the surface. This UV light would kill much of the marine life that forms the basis of the food chain, resulting in the collapse many fisheries and the starvation of the people and animals that depend it. The UV light would also blind huge numbers of animals, who would then wander sightlessly and starve. The cold and dust would create widespread crop failures and global famine, killing billions of people who did not die in the nuclear explosions.

What about a small-scale nuclear war?
The "nuclear winter" papers were widely credited with helping lead to the nuclear arms reduction treaties of the 1990s, as it was clear that we risked catastrophic global climate change in the event of a full-scale nuclear war. But even a limited nuclear war poses a significant threat to Earth's climate, according to a paper presented at the American Geophysical Union meeting in December by scientists at Rutgers University and the University of Colorado. The scientists used a sophisticated atmospheric/oceanic climate model that had a good track record simulating the cooling effects of past major volcanic eruptions, such as the Philippines' Mt. Pinatubo in 1991. The scientists injected five terragrams of soot particles into the model atmosphere over Pakistan in May of 2006. This amount of smoke, they argued, would be the likely result of a limited nuclear war involving 100 Hiroshima-sized bombs in the region.

Figure 1. Global average temperature departure from normal since 1880 (top) and A.D. 1000 (bottom) in black, and those projected after a limited nuclear exchange of 100 Hiroshima-sized weapons in 2006 (in red). Temperatures are forecast to plunge 1.2°C (2.2°F) after such a war, reaching levels colder than anything seen in the past 1000 years. The 1815 eruption of Tambora in Indonesia produced a similar cooling, and led to the notorious "Year Without a Summer". Image credit: "Climatic consequences of a regional nuclear conflict" by Robock et al., 2006.

The black smoke, they found, absorbed far more solar radiation than the brighter sulfuric acid particles emitted by volcanic eruptions. This allowed the smoke to heat the surrounding air to much higher temperatures, resulting in stronger upward motion of the smoke particles higher into the stratosphere. Once the smoke reached the stratosphere, where there is no rain to rain out the soot particles, it stayed at significantly high levels for over a decade. The black soot blocked sunlight, resulting in global cooling of over 1.2°C (2.2°F) for two years, and 0.5°C (0.9°F) for more than a decade.

This magnitude of this cooling would bring about the coldest temperatures observed on the globe in over 1000 years (Figure 1). The growing season would shorten by 10-30 days over much of the globe, resulting in widespread crop failures. The effects would be similar to what happened after the greatest volcanic eruption in historic times, the 1815 Tambora eruption in Indonesia. This cooling from this eruption triggered the infamous Year Without a Summer in 1816 in the Northern Hemisphere, when killing frosts disrupted agriculture every month of the summer in New England, creating terrible hardship. Exceptionally cold and wet weather in Europe triggered widespread harvest failures, resulting in famine and economic collapse. However, the cooling effect of this eruption only lasted about a year. Cooling from a limited nuclear exchange would create two to three consecutive "Years Without a Summer", and over a decade of significantly reduced crop yields. The authors anticipated that the smoke in the stratosphere would partially destroy Earth's protective stratospheric ozone layer as well, but did not model how large of an impact this would have. Clearly, even a limited nuclear exchange could trigger severe global climate change capable of causing economic chaos and widespread starvation.

Climate change and the Doomsday Clock
It is sobering to realize that the nuclear weapons used in the Robock et al. study represented only 0.03% of the world's total nuclear arsenal of 26,000 warheads. While significant progress was made in the 1990s to reduce the threat of nuclear war, that threat has increased in recent years. Last week's move by the Bulletin of the Atomic Scientists to move the hands of their Doomsday Clock two minutes closer to midnight--the figurative end of civilization--helped call attention to this increased threat. In addition, they also mentioned climate change for the first time as part of the rationale for moving the clock closer to midnight. I believe that climate change does not pose an immediate threat to civilization--at least for the next 20 years or so--and there is still time to significantly reduce the threat of climate change to civilization if strong action is taken in the next 20 years to cut carbon emissions. Thus, setting the hands of the clock closer to midnight because of climate change is probably premature. However, climate change triggered by a limited nuclear war is a whole different situation. The twin disasters of a limited nuclear war, coupled with the devastating global climate change it could wreak, should remind us that there is no such thing as a small scale nuclear war. Nuclear war remains the greatest threat to the globe, and the most important cause to work for today is peace. There's no better way for an individual to do that than to make oneself more peaceful.

Next update
On Wednesday, I'll preview the coming blockbuster climate report due to be issued this Friday by the United Nations-sponsored Intergovernmental Panel on Climate Change (IPCC).

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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324. Thunderstorm2
5:21 PM GMT on January 30, 2007
ill be back later
Member Since: December 31, 1969 Posts: Comments:
323. Thunderstorm2
5:13 PM GMT on January 30, 2007
With that visible picture you posted at 1.50pm GMT i thought it looked like Arthur but probably not.
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322. hurricane23
5:09 PM GMT on January 30, 2007
Loop from NRL of Dora...Bondo?But not even close cause that was a powerful cyclone.

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321. Thunderstorm2
4:57 PM GMT on January 30, 2007
Good Morning everyone how are you all feeling today? H23,What recent storm does Dora remind you of with her structure and eye like feature?
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319. hurricane23
4:48 PM GMT on January 30, 2007
Yea it was changed briefly...Still at 65kts forcasted to make 90kts.
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316. Skyepony
4:03 PM GMT on January 30, 2007
I see 65kts on NRL...

CB, do you have any other sources??? I've been following that confrence. There is a huge push for the US & other large greenhouse contributers to give clean technoligigy to China & India as well as some money so they can do it right the 1st time. Bush has been leaning toward this as well, atleast for clean coal & pumping CO2 in the ground..stuff that leads to big energy profits.
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314. hurricane23
3:28 PM GMT on January 30, 2007
Skyepony winds are down to 55kts on NRL...
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311. Skyepony
3:03 PM GMT on January 30, 2007
Shear around Dora
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310. snotly
2:53 PM GMT on January 30, 2007
pwrgril - as you begin your trip the birds will sing and the flower will bloom in the perfect 76 degree, 45% humidity, gentle winds with a few light puffy clouds, weather, but, as you head over the mountains the lightning will become as we say "sufficient" from the southeast with a "scattering" of hail stones mixed with small angry fire ants developing towards the evening. Once you crest the ridge you should see the temp fall slightly into the -40 to -60 degree range as small orbs of superheated plasma mix in with the heavy freezing rain and gusty winds ranging to 300 - 400 m/s from the upper stratosphere... well I would continue but it kind of looks downhill from there...
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309. Patrap
2:10 PM GMT on January 30, 2007
The 10-day GFSx Model may help for your trip.Follow the dates in the right hand Upper corner...Link
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308. prowlergirl83
2:00 PM GMT on January 30, 2007
OK My weather experts, help me out. Leaving Thursday from DC in the afternoon headed to Cal. Will I be clear to travel all the way across or am I looking at a nasty, snowy delay along the way. 1 stop in TN half way through.
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307. hurricane23
1:54 PM GMT on January 30, 2007
Clouds indeed were a + for us in florida as it prevented a significant drop in temps.You can see on the infrared pic above that more clouds are indeed on the way towards the state.Clouds here

Part of discussion from miami NWS late last night.

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306. hurricane23
1:50 PM GMT on January 30, 2007
Dora has indeed intensified over night and is forcasted to futher intensify as its in good overall favorable environment.

Eye like feature on Dora showing up on modis.

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305. hurricane23
1:41 PM GMT on January 30, 2007
Morning everybody...

As i thought yesterday clouds did help keep temps a tad up across southeast florida.More clouds on the way.

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304. ProgressivePulse
1:34 PM GMT on January 30, 2007
Morning All! Loving this brief cooldown here in the deep south. Here is a neat loop of DORA! Forcast to be 90kts in the coming days.
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303. biff4ugo
1:20 PM GMT on January 30, 2007
I know volcano's turn our sunsets Red, I have seen the change. But did not know the rural areas are showing a more luminous night sky that dims the stars. Does anyone else have a comment on that? Do we know what frequencies it is emitting to know what kinds of particles are up there? Do we have any early ambient records to compare it against that might confirm it is an ionized particle from a nuclear test?
Member Since: December 31, 1969 Posts: Comments:
299. orionRider
12:35 PM GMT on January 30, 2007
Did anyone ever studied the climate impact of the more than 500 atmospheric nuclear tests conducted between 1945 and 1970?

Could it be the cause of the stabilisation of the anomalies that can be clearly seen on the graphic for the same period?
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297. pottery
11:55 AM GMT on January 30, 2007
So I'm out till tonight. Have a fine one..............
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296. pottery
11:53 AM GMT on January 30, 2007
Have to be out in the snarly City today. Dread. Traffic jams and CO2 ingestion. Not a good way to spand a day, but commerce calls......
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294. pottery
11:50 AM GMT on January 30, 2007
Its 70 here this morning. Very pleasant. Not a cloud between me and Africa......
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293. pottery
11:42 AM GMT on January 30, 2007
How is life, the universe and everything, Rand ?
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290. pottery
11:36 AM GMT on January 30, 2007
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280. Inyo
7:52 AM GMT on January 30, 2007
Posted By: MichaelSTL at 3:42 AM GMT on January 30, 2007.
Inyo, I think that is what the "life on earth as we know it may never recover fully" part was referring to - it would cause dramatic changes in the number and types of species, to the point where it would never be the same as before (99.9% of all species that have ever existed have become extinct). 0.1% is not really good odds...

Michael, I followed your link and the 99.9% refers to all species that have EVER gone extinct.. the estimate is that .01% of all species that EVER EXISTED still exist on earth, that includes the human caused mass extinction as well as all the ones in the past caused by volcanos, meteors, changes in axial tilt/climate, etc.

The huge mass extinctions tend to occur something between 50 and 100 million years apart, i think. Caldera eruptions probably occur every few hundred thousand years. They cause ice ages but generally not extinctions to the extent that the giant meteor (or humans) have caused. The yellowstone one is larger than most, so it would be more severe than most. But Long Valley blew off in the last million years too, and I think one in new zealand.

Posted By: cyclonebuster at 3:46 AM GMT on January 30, 2007.
Bwhaaaaa!!!!!Bwhaaaaa!!!!!!!Bwhaaaaaa!!!!! Isn't this "THE POT CALLING THE KETTLE BLACK"????

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