Did the Cold War era make the world colder too?

[Chris Knight]

While I agree that the dust and particles thrown into the atmosphere by nuclear testing could have cooled the earth, C14 almost certainly did not contribute to this.

The figure you quoted of 8.4% of the carbon over NZ being C14 is far far far too high.

All the nuclear tests in the world only created 1.75 tonnes of C14. Even if those 1.75 tonnes were released all in one go over New Zealand, C14 would make up only around 4.6 x 10^-9 % of the carbon in the atmosphere over NZ.

"Carbon-14 is also a weak beta emitter (156 KeV, no gamma), with a half-life of 5730 years (4.46 Ci/g). Atmospheric testing during the fifties and early sixties produced about 3.4 g of C-14 per kiloton (15.2 curies) for a total release of 1.75 tonnes (7.75x10^6 curies). For comparison, only about 1.2 tonnes of C-14 naturally exists, divided between the atmosphere (1 tonne) and living matter (0.2 tonne)."

From the webpage where Eddie got his information, it seems, based on the quote above:

http://www.cartage.org.lb/en/themes/Scienc...aponEffects.htm

The author goes on to say:

"Due to carbon exchange between the atmosphere and oceans, the half-life of C-14 residing in the atmosphere is only about 6 years. By now the atmospheric concentration has returned to within 1% or so of normal. High levels of C-14 remain in organic material formed during the sixties (in wood, say, or DNA)."

This 6 years for the amount of carbon dioxide produced in the Nuclear explosions of the 1960s to reduce by half is rather different to the 55y or 200y that some AGW proponents say the anthropogenic carbon dioxide hangs around in the atmosphere.

Carbon exchange means carbon dioxide exchange, as the carbon formed in the blast quickly oxidises to CO2, with the high temperatures and high levels of oxidising agents such as those produced by the blast in the vicinity. From the same article:

"The first energy to escape from the bomb are the gamma rays produced by the nuclear reactions. They have energies in the MeV range, and a significant number of them penetrate through the tampers and bomb casing and escape into the outside world at the speed of light. The gamma rays strike and ionize the surrounding air molecules, causing chemical reactions that form a dense layer of "smog" tens of meters deep around the bomb. This smog is composed primarily of ozone, and nitric and nitrous oxides."

The author also describes the process that leads to the genesis of C14:

"Although not important for acute radiation effects, the isotopes carbon-14 and tritium are also of interest because of possible genetic injury. These are not direct fission products. They are produced by the interaction of fission and fusion neutrons with the atmosphere and, in the case of tritium, as a direct product of fusion reactions. Most of the tritium generated by fusion is consumed in the explosion but significant amounts survive. Tritium is also formed by the capture of fast neutrons by nitrogen atoms in the air: N-14 + n -> T + C-12. Carbon-14 in also formed by neutron-nitrogen reactions: N-14 + n -> C-14 + p. Tritium is a very weak beta emitter (18.6 KeV, no gamma) with a half-life of 12.3 years (9700 Ci/g)."

On fallout:

"Fallout is a complex mixture of different radioactive isotopes, the composition of which continually changes as each isotope decays into other isotopes. Many isotopes make significant contributions to the overall radiation level. Radiation from short lived isotopes dominates initially, and the general trend is for the intensity to continually decline as they disappear. Over time the longer lived isotopes become increasingly important, and a small number of isotopes emerge as particular long-term hazards.

Radioactive isotopes are usually measured in terms of curies. A curie is the quantity of radioactive material that undergoes 3.7x10^10 decays/sec (equal to 1 g of radium-226). More recently the SI unit bequerel has become common in scientific literature, one bequerel is 1 decay/sec . The fission of 57 grams of material produces 3x10^23 atoms of fission products (two for each atom of fissionable material). One minute after the explosion this mass is undergoing decays at a rate of 10^21 disintegrations/sec (3x10^10 curies). It is estimated that if these products were spread over 1 km^2, then at a height of 1 m above the ground one hour after the explosion the radiation intensity would be 7500 rads/hr.

Isotopes of special importance include iodine-131, strontium-90 and 89, and cesium-137. This is due to both their relative abundance in fallout, and to their special biological affinity. Isotopes that are readily absorbed by the body, and concentrated and stored in particular tissues can cause harm out of proportion to their abundance.

Iodine-131 is a beta and gamma emitter with a half-life of 8.07 days (specific activity 124,000 curies/g) Its decay energy is 970 KeV; usually divided between 606 KeV beta, 364 KeV gamma. Due to its short half-life it is most dangerous in the weeks immediately after the explosion, but hazardous amounts can persist for a few months. It constitutes some 2% of fission-produced isotopes - 1.6x10^5 curies/kt. Iodine is readily absorbed by the body and concentrated in one small gland, the thyroid.

Strontium-90 is a beta emitter (546 KeV, no gammas) with a half-life of 28.1 years (specific activity 141 curies/g), Sr-89 is a beta emitter (1.463 MeV, gammas very rarely) with a half-life of 52 days (specific activity 28,200 Ci/g). Each of these isotopes constitutes about 3% of total fission isotopes: 190 curies of Sr-90 and 3.8x10^4 curies of Sr-89 per kiloton. Due to their chemical resemblance to calcium these isotopes are absorbed fairly well, and stored in bones. Sr-89 is an important hazard for a year or two after an explosion, but Sr-90 remains a hazard for centuries. Actually most of the injury from Sr-90 is due to its daughter isotope yttrium-90. Y-90 has a half-life of only 64.2 hours, so it decays as fast as it is formed, and emits 2.27 MeV beta particles.

Cesium-137 is a beta and gamma emitter with a half-life of 30.0 years (specific activity 87 Ci/g). Its decay energy is 1.176 MeV; usually divided by 514 KeV beta, 662 KeV gamma. It comprises some 3-3.5% of total fission products - 200 curies/kt. It is the primary long-term gamma emitter hazard from fallout, and remains a hazard for centuries."

Beta particles can be spectacular sources of cloud forcing. The track of a beta particle in a cloud chamber is about 12 feet for each MeV of beta energy, so I131, Cs137, and Sr90 decays each provide a string of water droplets over 6 feet long in supersaturated air, which puts cloud forcing by aerosols to shame. (1 aerosol particle = 1 droplet).

The beta track of C14 is only about half a metre long by comparison.

There were 210 atmospheric tests up to 1963 and 2 combat nuclear explosions, by the USA (some with UK collaboration). The USSR admits to 221.

Sources for these and much more, can be found at:

http://www.nv.doe.gov/library/default.htm in the historical section of the library, http://nuclearweaponarchive.org/ for all nations nuclear tests.

[Chris Knight]

Note the interesting links in Thundery wintry showers post above in the Peer reviewed papers thread

[jethro]

Hi Chris, the last of those links I posted in the opening post of the thread; it's curious stuff, I find it hard to believe it had no effect but I think establishing a link relies heavily on establishing the Cosmic Ray and C14 theory - alas still up in the air so to speak but in no way dead in the water. What I can say catagorically, with all science in agreement; high levels of C14 have historically been associated with cooling. Having researched this quite a lot, I definately believe the cooler interlude during the middle of the 20th century is more of an human induced anomoly than the recent warming, this stands out to a greater degree precisely because it is measured against the cooler period. Factoring in the C14 element during this time, also the much greater levels of sulphur based particulants and aerosols which were replaced due to the clean air act; the warming we've experienced recently is even less pronounced.

[Chris Knight]

Hi Chris, the last of those links I posted in the opening post of the thread; it's curious stuff, I find it hard to believe it had no effect but I think establishing a link relies heavily on establishing the Cosmic Ray and C14 theory - alas still up in the air so to speak but in no way dead in the water. What I can say catagorically, with all science in agreement; high levels of C14 have historically been associated with cooling. Having researched this quite a lot, I definately believe the cooler interlude during the middle of the 20th century is more of an human induced anomoly than the recent warming, this stands out to a greater degree precisely because it is measured against the cooler period. Factoring in the C14 element during this time, also the much greater levels of sulphur based particulants and aerosols which were replaced due to the clean air act; the warming we've experienced recently is even less pronounced.

Sorry I missed your original link, your original post was rather plagued by bad links :lol:

Hi Jethro,

I think the CR theory is going to be difficult to enter the mainstream, since the antagonism exhibited by the AGW camp towards any other theory than CO2 and GG positive forcing and aerosol negative forcing is so widespread. Yet there seems to be much more emotional, heated argument than rational, reasoned debate going on.

There is the question of whether ground based "atmospheric pollution" (as an all-inclusive term) affects weather/climatic systems in the same way as "atmospheric pollution" injected into upper reaches of the atmosphere, by aviation and nuclear explosions.

In the lab, it is simple to prove that products of a single nuclear decay event can form a large number of condensation nuclei in a supersaturated atmosphere. It is difficult to observe events in the global atmosphere and to scale up what happens under ideal lab conditions, because they are random and statistical in their nature, and it would be unethical to conduct a series of experiments with large scale releases of radioactive isotopes in the open air.

It is also open to debate if 30 year episodes of weather pattern changes are due to natural variation, due to complex causes, or due to ongoing human activities.

Logic only figures in the theories put forward. The science of past events will always be difficult to falsify (in the sense Karl Popper meant), witnessed by the arguments over Origins -Life, Universe, Species etc.

Weather and climate and man's role in what is a much bigger and more powerful system is yet another area which polarises ideas into different camps, with a lot of hot air on either side.

[jethro]

Sorry I missed your original link, your original post was rather plagued by bad links :lol:

Hi Jethro,

I think the CR theory is going to be difficult to enter the mainstream, since the antagonism exhibited by the AGW camp towards any other theory than CO2 and GG positive forcing and aerosol negative forcing is so widespread. Yet there seems to be much more emotional, heated argument than rational, reasoned debate going on.

There is the question of whether ground based "atmospheric pollution" (as an all-inclusive term) affects weather/climatic systems in the same way as "atmospheric pollution" injected into upper reaches of the atmosphere, by aviation and nuclear explosions.

In the lab, it is simple to prove that products of a single nuclear decay event can form a large number of condensation nuclei in a supersaturated atmosphere. It is difficult to observe events in the global atmosphere and to scale up what happens under ideal lab conditions, because they are random and statistical in their nature, and it would be unethical to conduct a series of experiments with large scale releases of radioactive isotopes in the open air.

It is also open to debate if 30 year episodes of weather pattern changes are due to natural variation, due to complex causes, or due to ongoing human activities.

Logic only figures in the theories put forward. The science of past events will always be difficult to falsify (in the sense Karl Popper meant), witnessed by the arguments over Origins -Life, Universe, Species etc.

Weather and climate and man's role in what is a much bigger and more powerful system is yet another area which polarises ideas into different camps, with a lot of hot air on either side.

Agreed; I'm afraid frustration at the antagonism got to me in the end. There are so many areas of climatic studies which we genuinely do have only limited knowledge of thus far, it seems to me to be too far fetched to claim to have any degree of certainty. More especially when that degree of certainty is hung almost entirely on our limited knowledge of how Co2 effects climate. The more I read and study, the more it appears that there is a wall of not wanting to know any more, a think tank of we've done the sums, we have the answers, we will defend them to the end. Completely illogical.

On a completely different note, way off topic, I saw Seasick Steve at the student uni in Bristol tonight, saw him earlier in the year too, he was absolutely bloody fantastic. Great night out, how anyone can make such a sound from a three string guitar, piece of pipe and a wooden box is beyond me, he should be bottled and prescribed on the NHS, beats Prozac any day of the week, highly recommended!! Go see him if you get the chance.