Whats the difference between Volcanic and Nuclear Winter?

[Phlosphr]

I guess besides the obvious [one is started by a bomb and the other by a volcano] Whats the actual difference between a nuclear winter and a volcanic winter, should one occur? This is pretty much straightup and too the point, anyone have any ideas??

[wolfstu]

Well, for one thing, in a volcanic winter, there’s a lot less radioactive isotope contamination.

[Fillet]

The general idea for both is that an increased volume of solid and/or aerosol particles in the atmosphere would reflect solar radiation back out into space before it could reach the Earth’s surface, leading to climatic cooling -> crop failure -> mass starvation -> fall of civilization as we know it. The key differences between the two scenarios are the volumes of particulates involved and where in the atmosphere that stuff goes.

In a volcanic winter scenario, you need enormous volumes of ash and aerosolized sulfuric acid injected forcefully and abruptly into the stratosphere, somewhere in the tropics. (Because of atmospheric circulation patterns, massive eruptions at higher latitudes will have regional rather than global effects.) The solid particulates fall back out of the sky relatively rapidly (in days to a few weeks), so they don’t have much of an impact. The aerosols, however, can persist for a few years, since they can’t be “scrubbed” out of the stratosphere by rain or snow (precip only happens in the troposphere below). The eruption of Tambora in Indonesia in 1815 gave us “the year without a summer” in 1816, a good example of the climatic impact of a large eruption (estimates of the amount of particulates ejected range between 37 and 100 cubic miles). To really bring on a “volcanic winter” lasting a number of years, you’d probably need either multiple volcanoes erupting violently and simultaneously in the tropics, or else a prolific volcano erupting more or less continuously for several years in a row. The chances of this happening may not be great, but it is considered within the realm of possibility, with volcanoes in Indonesia being the likely culprits.

In a nuclear winter scenario, the particulate matter is basically soot from fires ignited by nuclear blast(s). However, since the soot is by and large confined to the troposphere (again, latitudinal position of the fires has some influence, and maximum altitude reached is a function of the heat intensity of the fire), the shielding effects of the soot don’t last the way that volcanic aerosols can, and global-scale climatic cooling may not occur. That’s a turnaround from the commonly accepted view of the 1970’s and 1980’s; the change of opinion is the result of better climate modeling capabilities, as well as the failure of a small-scale but analogous soot-producing event - the burning of the oil wells in Kuwait during the Gulf War - to cause anything other than a relatively small and temporary change in regional temperatures. Of course, if you torch the top 100 major cities on this planet, it might be possible to trigger some climatic cooling that is then reinforced by other feedbacks on a global basis.

Some links that might be of interest:

Volcanoes and Climate, Past and Present
Pinatubo Climate Investigation
A Survey of the 1991 Kuwaiti Oil Fires

[Muffin]

With the volcanic winter you need flashlights.

[Gaspode]

*Originally posted by Muffin *
**With the volcanic winter you need flashlights. **

Because with a nuclear winter enrything glows in the dark?

[SCSimmons]

*Originally posted by Fillet *
**That’s a turnaround from the commonly accepted view of the 1970’s and 1980’s; the change of opinion is the result of better climate modeling capabilities, as well as the failure of a small-scale but analogous soot-producing event - the burning of the oil wells in Kuwait during the Gulf War - to cause anything other than a relatively small and temporary change in regional temperatures. **

Just to expand a little on this portion of the topic-the scientists who first developed the ‘nuclear winter’ scenario (one of whom was the late lamented Carl Sagan) tested their assumptions primarily against measured climactic effects of volcanic eruptions, so it’s not surprising that their preliminary estimates did not take into account the differences between the two particulate sources … they just didn’t have the computer technology to make the calculations we can now.

Sorry, just had to defend them a little more.

[Derleth]

*Originally posted by Gaspode *
**

*Originally posted by Muffin *
**With the volcanic winter you need flashlights. **

Because with a nuclear winter enrything glows in the dark? **

Even the most radioactive material only glows under certain situations, such as underwater. It’s called Cerenkov Radiation:

from Einstein velocity addition:
**When highly radioactive objects are observed under water, such as in “swimming pool” reactors and in the underwater temporary spent fuel storage areas at nuclear reactors, they are seen to be bathed in an intense blue light called Cerenkov radiation. It is caused by particles entering the water at speeds greater than the speed of light in the water. As the particles slow down to the local speed of light, they produce a cone of light roughly analogous to the bow wave of a boat which is moving through water at a speed greater than the wave speed on the surface of the water. Another analogy statement is to say that the Cerenkov cone is like a sonic boom except that it is done with light.
**

Cerenkov radiation does not, to my knowledge, happen in air, and not all radioactive material will exhibit it (unless I’m mistaken). And, contrary to popular myth, it’s blue (actually close to UV), not green: Those photons have a lot of energy, and blue is the high end of the visible spectrum.

[Mirage]

Well, according to Nuclear Winter and Other Scenarios (kind of a chilling read) there would also be the problem of a nuclear summer following the nuclear winter, I would doubt if volcanos would do this though:

Looking at the period following the nuclear winter, the author’s RCM and BIM indicate that temperatures might increase above normal levels, to four-day highs as much as 12ºC above normal extremes. This would be the result of many small contributions to the greenhouse effect, from CO2, H2O, O3, CH3 and various aerosols injected into the troposphere and stratosphere, from CO2 from the decay of dead plant and animal life, and from reduced surface albedo from rapid desertification. Positive and negative feedback factors were considered. The model predicts that the “cold trap,” which prevents H2O from entering the stratosphere, will collapse as the stratosphere is heated by the dust and soot, and that convective activity from the oceans and from patchiness in the cloud cover will allow as much as 5x1014 kg of H2O to enter the stratosphere. As the dust and soot clear, the cold trap should drop and most of the H2O vapor precipitate, but as much as 5x1013 kg of H2O could remain in the stratosphere, enough to cause a greenhouse warming of the surface of up to 8ºC. The model also predicts that 300 1-megaton deep seabursts could put as much as 5x1013 kg of H2O into the stratosphere, enough to cause about 1-2ºC of greenhouse warming. The model predicts about 3ºC of heating from increased CO2 and another 3ºC from about 30 other substances, mainly O3 and various hydrocarbons. These effects are not all additive, so it seems unlikely that warming by more than 12ºC would result, but even 6ºC would be enough to drastically affect most lifeforms, and 10ºC could bring sustained highs fatal to most land life on earth. The model indicates that the worst of this scenario, called the “nuclear summer”, would last until about 3-5 years after the nuclear war, but temperatures elevated by 3-6ºC could persist for many decades. Given certain reasonable assumptions, the long-term biological effects of the nuclear summer could be worse than those of the nuclear winter. Transition from the nuclear winter to the nuclear summer would be extremely complex, and the model does not attempt to predict how that might happen, except to suggest that stratospheric H2O vapor might accelerate the removal of dust and soot as it precipitates, shortening the nuclear winter somewhat. Conversely, dust and soot might remove more of the H2O than the model predicts.

[Chronos]

There are other circumstances where radioactive material can glow of its own power, with the most familiar being fluorescence. A piece of radioactive material (radium in the old days, more commonly tritium now) produces high-energy photons or other particles, which hit some other material (often phosphorus or a phosphorus compound) and are absorbed. The fluorescent material then re-emits the energy in several lower-energy photons which we can see. This is the principle used by permanent glow-in-the-dark paint, and often is greenish.

Theoretically, you can get Cherenkov radiation in any material other than vacuum, but it’s easiest with something with a high index of refraction, like water. If I recall correctly, air has an index of somewhere around 1.001, so a particle would have to be travelling at greater than .999 c to produce Cherenkov radiation in air.

[Essured]

*Originally posted by Muffin *
**With the volcanic winter you need flashlights. **

LMAO !