Slashdot Mirror

Hold on there mister, the Laschamp event only lasted less than 500 years, and occurred in the middle of an ice age, over 41,000 years ago. I don't know about you, but I see a whole lot of unknowns that make it very difficult to conclude that "the climate didn't change". ... I would prefer to not draw any conclusions from what little data we have of this event.

So your preferences are different than Richard Alley's. He concluded at 43:01 that "We had a big cosmic ray signal, and the climate ignores it. And it's just about that simple. These cosmic rays didn't do enough that you can see it."

Maybe this is because Richard Alley's estimate that the Laschamp anomaly lasted "for a millenium or so" matches other estimates that are longer than 500 years.

We have the technology to measure GCR's, and we have the technology to measure cloud cover. Let's verify the theory of GCR's and cloud formation, let's quantify it, and then let's see if we can accurately predict cloud cover and irradiance fluctuations based on this data.

I've explained that the maximum impact of this mechanism has been estimated to be responsible for no more than 23% of the 11-year cyclical variation of cloud cover. Furthermore, there’s no long term trend in Svensmark’s data, which would be necessary to explain the long term warming trend that’s been observed. For more information, see chapter 7.10 of this textbook.

Update: Other relevant papers include Kristjansson 2002 and Laut 2003, followed by Svensmark’s response and Laut’s rebuttal. More recently, Erlykin et al. suggest that the apparent correlation is due to direct solar activity, while Pierce and Adams state: “In our simulations, changes in CCN [cloud condensation nuclei concentrations] from changes in cosmic rays during a solar cycle are two orders of magnitude too small to account for the observed changes in cloud properties; consequently, we conclude that the hypothesized effect is too small to play a significant role in current climate change.”

Another update: Snow-Kropla et al. 2011 makes similar points.

Check out Svensmark (http://www.dsri.dk/~hsv/). The short version: Global warming is caused by cosmic rays, CO2 is a second order effect.

Take a look at these sites for influences that are not well understood by most. For instance, there is good evidence that the greenhouse anomaly has been growing for about 8000 years as a result of human activity. http://courses.eas.ualberta.ca/eas457/Ruddiman2003 .pdf
The course of events would have resulted in a cooling climate and a return to an ice age in the near future without the effect of the greenhouse gases from farming and land clearing. In addition, the undisputed effect of the rapid rise in greenhouse gases recently has been largely responsible for the warming so grnerally reported. There are other effects that moderate and perturb the result of such warming. The high level of solar activity in recent years is suggested as being responsible for the more rapid warming of the polar regions, while moderating the tropical heating effects. This would result from a proposed connection between sunspots and cloud formation. Clouds would retain winter heat in the polar regions where long periods of low or no light usually results in rapid cooling. Similarly, tropical areas would be reflecting more light and thus not heating as rapidly. http://www.dsri.dk/~hsv/Noter/solsys99.html
There are other inputs that are potential wild cards in the equation, such as the decomposition of organic matter currently held in permafrost. This input could result in a doubling or even tripling of atmospheric CO2, but the time frame would be long and require the continued melting of the permafrost, and it neglects binding of CO2 in new forest growth etc.

Okay, here is the link to
Henrik Svensmark, Danish Space Research Institute and his papes on
Cosmic rays and Earth's Cloud Cover. He is quoted in the story.

I am providing this in self defense since I prefer to discuss intelligently with people who do not need that popular science website (which is fine on its own) to provide a link to every darned word in the article. I think it is up to the Editors to do this sort of thing to promote some you know, talk about science and technology around here.

Anyway they also link to the Fermi paradox about where are they (the aliens). But I saw it just after reading about how vortices are thought to push dolphins forward and solve Gray's paradox about how they swim so fast. It is nice how paradoxes have ways of getting resolved over time. Oh, that's alright then.

Okay, I didn't like the term cosmic rays.. Wikipedia says it covers lots of things including the helium nuclei that remained in my head. Which is a lot more than just the gamma rays from Supernovae that I thought caused extinction events.

Anyway, as some posters mention it seems likely that lots of life in the galaxy must have died back or been sterilized in high radiation eras and what we need now is some kind of chronological and spatial map of what regions were affected to that degree and when. If our local neighbors failed to survive such radiation, then our biological histories are all of approximately the same age. Perhaps having deep oceans or thick ice sheets, would have something to do with preserving that too.

Now my guess has always been that even so, the geographic scale of time we are talking about, and the comparatively very rapid industrialization and advancement of a planet once the biology reaches a critical stage (perhaps a certain number of organisims at near human level?), meant that even so it most certain that civilizations hundreds of thousands or millions of years more advanced than us must exist. My picture was always that supernovae were the killer but we had been lucky... and we need to continue to be lucky until we can spread out and shield ourselves or move to safer places for the long term.

But now, it might mean that a relatively short window of time has been available to all planets in this local region to develop life. It is not clear how many times we failed or whether other planets would have to go through all the stages we did. It seems logical to have the planetary chemistry alterations in order like we had, with vegetation, and big plant eaters. Maybe the meteor that killed them was not the only problem? Anyway it took this long to get where we are. It is possible our type of chemistry is the only one that works, since the world we have obviously came from a darwinian evolution it would appear to be a result of very high probability.

So now I am looking on the web to see if there is information about just how long the part of the galaxy we know anything about could have survived biologically intact to the present day, how far back does the current window go, and how long are windows on average. It also seems that we should look for signals from areas that got hit with high radiation far away but maybe had time to beam something at us from the other side of the galaxy - to us who would evolve in the next window... Anyway it would be interesting (if we had the data which I guess we don't maybe) to be able to plot a 4D map of garden regions that did not get totally ionized and disrupted, and to see where in our neighborhood is the oldest such area.

The direct effect of changes in solar brightness are probably small. (These guys http://pda.physorg.com/lofi-news-solar-since-sun_6 15.html are a respectable source.) A more controversial idea is that the modulation of the cosmic ray flux by the heliospheric magnetic field affects the rate of cloud formation on Earth ( http://www.dsri.dk/sun-climate/NewPublications.htm ). The idea isn't silly, but it's definitely "fringe", plus nobody really knows what effect it would have on climate if it was true.

Btw, I'm very impressed with the standard of some of the discussion here. It's good to see people rationally debating the merits of prevention v. adaptation, for example.

http://physicsweb.org/articles/news/2/11/11
http://www.state.nd.us/ndgs/Newsletter/NL01W/PDF/c limateW01.pdf/
http://www.dsri.dk/~hsv/
http://www.space.com/scienceastronomy/generalscien ce/global_warming_001110_wg.html

Irrelevant. This is an 11-year cycle. Global warming has been proceeding for much, much longer than that.

Taken only as part of an 11-year cycle, I'd agree with you. However, overall solar output has been increasing since measurements first began to be taken. This output is assumed to be cyclical and may have contributed to past ice ages and so forth. However, nobody really understands what's going on with the sun completely. But the sun is the single largest contributor to any heating equation involving this planet. If it's getting warmer, the planet will get warmer, and extremely minor increases in solar output can cause relatively major increases in atmospheric temperatures.

Scripps Institution of Oceanography, University of California. Readings taken at Mauna Loa.

How about a damned link?

No you haven't. You have given a link to one web page about an 11-year cycle.

Then you're obviously blind, because I get you links to two completely different studies. Did you fail to follow them? I did neglect to post the ORNL link, and I can't remember where I found it now. However, I can leave you with this and this which presents equally compelling evidence supporting the solar input increase model.

As weak as using an 11-year cycle to explain nearly a century of warming? I think not.

The only possible way you can say that is because you didn't follow the links, because there's much more in there than just the 11-year cycles. That is a part of it, and it is likely related to the overall increase in hurricans over the last few years. However, global warming is over a much longer period of time, longer I'm afraid than humans have been putting out large amounts of greenhouse gasses. That alone shows the flaws in your "blame it all on American SUV's" argument, but you refuse to see it.

Actually the intermediate link you propose about the weather is correct. Recent discoveries by Eigil Friss-Christensen at Danish Space Research Institute indicates that there IS a correlation between solar activity (and sunspots) and mean temperature here on earth.
The correlation is that high solar activity and hence high solar wind density excludes some of the cosmic rays from the inner solar system.
The lack of comsmic rays then cause fewer clouds to condensate and fewer clouds results in higher temperatures.

(check here for a link to the publications on this subject; search for 'Friis-Christensen' to find the relevant ones).

Yours Yazeran

Plan: to go to Mars with a hammer some day

Actually the intermediate link you propose about the weather is correct. Recent discoveries by Eigil Friss-Christensen at Danish Space Research Institute indicates that there IS a correlation between solar activity (and sunspots) and mean temperature here on earth.
The correlation is that high solar activity and hence high solar wind density excludes some of the cosmic rays from the inner solar system.
The lack of comsmic rays then cause fewer clouds to condensate and fewer clouds results in higher temperatures.

(check here for a link to the publications on this subject; search for 'Friis-Christensen' to find the relevant ones).

Yours Yazeran

Plan: to go to Mars with a hammer some day