Well, actually not. I live in Anchorage now, but the county immediately to the north of where I grew up is the fourth-largest emitter of carbon dioxide in the United States. A dubious honor at best.
The data comes from the Vulcan Project, which recently generated some of the most interesting visualizations of CO2 emission that I’ve seen.
Scientists using the Vulcan system have generated the most detailed temporal-spatial maps of CO2 in the United States.
Vulcan directly measures carbon monoxide, nitrous oxide, and other air pollutants. But there is a strong correlation between CO2 emission and the emission of these other pollutants, so the Vulcan data allows you to accurately calculate the presence of the global warming gas.
Purdue’s press release has some interesting fodder.
“For example, we’ve been attributing too many emissions to the northeastern United States, and it’s looking like the southeastern U.S. is a much larger source than we had estimated previously,” says Kevin Gurney, an assistant professor of earth and atmospheric science at Purdue University and leader of the project.
The steamroller of evidence on the anthropogeny of greenhouse gas increases continues to move on pretty relentlessly, with the last few months showing a number of really impressive visualizations of CO2 data. I think at this point that astronomers like myself don’t have visualizations as impressive as this one….
One of the common arguments trotted out by global warming denialists is that:
This is based on the research hypothesis of Henrik Svensmark of the Danish National Space Center, so this is not a lunatic idea. What is lunatic is the way that the denialists latched on to the idea before it was tested, and presented it as fact, used it to denigrate other scientists and suggest they are fools, and so on. In real science, you come to these conclusions after the experiments have been done, not before.
But now some experiments have been done, and the hypothesis has not held up very well in testing. Several experiments and analyses have called the hypothesis into serious question over the last couple years.
Now, there’s yet another scientific study which shows that things just don’t work like that. Or at least if they do, the differences between strong and weak solar wind periods are way to small to have a noticeable effect on clouds.
The abstract is not particularly difficult, but I want to make some remarks on it anyway, so here it is with my comments interspersed:
A decrease in the globally averaged low level cloud cover, deduced from the ISCCP infrared data, as the cosmic ray intensity decreased during the solar cycle 22 was observed by two groups.
So cloud cover was observed to decrease, and cosmic ray intensity decreased; this much is known.
The groups went on to hypothesize that the decrease in ionization due to cosmic rays causes the decrease in cloud cover, thereby explaining a large part of the currently observed global warming.
This hypothesis takes advantage of the fact that many times, correlation really does mean causation. Not always - but sometimes.
We have examined this hypothesis to look for evidence to corroborate it.
Yay science! That’s how it works. Someone comes up with an idea about how things might happen, and you get a bunch of interested scientists doing experiments to see if that idea is right.
None has been found and so our conclusions are to doubt it. From the absence of corroborative evidence, we estimate that less than 23%, at the 95% confidence level, of the 11 year cycle change in the globally averaged cloud cover observed in solar cycle 22 is due to the change in the rate of ionization from the solar modulation of cosmic rays.
How does this hurt the denialists’ cause? Well, it doesn’t, because they’re denialists. Mere facts won’t get in the way of their political agenda.
But if they did respect evidence, this analysis puts an upper limit on just how strong the cosmic ray/cloud cover correlation could possibly be. And that upper limit isn’t anywhere near what is required to account for the observed climate change.
The researchers are still arguing about things, with Svensmark basically calling Terry Sloan, the PI of this study, an idiot:
“Terry Sloan has simply failed to understand how cosmic rays work on clouds,” he told BBC News.
To me, saying that a highly-qualified researcher in the same field simply doesn’t understand is a strong sign that the person saying it is on weak ground, although we don’t really know what Svensmark said that didn’t get into the BBC story. But Slaon describes the very elegant experiment that he and his co-investigators did, and it is compelling:
Professor Sloan’s team investigated the link [between cosmic rays and cloud cover] by looking for periods in time and for places on the Earth which had documented weak or strong cosmic ray arrivals, and seeing if that affected the cloudiness observed in those locations or at those times.
“For example; sometimes the Sun ‘burps’ - it throws out a huge burst of charged particles,” he explained to BBC News.
“So we looked to see whether cloud cover increased after one of these bursts of rays from the Sun; we saw nothing.”
Dang, that is good science communication. That boils a really complex and difficult series of physical processes down to something that anybody will have enough attention span to listen to. Kudos to Terry Sloan.
The experiment makes a lot of sense to me. The Earth is not a point collector of cosmic rays; different locations on the Earth gather them unequally. Cosmic rays are highly localized. We see them all the time in CCD camera images of the night sky in my asteroid research1, and occasionally some images have a striking abundance of cosmic ray strikes that hasn’t occurred at a nearby observatory. Dedicated cosmic ray detectors show that some parts of Earth can experience a veritable storm of cosmic rays, while other parts get the usual amount.
The fact that Sloan took advantage of this well-known localization of cosmic ray strikes, and found no evidence that cosmic rays were even correlated with clouds - let alone causative - is very strong evidence against the denialists’ position.
As I mentioned above, this is probably not going to penetrate the denialists’ understanding, and will make no difference to them in terms of aggressively pursuing their scorched-earth political agenda. They’ve irrevocably burned into their mind the false notion that believing in global warming means you are an enviro-communist. They don’t understand the research, and they don’t want to. But there’s something else they don’t understand: that people can accept the evidence for global warming, and yet still want to drive gasoline-powered automobiles that pollute less. And that pursuing a vigorous domestic and alternative energy policy would result in a strong economic stimulus.
Anyway - scientific evidence is cool2, and we’ve got an interesting case here.
Researchers using SCIAMACHY, an instrument on ESA’s Envisat, have now imaged excess carbon dioxide in populated regions of Earth.
The researchers explain:
Dr Michael Buchwitz from the Institute of Environmental Physics (IUP) at the University of Bremen in Germany and his colleagues detected the relatively weak atmospheric CO2 signal arising from regional ‘anthropogenic’, or manmade, CO2 emissions over Europe by processing and analysing SCIAMACHY data from 2003 to 2005.
“The natural CO2 fluxes between the atmosphere and the Earth’s surface are typically much larger than the CO2 fluxes arising from manmade CO2 emissions, making the detection of regional anthropogenic CO2 emission signals quite difficult,” Buchwitz explained.
“This does not mean, however, that the anthropogenic fluxes are of minor importance. In fact, the opposite is true because the manmade fluxes are only going in one direction whereas the natural fluxes operate in both directions, taking up atmospheric CO2 when plants grow, but releasing most or all of it again later when the plants decay. This results in higher atmospheric CO2 concentrations in the first half of a year followed by lower CO2 during the second half of a year with a minimum around August.
“That we are able to detect regionally elevated CO2 over Europe shows the high quality of the SCIAMACHY CO2 measurements.”
The main reason this is of interest to me is that Alaska has a very substantial population of global warming/climate change/anthropogenic CO2 conspiracy theorists and denialists. And now there are pictures. It is hard to just explain away pictures, but I’m sure they will try, when they stop ignoring the research (which is their main tactic for dealing with the issue).
There is a minor burst of discussion on Slashdot to the effect that solar cycle 24 has “officially” begun.
It hasn’t, officially.
And even if it has begun in any meaningful sense, we don’t know that for sure yet. And even if some “official” body supposedly governing the Sun has declared it so, they will probably change their minds.
Let me explain. No - there is too much. Let me sum up:
The solar cycles in question are roughly 11 year cycles of increased and decreased solar activity. They vary quite a bit - sometimes they are ten years, sometimes twelve. And their boundaries are a bit fuzzy. But they average out to about 11 years, and the “11 year cycle” is an elementary part of solar physics.
The most visible solar activity that follows this 11 year cycle are sunspots and other magnetically-related phenomena - prominences, large flares, and so on. During solar maximum, there are lots of sunspots, they form in groups, and they are big; during minimum, the sun can be free of sunspots for weeks or months at a time, and when there are sunspots, they tend to be small and isolated. A sunspot is just an area on the Sun in which solar gasses are kept from moving around as much as on the rest of the surface, so that less hot gas from the Sun’s interior circulates to the surface. As a result, the gasses in a sunspot tend to cool a bit and become dimmer than the rest of the sun - appearing as a dark sunspot.
We’ve been at minimum in Cycle 23 for quite a while now. For well over a year there hasn’t been much in the way of sunspots, and looking at the sun (with proper safety equipment please) has, at times, been a bit - dare I say it? - boring.
One way of distinguishing that a cycle is ending and a new one is beginning is that the magnetic polarity of the sunspots reverses, and these new magnetically reversed sunspots appear in a high solar latitude.
Just a few days ago a magnetically reversed sunspot (”activity”) appeared at high solar latitude after a long period of no sunspots (”inactivity”). The blog reporting the “official start” of the new cycle apparently finds this to be significant, but NOAA, who know something about space weather, are considerably more reserved.
A new 11-year cycle of heightened solar activity … showed signs it was on its way late yesterday when the cycle’s first sunspot appeared in the sun’s Northern Hemisphere, NOAA scientists said.
Wikinews has also jumped on the hype bandwagon.
Why are the scientists being a tentative and the media being credulous? Simple: the media don’t know the topic.
There were some high latitude reversed sunspots in the summer of 2006 that could have portended the new cycle just as well as today’s spots. But they didn’t - we had 1.5 years of vanishingly low activity after that.
Even if these recent spots are portents of the new cycle, we will likely be seeing spots of both polarities for another year or so. Typically, there is no sharp transition in terms of spot polarity - it takes a while to go from all spots being “magnetically north” to all of them being “south,” or vice-versa. It could be that in two months we will have more spots characteristic of Cycle 23 on the Sun than ones that would characterize Cycle 24. If so, that will certainly muddy the waters a bit.
Scientists react to this sort of thing by not finding it very significant except in retrospect. I’m sure everyone in the solar science and space weather communities has their opinions and hopes about the new cycle and when it is likely to begin, but nobody’s going to rush to publication today saying that a spot found two days ago marks the “official” boundary between cycles - if there even is a scientist or establishment that considers itself the official arbiter of solar cycles. It just isn’t done that way. Conclusions of the transition date of a new cycle are arrived at years later, by people analyzing months of data as the new cycle gets more active, and the dates they arrive at can be as late as two or three years after the first appearance of magnetically reversed spots.
So, solar cycle 24 may or may not be here. It doesn’t really matter if it is, because nobody will figure that out in any definite way for at least a few years, and even if Cycle 24 is well underway we’ll still have months of low activity before things get going.
The blog reporting all this says that this cycle, if a quiet one, might provide a test of global warming denialists’ crazy notions that solar activity, not CO2 and other greenhouse gasses, is the cause of global warming. If they have such hopes, these antiscience folks haven’t bothered to learn the first thing about solar physics. In the course of the cycle, irradiance in the Earth’s upper atmosphere varies from 1366.6 Watts per square meter at maximum, to 1365.5 Watts per square meter at minimum - a difference of one whole Watt/m2, or a whopping seven one hundredths of one percent - with variations of plus or minus one Watt/m2. It isn’t nearly enough to measurably affect the temperature of Earth. (And if it was, why are we still setting temperature records in years like 2007, which was in the middle of a solar minimum?) This kind of substitute for thinking doesn’t even allow for a good joke.
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