Naked Science Forum
Life Sciences => The Environment => Topic started by: CliffordK on 15/01/2011 04:49:34
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Let me preface this that I do believe that we have some critical impending issues to the environment including fuel and oil consumption, resource depletion, and especially growing overpopulation and habitat destruction.
However, climate changes should not be considered caused by a single Anthropogenic component.
The most recent discussions about temperature changes on Earth have ignored the most important aspect of our weather.
THE SUN
The sun has now lost nearly all of its spots.... AGAIN (January 14, 2010).
http://spaceweather.com/
http://spaceweather.com/images2011/14jan11/hmi4096_blank.jpg
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What is a sunspot?
A sunspot is a darker region of the sun, I.E. releasing less visible light, but indicative of higher local activity on the sun, and higher UV radiation output. The more, and the larger sunspots, the more total solar activity.
Sunspot activity increases and decreases on about 11 year cycles as visualized below.
In many senses, the sunspots are so indicative of the solar output that they've become the “gold standard” despite new solar irradiation measurements.
Indications are that over the past 95 years, we've both had unusually high solar activity, and the sun has failed to return to the normal minima.
Direct sunspot observations indicate that a drop in solar irradiation (sunspots) was directly related to the “Little Ice Age” between about 1650 and 1715, along with another temperature drop around 1800, along with another weaker minimum at the beginning of the 20th century (often used as a baseline for current temperature measurements).
http://www.npr.org/2011/01/12/132865502/last-year-was-the-warmest-year-on-record-again
http://www.ncdc.noaa.gov/sotc/global/2010/13
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fmedia.npr.org%2Fassets%2Fimg%2F2011%2F01%2F12%2Fglobal-temps_enl.jpg&hash=2d00bdc06efd4d4ded45b98d3f9c6a85)
http://en.wikipedia.org/wiki/Sunspot
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2F2%2F28%2FSunspot_Numbers.png%2F800px-Sunspot_Numbers.png&hash=f185d12f1958f78f0aef039f4de1cefe)
While the absolute value of the sunspots/solar activity hasn't been increasing as much with every cycle, there have been comments that there may be a cumulative effect, as well as notes of a departure from returning to a zero minimum.
Some studies indicate that the activity over the last century has been the highest solar activity since at least 9,000 years ago, if not 11,000 years ago, at the very beginning of the Holocene Epoch.
http://www.ncdc.noaa.gov/paleo/pubs/solanki2004/solanki2004.html
http://cc.oulu.fi/%7Eusoskin/personal/nature02995.pdf
http://www.cfa.harvard.edu/events/2009/soho23/PDF/Temmer_SOHO23.pdf
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.ncdc.noaa.gov%2Fpaleo%2Fpubs%2Fsolanki2004%2Ffig3a.jpg&hash=b03851496572380d82158225b8ae2761)
Earth's interaction with our sun has driven severe climate changes from about 8°C lower than our current temperature up to at least 10°C warmer than our current temperature throughout history with multiple periods of history the antarctic shifted from being ice free to being frozen.
What is normal? It is hard to tell due to increasing solar activity over the last couple of centuries. However, the longer term proxy studies, and observations over the last 400 years seem to indicate that normal should be:
Zero at solar minima
Combined rating scale of around 50 or less at solar maxima (see http://spaceweather.com/glossary/sunspotnumber.html)
What have we been experiencing for the past 95 years?
Sunspot Maxima of 150 to 200.
Sunspot Minima of not returning to zero.
What does the future look like?
We are now experiencing the deepest solar minimum since 1915, with 819 spotless days on the sun. The sunspots also seem to be changing character, becoming much less distinct.
Predictions have been revised over and over again from the next solar cycle (24) which we are now beginning.
In 2006, it was predicted to be one of the highest ever.
However, it is now being expected to be one of the lowest of the century.
http://solarscience.msfc.nasa.gov/predict.shtml
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fsolarscience.msfc.nasa.gov%2Fimages%2Fssn_predict_l.gif&hash=a8e5420fbde086f5878da3609c61b7f1)
The future is very much unknown, and predictions over 15 years in advance have little true weight. However, some people are predicting the sun to once again enter into an extended quiescent state.
http://www.physorg.com/news203746768.html
http://www.iceagenow.com/New%20Little%20Ice%20Age.htm
http://www.leif.org/EOS/2009EO300001.pdf
In many senses it is too early to tell what is around the corner.
How has it affected our climate so far?
In the past, the temperature has been increasing stepwise. There has been little change in the global temperatures since 1998 (except a slight drop in temperatures from 1999 to 2001).
The last 2 harsh winters in Europe are being attributed, in part, to the unusually low solar activity.
So...
While the Alarmists have repeatedly ignored the sun's effect.
This current decade will tell us a lot about the role of the sun vs the role of carbon dioxide and methane in the global warming and climate change debate.
If the temperature continues to rise until about 2018 or so, then we will be forced to continue considering the Anthropogenic components of global warming.
If the temperature drops by 2018, then we won't be able to ignore the sun's earlier contribution to global warming.
And, if the temperature continues to remain stable, then we will likely be considering both the contribution of the sun and the Anthropogenic components.
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Fair enough.
But the problems of warming are still real
There's no debate about the effect of CO2 on the absorption and re radiation of energy through the Earth's atmosphere.
If a change in the sun is already making the planet hotter then now is not a good time to be putting another blanket on it.
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Ahhh... CO2... Yes... I thought that might come up.
Here is a spectrum diagram of atmospheric gasses from Wikipedia.
http://en.wikipedia.org/wiki/Greenhouse_gas
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F7%2F7c%2FAtmospheric_Transmission.png&hash=f0df5813b3bd8fbd87f8666b51e00407)
What is immediately obvious is that there is an IR Window between about 8μm and 14μm.
There is minimal IR Transmission between 14μm and 16μm where the primary absorption of CO2 is.
I.E.
If you take a glass window and paint it black, it will stop visible light transmission.
If you continue adding more layers of black paint, it still stop visible light transmission, but won't stop the transmission of any more light.
Methane, with a concentration of about 1.8 ppm, or about 1/200th of CO2, on the other hand, has a weak peak around 8μm, which is in Earth's primary IR Emission window. The peak is currently low due to the low concentration of Methane.
Now, if you are astute, you will notice that there are small CO2 absorption peaks around 9μm and 10μm, as well as not quite perfectly straight sides on the existing peak. I haven't seen a lot of discussion about those other small absorption peaks. They are dwarfed by water. However, since the absorption is additive, they may still be important.
This article actually suggests that the actual "forcing" from doubling the CO2 concentration should be on the order of 0.012°C to 0.015°C.
http://www.john-daly.com/artifact.htm
The conclusion has to be that there is a very much non-linear effect of Carbon Dioxide on the Earth's temperature.
Now, the spectrum above from Wikipedia is calculated based on atmospheric concentration of gasses. And, I think it assumes a uniform distribution of gasses.
There is supposed to be somewhat of a temperature component in the absorption which seems to be left out of some of the equations. I don't believe the CO2 concentration in the air is uniform. And, increasing the concentration may lower the altitude of absorption in the atmosphere. While it wouldn't have a significant effect on the overall radiation of heat, it might concentrate the heating effect slightly at lower atmospheric levels.
Other CO2 IR Absorption bands less than about 4μm don't seem to be major contributors to either the Sun's incoming electromagnetic radiation spectrum, nor the Earth's outgoing IR Emissions (or reflected light spectra), in part because they are masked by very strong water absorption bands, although this effect would depend on water concentrations.
What I'm missing are the empirical IR Spectral observations of Earth, perhaps with observations by altitude. The empirical data has to exist somewhere... or it needs to be taken. With it, one should be able to better calculate the actual influence of Carbon Dioxide.
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Some of the earth's climate is definitely due to solar activity, but this has been extensively studied and the consensus among scientists is that the observed climate change cannot be explained entirely by solar activity, and that human activity causes is. I know this is a hotly debated issue, and it's so politically charged that every side has data and figures like you present above "proving" that their view is correct.
For examples of the opposing view, see:
http://www.newscientist.com/article/dn11650-climate-myths-global-warming-is-down-to-the-sun-not-humans.html
http://stephenschneider.stanford.edu/Publications/PDF_Papers/DamonLaut2004.pdf
Since I'm not a climate scientist, I can't really sort through all the plots and choose who's right or not. In the absence of that, I trust the consensus of those who are experts, and their studies show that the sun isn't the main cause of warming since the industrial age.
But as you say, even if you doubt anthropogenic causes of climate change, there are plenty of other reasons to lower carbon emissions.
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I claim no expertise in this field, but I am a little concerned that this topic has become so politically supercharged that any professional scientist who dares to challenge the "concensus" is liable to be branded as a heretic and lose his government funded job, assuming he or she is not actually burned at the stake first.
Surely this cannot be such a difficult problem for science to solve in a way that there can be little doubt one way or the other? The Earth is like any other thermal system. If you shove heat in faster than it can escape, it's gonna get hotter.
I think (or hope) we have a pretty good idea of how to quantify the input sources, and, considering the amount of junk we've put into orbit around our planet, I'm having a really hard time understanding why it's so difficult to quantify the amount of thermal energy that escapes.
The "evidence" of receding glaciers, rising sea levels and displaced polar bears is interesting, but IMHO it's not really relevant if we can't quantify total heat in versus total heat out. If there is a straightforward paper out there that lays this out in a way that most people can understand (minus the scary stories about penguins, polar bears, imminent liquid inundation and icebergs the size of Texas), please point me at it.
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So much of what is being presented to the public is pure propaganda. And in a sense, to sway the masses to one's viewpoint, it has to be so as most people don't like hardcore science. I even prefer charts expressing a system output over looking at the input equations. But, exaggeration just makes one's overall point weak. Do we really believe Mt. Everest will be Glacier Free in 2035? I'm ready to hike up there in a T-Shirt [:D] Or do the Himalayas not include Everest?
When was the last time you watched a video showing ice sublimation in Antarctica? Such a captivating subject you could watch it for hours [:)]
Here is one of my favorite photos.
http://www.sciencedaily.com/releases/2008/08/080825210415.htm
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.sciencedaily.com%2Fimages%2F2008%2F08%2F080825210415.jpg&hash=f626c647513ea526a7aba61289c0e5f0)
It looks like he can barely tolerate the typical 50°F (+10°C) winters, and 75°F (+20°C) summers...
Yeah... he sure is suffering from Global Warming. At least based on the last glacier retreat from where I am guessing his current home probably is in San Diego.
For examples of the opposing view, see:
Nearer our own time, the coming and going of the ice ages that have gripped the planet in the past two million years were probably triggered by fractional changes in solar heating (caused by wobbles in the planet's orbit, known as Milankovitch cycles (http://en.wikipedia.org/wiki/Milankovitch_cycles)).
That is actually at the heart of the problem that many people are having with the current Global Warming debate.
While the glacial/interglacial periods don't necessarily have to be explained by the global warming theory, they indicate huge, rapid temperature oscillations completely independent from humanity. And the Holocene Epoch is already at, or has exceeded the average duration of an interglacial period (not that I expect another glacial period to return overnight).
Approximately every 100,000 years the planet has been experiencing a rapid upswing in temperature followed by a rapid decline and then more gradual decline in temperature.
The predicted Milankovitch cycles have several aspects. The one that has the most obvious 100,000 year component is the eccentricity of the planet's orbit, which we are currently at a local high of about a 3% elliptical orbit. However, it is far less than the 6% or so maximum elliptical orbit that has occurred during previous interglacial periods. In fact the 3% elliptical orbit is about the same as the minimum during 2 of the 3 previous interglacial periods.
The shortest duration component is the precession of the equinoxes, about 23,000 years total, or 11,500 years for a half a cycle. During the Holocene Epoch, we've now passed through an entire half precession cycle, going from where the Northern Hemisphere was closest to the sun in the summer (short hot summer and long cool winter) to where the northern hemisphere is now closest to the sun in the winter (short hot winter, long cool summer).
There are several notes about the insolation at 65°N. However, this ignores the global aspect of the warming, and would seem to imply more discrepancy between the Antarctica and Greenland ice cores than actually exists. While there are some significant differences between the two areas, the overall trends have matched closely in the past.
The best correspondence to the Milankovitch cycles seems to be the smaller temperature variations within a cycle, but not the large temperature swings.
Nor do the Milankovitch cycles account for temperature variations at a decade or century timeframes.
http://upload.wikimedia.org/wikipedia/commons/5/53/MilankovitchCyclesOrbitandCores.png (larger image)
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As far as instruments?
Yes
We absolutely need better 24 hr day and night emission/reflection readings from the earth from all latitudes. Unfortunately I doubt that it will be an easy problem to solve.
If you look at the solar irradiance charts:
http://www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant
ftp://ftp.pmodwrc.ch/pub/Claus/ISSI_WS2005/ISSI2005a_CF.pdf (http://ftp://ftp.pmodwrc.ch/pub/Claus/ISSI_WS2005/ISSI2005a_CF.pdf) Discussion of the plot
ftp://ftp.pmodwrc.ch/pub/data/irradiance/composite/DataPlots/org_comp2_d41_62_1009_vg.pdf (http://ftp://ftp.pmodwrc.ch/pub/data/irradiance/composite/DataPlots/org_comp2_d41_62_1009_vg.pdf) Larger chart.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.pmodwrc.ch%2Ftsi%2Fcomposite%2Fpics%2Forg_comp2_d41_62_1009.png&hash=ae53fad2c291e3737f75575f0942c0be)
Most of the satellites give about a decade long data collection period, which isn't bad considering computers and instruments up in space. In the article they talk about sensor degradation over time with various time based correction methods including using a backup "secondary sensor" in some of the probes to periodically recalibrate.
However, all the different satellites seem to show about a 15 watt difference in their calculations which would certainly be significant in any absolute power flux calculations.
Look at the green sections in the composites, 1978-1979 and 89-91, and notice they have very different shapes.
It turns out then that all 3 plots of subtly different shapes, especially when compared to the baseline which could indicate either a subtle increase in average solar irradiation, or subtle decrease in it (prior to 2008). As mentioned above, the next solar cycle is predicted to have about half (or less) of the magnitude of difference that more recent cycles have had.
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I was thinking about what someone in another topic mentioned:
http://www.thenakedscientists.com/forum/index.php?topic=36636.0
15,040,000,000,000 Watts Consumed by the world per year.
255,036,000,000,000 sq meters (on half of the earth) * 1365 w/m²
And our energy consumption is about 1/23,000 of the sun's light striking earth, or about 0.004% of the sun's total power striking earth.
It, along with lots of blacktop is enough to make our cities hotter, but perhaps not enough overall to make a significant difference in the earth's temperature. That number could be under-reported though, and could lack many non-commercial energy sources and wasted energy.
If the sun's temperature, however, varies by 1 watt/m²... while the actual percentage is low, it would be the same as hanging a 100W bulb over every 10m x 10m (33'x33') part of land & water (for half the day), and would require 20x the entire world's power output.
The ½°C cumulative temperature change over a few decades isn't much, and would probably be too small for our instruments to read in watts/hour, especially considering the extreme day to day temperature variations and the likelihood that one would need different instruments to measure the sun and earth.
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Seems we do not know much about climate. Even our sun is not really known e.g. 'Sun provides Earth with less energy than we thought': http://physicsworld.com/cws/article/news/44869
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Look, what is this?
If you don't want to accept the scientific census then that's cool, but as in all debates state what's 'main stream' and what's not. Don't make sweeping statements, but say what you wonder about. "and I think that they have missed to look at ***" etc. That makes it possible to look at what's in question.
Hand picking different cycles and 'posts' won't change the statistics we have. It's all too easy to see what's happening, and there's no doubt anymore that it is a man-made Global warming, although sun cycles make a difference too. But so will most everything involved with heat, do anyone really think that all of those scientists have missed the sun?
Seriously? That debate have been on for? ten years?
Or more? Yeah more. And been shown to be the wrong answer again and again.
To put it into doubt at the same time as we see the Arctic dying?
Not a very good timing. It's weird that people doing climate research all are expected to be amateurs? If physics was treated the same I doubt any sane scientist would want to moderate it.