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Wednesday is Earth Day, so let's start things a little early with some science.

The EPA recently announced that greenhouse gases pose a threat to health and welfare through their role in climate change. Climate change is a complex, nebulous thing that we seem to find difficult to attribute to anything tangible. So what is climate, this thing that is threatening to change in a way that can end society as we know it and possibly worse?  There are a number of answers, depending on the nature of the question: "Climate is what you expect, weather is what you get". Climate is the mean state of the atmosphere. It is the time-averaged temperature and humidity of a region. This last answer provides the key, for both temperature and humidity are related to energy.

So let's take a step back and look at the big picture: climate is a manifestation of the energy budget at the surface of the Earth. Climate change is the variation of that energy budget.

The surface of the Earth takes in energy, and it also loses energy (it radiates out to space). Temperature stability is achieved when energy in = energy out. If energy in > energy out, the Earth's surface will warm; if energy in < energy out, it will cool. The details are important here, and those details are found in the energy budget, which is concerned with

  1. the magnitude of the sources
  1. how the energy gets from the source to the Earth
  1. how much is retained at the surface.

Note that all of these are important, and that each changes on its own timescale. Some of these factors may be more important than others at a given point in time; others of these factors may be more important at another point in time. Some factors are more important than others on one timescale but less on another.

Energy sources:
There are two of any consequence, the Earth itself provides a planetary heat flux, and a raging nuclear fireball 150 million km away we call the Sun. Solar energy falling on the Earth is known as insolation. Solar insolation provides far more energy than the Earth heat source.

Planetary Heat Flux
The temperature at the Earth's core is not well known, as we cannot measure it directly, but is thought to be at least 4000K (at the boundary with the mantle) and less than 8000K. We occasionally see molten rock spewing out of exploding mountains so we know the interior is hot. But the Earth's crust is a good insulator, and except for the odd volcano the heat flux from the interior of the Earth to the surface is surprisingly small. This too is difficult to measure and suffers from severe sampling bias (lots of measurements in the US and Europe, very few in the remote Pacific), but most estimates have it between 50 and 100 mW/m2 (milliwatts per square meter: flux is something per unit time per unit area, so an energy flux has units of energy/(time area) = power/area) in the mean. The estimate of Pollack et al. (Rev. Geophys., 31, 1993) of 87 mW/m^2 is typical. The heat flux is not uniform: here's a figure from Shapiro and Rollwitz, Earth Plan. Sci. Lett., 2004.

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Note that the large variations in Antarctica are not reflected in the surface temperatures. This is because the planetary heat flux is tiny compared to solar insolation and the rate of radiative cooling out to space. As a direct heat source we can ignore it, although it does indirectly exert a control on very long (10M - 100M year) timescales through atmospheric composition, albedo, and ocean circulation. The first is due to the burial and uplift of reduced carbon and sulfur, the other two from moving tectonic plates around.

Solar insolation
At the top of the atmosphere (TOA) we get about 1366 W/m2 from the Sun. This is known as the solar constant, and is only approximate because the solar constant is not actually constant. This varies on a huge range of timescales, raging from very short term fluctuations to an 11 year sunspot cycle to the billion year timescale of stellar evolution. Today we have excellent satellite data of the solar constant -- this figure from NASA shows that we are near if not at a minimum in the 11 year solar output cycle (high sunspot number = high solar output, low sunspot number - low solar output). The next peak in solar output is expected to take place in 2012-2013, although the Sun appears to be defying that prediction and output remains lower than expected.
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Note that there is a slight decrease in the mean output over the last 30 years or so. That follows a general increase over the first half of the 20th century (reconstruction by Lean et al, 1995):
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The 1366 W/m2 is TOA: at the surface, on a clear summer day in lowish to middle latitudes around solar noon we get a bit more than 1000 W/m^2. Of course this is lower in winter, at higher latitudes, in cloudy conditions, and goes to zero at night. Globally averaged over day, latitude, season, we get about 180 W/m2, or 2000 times that from the Earth (image from the Encyclopedia of Earth).
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Essentially all of the direct heat input to the surface of the Earth is from the Sun. However, it does not follow that solar variability is always the primary driver of climate variability or even the current primary driver (though it has been more significant in the past, such as during the Maunder minimum in the so called "Little Ice Age", and no doubt it will again in the future): if that were true, the global temperature record for the last 30 years would be controlled by the solar term for the last 30 years (see figure above), which is obviously not the case (figure from newscientist.com using data from NASA GISS):
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In fact, while the solar variability term always contributes to climate variability, it is not generally the controlling term.

There is also a  v e r y  long timescale variation as well: like all stars, the Sun evolves, and the young Sun put out perhaps 70% of the energy it does today (that there was liquid water then is most likely due to more of what energy reached the Earth being retained in the Earth surface by greenhouse gases). Eventually it will blow up into a red giant, then collapse into a white dwarf. Both of which will have severe implications for Earth's climate.

Sun to Earth
Except extremely locally around hydrothermal vents or volcanoes the planetary heat source provides an insignificant direct forcing, so we'll ignore it from here on in. The Sun is, of course, 150 million km away, so how solar energy gets from there to here is also important.

The Earth moves in an elliptical orbit around the sun. It rotates, and its axis of rotation today is tilted 23.5o from the orbital plane (the ecliptic). But its orbit is not quite regular: the ellipticity varies with time, sometimes more elliptical, sometimes less, and it varies on a timescale of about 100000 years. Nor is its axis of rotation fixed -- it "precesses".  That is, today the axis at one end points roughly to Polaris, in the constellation Ursa Minor (the other end doesn't point to anything obvious); however in 2000 years it will be in the constellation Cepheus, in 10000 years in Cygnus, in 25800 years back to Polaris, as the axis of rotation precesses about the North Ecliptic Pole (the perpendicular to the orbital plane in the northward direction), which is actually in Draco -- the South EP is in Dorado. Finally, the tilt from the ecliptic, or "obliquity",  varies from about 21.5o to 24.5o on a timescale of about 41000 years. Actually, since the Earth is affected by the gravitational potentials of other planets, there are other periodic signatures, the strongest at 19000 years, 71000 years, and 400000 years. So the Earth does not orbit the Sun in a pure Platonic orbit -- there's a lot of jigging and bouncing around out there.

One more thing. A light source directly overhead delivering 1 Watt over one square meter delivers 1/2 W/m2 over 2 m2 if it's tilted at 60o from the vertical (the "solar zenith angle" for the sun; you can also think of the "solar elevation angle" above the horizon if you want, but most people use SZA). The sun is a lot stronger in Cairo than it is in Dublin because it is more nearly overhead. Summers are hotter than winters because the sun is more nearly overhead in summer.

Clearly changes in eccentricity affect solar insolation. Obliquity is a little less obvious. When obliquity is low, the difference between summer and winter temperatures is less because of the smaller range in SZA, and cooler summers mean less ice melt, which generally means more glaciation. Precession determines when summer and winter occur: right now the Northern hemisphere summer occurs near aphelion (Earth's farthest point, happens on July 4 this year. Earth was closest to the sun -- at perihelion -- this past January 4). The combination of all these periodic variations in the Earth-Sun distance (eccentricity) and Earth-Sun angle (obliquity and precession) affects the amount of solar energy that reaches the Earth. This behavior is known as Milankovitch cycles, after Milutin Milankovitch, the first guy who worked through the orbital calculations. Here's a figure from Russ Joesten of the University of Connecticut showing the net effect:

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Here "tilt" refers to obliquity. The right-most plot is a proxy for global temperature. The correlation between solar insolation and temperature strongly indicates that orbital variability is the primary climate driver on the 104 to 105 year timescale. The correlation is quite good but not perfect, indicating that other factors are at work as well, but then, we should hardly expect otherwise. If orbital variation were the controlling forcing today we would be sliding into an ice age.

Energy budget at the surface
Now it gets complicated. The key thing to remember is this: at equilibrium energy in = energy out. Change one part of that equation and the system will either warm (in > out) or cool (in <out), until equilibrium is reached again. There are two major issues here:</p>

  1. How much solar energy is reflected back into space
  1. How solar energy absorbed at the surface behaves

Albedo
The first of these is controlled by the reflectivity of the Earth, or its albedo. Specifically, our bond albedo is 0.29. Clearly if this changes, the amount of solar energy retained by the Earth also changes. If albedo increases, more solar energy is reflected out to space and the planet cools; similarly, if albedo decreases, more energy is retained in the Earth system and the planet warms.

Odd factoid: the surface of Venus gets less solar insolation than the surface of Earth. Its orbit is 72% that of Earth, so that at the top of the atmosphere it gets nearly twice as much sunlight per square meter as we do (light falls off as the square of the distance, so Venus gets (1/0.72)2 = 1.93 times what we do). However, the albedo of Venus is much higher than ours, though oddly enough that's not a well-known figure, with most estimates ranging from 0.65 to 0.77. Let's take the lower number, which means that 35% is absorbed. Then at the surface, they get (1.93)(0.35) = 0.675 of what we get at the top of our atmosphere, while we get (1)(0.71) = 0.71 of our TOA. The surface temperature is far hotter on Venus -- 740K vs our 288K -- not because it is closer to the sun, but because of a massive greenhouse effect.

Various surfaces have different albedos. Here's a table from the Encyclopedia of Earth:
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Variability in albedo is complex because albedo and the temperature response are not independent and feed back on each other. This is not the case for, say, orbital variability or changes in solar output. Probably the best known of these is the ice-albedo feedback: if global temperatures cool, ice sheets grow. As ice sheets grow, the planetary albedo increases, reflecting more solar energy out to space, lowering global temperatures. There have been times in Earth's history when it is thought that ice sheets covered much of the world, and it is not entirely clear how we got out of snowball Earths (increased outgassing of CO2 plays a role, but evidence for releases of sufficient magnitude is thin). Conversely, a warming Earth leads to smaller ice sheets, which decreases albedo and causes the Earth to absorb more solar energy, further increasing the warming. The ice-albedo feedback is an example of a positive feedback loop  (changes in one strengthen changes in the other in the same way). There needs to be something that triggers the feedback, however; in the past triggers include orbital variability, episodes of extended volcanism, changes in landmass location, and no doubt other things we don't fully understand.

A warming world will lead to more evaporation and a higher absolute humidity (see here for a discussion of humidity scales), which may lead to more cloud formation. If it does, and the clouds are low clouds, planetary albedo may increase, which would tend to mitigate the temperature change, as low clouds have very high albedo (high clouds lead to net warming). This would be an example of a negative feedback loop -- if warming actually leads to an increase in cloudiness.

Note that conversion of forest or grassland to agriculture or urban areas will also change albedo. So will moving landmasses around (landmasses over the poles tend to accumulate larger ice sheets).

Absorbed solar energy

Here we are interested in the solar energy that is not reflected out to space. What is not reflected is absorbed, and now it gets seriously complicated. Most of the energy radiated by the sun is in the visible (not surprisingly we are adapted to sense it well), a region of the electromagnetic spectrum to which the atmosphere is quite transparent.
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Figure from here -- the vertical scale is absorption of radiation. For reference, the visible spectrum ranges from about 0.4 microns (violet) to 0.76 microns or so (deep red). Anything shorter is ultraviolet, longer is infrared. The point is that most solar radiation makes it to the surface of the Earth, whereas a significant fraction of outgoing thermal radiation is absorbed in the atmosphere and converted to heat -- this is the greenhouse effect. The absorption hole at ~10 microns is right at the peak of the planetary emission term and is known as the "atmospheric window". If it weren't, more energy would be trapped in the atmosphere and we would resemble Venus a bit more closely.

Here's the energy budget of the surface-atmosphere system (figure from UCAR)

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It's a bit confusing, and the actual numbers shouldn't be taken absolutely literally, so take it in pieces. The stuff in yellow on the left is "shortwave", which is what comes from the Sun and is in the visible + UV + near infrared; the stuff in beige on the right is "longwave", or what is reradiated out, and is deep in the infrared.  First thing to note is that what goes in must come out. Of the 341.3 W/m2 incident, 102 are reflected, the remainder absorbed, either in the atmosphere or (mostly) at the surface (here they are apparently using 170.6 W/m2 mean insolation and a bond albedo of 0.299) The amount absorbed heats up the surface-atmosphere system, causing it to radiate that amount back to space. A fair amount of the incoming radiation is absorbed in the atmosphere, but nearly half is absorbed at the surface. The amount that does powers the great ocean currents, the ceaseless winds, hurricanes and tornados and blizzards, microscopic algae and giant sequoias, hummingbirds and blue whales and you and me.

The second thing to note is the amount exchanged between the surface and atmosphere. What is absorbed at the surface reradiates in the infrared; a fraction of this escapes out the atmospheric window, but most of it is absorbed in the atmosphere, primarily by water vapor, but also by CO2, methane, N2O, and other greenhouse gases. The atmosphere reradiates this absorbed energy (as well as the amount absorbed from incoming radiation), some out to space, some back to Earth, which reradiates back out to the atmosphere, etc etc ... this is why the gross heat flux out of the surface is greater than the absorbed shortwave.

Change
Nothing is ever static of course, and changes to the energy budget will either cause global warming or cooling. If the global temperature is changing, there is a net heat imbalance in the energy budget. In the figure above, Kiehl and Trenberth estimate a net absorption of 0.9 W/m2: because we are retaining more energy in the atmosphere, energy in > energy out, and we have global warming.

The primary ways to change the budget are either through albedo, as mentioned above, or by trapping more or less solar radiation in the surface-atmosphere system. This latter is done primarily by changing the concentration of greenhouse gases. Nothing is ever easy of course: the primary greenhouse gas is water vapor, but you cannot simply add or subtract water vapor -- its concentration depends on temperature and reequilibrates more quickly than changes in temperature. Increase or decrease temperature some other way -- by CO2 or methane, perhaps -- and water vapor will respond by amplifying the change. These and other feedback loops, some of which are positive (amplify change), some negative (mitigate change) couple to each other along a huge range of timescales and also couple to albedo, often indirectly, making for a very complex system. Here's a plot taken from the IPCC's AR4 summarizing changes to the energy budget (again, don't take the numbers too literally):

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Note that changes to albedo and energy retained (primarily by GHG) contribute in opposite directions, but the GHG term dominates and the net effect is warming: compare the CO2 trend with the temperature record and solar insolation figures above (figure taken from Keeling et al 2007)

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The correlation is not perfect, but then we should hardly expect it to be: many things are happening at the same time. Even so, the GHG trend is the only factor changing with sufficient magnitude on the observed timescale to explain the bulk of the global temperature trend.

Standard caveat applies: you cannot infer causation from correlation. Well correlated observations may have a causal link -- or they may all be responding to a forcing you haven't identified. Or they may not be related at all. You need a mechanism in your model. If your model results correlate well with reality, you gain some confidence that you got something right. If they correlate well over a wide scale of conditions and timescales, you are probably on to something. Science doesn't do proofs, so this is as good as it gets. But if your results do not correlate well with reality, you screwed up somewhere. So correlations are important -- you just can't infer causation from them.

A couple of final thoughts. Pretty much everything is driven by the Sun. Without that this would be a dead, cold planet. But we need to distinguish the actual energy budget from variability in that budget. One controls climate, the other climate change. Also, timescale is important. Orbital variations are much too slow to show up on the ~century timescale of the AR4 plot, but changes on that timescale to solar output do, and there is a small warming term from solar variability. All of the factors affecting the energy budget are constantly changing, of course, and all of these factors contribute, but some are more important at one time or another, on one timescale or another, than others. In our time, on our timescale, the primary -- but not only -- driver is change in greenhouse gas concentrations.

Originally posted to alefnot on Tue Apr 21, 2009 at 03:18 PM PDT.

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Comment Preferences

  •  Thanks (2+ / 0-)
    Recommended by:
    alefnot, kirbybruno

    This was a very informative bit of information that was apolitical, which is rare these days when referring to Earth Day and global warming.

    I'd like to ask, though, about your overall opinion of what should actually be done about this "global warming"?  CO2 is a factor, yes, but such a trivial one in comparison to the sun's variation in output and water vapor.  And CO2, in your graphs above, essentially angle up to the right at a very consistant rate whereas the temperature increases do not.  In other articles with solar irradiance superimposed on the temperature graph, there is a much stronger correlation.  This would imply that curbing CO2 emissions would do little to change things whereas learning to adapt to a warmer climate would be much more beneficial.

    I would just like to know your two cents.

    Again, great summary.

    •  If I may jump the gun (3+ / 0-)
      Recommended by:
      RunawayRose, alefnot, kirbybruno

      and provide an answer before alefnot, let me respond to your statement:

      "CO2 is a factor, yes, but such a trivial one in comparison to the sun's variation in output and water vapor."

      The applicable statement from the original post is this:

      "we need to distinguish the actual energy budget from variability in that budget. One controls climate, the other climate change."

      The sun's variability in output is comparable to that of current levels of CO2, but it goes up and down on 11-year cycles. If it were a dominant factor, then we wouldn't be seeing secular increases in temperature; we'd see only an 11-year cycle of heating and cooling.

      In like fashion, water vapor's contribution is static. We have no reason to believe that water vapor's effect is increasing or decreasing. It's a constant.

      In other words, in order to understand the change that's going on, we have to concentrate on the magnitudes of the changes in the controlling factors. And that's where CO2 comes into play. It's changing much more than any of the other factors.

      •  Ok, I think I get it (0+ / 0-)

        I understand the energy budget from variability part, but the change in the budget will have a dramatic impact on the change in climate.  If you check the link I posted in the response to alefnot, it showed the solar variance and temp changes, and they were fairly strongly related.  CO2 had little correlation, other than it went up in general when the temp went up.

        The 11 year cycle is one part of the many cycles in both solar and earth activity.  When one puts the CO2 vs temp graph from the ice core data, one sees CO2 lagging temp changes by roughly 800 years.  A general explanation of this, I have read, is that when the oceans heat up for whatever reason, they can hold less gas and thus more CO2 is released into the atmosphere.  

        Additionally, the impact CO2 has on retaining heat is logarthmic  and not linear.  Thus, additional CO2 will have less of an impact than earlier additions, eventually reaching a point where doubling CO2 concentrations will have little to no further impact on heat retention in the atmosphere.  Which again leads me back to solar variance as the primary driver.

        I'm not sure I understand water vapor's "static" contribution.  With more heat, there is more water vapor.  Less heat, less vapor.  I have read that there is little to no research being done on the increase or decrease in overall water vapor concentrations in the atmosphere, which would thus make it difficult to state conclusively that water vapor's impact is unchanging.  What am I missing?

        CO2 may be changing much more so than others in the manner in which we are measuring it.  Have all the critical factors been clearly identified?  I would have to guess no, as climate and weather are pretty much the most complex systems to understand.  One dramatic eruption wipes out all predictions of climate change for a few years.  There was an article out, that I did not read, that mentioned a venting process in the Pacific Ocean that could account for a significant amount of cooling.  

        I'm mentioning all this to try to rein in the hysterical nature in which everyone wants to restrict CO2 emissions when CO2 is not the conclusive driver in climate change - at least according to a lot of the data.  I wanted to begin discussions of adaptation, as that would be dramatically cheaper than mitigation.

        Thank you for your response.

    •  Couple of things (1+ / 0-)
      Recommended by:
      RunawayRose

      Solar variability today is quite small, and if it were the dominant forcing, we would have been seeing cooling for the last 25-30 years, over which would be superimposed the 11 year sunspot cycle.

      I would like to see other articles in which "with solar irradiance superimposed on the temperature graph, there is a much stronger correlation." The solar insolation record is quite good since we've put satellites up beyond the effects of weather, as is the global temperature record.

      Water vapor is a big one, and the primary greenhouse gas, as noted. But its lifetime is only on order 10 days, whereas the global climate system operates on a minimum timescale of a few years (some terms much much longer). IOW, water vapor concentrations equilibrate well before it can force a change in the climate system. This is why it is considered a "feedback" term, not a forcing. To change water vapor concentrations you would need to change temperature in some other way.

      And CO2, in your graphs above, essentially angle up to the right at a very consistant rate whereas the temperature increases do not.

      That's exactly correct, and part of the point of the post. It is not the only factor controlling the show, it never has been and never will be. But today it is the dominant factor.

      As for mitigation vs adaptation, IMO we are well past the point where mitigation only is a possibility. Adaptation is necessary, but both the magnitude and the cost of adaptation will be greater in the absence of mitigation. That it is so late in the game is no excuse for avoiding mitigation.

      •  Solar Variance Graphs (1+ / 0-)
        Recommended by:
        alefnot

        Alefnot,

        Thank you for the response.  I found an article that more or less shows what I wrote about:

        http://oldfraser.lexi.net/...

        Solar variability is quite small when compared with overall solar output, but the change does have a dramatic impact on weather conditions, and climate conditions, here on earth.  The five graphs do show a very strong correlation, which is why I posted my comments and questions.

        We would not have seen cooling in the recent past because solar activity over that time period was higher (your 25-30 year window).  There are predictions now of a drop in solar activity and thus a drop in global temps.  If this prediction does come about, with the continual increase in CO2 emissions, this should pretty much drop CO2 as a significant forcing in global warming - at least when compared to solar variability.

        I'm not sure I clearly understand what you meant in the water vapor comments you made.

        With the strong correlation of global temp change and solar variability when compared to global temp change and CO2 increase, I do not see how CO2 change is the dominant factor.  It is "a" factor, but not the game changer, as the graphs show at least.

        I posed the adaptation vs mitigation because it seems that all anyone ever talks or writes about are the changes we need to stop CO2 output.  Very little is written or spoken about the cost to adapt.  Many dire predictions are extremely exaggerated in order to push the agenda that mitigation is the ONLY option, which is not at all true.  Adaptation to a warmer climate, if we are even headed that way, appears relatively cheaper and much easier to do.  Besides, there are many good things about living in a warmer climate.

        All said, I sincerely appreciate your response.  I enjoyed the original entry as well.

        •  Several points (0+ / 0-)

          First, a rec for looking into it.

          Dealing with the Soon and Baliunas paper would require a full post of its own, but here are the main points. (Some of the points they make are out of date, such as the use of the IPCC Second Assessment Report, but this is a 10 year old paper and it would not be fair to criticize it for that -- but it should be noted that the science is moving rapidly and 10 years is a long time in this field)

          They criticize current global climate models for having large uncertainties. That's a legitimate point, even 10 years on: uncertainties remain large, far too many things still have to be parameterized, far too many things are too poorly understood, and those are only the known unknowns. That said, the test for any model in any field is predictive ability, and here GCMs have done a resonably good job, considering the uncertainties. Here's a composite summary plot to 2005 (blue is the natural component, pink the sum of natural and anthropogenic, black the observation.) GCMs miss much of the fine structure, and there is a systematic underprediction in the larger trend (the systematic underprediction continues to this day).

          In place of GCMs they argue by correlation. This makes no sense. You cannot simply show solar sunspot number and say "Such changes in irradiance could, if large enough, drive significant climatic change and the climatic record" without quantifying the effect of the change in insolation on temperature. You cannot simply plot length of solar magnetic cycles with suitably scaled Northern Hemisphere temperature records without quantifying a causal mechanism.

          We would not have seen cooling in the recent past because solar activity over that time period was higher (your 25-30 year window).

          Actually this is incorrect. We have excellent solar records at the top of the atmosphere over that timespan, and we've seen a slight decrease since about 1980. Not as strong as the increase over the first 50 years of the previous century, but still noticeable.

          With the strong correlation of global temp change and solar variability when compared to global temp change and CO2 increase

          There is a correlation for the first half of the last century, for the last 3 decades it's an anticorrelation. But even a positive correlation cannot tell you that the positively correlated quantity is the driving factor, though it can tell you that a negatively correlated one is not.

          I'm not sure I clearly understand what you meant in the water vapor comments you made.

          Let's say you had some means of instantly halving global water vapor concentrations. The system is now out of equilibrium, and it will attempt to reach equilibrium by increasing evaporation. The water cycle turns over in about 10 days, you will reach equilibrium in a few cycles, or about a month. Global temperatures have much longer timescales, from a few years up to a few hundred million. The climate system simply doesn't react to fluctuations on a weekly or monthly timescale. Similarly, if you could instantly double global water vapor, it would return to equilibrium by precipitation. The equilibrium state is strongly dependent on temperature. To make water vapor more or less significant than it is now, you need a way to sustain or suppress wv concentrations on a timescale relevant to climate processes, and the only way to do that is to change global temperatures some other way. If you can do that, water vapor will then act as an amplifier in whatever direction the forcing maintains. CO2 is different, because its charateristic timescales range from ~decade to millennia. This is why water vapor is considered a feedback term, CO2 a forcing term.

          Hope that helps!

          •  Thanks Again, Yes (0+ / 0-)

            it did help quite a bit.

            Some additional comments, again because I would like to know more.

            Your graph indicating temps from natural and anthropogenic causes, and the observed, raises a question.  How can one distinguish between natural and anthropogenic causes and its affect on temps?  I do understand what are anthropogenic causes (changes in landscape from forest to farmland, cities or housing, fuel emissions, factory emissions, etc.), but how does one account for the temp difference seen in the climate, or the local temp due to these specific changes?  Small point, but one I wanted to understand better.  I've read and understood the absorption argument on landscape change, and I read and understood the amount of CO2 emissions man contributes compared to nature, but I have never read what affects those have on temps in a statistical or numeric manner.

            Your comment:

            In place of GCMs they argue by correlation. This makes no sense. You cannot simply show solar sunspot number and say "Such changes in irradiance could, if large enough, drive significant climatic change and the climatic record" without quantifying the effect of the change in insolation on temperature. You cannot simply plot length of solar magnetic cycles with suitably scaled Northern Hemisphere temperature records without quantifying a causal mechanism.

            It seems to me that the same argument is currently used with CO2 to great affect.  CO2 goes up, and so does the temp, except when it doesn't, but CO2 is still considered the driver.  Then one looks at the ice core data and we find that it lags temp by 800 or so years.  So how is it a driver?  When sun spots are observed (and I believe they have been observed for several hundred years) and then comparisons are made to temp, there is a direct correlation with temperature change - increased sun spot activity leads to increased temps and a decrease in sun spot activity leads to a decrease in temps.  I understand, only from ignorance (ironically), that there is not a quantifiable change in temp with sun spots.  I take that to mean "there will be a 0.5C temp change over the next ten years because there were 26 fewer sun spots last year", and I do not know that, nor have I read that anywhere.  It simply seems more logical to me that the sun would have a much greater impact on temps than CO2, for whatever reason, although there are many - source of all energy, protection from cosmic rays, cloud formation, etc.

            We would not have seen cooling in the recent past because solar activity over that time period was higher (your 25-30 year window).
            Actually this is incorrect. We have excellent solar records at the top of the atmosphere over that timespan, and we've seen a slight decrease since about 1980. Not as strong as the increase over the first 50 years of the previous century, but still noticeable.

            What I meant by this was, we had roughly 30 years of increased solar activity and roughly 30 years of increased temps.  Then, we had about 8 years of reduced solar activity and about 8 years of cooling or stagnant temps.  That is why I believe that the solar variance more directly reflects the changes in temps we have seen.  I don't recall the anti-correlation, though I might have heard about it before.  If there is a more current graph on this, please point the way.

            Thank you for the very clear explanation about the water.  A question, though:  is the difference, then, between a feedback mechanism and a forcing mechanism the length of time it is in the system?  I ask this because it seems like CO2 behaves in a similar fashion as wv (more of it, retains more heat, generates more of it - or positive feedback), it's just that it happens on a longer time scale.

            •  Need to quantify your mechanisms (0+ / 0-)

              Your graph indicating temps from natural and anthropogenic causes, and the observed, raises a question.  How can one distinguish between natural and anthropogenic causes and its affect on temps?

              It's a model result. You know what the model expects for a system with preindustrial CO2 levels and land use, so all of the changes are driven by solar insolation, volcanic aerosol, etc. That's the natural term. Add to that known anthropogenic changes in GHG, aerosol, ozone, land use, etc and you get the sum of natural + anthropogenic.

              Please understand that the model is mechanism driven. There is a lot of covariance analysis out there to try to figure out which mechanisms are most important (in this case it's GHGs) but when you're actually making predictions you need to quantify those mechanisms. That is, you need to answer: for X change in A, what is the magnitude of change in B? Not, A is changing, so is B, ergo one must drive the other. Eg, we know the IR absorption of CO2, we know how much there is in the atmosphere, so we can quantify the heating driven by CO2 absorption. There are many feedbacks and second order effects, so it's not quite that easy, but that's the approach you have to take, not correlation.

              How good is the model? Well, there is exactly one test: experimental validation. So far it is working pretty well over the observed range of GHGs, insolation, aerosol, ice cover, etc. It misses a lot of fine structure, and it systematically underpredicts, but it gets the general trend right.

              That is not proof that our understanding is essentially correct, but science doesn't do proofs. We have been unable to identify anything else changing in the right direction, of the right magnitude, on the right timescale, that could explain the trend besides GHGs. We have been able to identify one possibility that does -- GHGs. Maybe something else is indeed controlling the show, and we just don't know about it. But we have no reason to believe that.

              Then one looks at the ice core data and we find that it lags temp by 800 or so years.  So how is it a driver?

              In this case it isn't. This is exhibit A in conflating causation and correlation. We know that increasing CO2 without directly affecting T will trap more outgoing IR so T will rise. What if we increase T without directly affecting CO2? That's what we see in the ice cores, as orbital variations take us out of an ice age. Greater insolation will lead to greater ice melt. That turns some areas that were once covered in ice into first a wetland. You now get respiration which releases CO2. As it continues to warm, the wetland dries up (eg, most of Wisconsin, once covered in ice, is not a swamp but prairie and forest), so we get increased respiration, from less efficient anaerobic methanogenesis to aerobic respiration. A fraction of the organic matter once buried under ice turns into CO2, so CO2 rises. As CO2 rises, it increases temperature by IR absorption, which increases CO2 etc etc until orbital variability turns the system around into another ice age. This is an example of a positive feedback, and in this case CO2 is a feedback amplifier, not the direct forcing (orbital variability is the forcing).

              Note that it doesn't matter which one starts first, T or CO2, they amplify each other -- that's the nature of a positive feedback. But just because one is the forcing at some times in the past doesn't mean it always is. The climatic changes leading to the Permian extinction were almost certainly driven by CO2 emissions from the Siberian Traps. But that drove a T increase, which accelerated not only CO2 but methane increases. There are examples in Earth's history in which T changed first, and examples in which CO2 changed first. But the result was the same -- further increases in both T and CO2.

              Today the orbital and solar output terms are tending to drive temperatures down, CO2 is tending to drive it up. Which wins depends on relative magnitude.

              What I meant by this was, we had roughly 30 years of increased solar activity and roughly 30 years of increased temps.  Then, we had about 8 years of reduced solar activity and about 8 years of cooling or stagnant temps.

              Where are you getting your insolation data? Over the last 120 years, we've had 80 years of increased solar output, until about 1970, 10 years where the trend leveled off, to about 1980, and 30 years of decrease (see figures above). There is also an 11 year sunspot cycle overlying the longer trend. The last 30 years have the highest quality data, since those are taken above the atmosphere (the others are from ground observations). The last 30 years have also seen the strongest warming. Even so, you cannot say that the warming of the first 80 years was driven by solar output (or, for that matter, CO2 or anything else) -- you need to quantify your mechanisms (current estimates are that solar increases contributed about half the warming term up to ~1960 with the balance in GHGs and volcanic effects. Since then the GHG term has taken off). Correlation != causation.

              A question, though:  is the difference, then, between a feedback mechanism and a forcing mechanism the length of time it is in the system?

              Relative timescale is key. If the timescale of the mechanism is very short compared to the timescale of the change, it can only act as a feedback. Of course, if the mechanism is external to the change, there can be no feedback (as far as we know, global climate change has no effect on Milankovitch cycles, eg). CO2 has a multitude of timescales, ranging from the very short (marine biota) to the very long (geological processes) so it's more complex than something like water vapor and can act as both forcing and feedback.

              •  Keep it coming (0+ / 0-)

                I sincerely appreciate the time you have taken to respond to my series of questions.  You have given me several new bits of information and new ways of looking at the old information I thought I understood.  So thanks.

                Still a couple of questions:

                I understand the best way to test models is through experimental validation, or testing its predictions and then observing what actually happens.  Additionally, though, isn't it useful to test the model on the past and see if it can replicate past climate?  From what I have read, no model can accurately predict the past  for extended periods of time, which leads to the argument that if the model cannot accurately model the past, how can it accurately model the future?  But now I understand the point that I had not thought of earlier, which is how CO2 can at one point in time be an amplifier and at another time be a driver, which would make the model more complicated.  But I'm sure modellers have overcome that one...

                I am curious as to how you can say that nothing besides GHG can explain warming because of my earlier graph of solar activity.  I would say GHG's do play a role, but, especially in the 20th century, solar variance much more accurately followed temp changes than did CO2 concentrations.  

                I am really harping on the idea that CO2 is a main driver simply because of all the hype surrounding it and the policies being enacted to control it.  If man generates less than 3% of all CO2 generation and CO2 makes up a fraction of a percent of all GHG's in the atmosphere, I personally believe we should be looking elsewhere for a serious driver.  Or even still, if it is a driver, then learn to adapt to changing conditions as, based on that paragraph you wrote in the last response about changing from ice to a swamp, more plants, more CO2, etc., then we can't really stop it anyway.  Enough said there for the moment.

                In response to your question, I do not have "insolation" information.  I am guessing you are referring to my information on solar activity and temp scales or graphs, which I posted earlier.  Other than that, I read quite a bit, but not for the purposes of publication, simply information.  I have read, though, that the solar variation link does not accurately reflect temp variation from the 1990's.  However, since 2000, temps have flattened or dropped overall.  Somewhere along the way, I have read the argument that it takes a great deal of time to change the temp of the oceans, either up or down, which is logical.  This carries a kind of momentum, so to say, in that if temps are rising, it should take some time to slow and reverse, as the ocean is a tremendous heat sink or source and thus causes the atmospheric temps to change slowly.  Same if temps dropped.  There should be some kind of time lag.  Additionally, with all the other variables changing, specifically CO2 which is a positive feedback mechanism or driver, which would help continue to drive the temps in the current direction, even with the ocean exerting its influence.  That was the argument as I understood it.

                I have not researched more recent solar variance information as I do not have general access to research sites.  When I have time, I look.  Most of my information comes from websites that post some research papers, or books both supporting and refuting anthropogenic global warming.

                Again I would appreciate any recommendations for personal research in this area - books, websites, articles.

                Thank you again for your detailed responses.

                •  Hmm, tried to reply but didn't take (0+ / 0-)

                  Additionally, though, isn't it useful to test the model on the past and see if it can replicate past climate?  From what I have read, no model can accurately predict the past  for extended periods of time, which leads to the argument that if the model cannot accurately model the past, how can it accurately model the future?

                  Hard to tell how well models work if you go back very far -- the uncertainties in temperature reconstruction also get very large. However, models are "spun up", that is, the output has to match the past (how far back depends on the question being asked) before it can project into the future, and if the model cannot replicate at least the recent past you have to go in and fix it.

                  The further back you go the more dependent you are on proxies. Even as recently as 100 yrs ago you have to watch sample bias (lots of data in Europe and US, not so much from elsewhere). Data quality of the last 4-5 decades is excellent, however (in part because of Cold War issues).

                  I am curious as to how you can say that nothing besides GHG can explain warming because of my earlier graph of solar activity.

                  That link does not show solar insolation, and certainly shows no data since 2000, since that paper dates back to 1999. Soon and Baliunas do show variability they claim arises from solar activity overlying an increasing trend they attribute to GHG emissions (Fig 4).

                  If man generates less than 3% of all CO2 generation and CO2 makes up a fraction of a percent of all GHG's in the atmosphere

                  Current anthropogenic carbon flux to the atmosphere is ~8 Gtons C/yr (you might be interested in an earlier diary) This is small compared to the ocean outgassing flux of ~90 Gt/yr and the 60 Gt/yr from forests (and similar amount from soils). But take away the ocean uptake flux is also ~90 Gt/yr; the terrestrial biosphere uptake flux is ~120 Gt/yr. IOW, the anthropogenic gross flux is quite small compared to the natural terms, but it is the entirety of the net flux. How do we know this? Because before the industrial revolution CO2 levels were bouncing around in a narrow range about 280 ppm. If the atmospheric carbon reservoir is ~constant in size, the input and output fluxes have to match.

                  CO2 is second only to water vapor in GHG abundance, and we've already talked about water vapor.

                  Or even still, if it is a driver, then learn to adapt to changing conditions as, based on that paragraph you wrote in the last response about changing from ice to a swamp, more plants, more CO2, etc., then we can't really stop it anyway.

                  Probably we can't, but I have yet to hear a rationale how adaptation would be easier and cheaper in the absence of mitigation. We do have a couple of natural tendencies working for us right now, however: orbital variability would put us into an ice age (although that operates on a 104 - 105 yr timescale its effect on a 10-100 yr timescale is extremely small), and solar activity is currently in a low output mode. But we have no idea how long it will stay that way, and insolation from the sunspot cycle is scheduled to increase in about 2 years. Anyway, starting early is easier than starting late.

                  This carries a kind of momentum, so to say, in that if temps are rising, it should take some time to slow and reverse, as the ocean is a tremendous heat sink or source and thus causes the atmospheric temps to change slowly.

                  The atmosphere responds very quickly, land surfaces more slowly, oceans even more slowly, ice cover highly nonlinear. If you're going to argue momentum you need to quantify the amounts. The best way we have to do this is by models, which show there is a significant amount of warming "locked in" the system even if we were to cap GHG emissions today. (This has corroboration from the ice core record, in that the CO2 trend wrt temperature is far from equilibrium, according to past history. But as they say on the prospectus: Past history is no indicator of future performance)

                  Again I would appreciate any recommendations for personal research in this area - books, websites, articles.

                  The best one is the IPCC's 4th Assessment Report. You can download the Technical Summary (30 pp or so, IIRC) or the full report (>1000 pp). It has already been shown to be conservative (they do a poor job with ice) so keep that in mind. Still, it's quite comprehensive, lays out everything, so if you have issues with it you can at least pinpoint where those are and go to the literature.

                  Occasionally other agencies do similar reports: the Pentagon's scenario from a few years ago had some seriously scary hair-on-fire stuff, but maybe that's their job -- here's coverage on it. That was a low probability(?)/extreme impact scenario Taleb might call a Black Swan -- or Grey Swan, since it's not quite unforeseen, but those are frequently the events that change everything.

                  UCAR also has an intro online, but it's not very quantitative.

                  •  Again thanks, (0+ / 0-)

                    I thought you might have given up.

                    I'll tackle this in the order presented above:

                    I understand the modelling and errors getting bigger the further you go into the past.  Chaos theory in action, in a way.  However, you made one statement that concerns me in that you wrote that the recent data is very accurate.  I recently read a report on the temp measuring stations in the US and found that the data is extremely unreliable and that the errors in temp explains temp increases seen simply in the margin of error.  It was an enlightening report in that I had heard rumors and pictures of these claims many times.  However, this report was hard data with pics on many of the stations.  The guy had a website at www.surfacestations.org, but I didn't look for the report there.  With garbage data from land readings, how does one compensate for that?  Or should we hold off action until we get more reliable data? Or how does one correct for the errors?

                    I believe I understand the net flux of CO2 you wrote about.  However, the industrial revolution coincided unfortunately with the end of the little ice age.  For arguments sake, if the temp happened to increase on its own, would that not change the equilibrium?  Then there would be a net change in CO2 in the atmosphere simply due to the re-establishment of equilibrium where the atm CO2 is higher than it was earlier.  How would it then be possible to determine what flux amount was due to man and what was due to nature?

                    Along the same idea as the equilibrium argument you present, the manmade CO2 does not all go into the atm and stay there indefinitely.  Nature takes up some in order to reach a new equilibrium.  I do not know the lag time for that to occur, but I'm hoping you might as that would be a large factor in modelling I am sure.  But continuing, if man emitted enough CO2 to double the CO2 concentration in the atm, then the oceans would necessarily have to take up a very significant amount of CO2 in the air in order to establish a new equilibrium.  Thus, man would need to emit a lot more CO2 than just enough to double all that in the atm today.  Obviously, man had been freely emitting CO2 into the atm for over 100 years and we have yet to double it yet.  Thus, it would take a hell of a long time to do that.

                    My point here is that man's changes are small and would change the equilibrium by a very small amount by itself (man's contributions) when compared with what nature could do on its own.

                    Actually, I have heard many, many ideas on how adaptation is not only cheaper, but much more beneficial.  We have an idea, low ball estimates though, on what the costs of lowering CO2 emissions would be - trillions and trillions of dollars to world wide economies, less reliable energy, less energy, more expensive energy, longer times for third world countries to come out of poverty, etc.  Adaptation has more benefits than simply improving our ability to survive in a warmer climate.  Keeping energy costs low and allowing all nations to develop fossil fuel sources that they have would speed up economic development rather than hinder it.  Economic development has led more people out of poverty than anything else in human history.  With an improved economy, nations can more easily protect their environment at a lower cost, percentage wise, than if they had remained poor.  I don't know what exactly you would need to see in order to realize adaptation is easier, less costly, and makes more sense than trying to strangle our world economy in order to reduce one GHG in the hopes of lowering temps 0.7C in 100 years, if we're likely.  Adaptation has much more measurable positive results.

                    I don't have information on specific temp changes wrt the momentum I mentioned earlier.  It is simply an idea that I read about and seemed logical in that the ocean is an extremely large heat sink wrt earth and largely controls the weather and hence the climate.  Yes, atm temp changes quickly, but much less so when near large bodies of water than when far away from water.  WRT momentum, I simply was stating or implying that when water is warm, it takes a very long time to cool a very large body of water.  With that in mind, and the idea that atm temps do heavily depend on water temp, it would take a long time to change temps in the atm for that reason.  All those things are relative, obviously, and no I have no quantitative data to support that at this time.  There was the slow down in the Atlantic current (forgot the name at the moment) that supposedly helped create or exaggerate the little ice age that is an example of my argument.

                    Thank you for the rec's.  I have read much of the IPCC, including the latest info.  However, I have also read a lot from scientists who used to be writers for the IPCC and even the head guy for the IPCC and they often look at the IPCC as having a very strong political agenda, and a very weak desire to be scientifically accurate.  Thus I am skeptical of their publishings.  I look at research papers or articles from scientific publications that are more or less free, or occaisionally pick up a Sci American or Science mag, or the occaisional book.

                    Thanks again for the very insightful information.

                    •  several points (0+ / 0-)

                      I recently read a report on the temp measuring stations in the US and found that the data is extremely unreliable and that the errors in temp explains temp increases seen simply in the margin of error.

                      Temperature measurements are among the easiest to do and precision is quite good. There were issues with sampling bias (urban heat effect) and satellite calibration about 15-20 years ago that did require correction. This was dragged up again in more recent years, but those criticisms are out of date.

                      the manmade CO2 does not all go into the atm and stay there indefinitely.  Nature takes up some in order to reach a new equilibrium.  I do not know the lag time for that to occur, but I'm hoping you might as that would be a large factor in modelling I am sure.

                      Works on multiple timescales, from the very short to the very long. If you look at the carbon cycle figure in the diary linked above you will note that uptake fluxes for both oceans and terrestrial biosphere > outgassing fluxes, indicating that those reservoirs are not at equilibrium. They account for roughly half of the net fossil fuel/land use flux, the remainder is in the atmosphere. It's all about relative rates.

                      Obviously, man had been freely emitting CO2 into the atm for over 100 years and we have yet to double it yet.

                      A 40% increase in 150 years is dramatically fast, on the timescales of natural processes. Again, it's all about relative rates.

                      Actually, I have heard many, many ideas on how adaptation is not only cheaper, but much more beneficial....Economic development has led more people out of poverty than anything else in human history.

                      I would certainly appreciate references on those ideas. Extreme poverty is certainly at least as destructive as extreme affluence. And I am no economist. Yet those economists who work to help developing countries -- the most prominent names are Jeffrey Sachs and Joseph Stiglitz -- certainly do not agree that adaptation in the absence of mitigation is workable.

                      I don't know what exactly you would need to see in order to realize adaptation is easier, less costly, and makes more sense than trying to strangle our world economy in order to reduce one GHG in the hopes of lowering temps 0.7C in 100 years, if we're likely.

                      Do you have a quantitative basis for this statement? There are a number of studies out there that show otherwise, such as the Stern Review and the McKinsey Report. You may not agree with some or all of their assumptions or conclusions, but they do lay those out clearly and thus provide a basis for discussion. Perhaps you could do a diary on one of them.

                      There are also a number of major industrial companies, including energy, transportation, and heavy industry, who would not agree with you either, such as Shell Oil, Volkswagen, Rolls Royce, Repsol (oil company), GE, DuPont, Johnson and Johnson, Shanghai Electric, Statoil, and others.

                      However, I have also read a lot from scientists who used to be writers for the IPCC and even the head guy for the IPCC and they often look at the IPCC as having a very strong political agenda, and a very weak desire to be scientifically accurate.

                      Normally I stick to what is quantitative, but understand that a statement like this without independent evidence amounts to an ad hominem criticism. It is true that this time around (AR4) the scientists were pushing for stronger statements than the economists or policy experts of the IPCC. But it wasn't because of a "political agenda".

                      In the end however, irrespective of any political agenda the scientists or their critics may or may not have, there is exactly one test the scientists have to pass, and that is experimental validation.

                      We've been modeling climate for at least 3 decades, with significant improvements over time. 30 years is not terribly long in terms of natural timescales but it is long enough to tell us whether we're completely off. If you look at the initial projections from the early Assessment Reports you will note that we're doing pretty well. Actually we've been a little on the low side since 1992.

                      •  Sorry about the wait, (0+ / 0-)

                        been very busy.  In response:

                        You wrote:  Temperature measurements are among the easiest to do and precision is quite good. There were issues with sampling bias (urban heat effect) and satellite calibration about 15-20 years ago that did require correction. This was dragged up again in more recent years, but those criticisms are out of date.

                        I don't see how they can be "out of date" when the report I mentioned was completed in 2009, which you can read here: http://www.heartland.org/...

                        The criticisms are definitely not out of date, nor have the issues been addressed or the problems of bad temp stations been corrected.  This is a severe issue and goes to the heart of the "global warming" argument - is there actually warming going on?  Most scientists consider the data collected in the US as the most accurate and reliable, yet this report absolutely refutes that assumption.  Can you point me to information that says the temp measuring issues identified in this report has been corrected in any meaningful way?  If the raw data in the most reliable region is inaccurate or questionable, what does that say about the rest of the world's data set?  Satellite data only goes back a couple of decades, and that does not a climate record make.

                        I'll have to look at the link you included again to review relative rates and establishing new equilibriums.

                        The costs of implementing Kyoto-like changes to our economy are everywhere, so I doubt I need to provide you that information.  The costs of adapting to a warmer climate, or a changing climate, is dramatically less based on the common sense that that is what mankind has been doing since his arrival.  If we don't have enough land where we are, we make more (Japan, Netherlands) or build walls to hold water out.  If it rains too much, we build bigger canals.  The list is endless in how we adapt to a changing environment.  Cutting energy use makes us weaker and less able to adapt.  Increasing energy supplies makes us stronger and helps us to adapt much more easily than without it.  For arguments, see DVD Evangelicals & Global Warming.  It is a debate at a religious college, but it is all science.  One of the three areas covered was the costs of either adopting Kyoto as written or adapting.  It was quite informative.  

                        The costs of adapting as opposed to cutting energy are also highly exaggerated when the absolute extremes in Al Gore's movie are taken as true.  When actual consequences predicted by  even the IPCC are used, adaptation to the changes is nearly nothing.  There has been no sea level rise on islands in the Pacific, no increased hurricane activity, no increase in severity of storms, basically zippo Inconvenient Facts that foretell the coming doom portrayed.  Thus, there is no cost to date to adapt and huge cost to give up our cheap fossil fuel energy supplies.

                        I was thinking of a diary, but I haven't tried it yet.  I will check out the links you provided and provide other cost/benefit analyses as needed.

                        Major energy companies that do not agree that adaptation is better than not using fossil fuels?  I will have to check the link on that one, but on face value, it is political or simply jumping on the bandwagon so one does not look bad.  Shell recently gave up on its alternative energy development because of costs.  Without government aid, nothing but fossil fuels would be used based purely on economics.  Ok, hydro and geothermal are cheap as well.

                        I don't believe that repeating what a lead author of the IPCC writes is an ad hominem criticism.  It is stating facts as presented.  The author described the process of creating the IPCC reports on global warming in extreme detail.  As he was lead author in 2001, he would know.  He quit specifically because it was politicized, the process that is.  Scientific opinions were discarded when they could not support the summary that was written prior to the scientific evidence being reviewed.  If the summaries were written for the politicians and these summaries were not in following with the scientific evidence, then what agenda were they following if not a political one?

                        Experimental validation is correct as being the only evidence that supports or refutes a theory.  As the evidence sits now, there is nothing out there that proves anthropogenic global warming.  There is also nothing out there that proves man does not cause global warming.  What is out there simply supports the common sense notion that climate changes.  Since 1998, the data basically says there has been no statistical warming, and there may have even been cooling.

                        I've reviewed the IPCC modelling info through their history.  The range is very large overall.  I am not sure how to quantify error in all the modelling projections, and that would be good info to have.  But based on memory, accuracy is not all that important for this, but when modelling gives a range of temp change from 0.5 to 3C over 100 years, that seems rather an extreme range.  Given that our measuring techniques are not that great (see report above) maybe that is good considering we can't measure that well now, I don't know.  In the end, I don't agree with asking the world to do without unless it can be proven beyond a reasonable doubt that doing without will bring about a reasonable change to our collective benefit.  I see all pain and no gain.

                        Thanks again for the info.  I'll write more after reviewing the above links.

                        •  Another interesting bit of info (0+ / 0-)

                          Here is an article I found that again points out the inaccuracies of surface temps and the misinterpretation of the data it does collect:

                          http://money.cnn.com/...

                          It also mentions, as do many other similar articles, that, for the cost demanded, there is little to no benefit of imposing all these CO2 restrictions on the US.

                          Thought you would be interested.

  •  Thank you (2+ / 0-)
    Recommended by:
    RunawayRose, alefnot

    I will have to read this several more times to even begin to understand some of it, but I appreciate the time and effort you put into this!

  •  This is great (3+ / 0-)
    Recommended by:
    RunawayRose, alefnot, kirbybruno

    I have read many expositions of basic energy budget, and this is one of the best I've seen. I intend to bookmark it and use it as a reference when I need to provide people with a thorough explanation of the energy budget.

    Thanks much!

  •  I seem to recall reading (2+ / 0-)
    Recommended by:
    RunawayRose, kirbybruno

    that in the lower atmosphere, water vapor and some level of CO2 well below current levels was effectively "saturated" in terms of trapping energy and that an increase in GHGs there would have little if any effect. However, the principle driver of increasing temperature was increasing CO2 concentrations in the upper atmosphere (which all still comes from the same sources anyway, so it's makes little difference in terms of fixing the problem).

    As I recall, the article was essentially a history of theories about the greenhouse effect (derived from trying to explain how ice ages were possible), and the greenhouse effect lacked solid footing until the science about upper atmosphere effects was resolved.

    Is that essentially correct?

    Je suis Marxiste, tendance Groucho

    by badger on Tue Apr 21, 2009 at 04:56:17 PM PDT

    •  It depends a lot on latitude (4+ / 0-)
      Recommended by:
      badger, RunawayRose, alefnot, kirbybruno

      I won't address the upper atmosphere effect; for now I'll concentrate on just the lower atmosphere effect because it's easier to explain and I'm lazy. Yes, in the tropics, there's so much water vapor in the atmosphere that we see little effect from CO2. The polar regions, however, have very low water vapor concentrations and so water vapor has very little greenhouse effect in the polar regions. This is where we would expect to see the largest effects of CO2 increases, and in fact the data bears this out: the biggest temperature increases are in the Arctic.

      •  Albedo more important (2+ / 0-)
        Recommended by:
        badger, RunawayRose

        You do get more radiative cooling at the poles, and there is "meridional" heat transport (energy from tropics exported to poles) but that's more an atmospheric circulation thing. It's basically always true, even when temperatures are steady.

        The change that's so strong in polar regions is dominated by the ice albedo feedback.

    •  Look at the atmospheric absorption plot (2+ / 0-)
      Recommended by:
      badger, RunawayRose

      The plot is absorption for the whole column (surface to TOA). The window overlaps well with planetary radiation and prevents us from becoming Venus. There are some lines which are pretty much saturated (absorption goes to 100%) but it doesn't cover all of the IR where the Earth is radiating.

    •  Energy escapes from the edge of the atmosphere (2+ / 0-)
      Recommended by:
      badger, alefnot

      ...sometimes going straight through from earth's surface, sometimes after being absorbed and reradiated many times. Radiation heading up, if absorbed, is reradiated in a random direction and may come back to ground level. More CO2 in the thin upper atmosphere retards the escape of energy, although all wavelengths up there can escape. The rate of energy leaving earth through the "surface" of the atmosphere is the key factor regardless of saturation down below. Similarly, the rate of escape of energy from the surface of the sun determines the temperature deep down. And if escape of energy from the earth's crust could be retarded, heat would build up until there was an extreme volcano.

  •  You've Been Rescued (1+ / 0-)
    Recommended by:
    dufffbeer

    "What the cynics fail to understand is that the ground has shifted beneath them"

    by ItsJessMe on Wed Apr 22, 2009 at 08:21:08 PM PDT

  •  I dunnoooo...I'm still not convinced **snark** (1+ / 0-)
    Recommended by:
    dufffbeer

    Excellent diary!

    It's a grift. They probably had grifter parents and grifter grandparents and someday they'll each spawn little grifter kids.

    by Muskegon Critic on Wed Apr 22, 2009 at 09:03:08 PM PDT

  •  letter to congress (3+ / 0-)
    Recommended by:
    Xapulin, dufffbeer, alefnot

    I wrote this letter to my representatives in Congress. I want people to know the younger generation (my generation) cares about environmental issues and is not a bunch of slackers. Please tell me what you think:

    Dear Congress,
    My name is Daniel Knickelbein and I am 17 year-old high school student from Oak Park, Illinois. I guess you could call me an “environmentalist,” based on the fact that I believe that global warming is a serious threat to mankind and I believe in the conservation of natural lands and resources in their purest form. But I don’t think I can be labeled as a crazy left-winger because, well, who doesn’t like clean water, or land available for fishing or hiking, or restoring natural forests to their original beauty.
    The reason I am writing this letter is because I believe that starting TODAY, the United States Congress must act to pass serious climate change legislation, and must also recognize that we must conserve the few natural lands we still have left in this country.
    The science on global warming is unmistakable. When 97 percent of climatologists in this country believe that global warming is man-made and will have serious effects on our world, we must act to do something about that. It is unfathomable to me how some of you in Congress can not address this issue, while you sit and bicker about party ideals.
    For those who say that addressing climate change and global warming will hurt the economy, you must think again. As many economists and scientists point out, a “green” economy is an investment in the future, sort of like beginning to tackle the large deficit that has been passed down by many presidents. Now some of you skeptics will say that I am an affluent suburban teenager who has no idea what it is like to experience financial hardship that you say will be cause by tackling global warming. Please think again. My father was a chemist employed at his dream job for 20 years, but when the recession hit, his lab was forced to fire him because of lack of funding. While I am currently by no means poor, my father’s misfortune has left our family in a somewhat difficult situation.
    Now, we have any opportunity to help millions of other Americans like my father. If our country (you guys and girls in Congress) decide to invest in my future with green technologies, my father might be able to work again. And yes investing in renewable energy and green technology is MY future. Long after all 535 of you are gone, I would like to live in a safe and prosperous planet, not a planet where I have to worry about where I find my next meal, or my next glass of water. If we continue to allow global warming to go unchecked, that scenario is not exactly science fiction, it could and very well may become reality.
    So today, on the 39th Earth Day, I ask every single member of Congress to consider their priorities as some of the most powerful people in the United States. Do you wish to leave your children and grandchildren in a safe and prosperous world? Should we leave them in a place that is dangerous and unhealthy? Should we allow the few remaining natural lands to be destroyed for a profit? These are questions that I hope you will consider when voting on a climate change bill. The only thing I ask of all of you is to please read my letter, and to consider what I have said.
    I also want to give thanks to every single one of you for the service you do for your country. I am very lucky to be able to live in a country where I can write this letter freely, and a country where I am able to express my opinions without afterthought.
    Please consider what I have said in this letter.
    Sincerely,
    Daniel Knickelbein

    •  great letter (0+ / 0-)

      sorry to hear about your dad

      "I'm going to be on you like a numerator on a denominator." -Principal Skinner

      by dufffbeer on Wed Apr 22, 2009 at 09:35:25 PM PDT

      [ Parent ]

    •  Thank you very much (0+ / 0-)

      For good or ill, this is really going to end up in the laps of the younger generation. The timescales involved are such that the longer we put off dealing with it, the more difficult and expensive it becomes to deal with the consequences. So keep pressure on them, and get people you know involved.

  •  Good info (0+ / 0-)

    I would like to see the temperature graph from 2000 to 2009. Isn't it curently going down? Based on my research I simply see no measurable anthropogenic effect.

    •  It's bouncing around a plateau (1+ / 0-)
      Recommended by:
      Lava20

      with very large excursions. 2005 was the warmest year on record, and most of the ten warmest years on record were in the last 2 decades. Even if you want to claim 1998 and 2005 were outliers, most of the warmest years on record have taken place in that time. Here's a plot. (2009 data obviously aren't available yet).

      There are fluctuations on a number of timescales, and in the last 50 years there have been a number of 5-year spans with decreases and others with very sharp increases. You cannot use either trend to project the larger trend, which is significant warming. Similarly, you cannot extrapolate from the larger trend to say anything about the future: any such statement must be based on physical and chemical mechanisms, not on correlation.

    •  If by research you mean memorizing Faux News (2+ / 0-)
      Recommended by:
      Mike S, BlueInARedState

      talking points verbatum, then good job, banned moran troll.

      "Life is what happens to you while you're busy making other plans." John Lennon

      by trashablanca on Thu Apr 23, 2009 at 03:29:29 PM PDT

      [ Parent ]

  •  Thanks for a great presentation... (1+ / 0-)
    Recommended by:
    alefnot

    of a very complicated subject.  I'm saving the link for future reference, since my brain has a fairly high albedo (so to speak.)  But as the first couple commenters discussed, this provides a lot of background into the many factors that affect climate, and which ones we are affecting.
    I learned some interesting things this morning and I thank you for that.

  •  Thanks (0+ / 0-)

    Very good piece.

    Mind if I crosspost it to GESN!!!?

  •  Great Diary (1+ / 0-)
    Recommended by:
    alefnot

    Alefnot you have done a great job here.  I encourage those who want to get into the nitty gritty details to go over to realclimate.org.  I was lucky enough to work for a time on the JOIDES Resolution in the mid 90's and talk with some of the scientists who were nailing down (among other things) the fact that an asteroid did hit 65 million years ago and wipe out the dinosaurs.  Several of them were also working on correlating various things found in deep ocean cores with climate and discussions with them clinched the reality of global warming for me.  With regard to mitigation vs adpation, this is not a matter of getting used to spring starting a month earlier.  Think what happens to major cities if the ocean comes up 4 to 5 feet.  Think what happens to our food production if rainfall drops a few inches in the midwest and it is 3 degrees warmer.  And lastly, as discussed in this month's Scientific American, think what happens if 30 or 40 nations fail and turn into Somalia because of economic dislocations and inability to grow food anymore.  In my mind, global warming is the main challenge humanity faces over the next 200 years.

    •  RealClimate an excellent source (0+ / 0-)

      I find they can get dismissive and snippy at times (even as I sometimes sympathize), but the science is sound and they provide literature references.

      •  Yeah, they do (0+ / 0-)

        get a little dismissive at times.  But, the same trolls show up saying the same crap day after day.  I know it would drive me nuts.  Anyway, good job again, when are you going to post round 2?

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