Stratospheric water vapor may have contributed about a third of the warming 1980-2000 but now is in decline

Don’t Ignore Nature

From the Global Warming Policy Foundation by Dr. David Whitehouse

How many times have you seen, read or heard some climate ‘expert’ or other say that mankind’s greenhouse gas emissions are largely responsible for the unprecedented warming we have seen over the past century, and especially what we have seen over the past 30 years. It is as if to some that nature has stepped back leaving mankind to take over the climate. In reality, whatever one’s predictions for the future, such claims are gross exaggerations and misrepresentations. Natural and human climate influences mingle and even today natural effects dominate.

I’ve been reading the paper by Hurst et al on measurements of Stratospheric Water vapour (SWV) over Colorado. In the past year or so SWV has become a very interesting topic in climate science as it is clear that small variations in SWV play a larger role in the Earth’s radiation budget than had been supposed.

Solomon et al looked at variations in SWV and concluded that it had been declining since about 2000 and this decline may have partly compensated for the temperature rise expected in the past decade due to AGW. It can’t be the only cooling factor involved that has kept the global annual average temperature constant within the errors for the past decade.

For me, there was another conclusion drawn in the Solomon paper that fascinated me, albeit at a lower level of statistical confidence (but still respectable.) It is that the data show that SWV started to increase around 1980 and continued to increase until about 2000 and that it may have contributed about a third of the warming observed in that period.

A third is no small factor and yet another indication that we are finding out new things about climate change all the time that belie the claim that the science is settled.

Looking at HadCrut3 the temperature rise seen since 1980 is about 0.5 degree C with, I suppose, an uncertainty of about 0.05 deg C either way. Removing the SWV component brings that down to about 0.35 deg C which is less than the global temperature rise seen between 1910 and 1940. So much for the claim that the recent warm spell has seen temperature rises that are unprecedented. If the SWV contribution is correct its removal has another ramification. It takes the current global temperature to below that of the Medieval Warm Period (MWP). (I know some argue that the MWP was not global to which I would counter that new research shows a much wider influence for the MWP than once supposed. I would also point out that today’s warming is likewise patchy and not globally uniform.)

But what else has been going on since 1980?

The variations that occur in the Earth’s climate over such periods are called decadal changes and their study is in its infancy. Climate models only capture some aspects of observed decadal variations.

The observed global temperature is clearly a mixture of various influence occurring over various timescales. The sun has a a decadal influence of about 0.1 deg C (some solar physicists say slightly larger) and the exact nature of that influence is uncertain given the recent paper by Haigh et al describing the effect of differential spectral variations from the sun on the earth’s atmosphere. Despite this – for I think the jury is still out – 0.1 deg C seems to be a good ballpark figure that is often quoted as the major  climate driver before 1950. Clearly, whenever AGW became dominant (1960- 80 according to the IPCC), the sun’s influence did not suddenly go away, especially at a time of historically high solar activity. Scafetta and West maintain that the sun can account for 25 – 30% (possibly more) of the temperature rise since 1980 starting an interesting debate.

So perhaps we can conservatively account for another 0.1 deg C per decade since 1980 which, in our hypothetical game of accounting for the recent changes on Earths temperature might account for up to 0.2 deg C, leaving about 0.2 deg C unattributed since 1980.

So what else happened around 1980?

The North Atlantic Oscillation went strongly positive around 1980, and so did a few years later the Pacific Decadal Oscillation. The scientific literature contains a range of estimates of the influences of these factors but, again being conservative, 0.1 deg C for both of them doesn’t seem too outrageous.

With the NAO and PDO we are down in the noise of the post-1980 warming period having only considered four factors. There are many more that will have exerted a warming or cooling influence since 1980, including AGW.

Clearly things are not that simple. The spatial patterns of climate variations have to be considered and compared to what is being seen today although there exists considerable uncertainties in interpretation. Since 1910 warming has been more extensive over land than over the ocean, where it has been relatively homogenous, except for some weak cooling in the North Atlantic and some extra warming in some parts of the Southern Ocean.

Whatever is happening with decadal fluctuations, the temperature of the Earth has to start increasing. The current explanations for the standstill seen in the past decade or so are wearing thin. At issue isn’t wether CO2 is a greenhouse gas, or that it’s accumulating in the atmosphere, or that the world has warmed. What is at issue are questions of climate sensitivity, feedback mechanisms and the relative strengths of other variations.

Have we just lived through a period where a handful of natural decadal and longer variations have conspired to act in the same direction pushing temperatures up? When I read a peer-reviewed paper in a major journal (Solomon’s paper was published in Science) that plucks from the air an explanation for a third of the warming seen since 1980 via a previously little regarded mechanism, I begin to wonder.

Feedback: david.whitehouse@thegwpf.org

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29 thoughts on “Stratospheric water vapor may have contributed about a third of the warming 1980-2000 but now is in decline

  1. This implies that we must evaluate the contribution of the water vapor from the exhaust of high altitude jet aircraft.

  2. At issue isn’t wether CO2 is a greenhouse gas, or that it’s accumulating in the atmosphere, or that the world has warmed. What is at issue are questions of climate sensitivity, feedback mechanisms and the relative strengths of other variations.

    This is the money paragraph of the whole essay. In fact, it’s the money paragraph for the whole of the AGW debate. Spending trillions of dollars to mitigate an issue we barely understand is a fool’s mission. I cannot understand why more people are not up-in-arms at the incredible economic investments being proposed to fix a problem we don’t even know exists.

    And when we get to geo-engineering, then we really are skidding down a fool’s path – one we would surely regret . . .

  3. To me the data indicates that the rising temperatures in the 1980-2000 period were responsible for the increase in water vapour content through warming of the oceans. The rising temperatures were almost certainly due to factors external to the atmosphere and had very little to do with carbon dioxide or water vapour.

  4. theBuckWheat says:
    April 6, 2011 at 8:27 am
    This implies that we must evaluate the contribution of the water vapor from the exhaust of high altitude jet aircraft.

    Surprisingly few aircraft operate much above the tropopause as the engines become less efficient in less dense air remaining at or below the airframe limiting Mach number.

  5. “Ron Dean says:
    April 6, 2011 at 9:14 am”

    It’s only a fools’ mission if you are stuck on the payee’s side of the “carbon” (Tax, ETS whatever) issue, ie, the likes of you and I, which we have no real control over. Your observation is spot on however.

  6. I find it difficult reading articles that use the term “climate change” when “man made global warming” cant be used.

    It’s clear that “climate change” is a term that is been used to confuse people into believing in the man made global warming theory! the term “climate change” no longer means the changes in climate or climatic change, It means Anthropogenic global warming.

    The climatic change of the past 10 years has been what? global warming?, global cooling? What ever it is, It is called “climate change” ergo Man made global warming”.

    Confusing semantics!!

  7. For those who don’t subscribe to Science, here’s the full link to the Solomon research paper:

    http://www.climate.unibe.ch/~plattner/papers/solomon10sci.pdf

    Well worth the read. Stratospheric water vapor does indeed play an important role in modulation tempertures and, as the Solomon paper clearly outlines, there are many factors involved in SWV, with (as in we are dealing with a chaotic system) many interrelated feedback processes. Just to begin to get a handle on this, the Solomon paper is a great place to start, and it concludes with this excellent on-target statement:

    “This work highlights the
    importance of using observations to evaluate the
    effect of stratospheric water vapor on decadal
    rates of warming, and it also illuminates the need
    for further observations and a closer examination
    of the representation of stratospheric water vapor
    changes in climate models aimed at interpreting
    decadal changes and for future projections.”

  8. Co2, you may have been much maligned.

    Dr James Hansen et. al. – PNAS August 29, 2000
    “A common view is that the current global warming rate will continue or accelerate. But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols, the positive and negative climate forcings of which are partially offsetting. ”

    http://www.pnas.org/content/97/18/9875.full

  9. “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t”.

    Reminds me of that quote from the climate-gate emails.

  10. If the rise in the land based instrument record is mainly UHI, then that water vapor is responsible for 200% of the global rise in temperature?
    If you add up all the claimed positive forcings you get way more warming than reality and each study ignores the claimed forcings that don’t fit their theory and cherry pick the forcings that “prove” they are right. Hardly anyone in the warming camp are looking at negative feedbacks.
    So we end up with a bunch of theoretical warming signals that have no negitive feedbacks that can be picked and matched like corn and fried chicken at Hometown Buffet.

    More “Stratospheric water vapor” whoopie, lets write a paper. Meh!

  11. I guess it hasn’t been noticed before but Solomon’s stratospheric water vapour data covers exceedingly small areas. The chart at the beginning of the post is just for 35-45N (the latitude Boulder Colorado is in).

    One has to read the footnotes on the charts to see what was actually done here but this should not be considered as representative of global stratospheric water vapour levels.

    In another chart from Solomon’s paper, they are trying to match the SSTs in the Pacific Warm Pool area, north of New Guinea, to the water vapour levels measured over the Nino 3.4 regions in the eastern side of Pacific. These two areas are known to be anti-correlated (in terms of both temperature and water vapour levels). Why would they use two regions which have opposite signs most of the time?

    If one uses just the stratospheric water vapour levels from 10N to 10S shown in the paper, it is strongly correlated to the ENSO. In using the Pacific Warm Pool SST measurements as the index to correlate to, all they found was a drop in water vapour levels starting about 2000 (just as a strong La Nina was entering its second year).

    Almost climate science papers are like this. One has to very carefully read what was done and then a different explanation becomes apparent.

  12. Hi David!
    I’ve been looking at some data from Marion island.

    http://www.btinternet.com/~sa_sa/marion_island/marion_island.html

    it lies south of South Africa, in the South Indian Ocean
    Note that it has a lot of weather, which is why I wanted to study those particular data.
    In my opinion this is a good example of an average place on earth.
    My findings so far, over the past 35 years (for which I have data):

    Average mean temps. have stayed the same (0.00 degreeC/annum) – so heat content must have stayed the same.
    Max. temps. have been rising at a rate of 0.05 degrees C/annum, taken on average
    Min. temps have declined by 0.02 degrees C, per annum, taken on average..
    Average mean humidity has declined at a rate of 0.12% per annum
    Total monthly precipitation (rainfall) has declined by 1.27 mm per annum, taken on average.
    What do you (or anyone else here) make of these findings?

  13. theBuckWheat says on April 6, 2011 at 8:27 am:

    This implies that we must evaluate the contribution of the water vapor from the exhaust of high altitude jet aircraft.

    Ian W says on April 6, 2011 at 9:19 am:

    Surprisingly few aircraft operate much above the tropopause as the engines become less efficient in less dense air remaining at or below the airframe limiting Mach number.

    The big jets usually cruise above the tropopause at about 35,000 to 40,000 ft.

    For a long int flight, a Boeing 747 takes off with about 157,000 kg of fuel which will produce upon combustion about 494,000 kg of CO2 and 202,000 kg of water.

    The hot exhaust gases will rise to higher altitudes, and the water vapor which initially condenses to produce water droplets as seen as contrails will eventually evaporates.

    The tropopause is a barrier that retards mass exchange between the tropopause and the stratosphere.

    So the questions is: How long does this CO2 and OH2 hang around in the stratosphere?

    Another question is: How much of the upper atmospheric gases escapes thru the “holes” punched in tropopause as the jet flies from the troposphere into the stratosphere on ascent and from the stratosphere to the troposphere on descent?

    I posted a smililar comment over at SOD a few days and it got whacked.

    The CO2 and OH2 deposited in the stratosphere should cause some “extra heating” as these would absorbed some OLR.

  14. I thought this was predicted by Ferenc Miskolczi’s theory of a self adjusting saturated atmosphere, as CO2 goes up, water vapor decreases, without a net change in temperature.. he argued that the temperature rise seen was due to other factors.

  15. The graph starts at 1980, so they don’t know if there was a change during the 1970-1980 cool-to-warm shift?

  16. Have we just lived through a period where a handful of natural decadal and longer variations have conspired to act in the same direction pushing temperatures up?

    If the above is true, then that same handful of natural decadal and longer variations are all set up to deliver the exact opposite, and in relatively short order.

  17. Just a dumb question:

    Is it vice versa?
    Could the falling levels be caused by a cooling earth?

  18. “At issue isn’t wether CO2 is a greenhouse gas, or that it’s accumulating in the atmosphere, or that the world has warmed. What is at issue are questions of climate sensitivity, feedback mechanisms and the relative strengths of other variations.”

    Nicely said. You have got it in a nutshell. The IPCC knows this, its “very low level of scientific understanding” graphic shows how much is unknown. It is clear CO2 has some role to play, but it is totally unknown what that role constitutes.

  19. Here’s the graph (again) of solar activity vs specific humidity according to radiosonde data. Perhaps others will eventually make the same connection I did.

  20. Looking at HadCrut3 the temperature rise seen since 1980 is about 0.5 degree C

    Great posting… great research… great thinking…
    BUT
    Connections (and correlations) with the official temperature records may be overstated and/or understated and/or reversed because the official temperature records have been filleted, cooked and half-baked by the AGW Team chefs… this probably also applies to the official CO2 records… and other official records.

  21. CO2 has nothing measurable to do with “climate”, warming or cooling, except that crop yields are up considerable since circa 1945. Are chemistry and physics no longer taught in high school and college/university?

    A non-linear chaotic system is not predictable . . . whatever type of Tarot cards are used. Cut off the ugly head of government grants, and the issue would quickly go away.

  22. “What else has been going on since 1980″

    How about the phase out of leaded gasoline, and the cleanup of “acid rain”?

  23. tallbloke says:
    April 7, 2011 at 7:59 am
    Here’s the graph (again) of solar activity vs specific humidity according to radiosonde data. Perhaps others will eventually make the same connection I did.

    Crikey – Specific Humidity is controlling the number of sun spots!

  24. Why is it that CO2 gets all the attention when the primary byproduct of burning gasoline and natural gas is water vapor? Both are greenhouse gases but CO2 is seen as the real culprit. Maybe it would be a little more difficult to outlaw water. At least it is getting some attention here for a change.

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