Last year I posted an analysis of satellite observations of the 2007-08 global cooling event, showing evidence that it was due to a natural increase in low cloud cover. Here I will look at the bigger picture of what how the satellite-observed variations in Earth’s radiative budget compare to that expected from increasing carbon dioxide. Is there something that we can say about the relative roles of nature versus humanity based upon the evidence?

What we will find is evidence consistent with natural cloud variations being the dominant source of climate variability since 2000.

CERES Observations of Global Energy Budget Changes
The following graph shows the variations in the Earth’s global-average radiative energy balance as measured by the CERES instrument on NASA’s Terra satellite. These are variations in the imbalance between absorbed sunlight and emitted infrared radiation, the most fundamental quantity associated with global warming or global cooling. Also show (in red) are theoretically calculated changes in radiative forcing from increasing carbon dioxide as measured at Mauna Loa.

Since there is some uncertainty in the absolute accuracy of the CERES measurements, where one puts the zero line is also somewhat uncertain. Therefore, it’s the variations since 2000 which are believed to be pretty accurate, and the exact dividing line between Earth gaining energy and Earth losing energy is uncertain. Significantly, all of the downward trend is in the reflected sunlight portion, not the infrared portion of the variations. We similarly can not reference where the zero line should be for the CO2 forcing, but the reasons for this are more complex and I will not address them here.

In order to compare the variations in the CO2 forcing (in red) to the satellite observations, we need to account for the fact that the satellite observes forcing and feedback intermingled together. So, let’s remove a couple of estimates of feedback from the satellite measurements to do a more direct comparison.

Inferred Forcing Assuming High Climate Sensitivity (IPCC View)
Conceptually, the variations in the Earth’s radiative imbalance are a mixture of forcing (e.g. increasing CO2; clouds causing temperature changes), and feedback (e.g. temperature changes causing cloud changes). We can estimate the forcing part by subtracting out the feedback part.

First, let’s assume that the IPCC is correct that climate sensitivity is pretty high. In the following chart I have subtracted out an estimate of the feedback portion of the CERES measurements based upon the IPCC 20-model average feedback parameter of 1.4 W m^-2 K^-1 times the satellite AMSU-measured tropospheric temperature variations

As can be seen, the long-term trend in the CERES measurements is much larger than can be accounted for by increasing carbon dioxide alone, which is presumably buried somewhere in the satellite-measured signal. In fact, the satellite observed trend is in the reflected sunlight portion, not the infrared as we would expect for increasing CO2 (not shown).

Inferred Forcing Assuming Low Climate Sensitivity (“Skeptical” View)
There has been some published evidence (our 2007 GRL paper, Lindzen & Choi’s 2009 paper) to suggest the climate system is quite insensitive. Based upon that evidence, if we assume a net feedback parameter of 6 W m^-2 K^-1 is operating during this period of time, then removing that feedback signal using AMSU channel 5 yields the following history of radiative forcing:

As can be seen, the relative size of the natural forcings become larger since more forcing is required to cause the same temperature changes when the feedback fighting it is strong. Remember, the NET feedback (including the direct increase in emitted IR) is always acting against the forcing…it is the restoring force for the climate system.

What this Might Mean for Global Warming
The main point I am making here is that, no matter whether you assume the climate system is sensitive or insensitive, our best satellite measurements suggest that the climate system is perfectly capable of causing internally-generated radiative forcing larger than the “external” forcing due to increasing atmospheric carbon dioxide concentrations. Low cloud variations are the most likely source of this internal radiative forcing. It should be remembered that the satellite data are actually measured, whereas the CO2 forcing (red lines in the above graphs) is so small that it can only be computed theoretically.

The satellite observed trend toward less energy loss (or, if you prefer, more energy gain) is interesting since there was no net warming observed during this time. How could this be? Well, the satellite observed trend must be due to forcing only since there was no warming or cooling trend during this period for feedback to act upon. And the lack of warming from this substantial trend in the forcing suggests an insensitive climate system.

If one additionally entertains the possibility that there is still considerable “warming still in the pipeline” left from increasing CO2, as NASA’s Jim Hansen claims, then the need for some natural cooling mechanism to offset and thus produce no net warming becomes even stronger. Either that, or the climate system is so insensitive to increasing CO2 that there is essentially no warming left in the pipeline to be realized. (The less sensitive the climate system, the faster it reaches equilibrium when forced with a radiative imbalance.)

Any way you look at it, the evidence for internally-forced climate change is pretty clear. Based upon this satellite evidence alone, I do not see how the IPCC can continue to ignore internally-forced variations in the climate system. The evidence for its existence is there for all to see, and in my opinion, the IPCC’s lack of diagnostic skill in this matter verges on scientific malpractice.

I am still receiving questions about the method by which the satellite microwave measurements are calibrated to get atmospheric temperatures. The confusion seems to have arisen because Christopher Monckton has claimed that our satellite data must be tied to the surface thermometer data, and after Climategate (as well all know) those traditional measurements have become suspect. So, time for a little tutorial.

NASA’S AQUA SATELLITE
The UAH global temperatures currently being produced come from the Advanced Microwave Sounding Unit (AMSU) flying on NASA’s Aqua satellite. AMSU is located on the bottom of the spacecraft (seen below); the AMSR-E instrument that I serve as the U.S. Science Team Leader for is the one on top of the satellite with the big dish.

Aqua has been operational since mid-2002, and is in a sun-synchronous orbit that crosses the equator at about 1:30 am and pm local solar time. The following image illustrates how AMSU, a cross-track scanner, continuously paints out an image below the spacecraft (actually, this image comes from the MODIS visible and infrared imager on Aqua, but the scanning geometry is basically the same):

HOW MICROWAVE RADIOMETERS WORK
Microwave temperature sounders like AMSU measure the very low levels of thermal microwave radiation emitted by molecular oxygen in the 50 to 60 GHz oxygen absorption complex. This is somewhat analogous to infrared temperature sounders (for instance, the Atmospheric InfraRed Sounder, AIRS, also on Aqua) which measure thermal emission by carbon dioxide in the atmosphere.

As the instrument scans across the subtrack of the satellite, the radiometer’s antenna views thirty separate ‘footprints’, nominally 50 km in diameter, each over over a 50 millisecond ‘integration time’. At these microwave frequencies, the intensity of thermally-emitted radiation measured by the instrument is directly proportional to the temperature of the oxygen molecules. The instrument actually measures a voltage, which is digitized by the radiometer and recorded as a certain number of digital counts. It is those digital counts which are recorded on board the spacecraft and then downlinked to satellite tracking stations in the Arctic.

HOW THE DATA ARE CALIBRATED TO TEMPERATURES
Now for the important part: How are these instrument digitized voltages calibrated in terms of temperature?

Once every Earth scan, the radiometer antenna looks at a “warm calibration target” inside the instrument whose temperature is continuously monitored with several platinum resistance thermometers (PRTs). PRTs work somewhat like a thermistor, but are more accurate and more stable. Each PRT has its own calibration curve based upon laboratory tests.

The temperature of the warm calibration target is allowed to float with the rest of the instrument, and it typically changes by several degrees during a single orbit, as the satellite travels in and out of sunlight. While this warm calibration point provides a radiometer digitized voltage measurement and the temperature that goes along with it, how do we use that information to determine what temperatures corresponds to the radiometer measurements when looking at the Earth?

A second calibration point is needed, at the cold end of the temperature scale. For that, the radiometer antenna is pointed at the cosmic background, which is assumed to radiate at 2.7 Kelvin degrees. These two calibration points are then used to interpolate to the Earth-viewing measurements, which then provides the calibrated “brightness temperatures”. This is illustrated in the following graph:

The response of the AMSU is slightly non-linear, so the calibration curve in the above graph actually has slight curvature to it. Back when all we had were Microwave Sounding Units (MSU), we had to assume the instruments were linear due to a lack of sufficient pre-launch test data to determine their nonlinearity. Because of various radiometer-related and antenna-related factors, the absolute accuracy of the calibrated Earth-viewing temperatures are probably not much better than 1 deg. C. While this sounds like it would be unusable for climate monitoring, the important thing is that the instruments be very stable over time; an absolute accuracy error of this size is irrelevant for climate monitoring, as long as sufficient data are available from successive satellites so that the newer satellites can be calibrated to the older satellites’ measurements.

WHAT LAYERS OF THE ATMOSPHERE ARE MEASURED?
For AMSU channel 5 that we use for tropospheric temperature monitoring, that brightness temperature is very close to the vertically-averaged temperature through a fairly deep layer of the atmosphere. The vertical profiles of each channel’s relative sensitivity to temperature (‘weighting functions’) are shown in the following plot:

These weighting functions are for the nadir (straight-down) views of the instrument, and all increase in altitude as the instrument scans farther away from nadir. AMSU channel 5 is used for our middle tropospheric temperature (MT) estimate; we use a weighted difference between the various view angles of channel 5 to probe lower in the atmosphere, which a fairly sharp weighting function which is for our lower-tropospheric (LT) temperature estimate. We use AMSU channel 9 for monitoring of lower stratospheric (LS) temperatures.

For those channels whose weighting functions intersect the surface, a portion of the total measured microwave thermal emission signal comes from the surface. AMSU channels 1, 2, and 15 are considered “window” channels because the atmosphere is essentially clear, so virtually all of the measured microwave radiation comes from the surface. While this sounds like a good way to measure surface temperature, it turns out that the microwave ’emissivity’ of the surface (it’s ability to emit microwave energy) is so variable that it is difficult to accurately measure surface temperatures using such measurements. The variable emissivity problem is the smallest for well-vegetated surfaces, and largest for snow-covered surfaces. While the microwave emissivity of the ocean surfaces around 50 GHz is more stable, it just happens to have a temperature dependence which almost exactly cancels out any sensitivity to surface temperature.

POST-PROCESSING OF DATA AT UAH
The millions of calibrated brightness temperature measurements are averaged in space and time, for instance monthly averages in 2.5 degree latitude bands. I have FORTRAN programs I have written to do this. I then pass the averages to John Christy, who inter-calibrates the different satellites’ AMSUs during periods when two or more satellites are operating (which is always the case).

The biggest problems we have had creating a data record with long-term stability is orbit decay of the satellites carrying the MSU and AMSU instruments. Before the Aqua satellite was launched in 2002, all other satellites carrying MSUs or AMSUs had orbits which decayed over time. The decay results from the fact that there is a small amount of atmospheric drag on the satellites, so they very slowly fall in altitude over time. This leads to 3 problems for obtaining a stable long-term record of temperature.

(1) Orbit Altitude Effect on LT The first is a spurious cooling signal in our lower tropospheric (LT) temperature product, which depends upon differencing measurements at different view angles. As the satellite falls, the angle at which the instrument views the surface changes slightly. The correction for this is fairly straightforward, and is applied to both our dataset and to the similar datasets produced by Frank Wentz and Carl Mears at Remote Sensing Systems (RSS). This adjustment is not needed for the Aqua satellite since it carries extra fuel which is used to maintain the orbit.

(2) Diurnal Drift Effect The second problem caused by orbit decay is that the nominal local observation time begins to drift. As a result, the measurements can increasingly be from a warmer or cooler time of day after a few years on-orbit. Luckily, this almost always happened when another satellite operating at the same time had a relatively stable observation time, allowing us to quantify the effect. Nevertheless, the correction isn’t perfect, and so leads to some uncertainty. [Instead of this empirical correction we make to the UAH products, RSS uses the day-night cycle of temperatures created by a climate model to do the adjustment for time-of-day.] This adjustment is not necessary for the Aqua AMSU.

(3) Instrument Body Temperature Effect. As the satellite orbit decays, the solar illumination of the spacecraft changes, which then can alter the physical temperature of the instrument itself. For some unknown reason, it turns out that most of the microwave radiometers’ calibrated Earth-viewing temperatures are slightly influenced by the temperature of the instrument itself…which should not be the case. One possibility is that the exact microwave frequency band which the instrument observes at changes slightly as the instrument warms or cools, which then leads to weighting functions that move up and down in the atmosphere with instrument temperature. Since tropospheric temperature falls off by about 7 deg. C for every 1 km in altitude, it is important for the ‘local oscillators’ governing the frequency band sensed to be very stable, so that the altitude of the layer sensed does not change over time. This effect is, once again, empirically removed based upon comparisons to another satellite whose instrument shows little or no instrument temperature effect. The biggest concern is the long-term changes in instrument temperature, not the changes within an orbit. Since the Aqua satellite does not drift, the solar illumination does not change and and so there is no long-term change in the instrument’s temperature to correct for.

One can imagine all kinds of lesser issues that might affect the long-term stability of the satellite record. For instance, since there have been ten successive satellites, most of which had to be calibrated to the one before it with some non-zero error, there is the possibility of a small ‘random walk’ component to the 30+ year data record. Fortunately, John Christy has spent a lot of time comparing our datasets to radiosonde (weather balloon) datasets, and finds very good long-term agreement.

YR MON GLOBE NH SH TROPICS
2009 1 +0.304 +0.443 +0.165 -0.036
2009 2 +0.347 +0.678 +0.016 +0.051
2009 3 +0.206 +0.310 +0.103 -0.149
2009 4 +0.090 +0.124 +0.056 -0.014
2009 5 +0.045 +0.046 +0.044 -0.166
2009 6 +0.003 +0.031 -0.025 -0.003
2009 7 +0.411 +0.212 +0.610 +0.427
2009 8 +0.229 +0.282 +0.177 +0.456
2009 9 +0.422 +0.549 +0.294 +0.511
2009 10 +0.286 +0.274 +0.297 +0.326
2009 11 +0.497 +0.422 +0.572 +0.495
2009 12 +0.280 +0.318 +0.242 +0.503

The global-average lower tropospheric temperature anomaly fell back to the October level of +0.28 deg. C in December. The tropics continue warm from El Nino conditions there, while the NH and SH extratropics anomalies cooled from last month. While the large amount of year-to-year variability in global temperatures seen in the above plot makes it difficult to provide meaningful statements about long-term temperature trends in the context of global warming, the running 25-month average suggests there has been no net warming in the last 11 years or so.

[NOTE: These satellite measurements are not calibrated to surface thermometer data in any way, but instead use on-board redundant precision platinum resistance thermometers carried on the satellite radiometers.]

(edited 1 p.m. Dec. 31, 2009, to mention latent heat release)

The climate of the Earth is profoundly affected by two competing processes: the greenhouse effect, which acts to warm the lower atmosphere and cool the upper atmosphere, and atmospheric convection (thermals, clouds, precipitation) which does just the opposite: cools the lower atmosphere and warms the upper atmosphere.

To better understand why this happens, it is an instructive thought experiment to ask the question: What if there was no greenhouse effect? In other words, what if there were no infrared absorbers such as water vapor and carbon dioxide in the atmosphere?

While we usually only discuss the greenhouse effect in the context of global warming (that is, the theory that adding more carbon dioxide to the atmosphere will lead to higher temperatures in the lower atmosphere), it turns out that the greenhouse effect has a more fundamental role: there would be no weather on Earth without the greenhouse effect.

First, the big picture: The Earth surface is warmed by sunlight, and the surface and atmosphere together cool by infrared radiation back to outer space. And just as a pot of water warming on the stove will stop warming when the rate of energy gained by the pot from the stove equals the rate of energy loss by the pot to its surroundings, an initially cold Earth would stop warming when the rate at which solar energy is absorbed equals the rate at which infrared energy is lost by the whole Earth-atmosphere system to space.

So, let’s imagine an extremely cold Earth and atmosphere, without any water vapor, carbon dioxide, methane or any other greenhouse gases – and with no surface water to evaporate and create atmospheric water vapor, either. Next, imagine the sun starts to warm the surface of the Earth. As the surface temperature rises, it begins to give off more infrared energy to outer space in response.

That’s the Earth’s surface. But what would happen to the atmosphere at the same time? The cold air in contact with the warming ground would also begin to warm by thermal conduction. Convective air currents would transport this heat upward, gradually warming the atmosphere from the bottom up. Importantly, this ‘dry convection’ will result in a vertical temperature profile that falls off by 9.8 deg. C for every kilometer rise in altitude, which is the so-called ‘adiabatic lapse rate’. This is because rising warm air parcels cool as they expand at the lower air pressures aloft, and the air that sinks in response to all of that rising air must warm at the same rate by compression.

Eventually, the surface and lower atmosphere would warm until the rate at which infrared energy is lost by the Earth’s surface to space would equal the rate at which sunlight is absorbed by the surface, and the whole system would settle into a fairly repeatable day-night cycle of the surface heating (and lower atmosphere convecting) during the day, and the surface cooling (and a shallow layer of air in contact with it) during the night.

The global-average temperature at which this occurs would depend a lot on how reflective the Earth’s surface is to sunlight in our thought experiment. ..it could be anywhere from well below 0 deg F for a partially reflective Earth to about 45 deg. F for a totally black Earth.

So, how is this different from what happens in the real world? Well, notice that what we are left with in this thought experiment is an atmosphere that is heated from below by the ground absorbing sunlight, but the atmosphere has no way of cooling…except in a very shallow layer right next to the ground where it can cool by conduction at night.

Why is this lack of an atmospheric cooling mechanism important? Because in our thought experiment we now have an atmosphere whose upper layers are colder than the surface and lower atmosphere. And what happens when there is a temperature difference in a material? Heat flows by thermal conduction, which would then gradually warm the upper atmosphere to reduce that temperature difference. The process would be slow, because the thermal conductivity of air is quite low. But eventually, the entire atmosphere would reach a constant temperature with height.

Only the surface and a shallow layer of air next to the surface would go through a day-night cycle of heating and cooling. The rest of the atmosphere would be at approximately the same temperature as the average surface temperature. And without a falloff of temperature with height in the atmosphere of at least 10 deg. C per kilometer, all atmospheric convection would stop.

Since it is the convective overturning of the atmosphere that causes most of what we recognize as ‘weather’, most weather activity on Earth would stop, too. Atmospheric convective overturning is what causes clouds and rainfall. In the tropics, it occurs in relatively small and strongly overturning thunderstorm-type weather systems.

At higher latitudes, that convection occurs in much larger but more weakly overturning cloud and precipitation systems associated with low pressure areas.

There would probably still be some horizontal wind flows associated with the fact that the poles would still be cooler than the tropics, and the day-night heating cycle that moves around the Earth each day. But for the most part, most of what we call ‘weather’ would not occur. The same is true even if there was surface water and water vapor…but if we were able to somehow ‘turn off’ the greenhouse effect of water vapor. Eventually, the atmosphere would still become ‘isothermal’, with a roughly constant temperature with height.

Why would this occur? Infrared absorbers like water vapor and carbon dioxide provide an additional heating mechanism for the atmosphere. But at least as important is the fact that, since infrared absorbers are also infrared emitters, the presence of greenhouse gases allow the atmosphere — not just the surface — to cool to outer space.

When you pile all of the layers of greenhouse gases in the atmosphere on top of one another, they form a sort of radiative blanket, heating the lower layers and cooling the upper layers. (For those of you who have heard claims that the greenhouse effect is physically impossible, see my article here. There is a common misconception that the rate at which a layer absorbs IR energy must equal the rate at which it loses IR energy, which in general is not true.)

Without the convective air currents to transport excess heat from the lower atmosphere to the upper atmosphere, the greenhouse effect by itself would make the surface of the Earth unbearably hot, and the upper atmosphere (at altitudes where where jets fly) very much colder than it really is.

Thus, it is the greenhouse effect that continuously de-stabilizes the atmosphere, ‘trying’ to create a temperature profile that the atmosphere cannot sustain, which then causes all different kinds of weather as the atmosphere convectively overturns. Thus, the greenhouse effect is actually required to explain why weather occurs.

This is what makes water such an amazing substance. It cools the Earth’s surface when it evaporates, it warms the upper atmosphere when it re-condenses to form precipitation, it warms the lower atmosphere through the greenhouse effect, and it cools the upper atmosphere by emitting infrared radiation to outer space (also part of the greenhouse effect process). These heating and cooling processes are continuously interacting, with each limiting the influence of the other.

As Dick Lindzen alluded to back in 1990, while everyone seems to understand that the greenhouse effect warms the Earth’s surface, few people are aware of the fact that weather processes greatly limit that warming. And one very real possibility is that the 1 deg. C direct warming effect of doubling our atmospheric CO2 concentration by late in this century will be mitigated by the cooling effects of weather to a value closer to 0.5 deg. C or so (about 1 deg. F.) This is much less than is being predicted by the UN’s Intergovernmental Panel on Climate Change or by NASA’s James Hansen, who believe that weather changes will amplify, rather than reduce, that warming.

Most people don’t realize that Al Gore invented rock & roll music. Really…they don’t. Mr. Gore even had his own tour — called Live Earth — where he and his band, CO2 Fighters, rocked the house in London on July 7, 2007.

Al Gore and his band, CO2 Fighters, rock Wembley Stadium in London as part of Live Earth.

You might remember Live Earth. It was a worldwide string of concerts which frivolously wasted huge amounts of fossil fuels to help raise awareness of mankind’s frivolous waste of fossil fuels.

Now that Mr. Gore has moved on to other things such as winning Nobel Peace Prizes, it’s only appropriate that he should have a tribute band. At least that’s what my evil twin brother and rocker, Butch Spencer, told me. Butch and several of his musician friends got together a year or so ago and recorded a couple of songs (mp3’s and lyrics below) to honor Mr. Gore’s tireless efforts to Save the Earth.

The band was called EcoFreako, and it lasted about a week before everyone found better things to do with their free time. Since then, the songs have been wasting away on my computer until I re-discovered them when transferring files to my new, Energy Star-compliant desktop supercomputer.

So, Butch asked if I would make the songs available to the masses as a tribute to Mr. Gore. I listened to them first (I think beer might have been involved during the recording session). When I warned Butch that some people might be offended by these songs, he just smiled and exclaimed, “Cool!!” Butch also told me to include “apologies to Kiss and to Ted Nugent.” Whatever that means…I’m no rock music aficionado…just a geeky scientist.

I Want to Mock Al Gore All Night

He tells us Earth is going to pot
He keeps on sayin’ that it’s way too hot
We drive one mile, Al drives us crazy

We start the engine to go for a spin
The trip has just begun when he flies in
We drive one mile, Al drives us crazy.

You keep on shoutin’, we’ll keep on shoutin’

I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day

He keeps on saying we should walk for a while
We’re in our Honda as he travels in style
We drive one mile, Al drives us crazy

He shows us everything he’s got
A carbon footprint like a parking lot
We drive one mile, Al drives us crazy

You keep on shoutin’, we’ll keep on shoutin’

I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day
I wanna mock Al Gore all night, and nearly every day

EARTH HAS A FEVER

Well I don’t know where he comes from
but he sure does come
Some say he’s from Tennessee
And I don’t know how he does it
but he sure does it good
You’d better not disagree.

He says the Earth has a fever
Earth has a fever

Well the first time that I heard him I was just ten years old- he said-
“goodbye to the pretty seashore”
He said he was an expert, he said he had the cure
They call him Dr. Al Gore

He says the Earth has a fever
Earth has a fever
Earth has a fever
Earth has a fever

”It’s very dangerous
we can’t sustain
we’ve got to ch-ch-change” (he said)
”You know how hot it’s been,
there’s too much rain”
does this man have no shame, shame,
do you hear what he says?

Well we make the messy air
and destroyin’ the land
He says he’s blamin’ it on me
Well he knows just where to go
when he needs that carbon banned
clueless actors and the Greens

He says the Earth has a fever
Earth has a fever
Earth has a fever
Earth has a fever

The following article appears today in American Thinker, by David Douglass and John Christy, which tells their story of how scientists involved in Climategate did their best to protect the IPCC global warming party line through manipulation of the peer review process:

A Climatology Conspiracy?

by David H. Douglass and John R. Christy

“The CRU emails have revealed how the normal conventions of the peer review process appear to have been compromised by a team* of global warming scientists, with the willing cooperation of the editor of the International Journal of Climatology (IJC), Glenn McGregor. The team spent nearly a year preparing and publishing a paper that attempted to rebut a previously published paper in IJC by Douglass, Christy, Pearson and Singer (DCPS). The DCPS paper, reviewed and accepted in the traditional manner, had shown that the IPCC models that predicted significant “global warming” in fact largely disagreed with the observational data.

“We will let the reader judge whether this team effort, revealed in dozens of emails and taking nearly a year, involves inappropriate behavior including (a) unusual cooperation between authors and editor, (b) misstatement of known facts, (c) character assassination, (d) avoidance of traditional scientific give-and-take, (e) using confidential information, (f) misrepresentation (or misunderstanding) of the scientific question posed by DCPS, (g) withholding data, and more.

” *The team is a group of a number of climate scientists who frequently collaborate and publish papers which often supports the hypothesis of human-caused global warming. For this essay, the leading team members include Ben Santer, Phil Jones, Timothy Osborn, and Tom Wigley, with lesser roles for several others.”

READ THE STORY at American Thinker

The Fall meeting of the American Geophysical Union (AGU) here in San Francisco this week is amazing for it’s sheer size: many thousands of Earth scientists presenting talks and posters on just about every Earth science subject imaginable.

Today was my chance to try to convince other scientists who work on the critical issue of feedbacks in the climate system that some fundamental mistakes have been made that have misled climate researchers into believing that the climate system is quite sensitive to our greenhouse gas emissions. A tough sell in only 14 minutes.

It was standing room only…close to 300 scientists by my estimate. There were only a couple of objections to my presentation…rather weak ones. Afterward I had a number of people comment favorably about the ‘different’ way I was looking at the problem.

And while that should be comforting, it is also disturbing. Since when in science did the issue of ‘causation’ become a foreign concept? When did the direction of causation between two correlated variables (in my case, clouds and temperature) become no longer important?

If temperature and clouds vary together in ‘sort of’ the same way in satellite observations as they do in climate models, then the models are considered to be ‘validated’. But my message, which might not have come across as clearly as it should have due to time constraints, was that such agreement does NOT validate the models when it comes to feedback, and feedbacks are what will determine how much of an impact humans have on the climate system.

Andrew Lacis, who works climate modeling with Jim Hansen, came up and said he agreed with me that, in general, the feedback problem is more difficult than people have been assuming. In a talk after mine, Graeme Stephens gave me a backhanded compliment when he agreed with at least my basic message that the way in which we assume the climate system functions (in my terms, what-causes-what to happen) IS important to how we then deduce how sensitive the climate is to such things as our carbon dioxide emissions.

The three organizers of the session were very gracious to invite me, since they knew my views are controversial. One of the three was Andrew Dessler, who works in water vapor feedback. I had never met Andy before, and he’s a super nice guy. They all agreed that there needs to be more debate on the subject.

But most of the talks presented followed the recipe that has become all too common in recent years: analyze the output of climate models that predict substantial global warming, and simply assume the models are somewhere near correct.

There seems to be great reluctance to consider the possibility that these computerized prophets of doom, which have required so many scientists and so much money and so many years to develop, could be wrong. I come along with an extremely simple climate model that explains the behavior of the satellite data in details that are beyond even what has been done with the complex climate models…and then the more complex models are STILL believed because…well…they’re more complex.

Besides, since my simple model would predict very little manmade global warming, it must be wrong. After all, we know that manmade global warming is a huge problem. All of the experts agree on that. Just ask Al Gore and the mainstream news media.

UPDATED 12/16/09 1415 PST with final pdf version of talk…and press release, 1425 PST.

I decided to make my invited presentation on estimating cloud feedbacks from satellite measurements available here (final version-pdf):Spencer-Forcing-Feedback-AGU-09-San-Francisco-final. There will be a UAH press release on Wednesday, December 16, which is embargoed until 11 a.m. PST (1 p.m. CST).

UAHuntsville Press Release
EMBARGOED: For release after 11 a.m., PST, Wednesday, Dec. 16, 2009

Chicken and egg question
looms over climate debate

SAN FRANCISCO, Calif. (Dec. 16, 2009) — Which came first, the warmer temperatures or the clearer skies?

Answers to that and similar “chicken and egg” type questions could have a significant impact on our understanding of both the climate system and manmade global warming.

In an invited talk scheduled for today at the American Geophysical Union’s fall meeting in the Moscone Convention Center, Dr. Roy Spencer from The University of Alabama in Huntsville will discuss the challenge of answering questions about cause and effect (also known as forcing and feedback) in the climate.

“Feedbacks will determine whether the manmade portion of global warming ends up being catastrophic or barely measurable,” Spencer said recently.

Spencer’s interest is in using satellite data and a simple climate model to test the simulated feedback processes contained in climate models that are used to forecast global warming.

“I am arguing that we can’t measure feedbacks the way people have been trying to do it,” he said. “The climate modelers see from satellite data that warm years have fewer clouds, then assume that the warmth caused the clouds to dissipate. If this is true, it would be positive feedback and could lead to strong global warming. This is the way their models are programmed to behave.

“My question to them was, ‘How do you know it wasn’t fewer clouds that caused the warm years, rather than the other way around?’ It turns out they didn’t know. They couldn’t answer that question.”

One problem is the simplicity of the climate models. Because cloud systems are so complex and so poorly understood, all of the climate models used by the United Nations’ Intergovernmental Panel on Climate Change use greatly simplified cloud parameters to represent clouds. But the calculations that set those parameters are based on assumed cause-and-effect relationships.

Those assumptions might be working in the wrong direction, Spencer said. “What we have found is that cloud cover variations causing temperature changes dominate the satellite record, and give the illusion of positive feedback.”

Using satellite observations interpreted with a simple model, Spencer’s data support negative feedback (or cooling) better than they support positive feedback.

“This critical component in global warming theory – cloud feedback – is impossible to measure directly in the real climate system,” Spencer said. “We haven’t figured out a good way to separate cause and effect, so we can’t measure cloud feedback directly. And if we don’t know what the feedbacks are, we are just guessing at how much impact humans will have on climate change.

“I’m trying to spread the word: Let’s go back to basics and look at what we can and cannot do with measurements of the real climate system to validate both climate models and their predictions.”

A former NASA scientist, Spencer is a principal research scientist in UAHuntsville’s Earth System Science Center.

I’ll admit to being a skeptic when it comes to other skeptics’ opinions on the potential effects of sunspot activity on climate. Oh, it’s all very possible I suppose, but I’ve always said I’ll start believing it when someone shows a quantitative connection between variations in global cloud cover (not temperature) and geomagnetic activity.

Maybe my skepticism is because I never took astronomy in college (oops…my wife reminds me I took it 1st year). Or, maybe it’s because I can’t see or feel cosmic rays. They sound kind of New Age to me. After all, I can see sunlight, and I can feel infrared radiation…but cosmic rays? Some might say, “Well, Roy, you work with satellite microwave data, and you can‘t see or feel those either!” True, but I DO have a microwave oven in my kitchen…where’s your cosmic ray oven?

Now…where was I? Oh, yeah. So, since I’ve been working with 9 years of global reflected sunlight data from the CERES instrument flying on NASA’s Terra satellite, last night I decided to take a look at some data for myself.

The results, I will admit, are at least a little intriguing.

The following plots show detrended time series of monthly running 5-month averages of (top) CERES reflected shortwave deviations from the average seasonal cycle, and (bottom) monthly running geomagnetic Ap index values from the NOAA Space Weather Prediction Center. As I understand it, the Ap index is believed to be related to the level of cosmic ray activity reaching the Earth. (I will address the reason for detrending below).

Note that there is some similarity between the two plots. If we do a scatterplot of the data (below), we get an average linear relationship of about 0.05 W per sq. meter increase in reflected sunlight per 1 unit decrease in Ap index. This is at least qualitatively consistent with a decrease in solar activity corresponding to an increase in cloud cover.
(I’ve also shown a 2nd order polynomial fit (curved line) in the above plot for those who think they see a nonlinear relationship there.)

But just how big is this linear relationship seen in the above scatterplot? From looking at a 70-year plot of Ap data (originally from David Archibald), we see that the 11-year sunspot cycle modulates the Ap index by at least 10 units. Also, there are fairly routine variations on monthly and seasonal time scales of about 10 Ap units, too (click on image to see full-size):

When the 10 Ap unit variations are multiplied by the 0.05 scale factor, it suggests about a 0.5 W per sq. meter modulation of global reflected sunlight during the 11 year solar cycle (as well as in monthly and yearly variations of geomagnetic activity). I calculate that this is a factor of 10 greater than the change in reflected sunlight that results from the 0.1% modulation of the total solar irradiance during the solar cycle.

At face value, that would mean the geomagnetic modulation of cloudiness has about 10 times the effect on the amount of sunlight absorbed by the Earth as does the solar cycle’s direct modulation of the sun’s output. It also rivals the level of forcing due to anthropogenic greenhouse gas emissions, but with way more variability from year to year and decade to decade. (Can anyone say, “natural climate variability”?)

Now, returning to the detrending of the data. The trend relationship between CERES reflected sunlight and the Ap index is of the opposite sign to that seen above. This suggests that the trend in geomagnetic activity during 2000-2008 can not explain the trend in global reflected sunlight over the same period of time. However, the ratio of the trends is very small: +0.004 Watts per sq. meter per unit Ap index, rather than -0.045. So, one can always claim that some other natural change in cloud cover is overpowering the geomagnetic modulation of cloudiness. With all kinds of climate forcings all mingled in together, it would be reasonable to expect a certain signal to emerge more clearly during some periods, and less clearly during other periods.

I also did lag correlation plots of the data (not shown), and there is no obvious lag in the correlation relationship.

All of this, of course, assumes that the observed relationship during 2000-2008 is not just by chance. There is considerable autocorrelation in the reflected sunlight and geomagnetic data, which I have made even worse by computing monthly running 5-month averages (the correlation strengths increased with averaging time). So, there are relatively few degrees of freedom in the data collected during 2000-2008, which increases the probability of getting a spurious relationship just by chance.

All of the above was done in a few hours, so it is far from definitive. But it IS enough for me to keep an open mind on the subject of solar activity affecting climate variations. As usual, I’m just poking around in the data and trying to learn something…while also stirring up some discussion (to be enjoyed on other blogs) along the way.

UPDATE (12:30 p.m. 10 December 2009)
There is a question on how other solar indices compare to the CERES reflected sunlight measurements. The following lag correlation chart shows a few of them. I’m open to suggestions on what any of it might mean.

(last updated 9:05 a.m. 9 December 2009).

I get so many questions from readers about a variety of global warming issues that I thought I would whip up some Q&A for those who want to understand the views of skeptics a little better. I will try to update these with links and additional answers as time permits.

Climate science is complex and the study of it is highly specialized. Nevertheless, there is a common theme that runs through the claims of the global warming establishment, from Al Gore’s movie An Inconvenient Truth, to the UN’s Intergovernmental Panel on Climate Change (IPCC): Weather and climate events that happen naturally are being increasingly blamed on the activities of humans. So, causation is at the root of most beliefs about global warming and climate change.

As one digs further into the science, the direction of causation also emerges as a key theme, and it is one that can totally change the degree to which it appears humans affect the climate system. In my own area of research I have found that mixing up cause and effect when examining how cloud cover varies with temperature has greatly misled the scientific establishment regarding how sensitive the climate system is to our addition of greenhouse gases to the atmosphere.

Not all skeptics believe the same things, though, so some skeptics will object to some of what I have listed below. These represent my opinions, not all of which are necessarily ascribed to by other skeptics. Additional details on many of these issues can be found throughout this website, including a Q&A list I published on April 19, 2009.

The following list, in no particular order, are my responses to common claims and accusations about global warming skeptics. If other scientists or laypersons want me to add to the list, or want to argue for changes, email me and I will update it as appropriate. Please be sure to check back for the latest update (posted above).

1. Skeptics deny global warming. No, we deny that warming has been mostly human-caused.

2. Skeptics are paid by big oil. The vast majority of skeptics have never been paid anything by Big Oil (me included).

3. Skeptics don’t publish in the peer reviewed literature. Wrong…but it is true we do not have nearly as many publications as the other side does. But it only takes one scientific study to destroy a scientific hypothesis, which is what anthropogenic global warming theory is.

4. Skeptics are not unified with an alternative explanation for global warming. Well, that’s the way science works in a field as immature as climate change science. The biggest problem is that we really don’t understand what causes natural climate variability. Kevin Trenberth has now famously admitted as much in one of the Climategate emails, where said it’s a “travesty” that we don’t know why warming has stopped in the last 7 to 10 years. For century-time-scale changes, some believe it is cloud cover being modulated by cosmic ray activity, which is in turn affected by sunspot activity. A few others think it is changes in the total energy output of the sun (possible, but I personally doubt it). In my opinion, it is internal, chaotic variability in the ocean and atmosphere circulation causing small changes in cloud cover. Since clouds are a natural sunshade, changing their coverage of the Earth will cause warming or cooling. The IPCC simply assumes this does not happen. If they did, they would have to admit that natural climate change happens, which means they would have to address the possibility that most of the warming in the last 50 has been largely natural in origin.

5. But the glaciers are melting! Many glaciers which have been monitored around the world for a long time have been retreating since the 1800’s, before humans could have been responsible. A few retreating glaciers are even revealing old tree stumps…how did those get there? Planted by skeptics?

6. But the sea ice is melting! Well, the same thing happened back in the 1920’s and 1930’s, with the Northwest Passage opening up in 1940. It was just as warm, or nearly as warm, in the Arctic in the 1930’s. Again, this is before humans could be blamed. There were very low water levels in the Great Lakes in the 1920’s too, just as has happened recently. We have accurate measurements of sea ice cover from satellites only since 1979, so there is no way to really know whether sea ice cover is less than it was before.

7. But we just had the warmest decade in recorded history! Well, if thermometer measurements had started in, say 200, AD (rather than in the 1800’s), and it was now 850 AD, the same thing might well have been said back then. The climate system is always warming or cooling, and the Industrial Revolution (and thus our carbon dioxide emissions) just happened to occur while we were still emerging from the Little Ice Age…a warming period.

8. But the Antarctic ice shelves are collapsing! Well, sea ice around Antarctica has been expanding since we started monitoring by satellite in 1979….so which do we use as evidence? There is no convincing evidence of warming in Antarctica, except in the relatively small Antarctic Peninsula, which juts out into the ocean. Just as glaciers naturally flow to the sea, ice shelves must eventually break off. It is very uncertain how often this happens through the centuries, and what has been observed in recent years might be entirely normal. Similarly, it was warmer in Greenland in the 1930’s than it has been more recently.

9. But the sea levels are rising! Yes, and from what we can tell, they have been rising since the end of the last Ice Age. Again, the more recent rise might be just a consequence of our emergence from the Little Ice Age, which bottomed out in the 1600’s.

10. But we keep emitting carbon dioxide, which we know is a greenhouse gas! Yes, I agree. But the direct warming effect of moré CO2 is agreed by all to be small…and I predict that when we better understand how clouds change in response to that small warming influence, the net warming in response to more CO2 will be smaller still. This is the “feedback” issue, which determines “climate sensitivity”, the area of research I spend most of my time on. I and a minority of other scientists believe the net feedbacks in the climate system are negative, probably driven by negative cloud feedback. In contrast, all twenty-something IPCC climate models now exhibit positive cloud feedback.

11. But we can’t keep pumping CO2 into the atmosphere forever! No, and we won’t. Assuming fossil fuels will be increasingly difficult to find and access in the coming decades, the continuing demand for energy ensures that new energy technologies will be developed. It’s what humans do…adapt.

12. But we shouldn’t be interfering with nature! Actually, it would be impossible to NOT interfere with nature. Chaos theory tells us that everything that happens, naturally or anthropogenically, forever alters the future state of the climate system. I predict that science will eventually understand that more CO2 is good for life on Earth. This doesn’t mean it will be good for every single species…but when Mother Nature changes the climate system, there are always winners and losers anyway. In the end, this is a religious issue, not a scientific one. Interestingly I have found that the vast majority of scientists also have the religious belief that we should not be impacting nature. I believe this has negatively affected their scientific objectivity.