By Dr. Roy Spencer, PhD (reprinted from his blog with permission)
UPDATE (12:35 p.m. CDT 19 May 2011): revised corrections of CERES data for El Nino/La Nina effects.
While I have been skeptical of Svensmark’s cosmic ray theory up until now, it looks like the evidence is becoming too strong for me to ignore. The following results will surely be controversial, and the reader should remember that what follows is not peer reviewed, and is only a preliminary estimate.
I’ve made calculations based upon satellite observations of how the global radiative energy balance has varied over the last 10 years (between Solar Max and Solar Min) as a result of variations in cosmic ray activity. The results suggest that the total (direct + indirect) solar forcing is at least 3.5 times stronger than that due to changing solar irradiance alone.
If this is anywhere close to being correct, it supports the claim that the sun has a much larger potential role (and therefore humans a smaller role) in climate change than what the “scientific consensus” states.
BACKGROUND
The single most frequently asked question I get after I give my talks is, “Why didn’t you mention the sun?” I usually answer that I’m skeptical of the “cosmic ray gun” theory of cloud changes controlling climate. But I point out that Svensmark’s theory of natural cloud variations causing climate change is actually pretty close to what I preach — only the mechanism causing the cloud change is different.
Then, I found last year’s paper by Laken et al. which was especially interesting since it showed satellite-observed cloud changes following changes in cosmic ray activity. Even though the ISCCP satellite data they used are not exactly state of the art, the study was limited to the mid-latitudes, and the time scales involved were days rather than years, the results gave compelling quantitative evidence of a cosmic ray effect on cloud cover.
With the rapid-fire stream of publications and reports now coming out on the subject, I decided to go back and spend some time analyzing ground-based galactic cosmic ray (GCR) data to see whether there is a connection between GCR variations and variations in the global radiative energy balance between absorbed sunlight and emitted infrared energy, taken from the NASA CERES radiative budget instruments on the Terra satellite, available since March 2000.
After all, that is ultimately what we are interested in: How do various forcings affect the radiative energy budget of the Earth? The results, I must admit, are enough for me to now place at least one foot solidly in the cosmic ray theory camp.
THE DATA
The nice thing about using CERES Earth radiative budget data is that we can get a quantitative estimate in Watts per sq. meter for the radiative forcing due to cosmic ray changes. This is the language the climate modelers speak, since these radiative forcings (externally imposed global energy imbalances) can be used to help calculate global temperature changes in the ocean & atmosphere based upon simple energy conservation. They can then also be compared to the estimates of forcing from increasing carbon dioxide, currently the most fashionable cause of climate change.
From the global radiative budget measurements we also get to see if there is a change in high clouds (inferred from the outgoing infrared measurements) as well as low clouds (inferred from reflected shortwave [visible sunlight] measurements) associated with cosmic ray activity.
I will use only the ground-based cosmic ray data from Moscow, since it is the first station I found which includes a complete monthly archive for the same period we have global radiative energy budget data from CERES (March 2000 through June 2010). I’m sure there are other stations, too…all of this is preliminary anyway. Me sifting through the myriad solar-terrestrial datasets is just as confusing to me as most of you sifting through the various climate datasets that I’m reasonably comfortable with.
THE RESULTS
The following plot (black curve) shows the monthly GCR data from Moscow for this period, as well as a detrended version with 1-2-1 averaging (red curve) to match the smoothing I will use in the CERES measurements to reduce noise.
Detrending the data isolates the month-to-month and year-to-year variability as the signal to match, since trends (or a lack of trends) in the global radiative budget data can be caused by a combination of many things. (Linear trends are worthless for statistically inferring cause-and-effect; but getting a match between wiggles in two datasets is much less likely to be due to random chance.)
The monthly cosmic ray data at Moscow will be compared to global monthly anomalies the NASA Terra satellite CERES (SSF 2.5 dataset) radiative flux data,
which shows the variations in global average reflected sunlight (SW), emitted infrared (LW), and Net (which is the estimated imbalances in total absorbed energy by the climate system, after adjustment for variations in total solar irradiance, TSI). Note I have plotted the variations in the negative of Net, which is approximately equal to variations in (LW+SW)
Then, since the primary source of variability in the CERES data is associated with El Nino and La Nina (ENSO) activity, I subtracted out an estimate of the average ENSO influence using running regressions between running 5-month averages of the Multivariate ENSO Index (MEI) and the CERES fluxes. I used the MEI index along with those regression coefficients in each month to correct the CERES fluxes 4 months later, since that time lag had the strongest correlation.
Finally, I performed regressions at various leads and lags between the GCR time series and the LW, SW, and -Net radiative flux time series, the results of which are shown next.
The yearly average relationships noted in the previous plot come from this relationship in the reflected solar (SW) data,
while the -Net flux (Net is absorbed solar minus emitted infrared, corrected for the change in solar irradiance during the period) results look like this:
It is that last plot that gives us the final estimate of how a change in cosmic ray flux at Moscow is related to changes in Earth’s radiative energy balance.
SUMMARY
What the above three plots show is that for a 1,000 count increase in GCR activity as measured at Moscow (which is somewhat less than the increase between Solar Max and Solar Min), there appears to be:
(1) an increase in reflected sunlight (SW) of 0.64 Watts per sq. meter, probably mostly due to an increase in low cloud cover;
(2) virtually no change in emitted infrared (LW) of +0.02 Watts per sq. meter;
(3) a Net (reflected sunlight plus emitted infrared) effect of 0.55 Watts per sq. meter loss in radiant energy by the global climate system.
WHAT DOES THIS MEAN FOR CLIMATE CHANGE?
Assuming these signatures are anywhere close to being real, what do they mean quantitatively in terms of the potential effect of cosmic ray activity on climate?
Well, just like any other forcing, a resulting temperature change depends not only upon the size of the forcing, but also the sensitivity of the climate system to forcing. But we CAN compare the cosmic ray forcing to OTHER “known” forcings, which could have a huge influence on our understanding of the role of humans in climate change.
For example, if warming observed in the last century is (say) 50% natural and 50% anthropogenic, then this implies the climate system is only one-half as sensitive to our greenhouse gas emissions (or aerosol pollution) than if the warming was 100% anthropogenic in origin (which is pretty close to what we are told the supposed “scientific consensus” is).
First, let’s compare the cosmic ray forcing to the change in total solar irradiance (TSI) during 2000-2010. The orange curve in following plot is the change in direct solar (TSI) forcing between 2000 and 2010, which with the help of Danny Braswell’s analytical skills I backed out from the CERES Net, LW, and SW data. It is the only kind of solar forcing the IPCC (apparently) believes exists, and it is quite weak:
Also shown is the estimated cosmic ray forcing resulting from the month-to-month changes in the original Moscow cosmic ray time series, computed by multiplying those monthly changes by 0.55 Watts per sq. meter per 1,000 cosmic ray counts change.
Finally, I fitted the trend lines to get an estimate of the relative magnitudes of these two sources of forcing: the cosmic ray (indirect) forcing is about 2.8 times that of the solar irradiance (direct) forcing. This means the total (direct + indirect) solar forcing on climate associated with the solar cycle could be 3.8 times that most mainstream climate scientists believe.
One obvious question this begs is whether the lack of recent warming, since about 2004 for the 0-700 meter layer of the ocean, is due to the cosmic ray effect on cloud cover canceling out the warming from increasing carbon dioxide.
If the situation really was that simple (which I doubt it is), this would mean that with Solar Max rapidly approaching, warming should resume in the coming months. Of course, other natural cycles could be in play (my favorite is the Pacific Decadal oscillation), so predicting what will happen next is (in my view) more of an exercise in faith than in science.
In the bigger picture, this is just one more piece of evidence that the IPCC scientists should be investigating, one which suggests a much larger role for Mother Nature in climate change than the IPCC has been willing to admit. And, again I emphasize, the greater the role of Nature in causing past climate change, the smaller the role humans must have had, which could then have a profound impact on future projections of human-caused global warming.
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Is it only air / water temperature that causes reduced Arctic ice extent?
Have you considered soot?
I have not seen any correlation data for GCR and the global temperatures.
On the other hand there is 280 years long R^2 >0.7 correlation between CET (the world’s longest available temperature record) and the rate of change of the geomagnetic field in the North Atlantic.
Correlation of R^2 >0.7 for any climatic set of data (for a even much shorter period) is unprecedented. More details will be in a forthcoming article (email request will be considered) .
http://www.vukcevic.talktalk.net/dBz.htm
Worth a visit to Nigel Calder’s blog, (former editor of New Scientist, co-author with Svensmark of ‘Chilling Stars’), and associated comments, for tracking the latest on this topic.
http://calderup.wordpress.com/2011/05/17/accelerator-results-on-cloud-nucleation-2/
The temperature and OHC records have large variations away from the general rise, while the IPCC “projections”, for all their complexity and needing Brainiac computation, are fairly smooth. If this work gives the variations that observation finds, then the correlation to sun and cosmic rays will be better than to the linear, very smooth rise of CO2.
Good work. Looking forward to incorporation of other stations and their data. So NASA hasn’t done this? Hmmmmmm.
Dr. Spencer
A very interesting and suggestive attempt, but I would note one fairly glaring omission. You forgot to include the mandatory final paragraph where you point out the urgent need for more research funding to cover further explorations of this topic. I know you’ve been at this a lot longer than many of our current crop climate geniuses, but you really do need to bring yourself up to date with the evolved goals of modern climatology i.e. “Show me the money!”
R=0.6 and R=0.64 is quoted in the graphs above. I would expect Dr. Spencer to quote more customary R^2, but this for above values would give much lower and disappointing R^2 =0.36 and R^0.41, which would be considered ‘not worth the bother’.
Dave Wendt says:
May 20, 2011 at 3:03 pm
“[…]but you really do need to bring yourself up to date with the evolved goals of modern climatology i.e. “Show me the money!”
He also needs to smuggle in a “worse than we thought”…
richard telford says:
May 20, 2011 at 11:49 am
“And how can cosmic be important when there is no trend since the 1950s?”
The Beast sequals; Es kann nicht sein, was nicht sein darf! We only now enter a prolonged solar minimum. The knowledge of the sun’s influence MUST be suppressed!
So I just went to Amazon to download a copy of Chilling Stars for my iPad, because hey, we live in Panama and don’t need to ship dead trees to add yet more to GW. But not so! Not available on Kindle! Nigel, tell your publisher to get with the program or get a new publisher! Sheesh – even my friend Nick who self-published a book about his sorry-a**ed childhood has it on Kindle and has sold at least ten copies.
Maybe if everyone on this blog sends a nastygram to the publisher we can get more distribution (worldwide) for this important book.
Total planetary cloud cover closely tracks GCR up until 1994. Post 1994 there is an increase in solar wind bursts that create a space charge differential in the ionosphere and which removes cloud forming ions.
See this review paper by Eric Palle.
(See figure 2. Note low level clouds are reduced by minus 0.065% per year, starting in about 1994.)
http://solar.njit.edu/preprints/palle1264.pdf
The second process, considered by Tinsley and Yu (2003), namely electroscavenging, depends on the action of the global electrical circuit (see review by Rycroft et al. (2000)). The transport of charge by rapidly rising convective currents in the tropics and over continental land masses leads to a 200 kV positive charge of the ionosphere compared to Earth. This large voltage difference, in turn, necessitates a return current which must pass through the regions of the atmosphere where clouds are formed. As cosmic rays are the principal agent of ionization in the atmosphere above 1 km altitude, any modulation of the GCR flux due to solar activity is likely to affect the transport of charge to complete the global electrical circuit. Tinsley and Yu (2003) discuss how the build up of electrostatic charge at the tops and bottoms of clouds could affect the scavenging of ice forming nuclei (IFN) and cloud The solar wind bursts have abated and GCR is high however there is a third mechanism that is removing cloud forming ions.
..condensation nuclei (CCN) by droplets, and how this can lead to greater rates of precipitation and a reduction in cloud cover. They find that the electroscavenging process is likely to be more important over oceanic rather than continental regions and that it leads to a positive correlation between clouds and cosmic rays at higher latitudes and a negative correlation at low latitudes. Thus the electroscavenging process can explain several of the most striking features of Fig. 5, namely: (1) the peak in significant positive correlations at latitudes around 50 degrees North and South (Fig. 5a); (2) the tendency for a less significant but nonetheless evident trend to negative correlation coefficients at low latitudes (Fig. 5a); and (3) the location of the peak in correlation over one of the principal oceans, namely over the North and South Atlantic (Fig. 5c).
Once again about global warming and solar activity
http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf
Once again about global warming and solar activity K. Georgieva, C. Bianchi, and B. Kirov
We show that the index commonly used for quantifying long-term changes in solar activity, the sunspot number, accounts for only one part of solar activity and using this index leads to the underestimation of the role of solar activity in the global warming in the recent decades. A more suitable index is the geomagnetic activity which reflects all solar activity, and it is highly correlated to global temperature variations in the whole period for which we have data.
In Figure 6 the long-term variations in global temperature are compared to the long-term variations in geomagnetic activity as expressed by the ak-index (Nevanlinna and Kataja 2003). The correlation between the two quantities is 0.85 with p<0.01 for the whole period studied. It could therefore be concluded that both the decreasing correlation between sunspot number and geomagnetic activity, and the deviation of the global temperature long-term trend from solar activity as expressed by sunspot index are due to the increased number of high-speed streams of solar wind on the declining phase and in the minimum of sunspot cycle in the last decades.
Dr. Spencer: I will use only the ground-based cosmic ray data from Moscow
Dr. Svalgaard: Which is unfortunate because Moscow does not have very good control of the absolute values. They have numerous ‘glitches’ and ‘jumps’ which are instrumental. Hermanus is better, or Kiel, or just about any other station.
A comparison of the Moscow data with that from the Hermanus and Haleakala neutron monitors doesn’t reveal any ‘glitches’ or ‘jumps’ – plots of the three datasets show a remarkably similar profile.
Anyone who is interested can verify for himself :
Moscow Neutron Monitor (Russia)
Haleakala Neutron Monitor
Hermanus Neutron Monitor
For all three plots, please select “27-days” for the resolution, to match the Dr. Spencer’s monthly plot, and the “Corrected for Pressure” option from the “Type of Data” drop-down menu. For the date ranges, please select 2000-Jan-01 to 2007-Jan-01 (since the Haleakala and Moscow data only goes to the start of 2007 for some reason at this website).
You’ll see that the plots are almost identical in shape. The y-axis on the Haleakala plot shows that the % swings are smaller than for Moscow and Hermanus – the Haleakala monitor has a 13.4 GeV cut-off, compared to Moscow’s 2.43 GeV, and 4.6 GeV for Hermanus, and therefore the bulk of the cosmis rays it is recording are of higher energy.
The Hermanus data at the Izmiran website above does extend to the full range considered by Dr. Spencer, and it matches the Moscow plot presented here very well.
Dr. Svalgaard also suggests comparing to the Kiel neutron monitor.
This can be done at the NMDB website.
Please choose the MOSC and KIEL stations (and I suggest one other eg. OULU, otherwise the 2 plots don’t all fit on the graph, and the ‘zoom out’ option doesn’t seem to work). The date range can be the full 2000-Jan-01 to 2007-Aug-01 used by Dr. Spencer.
Again, it can be seen that the two plots are in excellent agreement.
The Moscow monitor does appear to exhibit a jump in 2010 August, but this is outside the period used by Dr. Spencer. So Dr. Svalgaard is correct about the presence of glitches (and not just for the Moscow monitor), but he is wrong to dismiss Dr. Spencer’s analysis since no glitches or jumps appear to be present in the data used by Dr. Spencer.
[One more try to post this]
Dr. Spencer: I will use only the ground-based cosmic ray data from Moscow
Dr. Svalgaard: Which is unfortunate because Moscow does not have very good control of the absolute values. They have numerous ‘glitches’ and ‘jumps’ which are instrumental. Hermanus is better, or Kiel, or just about any other station.
A comparison of the Moscow data with that from the Hermanus and Haleakala neutron monitors doesn’t reveal any ‘glitches’ or ‘jumps’ – plots of the three datasets show a remarkably similar profile.
Anyone who is interested can verify for himself :
Moscow Neutron Monitor (Russia)
Haleakala Neutron Monitor
Hermanus Neutron Monitor
For all three plots, please select “27-days” for the resolution, to match the Dr. Spencer’s monthly plot, and the “Corrected for Pressure” option from the “Type of Data” drop-down menu. For the date ranges, please select 2000-Jan-01 to 2007-Jan-01 (since the Haleakala and Moscow data only goes to the start of 2007 for some reason at this website).
You’ll see that the plots are almost identical in shape. The y-axis on the Haleakala plot shows that the % swings are smaller than for Moscow and Hermanus – the Haleakala monitor has a 13.4 GeV cut-off, compared to Moscow’s 2.43 GeV, and 4.6 GeV for Hermanus, and therefore the bulk of the cosmis rays it is recording are of higher energy.
The Hermanus data at the Izmiran website above does extend to the full range considered by Dr. Spencer, and it matches the Moscow plot presented here very well.
Dr. Svalgaard also suggests comparing to the Kiel neutron monitor. This can be done at the NMDB website :
Please choose the MOSC and KIEL stations (and I suggest one other eg. OULU, otherwise the 2 plots don’t all fit on the graph, and the ‘zoom out’ option doesn’t seem to work). The date range can be the full 2000-Jan-01 to 2007-Aug-01 used by Dr. Spencer.
Again, it can be seen that the two plots are in excellent agreement.
The Moscow monitor does appear to exhibit a jump in 2010 August, but this is outside the period used by Dr. Spencer. So Dr. Svalgaard is correct about the presence of glitches (and not just for the Moscow monitor), but he is wrong to dismiss Dr. Spencer’s analysis since no glitches or jumps appear to be present in the data used by Dr. Spencer.
My post seems to be disappearing, not even going into moderation. I’ll try a shorter one:
Dr. Spencer: I will use only the ground-based cosmic ray data from Moscow
Dr. Svalgaard: Which is unfortunate because Moscow does not have very good control of the absolute values. They have numerous ‘glitches’ and ‘jumps’ which are instrumental. Hermanus is better, or Kiel, or just about any other station.
The Moscow, Hermanus and Kiel data can be plotted at izmirran dot rssi dot ru website (for the first two), and at the NMDB dot eu website for Moscow and Kiel.
There don’t appear to be any glitches or jumps – all three stations are in good agreement for the period considered by Dr. Spencer (although the % swings vary due to the different cut-off rigidities). The Moscow station does appear to exhibit a jump just after the period, in August 2010.
Leif Svalgaard says:
May 20, 2011 at 12:33 pm
Moscow’s Monitor seems to be a bit ahead of the others, timewise.
I don’t know why this is, but thier data preceeds the rest of the stations.
Dr. Spencer: I will use only the ground-based cosmic ray data from Moscow
Dr. Svalgaard: Which is unfortunate because Moscow does not have very good control of the absolute values. They have numerous ‘glitches’ and ‘jumps’ which are instrumental. Hermanus is better, or Kiel, or just about any other station.
A comparison of the Moscow data with that from the Hermanus and Haleakala neutron monitors doesn’t reveal any ‘glitches’ or ‘jumps’ – plots of the three datasets show a remarkably similar profile.
Anyone who is interested can verify for himself :
Moscow Neutron Monitor (Russia)
Haleakala Neutron Monitor
Hermanus Neutron Monitor
For all three plots, please select “27-days” for the resolution, to match the Dr. Spencer’s monthly plot, and the “Corrected for Pressure” option from the “Type of Data” drop-down menu. For the date ranges, please select 2000-Jan-01 to 2007-Jan-01 (since the Haleakala and Moscow data only goes to the start of 2007 for some reason at this website).
You’ll see that the plots are almost identical in shape. The y-axis on the Haleakala plot shows that the % swings are smaller than for Moscow and Hermanus – the Haleakala monitor has a 13.4 GeV cut-off, compared to Moscow’s 2.43 GeV, and 4.6 GeV for Hermanus, and therefore the bulk of the cosmis rays it is recording are of higher energy.
The Hermanus data at the Izmiran website above does extend to the full range considered by Dr. Spencer, and it matches the Moscow plot presented here very well.
Dr. Svalgaard also suggests comparing to the Kiel neutron monitor. This can be done at the NMDB website :
Please choose the MOSC and KIEL stations (and I suggest one other eg. OULU, otherwise the 2 plots don’t all fit on the graph, and the ‘zoom out’ option doesn’t seem to work). The date range can be the full 2000-Jan-01 to 2007-Aug-01 used by Dr. Spencer.
Again, it can be seen that the two plots are in excellent agreement.
The Moscow monitor does appear to exhibit a jump in 2010 August, but this is outside the period used by Dr. Spencer. So Dr. Svalgaard is correct about the presence of glitches (and not just for the Moscow monitor), but he is too hasty to dismiss Dr. Spencer’s analysis, since no glitches or jumps appear to be present in the data used by Dr. Spencer.
Nice analysis Dr Spencer. I might add this is consistent with the correlation of previous solar cycle length and long term temperature (eg. see Butler & Johnston 1996).
TonyB.,
Of course we can’t live on earth without altering the atmosphere as that is what plants and amimals do. Now certainly if there were only a few million humans living in some primitive or low energy usage our impact would be far less.
The real divide comes down to those who are convinced that the science is robust enough to strongly suggest that the 40% increase in co2 and large increases in other GH gases since about 1750 is large enough to change the climate in a significant way
Sorry, a correction to my comment @ur momisugly May 20, 2011 at 4:25 pm:
The date range can be the full 2000-Jan-01 to 2007-Aug-01 used by Dr. Spencer.
That should’ve been “to 2010-Aug-01”.
Don B says:
May 20, 2011 at 11:24 am
“If enough articles such as this one in Physics World keep showing up, surely the media will notice, won’t they?”
All imortant news-media has editorial staff-meetings where they decide to ignore it.
The BBC for example. They notice, but they have decided to ignore it.
It is just like with Israel. All positive news from Israel, the only democracy in the middle east, is ignored. All negative news are enhanced. WUWT?
Gates says:
“…the 40% increase in co2 and large increases in other GH gases since about 1750 is large enough to change the climate in a significant way.”
There is no evidence to support that statement.
@R Gates
“The real divide comes down to those who are convinced that the science is robust enough to strongly suggest that the 40% increase in co2 and large increases in other GH gases since about 1750 is large enough to change the climate in a significant way”
++++++
There is no published or blogged science strongly suggesting that a 40% increase in co2 and large increases in other GH gases since about 1750 is large enough to change the climate in a significant way. The vastly dominant GHG is water vapour and there is no indication that the level of it has increased at all. The article above clearly shows that not even cloud cover is changed by water vapour, it is mediated by the prevalence of cloud condensation nuclei even as the water vapour level stays the same.
In your first post above you mention that the Arctic is melting, or has not recovered. NASA says the ice loss was due to it blowing out of the Arctic Ocean and provides a photographic animation to prove it. It was not caused by GHG’s nor was the ice melted in the Arctic.
The GCR theory goes a long way to explaining climate change on this planet at all time scales and now has experimental evidence to support it. Combined with other natural factors, like ocean cycles, we seem to have a pretty good working model of the Earth’s climate throughout history!
The CO2 theory of climate change, consisting largely of positive feedbacks, has no such supporting experimental evidence and only seems to fit the last 50 years or so, and only then if you ignore all other natural factors outside of volcanoes and the tiny changes in solar insolation.
The cognitive dissidence the warmest’s must live with seems overwhelming to me.
I have never met a climate change skeptic. Those of us who did not buy into the man-made climate change theory have always recognized that climate changes, but believed it was mostly natural and that the human impact was small, and certainly not a crisis! We have taken a more holistic view of climate change, believing that there are many factors to consider, and humanity is only a small part of the equation. The evidence is now overwhelming that this is the more accurate view of climate change (and actually, always has been).
The warmest’s are the only true ‘denialists’ in the debate. They are denying natural climate change exists. They hold the untenable argument that CO2 is the primary driver of climate change and, therefore, all evidence of climate change before the mid-20th century is invalid. That is a lot of denial-ism, right there! I would put it right up there with the idea that the Earth is only 6,000 years old.
I guess my point is that I want to shout this GCR news from the roof tops. I want CNN to do non-stop coverage. I want cities across the planet to plan ‘Natural Climate Change Days’ and celebrate our freedom from impending doom! I want Roy Spencer to be a bit more excited and not so darn cautious and qualifying. But that is not going to happen, is it.
The climate crisis is going to die a slow and agonizing death. Remnants of the ‘crisis that never was’ will linger for many, many decades, just like the tax we Americans still pay to finance the Spanish/American war! Only this time, the bureaucratic damage is on a global scale. We will never know the true cost of this climate change debacle, but there is a chance that we may learn from it. At least, we can hope.
R. Gates has the irritating behaviour of generally not initially revealing his references.
Smokey says:
Well spotted. And even when he produces such ‘evidence’ it may come up for debate. R. Gates, please back up all your claims. Even the IPCC avoids claiming statistically significant man-made AGW before 1950. Get a grip!
Smokey says:
May 20, 2011 at 6:06 pm
Gates says:
“…the 40% increase in co2 and large increases in other GH gases since about 1750 is large enough to change the climate in a significant way.”
There is no evidence to support that statement.
———-
Then about any time now the arctic sea ice should be returning to it’s long-term average…something it has not seen since 2004, and the permafrost should begin to freeze up again. The dramatic changes being seen across the arctic would say that you are quite wrong, and that there is plenty of evidence to suggest that the GCM’s are correct in showing that anthrogenic GHG’s are affecting climate.