No question there’s been warming and cooling over the past 2000 years (and for the past hundreds of thousands of years). My understanding is that, for many of those shifts, there is a decent understanding of the natural forcing that caused them (whether prolonged solar minimums (Little Ice Age), prolonged NAO warming (MWP), or the various Milankovich cycles, volcanic activity or natural GHG releases for millenia in the distant past). But we’re really struggling to articulate a natural forcing to explain the current warming trend. Certainly if the warming continues for the next few years despite a cool PDO, the low solar irradiance levels, the slight ice accumulation effects of current orbital (Milankovich) cycles, and the current la Nina, at some point we’re going to need to concede a greater causal effect for non-natural forcings.

Thanks in large part to your work and that of Dr Lindzen, there seems to be emerging some consensus that thin, low-level clouds cause warming, and a viable theory that increased moisture in the troposphere caused by something (the PDO from your view, anthropogenic warming from their view) will result in greater cloud cover. at the very least, you and Dr. Lindzen have succeeded in getting all of the major scientific compilations to acknowledge that clouds (whether as a feedback or a forcing) remain the great unknown in the global warming puzzle. Have we made any progress in accumulating empirical data as to the quantity of cloud cover globally?

Decreased cloud cover would then cause long term warming, which will show up more strongly over land (even if the ocean is the source). Climate scientists, though, assume cloud cover has always been the same…even though they know clouds are very complex!

Yes, increasing CO2 should have some warming effect, but assuming ALL of the warming is from CO2 is as much faith-based as it is science-based.

If you look at the 18-proxy average temperature reconstruction for the last 2,00 years, you will see evidence that nearly every century has experienced substantial warming or cooling.

While we know very little about natural climate variability, we do know a great deal about CO2 — because WE produce it! Blaming climate change entirely on humans is too anthropocentric for me.

With respect to the global temperature effect of the various oceanic and atmospheric cycles, I have studied them carefully (though admittedly not with your trained scientific eye). Obviously, like you say, the ENSO cycle has the greatest global effect. And as your most recent work suggests, there is certainly some rough correlation between warming and cooling phases and the PDO. Broadening to include the NAO, SOI, AO, ANO, AAO, etc., it doesn’t seem that there’s really any question that ocean and atmospheric oscillation cycles greatly affect the annual and even decadal variability in temperatures. I haven’t seen a serious AGW proponent who would argue to the contrary. But here’s the fundamental problem that I keep coming back to – over the course of the last century (1910-2010), each of these oscillation cycles averaged neutral, zero, no warming or cooling. The average global temp over that same century rose nearly 1 degree C. I want to try to understand how the cycles could be the dominant CLIMATE (as opposed to weather) forcing during that period.

We can even assume that, cumalitively, the combination of cycles was warm from 1977-2009, when temps went up 0.6 degrees C. And that they were warm from 1910-1942, when temps went up 0.4 degrees C. I assume you’d say the combination was cool from 1880-1910 (or at least the PDO was), but temps fell only 0.05 degrees C. I assume you’d say the combination (or the PDO) was cool from 1942-1977, but temps fell only 0.1 degrees. The warming during warm cycles is greater than the cooling during cool cycles. So, yes, the combination of oscillation cycles has an impact, even a significant one, on global temps. But I’m having a hard time understanding how, for long-term global average temps, the cycles can possibly be in control. The only data we have that correspond with the long-term average global temp is CO2 concentration levels in the atmosphere.

The last 30 years has experienced more frequent El Nino’s, and we know they cause quasi-global warming. What if More El Ninos have been responsible for most of the warming during that time? Whet if we start having more La Ninas, which might be happening now as the Pacific Decadal Oscillation looks like it has switched phase?

Also, ENSO is the most important climate cycle of interest to weather-sensitive industries. So, I report on its progress.

Also, when we have unusual warmth from El Nino, the media reports that this is what we can expect more of with global warming. If they are going to be objective, they need to state that unusual cold is NOT consistent with global warming. Otherwise, their reporting can not be relied upon to give an unbiased view of what’s happening in climate.

I’m sure others can think of more answers to your question…these were off the top of my head.

So is it .5? It cant be much lower because then you have to admit it must be the change in the ocean that is causing it,
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There is nothing about the theory of AGW that predicts the influence of ENSO will decrease. It predicts will continue to see large oscillations around a warming trend.

The warming trend observed in the UAH TL2 dataset is .14°C/decade or .014°C/year. We have an example of what a strong La Nina combined with the solar minimum gives us as recently as 2008. In 2011 we will remain under the influence of the longest and deepest solar minimum in 100 years, and this La Nina has started out gangbusters, so I would predict a similar temperature for 2011 as observed in 2008, plus the .014°C/year warming trend.

That would give us .051 + 3*.014 = .09°C as an average predicted temperature for 2011 in the UAH dataset, assuming the warming trend continues and we see similar influences at play as in 2008. 2008, though, did see the influence of back to back La Nina’s, which is unusual, so I’d probably bump the prediction up some to account for a more normal recovery to neutral conditions by mid 2011. So I’d put my final prediction around .2°C.

.09°C is right about what Mr. Bastardi predicts, being only a little higher than the .04°C seen for 1999, so I would say that if his prediction comes true it in no way would disprove AGW. How is it consistent with AGW? 1999 saw a warmer input from the sun than we saw for 2008 or can expect for 2011, and it had the lingering influence of the monster El Nino of 1998, both boosting temperatures over the influences at play in 2008 or, probably, 2011.

On the other hand he gives a 50% chance of seeing temps as low as during the influence of Pinatubo. Monthly anomalies reached as low -.39°C and trailing 12 month average as low as -.25°C in ‘92-’93. If we were to observe such lows in 2011, it would be a shocker that would bring mainstream theories into question, no doubt. I’d rate the chance of that happening in the absence of a major volcanic eruption to be very slim indeed.

This graph showing an interesting correlation between the SOI and AAO.

http://www.landscheidt.info/images/soi_sam.png

I dont think all these oscillations coming together is a coincidence, maybe it is just a normal trend influenced by low EUV during times of solar slowdown.

My personal view is that relatively cooler equatorial Pacific SSTs allow higher local (seasonal) atmospheric pressure anomalies, reduction of vertical convection, with affects on the NH jet stream N/S latitude and energy levels. A quick look at the current Bermuda High pressure pattern http://moe.met.fsu.edu/tcgengifs/ (GFS panel)
presents a less than organized appearance as result of NH jet stream distortions (IMO).

Again, thanks for your time and thoughts.