Those would be the warm oceans which haven’t been getting any warmer than 2003 then?

The data presented by Spencer is crap. Has he corrected his temps data yet? No? Color me non-plussed…

/sarc

1) I’ll have to do some additional reading and thinking before I can say for sure whether my initial claim on black carbon was accurate, so until I do that I tentatively withdraw the claim.”

It was not that big a deal. The main thing you (and I) missed was the reduction in sulfate aerosols reduced a negative forcing, as pointed out by MarkB.

“2) For something that people claim is settled science, the error bars in that study (and in the IPCC) are huge. “the IPCC AR4 range of -0.6 to -2.4 W/m2.” Wow. Let’s see. If I’m reading that correctly, the uncertainty range for aerosol forcings is slightly larger than the entire estimated forcing from CO2.

In terms of this study, the money quote is here: “we estimate that black carbon contributed 0.9 +/- 0.5ºC to 1890-2007 Arctic warming (which has been 1.9ºC total), making BC potentially a very large fraction of the overall warming there. We also estimated that aerosols in total contributed 1.1 +/- 0.8ºC to the 1976-2007 Arctic warming. ((snip)) the total observed Arctic warming during 1976-2007 was 1.5 +/- 0.3ºC…”

Again, that’s a huge uncertainty. The error range for total aerosol contribution is very close to the size of the contribution. Aerosols could be a minor contributor to arctic warming or they could be contributing more than the total observed warming, leaving all other sources having a negative warming impact.”

Not likely, but possible (for warming to date – CO2 will keep growing). Aerosol uncertainty will be greatly reduced within 5 years, and the prudent course is to assume that the middle of the range is most likely. Low aerosol impact is just as likely as a high impact, and what would you do once that was found to be true? Independent research from paleoclimate tells us that climate sensitivity to doubling CO2 is 2 degrees C (that is 3.6 Fahrenheit) regardless of how the aerosols work out.

“3) The author of the article, Drew Shindell of NASA GISS classifies Black Carbon as an aerosol: “This latter aerosol contribution to Arctic warming results from both increasing BC and decreasing sulfate..” I guess we’ll have to add him to the list of people that dhogaza needs to tell that they “need to understand some simple basics”, dude.”

Aerosol literally means a solution with air as the solvent. Black carbon (or brown as in Asian Brown Cloud) in the air is an aerosol, black carbon on the ground used to be an aerosol, is it OK to still call it an aerosol? It depends on how something is written and how it is perceived, which of course on a blog can be different for different people.

You may have thought that my long, drawn out responses were meant in total to be negative – much was explanatory to reduce the possibility of misunderstanding. One cannot presume what readers know and don’t know.

I want to be very clear here: We do NOT want to repeat the Eocene experience. However, that experience does tell us that there are constraints on how far positive feedback pushes up temperatures.

And events like the PETM show us that the constraints are loose enough that unconstrained fossil-fuel CO2 emissions are very likely to cause major climatic upheaval (from the perspective of human civilization).

The reall story of how our climates work is still unfolding, for those who haven’t already closed their minds.

this is my second favorite. (1st).

“the known is small and the unknown is large,” says the person who doesn’t know. “therefore we should pump as much active material into the system as possible, so that we can learn about the effects more quickly, to advance the science.”

this is the kind of out-of–box thinking we need. climate science needs to get out of the (computer) laboratory and into the real atmosphere. again. and again after that. and some more. we must learn. we must… make mistakes.

BTW, is it me, or does that leaf contain carbon atoms that were liberated from the ground to power british steamships?

Thanks for your excellent and informative contributions to this thread Ben.

The Earth has spent a lot more geological time at temperatures around 8C higher than they are today than it has at a few degrees above ice age conditions which is where we are now. Clearly there are mechanisms which lift us out of ice ages, and others which limit the warming.

Warmer temperatures increase evaporation, which leads to more cloud cover in the tropics. Cloud albedo in the tropics has a greater effect on earth’s temperature than ice at the poles by virtue of the simple geometrical considerations of incident sunlight.

Despite the current GCM’s counting cloud cover as a positive feedback, the data presented by Spencer among others says otherwise. (Time for a bit of Spencer bashing guys). There are many peer reviewed papers including those by scientists JR and others here would regard as ‘on side’ who correctly point out that GCM’s modelling of clouds is wholly inadequate to the real world.

The earthshine project’s data has now been reconciled with the satellite data and shows that cloud cover generally increased post late ‘98 following the strong el nino, and has stayed at an elevated level since. As Pielke Sr points out, the oceans have not been gaining more heat since 2003 according to Willis’ corrected ARGO data.

The reall story of how our climates work is still unfolding, for those who haven’t already closed their minds.

Responding to dhogaza:

dhogaza says: It might help if you remember he’s part of the “team”

Me: Yeah, as I stated in my post. By the way, since he classifies black carbon as an aerosol, are you going to tell him that he “need to understand some simple basics”, dude?

dhogaza says: “The NASA GISS people (like others studying this) had a mystery on their hands: CO2 forcing and known feedback amplification couldn’t possibly explain what was being observed.

There had to be something else going on.”

Me: Right. Unfortunately, climate science is filled with little unknowns like that, and a close reading of this study indicates that they still aren’t sure what is causing the excess arctic warming. Given the error bars involved, aerosols may or may not be a major factor, though the probability is that they are.

This kind of thing is a lot of what generates skepticism. Sites like this trumpet that “the science is settled”, but the reality is that there are a great many uncertainties, of which the true role of aerosols is one of the biggest.

To quote my original statement: “If you look at the working papers for the IPCC, you’ll see that the aerosols are a major source of uncertainty. The problem is that aerosols of various kinds of different affects on climate. Even the same aerosol can have a different impact at different altitudes. Recent studies seem to show that one type of aerosol (black carbon) has a much larger impact than people initially thought.” I went on to extend that in a way I’m not entirely sure is correct after rereading the study, but the major point, the fact that aerosols are a major source of uncertainty, still stands and is endorsed by at least one member of “the team” if such a thing exists.

dhogaza says: Own goal. Congrats!

Me: Let’s see: you basically confirm what I said initially about aerosols and uncertainty. If you want to claim that as some kind of triumph, feel free.

dhogaza says: Interesting that you failed to mention the most obvious consequence, well known to scientists:

The ocean has a far lower albedo than ice, thus will absorb more energy from the sun, setting up a positive feedback.

Me: You did read the part of the post where I said, “And that just scratches the surface.”, right? I would be interested in a source on the bit about ice versus open water being the most significant source of feedback. I’m not saying you’re wrong, but I would like to see a source on it.

responding to caerbannog:

caerbannog says: “And it *did* happen in the past, some 55 or so million years ago. Google up the literal string “PETM -PetSmart” for details.

Me: I was referring to the event 55 million years ago when I talked about tropical forests extending into the Pacific Northwest during the Eocene. Obviously no man-made warming was involved there. There is no consensus on what was involved, though a methane blip is sometimes suspected. I want to be very clear here: We do NOT want to repeat the Eocene experience. However, that experience does tell us that there are constraints on how far positive feedback pushes up temperatures.

As I’ve mentioned a time or two here, methane worries me far more than CO2 does.

Okay. Enough. I would love to keep doing this, but I absolutely have to get back to work. I’ve enjoyed interacting on the site, and I’ll stop by again in a week or two.