Andrew, first there has been a couple of papes looking at whether we might plant aerosols in the upper parts of the atmosphere as a means to offset the heat trapping aspects of CO2. This would involve putting those aerosols high enough so as to not become health pollutants. My concern about this is whether reflecting sunlight might create problems for photosynthetic organisms.

Second, you gotta love the victimology of current skeptics. From the Weekly Standard: "The rollout of the IPCC report and the Guardian story attacking us coincide with the climax of what can be aptly described as a climate inquisition intended to stifle debate about climate science and policy. Anyone who does not sign up 100 percent behind the catastrophic scenario is deemed a "climate change denier."

Well, that's not true, because Roger Pielke Jr. has been taking calls left and right from the press and was even invited to give congressional testimony from the Republicans.

Benny Big Eye

It seems the carbon skeptics are losing collective credibility and their voice in the press.  People, including journalists, are aware that the conservative IPCC AR4 does not evaluate many positive feedback mechanisms.

The next battlefield will be "solutions" policy.  The AEI may find new funding for that battle.  Where does the funding come from (more than $160 million the last seven years)?

>> a climate inquisition intended to stifle debate about climate science and policy. >>

The main technique to quell open discussion is silence.

If there was nothing to hide, why the silence?????
Surely an open debate addressing the causes of Global Climate Change is of world importance, or is there something more important that this world......

Mad people would say here and now is more important that tomorrow, and that money and lifestyle must not be assailed even if this attitude leads to the total destruction of civilisation.....

If a dissenter has something to say, then science can cope with that, so really there is nothing to fear with the science, it is the mad people and their hidden agendas and their precious egos that wish to silence dissent.  

We all fought hard to counter this trait in dominating human beings, but now apathy and  effluent affluence has made we just can't be bothered.

LOL y'all are complicit, but y'all will have to pay the piper the day after tomorrow, which is not very far off.

Andrew, just to make sure I have this straight, this would not affect Hansen's .5C lag figure, but could change the rate at which it's made up?

Steve-

I'm not sure what 0.5°C lag Hansen's talking about.  When most people talk about lag in the climate system, they are talking about thermal lag caused by the oceans.  This aerosol effect would be an additional warming that would occur after developing countries clean up their air.  

Thanks!

>> thermal lag caused by the oceans>>>

That trapped heat has massive potential to disrupt civilisation, because the ocean heat must be lost via evaporation (whenever that can occur) and the result of that process is cloud banks.

It is the cloud banks that deliver the ice and snow for an Ice Age to occur.  Heat drives an Ice Age, not cold.

Tis somewhat interesting that AD, a climate scientist remains silent....... something to hide Andrew?

>> something to hide Andrew?

Indeed and all the other so called environmental blogs are all set up by Big Oil it would appear.

You the readers, are being hoodwinked into believing their insipid crap.  They tell you greenhouse gases are your fault, no! they are Big Oil's fault.

They have turned your head away from the real problems and made you run scared.

And the blog organisers, here, real climate and many others are just spreading propaganda sanctioned by Big Oil.

If this is not true, why the censorship, and why the lack of meaningful discussion and why the head in the sand attitude.

All the so called research is based upon the Northern Hemisphere, and it is all corrupted by inadequate computer programmed projections.

>>> Two of Greenland's largest glaciers shrank dramatically and dumped twice as much ice into the sea during a period of less than a year between 2004 and 2005. And then, less than two years later, they returned to near their previous rates of discharge. >>> University of Washington

Sadly you guys are falling for it.

Oil is the problem and yes the oil companies must suffer.

Would you rather Them or You.

Remember the owners of this Earth are the children, and you never think of them do you.  

THE neocon rag dissing GHG climate change?  I thought neoconmen only cared about invasion, occupation, and nation building.

Anyway, catch the "Colbert Report" rerun today.  Colbert goes through all the objections to the IPCC and even invents a couple more.  Excellent!

http://amazngdrx.blogharbor.com/blog

Lockforward-

First, the Weekly Standard article clearly refers to man's impact on warming, which my post addresses and shows is simply wrong.  If they were referring to sea level, I assume they would have said sea level.

The 2007 IPCC temperature estimates are presented in a completely different format than the TAR's.  The numbers you quoted, 1.4-4, is the range of "best estimates" of the six scenarios.  If you include the "likely" range of each scenario, the upper end extends to over 6 deg C.  Pretty similar to the 2001 report, which did not explicitly break out "best estimates" from "likely".  

As far as sea level goes, I view the 2001 and 2007 reports as roughly similar.  The 2001 IPCC did not give a "best estimate", but if they did it would probably lie within the 2007 range.  And considering the uncertainties, including known processes not included in the models, there is actually great consistency in the results.

Regards

Thanks for your reply, Andrew.

On closer examination, I think you are right about temp, but not sea level. Look at chart 5d on p.14 in the TAR. The outer perimeters of each seem to be the extreme ends of the models, and thus a closer statistical match to range and not the best estimate numbers in the 2007  report.

Likewise, 5e, dealing with sea level, is in the same format, and yields the 8 to 99 cm. range. As you note, the 2007 IPCC gives no best estimate of the models, only their range, and thus the 2007 18-59cm range seems to be the statistical twin of the 2001 8-99 cm range. That a "best estimate" range would take that upper end even lower than 59 cm is even more encouraging, though such a range would not be   comparable to the 2001 range.

So, while I'm encouraged by the lowering of the best estimate range for temps, your point is well taken. It does appear, however, that a substantial downward revision has occured for projected sea level increases.

What do you think?

Regards,

Bill

You've clearly done more work comparing the 2001 and 2007 reports for sea level than I have.  However, I do have a sense that given the rate at which our knowledge of sea level change is evolving, as well as processes that we know are missing from the models, I take the model estimates as "order of magnitude" only.  

Thus, we know sea level rise will very likely not be 5 cm and it very likely will not be 5 meters, but within the 10 cm to 100 cm, we really just don't know.  That's my interpretation, anyway.  

Thanks for your comments.

The AR4 sea level ranges exclude "future rapid dynamical changes in ice flow" (page 13) which is why it differs from the TAR.  That is because recent and rapid ice melt has defied understanding, and not in a good way.

It also does not "abandon" the "Hockey Stick."  Quite the opposite, since it makes an even stronger statement.  "Paleoclimate information supports the interpretation that the warmth of the last half century is unusual in at least the previous 1300 years" (page 10).

The sea level rise depicted in Gore's movie would be the inevitable result of the breakup of Greenland or West Antartica, which would take some time.  The sea level estimates are for this century only.  If there exists a tipping point, little to nothing we do could reverse this once underway.