2011-07-23 03:00:07New summary paper on global brightening and dimming
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

"Enlightening Global Dimming and Brightening"

2011-07-23 04:54:39
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Just skimmed it over and will mention it in the first Michaels Mischief post.  I think it deserves its own post though.  It's a good follow-up to Rob P's post on Kaufmann.

Basically there was significant global dimming observed 1950-1980, followed by significant brightening until 2000, since when there's still been brightening over N America and Europe, but dimming over east Asia, as expected due to their aerosol emissions.

2011-07-23 09:03:34
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.226.173

Another paper on aerosols: The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change -Solomon (2011)

Don't know about you guys, but the 'Faustian bargain' is looking a lot worse than I imagined.

2011-07-23 09:44:19
Rob Honeycutt

robhon@mac...
98.207.62.223

OMG!  RF of -0.1W/m2 since 2000?  That's a shocking number!

2011-07-23 09:55:29
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

RobH,

Yeah, saw that.  Not exactly huge is it...

2011-07-23 10:02:47
Rob Honeycutt

robhon@mac...
98.207.62.223

I thought the opposite.  But I just realized I was confusing W/m2 with degrees per decade.  What is the change in RF for CO2 over the course of a decade?

Let's see.  She states that...

"As a point of comparison, over the decade since 2000, carbon dioxide increased by about 0.5% per year (2), leading to a change in radiative forcing of about +0.28 W/m2. Thus, the rapid rates of observed change of stratospheric aerosol imply decadal changes in radiative forcing that are significant compared to those of the much larger but more slowly varying abundance of carbon dioxide since 2000."

 

2011-07-23 13:08:31
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.45.39

Yeah, I thought the opposite too. Not only are human-caused troposheric aerosols shielding us from further warming, but stratospheric volcanic aerosols too. Coupled with a period of extremely low solar activity and we still are experiencing warming and profound changes in weather. What's gonna happen when the 'aerosol mirror' is shattered? Abrupt global warming? Horrendous heatwaves?

2011-07-23 13:16:53
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
64.134.160.12

Verily, 'tis Fenris at the door...

2011-07-23 15:56:22post
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.106.238
You gonna do a post on either of these papers, Rob P? You could even combine them into one. You can be our resident aerosols expert :-)
2011-07-23 15:58:28
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.106.238
Oh and yeah, CO2 RF is 5.35 * ln (390/370) = 0.28 W/m2 over the past decade. Aerosols being one-third as large is pretty significant.
2011-07-23 16:08:07
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.220.226

Ah, bugger!, I was going to start writing about heatwaves and floods. Righto, I'll get right on it -seems consistent with the OHC and surface temperature records.

2011-07-24 02:56:33
Rob Honeycutt

robhon@mac...
98.207.62.223

Yeah, that's what I thought.  Solomon is saying that a great deal of the warming of the past decade has been masked by aerosol effects.  So, I think the past decade has seen about 0.12C of warming.  That places the actual CO2 induced warming back to 0.16C/decade.  Same as the previous 30 years.

So, my question would be, if China starts cleaning up their aerosols does that CO2 induced warming jump back in?  We won't just see a resuming of the 0.16C/decade, we'll see an acceleration that brings us back into line with that rate of warming that is occurring over the longer timeframe.  Does that make sense?

2011-07-24 03:32:37
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.106.238

It just depends on the degree that China reduces their aerosol emissions.  Like if they suddenly reduced them to near zero, yeah, we would see very rapid warming.  But it will be a more gradual process, so the warming trend should gradually be unmasked, so the trend should accelerate, but relatively slowly.

2011-07-24 04:03:06
Rob Honeycutt

robhon@mac...
98.207.62.223

Dana... Thanks, that confirms the point for me.  The CO2 induced warming is still accumulating even though it's being masked.  This is maybe an important point to clarify in an article.  As SO2 is reduced there should be a catch up period that brings us into line with the longer term warming trend.

Maybe it's getting close to time to go back over to NoTricksZone and double down on that bet.  ;-)

2011-07-24 04:13:59
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Hi all,

I stand corrected.  That is indeed a significant negative forcing.  I think I was getting confused with the net direct negative forcing from aerosols ~ -1 W m-2.

2011-07-24 14:09:28
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.73.57

Waiting for this paper to be published: Patterns of surface solar radiation dimming and brightening at the turn of 21st century - Hatzianastassiou (2011) 

"An overall global dimming (based on coastal, land and ocean pixels) is found to have taken place on the Earth under all-sky conditions, from 2001 to 2006, arising from a stronger solar dimming in the SH (SSR = -3.84 W m-2 or -0.64 W m-2/yr) and a slight dimming in NH (SSR = -0.65 W m-2 or -0.11 W m-2/yr), thus exhibiting a strong inter-hemispherical difference."

2011-07-25 05:42:18
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Interesting Rob,

OK now those numbers are quite alarming.  It looks like Hansen's hypothesis may be right....