Probably yes, with good reason.

But if we are talking about advanced capabilities, I see considerable popularity for a service (space based mirrors?) that could offer seasonal reduction in mid-day sunlight strength to local areas. Selling that sevice (say to southern US cities) could a profitable business.

Taking up the sci-fi notion of costless global climate control, it would be tempting and probably a temptation humanity would not resist, but I would only advocate extreme caution. Natural systems have a way of surprising us with unforeseen consequences and subtle interconnectivities.

Who could guarantee a little tweak to ease Canadian prairie winters would not alter percipitation patterns over major agricultural regions etc?

As you say, Scott, the first order of business would be to halt the continuing rise of CO2, not as interference with nature but as the cessation of interference, and then I would advocate lowering it til we are sure sea levels won’t rise, there is just too much global infrastructure dependant on the sea’s current level. If that mean temps around what they are now, I think we would be alright though it seems likely Australian droughts and corral reef death could continue…so a little lower might be safer.

Would we really imagine that life could be so much better with a climate tweak (or two, or three) that the risk of experimenting with our only viable home planet is worth it?

Another thought that occurs to me, in anticipation of more accusations of being a luddite, is that such geo-engineering projects would surely require the kind of global organization that seems to so frighten the anti-UN, anti-Kyoto crowd. Would the same people who fight global emissions controls on the grounds that the UN will take over the world advocate some necessarily similar global organization playing with the world’s climate?

I accept your facts, but not your implications. There are a couple of problems with your #1. First off, as we all know but the dogma makes us frequently forget, temperature leads CO2 so the statement “it is a physical impossibility for GHGs to have caused more than the 33 deg C warming in this time” is a non sequitur. Further, even if it were true that CO2 actually caused all the warming, the heat sink of the ocean and ensuing time delay of heating makes your statement irrational anyway.

Your #2 is correct, but has absolutely nothing to do with anything I said.

The biggest problem with your logic is that you are attributing the entire 33 deg C to ghg’s. You are neglecting convection – by convection I mean vertical convection. The lapse rate is approximately the wet adiabat, and that is not a coincidence. We would approach 33 deg C colder without any ghg’s, but there would still be some (very minor) convection, therefore some lapse.

If there were no convection the 33 deg C difference would be much greater. Convection moderates the surface temperature toward the wet adiabatic lapse rate. So, the question *really* is, how much lapse is due to the mechanics of convection vs. radiative effects. If one considers (apples and oranges I know, but putting a “number” on it) that convection controls 23 deg C, then there is only 10 deg C left for ir. 10 deg C was a number I pulled out of … thin air. On the other hand, if we remove the feedback of convection, the surface temp under pure forcing could be 40 deg C or greater – another number I pulled out of thin air.

Maybe you can tell me – Since convection would be basically nil with no ghg’s, how much would it increase going from 280 ppm to 380 ppm, or 480 ppm (assuming the locomotive of flora does combine with future inherent efficiences based on the market to prevent us from actually getting there) – let alone to 560 ppm.

Thanks for your comments.

It appears you are seriously misinformed when you say “GHG’s have caused from 10 to 40 deg C of global warming since humans arrived”.

Consider these widely accepted facts:

(1) Homo sapiens sapiens has existed on the planet for less than one million years.
(2) Current levels of GHG have not been exceeded for at least 3 million, and possibly 20 million years.
(3) The antarctic ice core data shows us that the ice ages over the last million years or so experienced minima of about 180 ppm for CO2, and about 8 deg C less than pre-industrial for temperature.
(4) The current global average temperature is about 15 deg C. In the complete absence of GHG, the global average equilibrium temp is about -18C deg C, or 33 deg C less than today.

These facts imply:

(1) That because humans have never lived in a world that had more GHG than today, it is a physical impossibility for GHGs to have caused more than the 33 deg C warming in this time (i.e. the whole warming effect of GHG). This rules out the top third of the 10-40 range you assert.
(2) In fact, the earth would be uninhabitable by humans (and most other forms of life) if GHG ever were completely removed from the atmosphere (the closest we every got is arguable the “snowball earth” events of 600-800 million years ago, and there was considerably more than zero GHG then, even though the global surface temperature was below freezing almost everywhere). Thus, about the middle third of your 10-40 range is also ruled out as a biological impossibility.
(3) In fact, the paleoclimatic evidence tells us the answer is indeed smaller than the physical and biological impossibilities that your range implies: that CO2 was as low as about 180 ppm, and the temperature about 8 deg C less. This is 100 ppm variation in CO2 (other gases varied as well) and an 8 deg C variation in temperature over the course of human presence on the earth (entirely outside of your asserted range, though given uncertainties variations as high as 10 deg cannot entirely be ruled out). This is what I was referring to in my original comment when I said “relatively modest” variations in GHG forcing.

Further, since the rise of large human civilizations (i.e. the invention of writing and agriculture, probably about 10,000 years ago, and in any case since the last deglaciation) there has been very little variation in GHG forcing at all. It is in that context that the large scale GHG changes stretching back over long time periods (hundred of millions to billions of years, including periods when CO2 is believed to have been 10-30 times current levels) are likely irrelevant to the history of specifically human experience with climate.

Hope this helps clarify some of your apparent confusions,

Best,
Scott

“Compared to what humans are doing now, there has been only relatively modest GHG forcing since humans have been on the planet” is a wholely incorrect statement. Ghg’s have caused from 10 to 40 deg C of global warming since humans (depending on one’s classification of “Homo sapiens”) arrived, and the ultimate consideration of the role of convection, which is quite unknown at this time.

So, what we are causing now is an increase of less (maybe much less) than a 10% increase.

And Coby – my simple response is LOL. I relented and checked out your blog – it’s easy to see your target audience is not … shall we say … enlightened.

Let me ask you, how much experience have you had with calculations involving one small word -”joules”?????

A picture of alarmists is clearly emerging – Either:

A: Carbon traders

B: Those on the fear of change (in particular here global warming) dole,

C: Those who fall under the spell of A or B above.

Nordic – How’s this: Skiing into the midnight sun off Mt. Michelson? Of course I’d rather downhill…

There. Feel better now?

And just so you know, I like to cross-country ski in the winter and fish for trout in the summer. Therefore we should set the gobal temperature to something analagous to the depths of the little ice age. This would greatly expand the days available for skiing and streams suitable for trout habitat (in this country). Seems like an ideal solution to me.

What are you waiting for? Get crackin’!

I don’t agree. The world was in the middle of the Little Ice Age before the Industrial Revolution. I fail to see how the Little Ice Age is a clear goal.

Yes, you are absolutely right, but that is largely irrelevant to the human-centric problem that is current-day global climate change. Compared to what humans are doing now, there has been only relatively modest GHG forcing since humans have been on the planet (only enough to cause the last ice-age), and essentially none at all (relative to what is now underway) since the dawn of recorded human history (which only really got underway after the glaciers of that last ice age receded).

Indeed, for our present predicament, most paleoclimatologists seem to view climate changes of times past as more cautionary tale than reassurance. I wouldn’t have wanted to be around for the “snowball earths” of the neoproterozoic (600-800 million years ago), for example.

Best,
Scott

From my perspective, the “obvious starting point” is to slow, and eventually halt, the build-up of GHG in the atmosphere. I suspect we agree on that much. If we seriously engage the hypothetical (where we are free to “tune” the climate to whatever people agree on), however, I am not sure what is obvious. If we go even further: assume climate manipulation is free, and we can even fine tune different parts of the earth differently. Wouldn’t some (maybe even many) want to make their part of the world at least “a little bit” better than what nature gave them? Mightn’t Russia want warm water ports and a breadbasket in Siberia? Mightn’t Canada want a real northwest passage? Maybe the Maldives (and perhaps New Orleans and Denmark?) would actually prefer a little sea-level lowering. Climate becomes another nature resource fully or partially co-opted by human technical know-how. Whether that is good or bad, the question is: what do we do with it, how do we manage it?

Granted, we are in the realm of science fiction here, but to paraphrase Isaac Asimov (or was it Robert Heinlein?) for practical purposes, the world 100 years from now is probably indistinguishable, as far as we are concerned, from science fiction anyway.

Best,
Scott

(FYI, in case you care whether I engage you or not, the only reason I have bothered to reply to you this time is because I am charitably assuming you just don’t know what luddite means)