Hansen's estimate is quickly becoming outdated (well it is already quite much) - present dimming is significantly more potent than just -1.2C global average.
There is artificial (intentional, we can indeed call it "geo-engineering") component to it last couple years, which is quickly increasing. The technology which is in part described by US patent 5003186 (
http://patft.uspto.g...RS=PN/5,003,186 ) - is being used on a massive scale nowadays - there are reports of Al oxides in lakes, ponds and soils with concentrations about 50-60 times above allowed (officially safe) maximums.
The thing was supposed to halt the warming, i heard one of most significant US researchers in this area saying that the thing is "riding on our grandkids' necks" when he was talking about (un)ethics of the thing. However, it seems that the technology only slowed the warming, somewhat, in late 2000s and early 2010s, but did not halt it. No wonder. Thermal intertia of the oceans. And now that Arctic snowpack is reduced roughly speaking by half, september sea ice volume by more than 80% - both things in compare to 1979 values that is, - well known albedo effects kick well in, pushing the Arctic into massive further warming (methane emissions which already are much intensified, too).
I have no doubt Hughes&Co can properly see the dynamic. If they could halt the process, they would. THey did not. Means they can not. Now, it is even harder to do than it'd be just a few years ago. This means they can't do it, at least with this tech, for sure now.
But slowing is still achievable, even if increasingly little slowing; and is desirable. Thus expect further increase in global dimmming, - and further increase of "hit back" when (not "if" - when) the spraying will stop, and i mean both geo-engineering spraying stopping and "side-effect" spraying such as micro-soot particles from coal power plants and such.
By the time it'd stop, i think the impact - in the form of rapid additional warming, - would be on the order of extra 2...5.5 degrees celcius, i estimate. This estimate includes positive feedbacks such as increase of methane emissions due to initial smaller increase of temperature, which in turn will make more greenhouse effect and thus further rise of temperature; but this estimate also includes negative feedbacks, for example the cornerstone fact that amount of energy radiated by hot body (the Earth in this case) into colder surrounging (the space at ~0 kelvin near Earth, in this case) - is proportional to 4th power of temperature difference.
And on the unrelated note, there are places on Earth which are very far from any industries, any major airlines, and major human population - but which nonetheless have some relatively small cities significant enough to keep the temperature record locally. In such places, effects of global dimming are much reduced - especially when main winds of the region are not blowing from much "dimmed" areas, but from relatively cleaner parts of the Earth. One such place is russian city of Petropavlovsk-Kamchatskiy - in the very far east of the country, well within Pacific ocean system, circulated by relatively clean - non-dimmed, - air masses. Its wikipedia page lists average temperatures for each month for years 2001....2012 (
check the 3rd table, columns are 12 months and last column is annual averages). Someone deleted values in the last column of the table. May be because they thought there is some mistake. May be because they didn't want people to get alarmed. But there was no mistake, and indeed in this region of the Earth, average annual temprature did indeed rise by about 3 degrees celcius just during 2001...2012 - one can easily see it from monthly values in the said table, anyways.
*Moderator note-Readers-second link, you'll have to hit the translate button-it's in Russian.
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F.Tnioli, on 10 April 2013 - 01:59 AM, said:
