Clifford Posted April 25, 2011 Share Posted April 25, 2011 A most interesting documentary. About 10% to 20% LESS sunlight reaching the planet's surface over the last few decades. http://www.directdow...atch-online-02/ http://video.google.com/videoplay?docid=-2058273530743771382&hl=en# (Google Link Added) Link to comment Share on other sites More sharing options...
skierinvermont Posted April 25, 2011 Share Posted April 25, 2011 A most interesting documentary. About 10% to 20% LESS sunlight reaching the planet's surface over the last few decades. http://www.directdow...atch-online-02/ As the documentary discusses, these aerosols have a strong cooling effect, which makes it all the more remarkable how much we have warmed. From the IPCC report: Link to comment Share on other sites More sharing options...
tacoman25 Posted April 25, 2011 Share Posted April 25, 2011 As the documentary discusses, these aerosols have a strong cooling effect, which makes it all the more remarkable how much we have warmed. From the IPCC report: There were a lot more aerosols in the atmosphere in the 1950s-1970s. Which is what some scientists attribute the lack of warming in that period to - others more to the -PDO phase. Link to comment Share on other sites More sharing options...
skierinvermont Posted April 25, 2011 Share Posted April 25, 2011 There were a lot more aerosols in the atmosphere in the 1950s-1970s. Which is what some scientists attribute the lack of warming in that period to - others more to the -PDO phase. I don't think so.. I think that's when aerosols were increasing the fastest. Are you sure about that? EDIT: well I found this which appears to indicate aerosols have continued to increase.. one is for the surface and one graph if for the atmosphere as a whole: Link to comment Share on other sites More sharing options...
superjames1992 Posted April 25, 2011 Share Posted April 25, 2011 Time to get some old-school (pre-Montreal Protocol) aerosol cans and spray some CFCs into the atmosphere to get some cooling going on, the ozone layer be damned!!! Link to comment Share on other sites More sharing options...
skierinvermont Posted April 25, 2011 Share Posted April 25, 2011 Yeah I'm pretty sure aerosols have continued to increase. Link to comment Share on other sites More sharing options...
Clifford Posted April 25, 2011 Author Share Posted April 25, 2011 Time to get some old-school (pre-Montreal Protocol) aerosol cans and spray some CFCs into the atmosphere to get some cooling going on, the ozone layer be damned!!! Sorry, You can put your hair spray away. I think they are discussing a different type of Aerosol. The question that should come up though... is ULSD a true benefit? At this point, I think there is still benefit of cleaner air. In the film, they discussed that the main contribution of jet trails (contrails) causing high level clouds was the decrease in the difference between High & Low Temps. I.E. Cooling in the day & warming at night, which is likely the greatest contribution of water vapor. Keep in mind that plants require sunlight to grow which is not the same as heat. Link to comment Share on other sites More sharing options...
tacoman25 Posted April 25, 2011 Share Posted April 25, 2011 Yeah I'm pretty sure aerosols have continued to increase. NASA disagrees. http://www.nasa.gov/centers/goddard/news/topstory/2007/aerosol_dimming.html Link to comment Share on other sites More sharing options...
skierinvermont Posted April 25, 2011 Share Posted April 25, 2011 NASA disagrees. http://www.nasa.gov/...ol_dimming.html Yeah but I think that only includes certain types of aerosols located in the LT.. aerosols near the surface and aerosols in the stratosphere also matter a great deal I believe. I'll do some more digging tomorrow but a couple things I've read indicate it's continued to increase. Link to comment Share on other sites More sharing options...
tacoman25 Posted April 25, 2011 Share Posted April 25, 2011 I don't think so.. I think that's when aerosols were increasing the fastest. Are you sure about that? According to theory, aerosols that block sunlight only remain in the atmosphere for a few years. So after the Clean Air Act was passed in the 1970s, areosol pollutants were reduced significantly. Which is part of the reason some scientists believed the global warming trend resumed about the same time. However, it wasn't until about 15 years or so later in the early 1990s that the global dimming trend appeared to reverse (as in, over the last 20 years the world has actually been getting less dim), so the link is sketchy at best. Real Climate has actually done an article about global dimming and aerosols and the uncertainty involved, I read it awhile ago. Link to comment Share on other sites More sharing options...
tacoman25 Posted April 25, 2011 Share Posted April 25, 2011 Yeah but I think that only includes certain types of aerosols located in the LT.. aerosols near the surface and aerosols in the stratosphere also matter a great deal I believe. I'll do some more digging tomorrow but a couple things I've read indicate it's continued to increase. Everything I have read indicates that the global dimming trend reversed a couple decades ago. Not sure about the link to aerosols. Link to comment Share on other sites More sharing options...
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