Smog and haze in cities reduces the amount of sunlight arriving at ground level. Cleaning aerosol particulates from cities increases the amount of sunlight arriving at ground level. The researchers have found that the clean up can result in a 20% increase in solar radiation.
Firstly, a 20% increase in solar radiation does not imply a 20% increase in temperature. So the immediate question is what impact does that have on temperatures in the locations they examined?
Secondly, the region they examined was picked because it shows a reduction in aerosol particulates over the past 10 years. This means the selected area cannot be representative of the whole planet. So what relevance this research has in terms of global warming is questionable. Certainly the authors don't even mention it in the abstract.
What this question shows is the danger of abstracts. This paper probably has nothing to do with climate change. Why assume it does? Or was it the 20% that caught your eye which, coupled with a bit of bias, led you to draw the conclusion that it 'coincided with the recent strong warming period'. That's a leap. And a leap too far.
It's for a small area that is fairly far north. Most of the sunlight absorbed by the planet is done at the equator. So a 20% increase for a small region at high latitude isn't as large as it might seem in terms of the global energy balance. Not that you really give a hoot about a rational interpretation. Nor, of course, does Watts, where you got this from. But don't let me stop you ding-a-lings from getting led around by your little nose rings.
A decrease in aerosols, but a big increase in particulates. Have you checked the MODIS over Asia for the past few years? I thought that this would have caused more cooling. What do say, Mike? I'll see your less aerosols and raise you some particulates. Or, do you just want to declare a split pot?
I'm finding that natural climate variability is way too strong to contradict. A recent enlightening statistic that the actual change that humans have caused in our atmosphere is less than 0.00336% since 1880.
A change in the atmospheric CO2 content as it pertains to the entire atmosphere (0.0112% or 112ppm) multiplied by the inferred human contribution (3%)
There's no evidence of any other catastrophes since 1880 that haven't happened before. Temperatures are well within natural variability and then I found that the IP CC was way off base in their 2001 predictions (1C rise by 2010). It is becoming more evident that we really don't have that much impact.
It is a good point. I wonder why they don't at least go back to the 1970s. It would be instructive to look at China and Asia as well if we are going to figure out what anthropogenic aerosols cause. China and India (and others) have been blamed for causing the recent cooling. Our "clean" air is now blamed on the recent warming which is of course missing. Very odd indeed.
This applies mainly to Northern Europe, where in the 80's and 90's brightness was found to increase a lot, but this leveled out as is not increasing.
I believe that with soot, aerosols, smoke, we alter our climate more than with CO2
They have put a number on global dimming which explains the mid-century cooling. Other than a specific number this adds nothing to what has been long known. The analysis does not cover North America so I have no idea why you even mention it.
Here is the abstract with the paper unfortunately behind a paywall: http://proceedings.aip.org/resource/2/apcpcs/1527/1/579_1?isAuthorized=no
My first thoughts are that the paper mentions "the last decade" as a time frame. A decrease in aerosols should have been accompanied by some warming which is certainly not the case for the past decade. As well, the start of the decrease in aerosols began at least in NA with the Clean Air Act in the late seventies. This coincides with the recent strong warming period up to 1998 (end of 20th century).
It seems to me this might be another case of negative discovery in climate science. It sure has me confused.
Does anyone have any other insights?
