Could Global Dimming be the cause for the divergence between tree ring data and actual temperature?

[Uncle Joe]

Most plants needs sunlight for photosynthesis, if the sun's radiation reaching Earth's is reduced, I would imagine this would have an adverse effect on tree growth, in spite of real rising temperatures due to the heat trapping effects of global warming? If that's the case then disregarding modern tree ring data as a determinant of global temperature, for actual recorded temperatures seems logical to me.

Furthermore, it seems to me, if this is in fact the case, the act of having to disregard modern tree ring data for this reason strengthens the argument that humanity; and it's industrial creations have evolved to the point of having major influence on Earth's Biosphere.

http://www.realclimate.org/index.php/archives/2005/01/global-dimming/

<snip>

“Global dimming is indicated by measurements over land areas in many regions in the world and may therefore be a real phenomena. Though there are serious issues with the quality of some of the data (birds drinking out of uncovered evaporation pans, drift and inhomogeneities in the solar radiation measuring instruments), in the most global assessment, Beate Liepert estimated that there was globally a reduction of about 4% in solar radiation reaching the ground between 1961 and 1990. While more recent indications are that the trend may have reversed in the last decade, it could still be significant. Assuming for the sake of argument that these data are valid, what could have caused this? A change of that magnitude in the incoming solar radiation itself is not possible since satellite observations would have seen it. Thus, it must be something that is happening in the atmosphere to intercept solar radiation. There are only a few possibilities: clouds, water vapour or aerosols.”

<snip>

http://www.globalissues.org/article/529/global-dimming

<snip>

Burning of fossil fuels is creating two effects

Two effects of fossil fuel productions are:
• Greenhouse gases that cause global warming
• By-products which are pollutants that cause global dimming

As well as fossil fuel burning, contrails is another source
Contrails (the vapor from planes flying high in the sky) were seen as another significant cause of heat reflection.

During the aftermath of the September 11, 2001 terrorist attacks in the United States, all commercial flights were grounded for the next three days.

This allowed climate scientists to look at the effect on the climate when there were no contrails and no heat reflection.

What scientists found was that the temperature rose by some 1 degree centigrade in that period of 3 days.

Global Dimming is hiding the true power of Global Warming

The above impacts of global dimming have led to fears that global dimming has been hiding the true power of global warming.

Currently, most climate change models predict a 5 degrees increase in temperature over the next century, which is already considered extremely grave. However, global dimming has led to an underestimation of the power of global warming.

<snip>

P.S. Edited for bolding on last column.

[kestrel91316]

1. Ask a PhD climatologist. I'm tired of arguing about this denialist crap.

[Uncle Joe]

2. One thing I remember vivdly, after 9/11 when the planes didn't fly for several days,

the sky never looked bluer.

[kestrel91316]

6. Exactly. The sky these days is more white than blue, and it's from

all the crap up there that gets in the way of the photons and scatters them.

[jpak]

3. Deniers claim that enhanced solar activity is responsible for global warming

even though the trends in global temperature and solar radiation are opposoite in sign.

It appears they cannot keep their stupid ignorant stories straight...

:thumbsdown:

[Uncle Joe]

4. Where did you get that out of the O.P.?

:shrug:

[jpak]

5. It's ignorant stupid psueodoscience nonsense - and other deniers make the opposite claim

but your concern is noted

[Uncle Joe]

8. I still don't know what you're talking about.

1. I'm not a global warming denier.

2. I posed a question based on logic and my understanding of the facts, which part of that is pseudoscience?

[jpak]

11. Solar radiation reaching the Earth varies by only 0.1% over the 11 year sunspot cycle

That insignificant change in solar output does NOT affect global or regional photosynthesis - any claim to the contrary is ignorant pseudoscience.

[Uncle Joe]

12. I never said it did, Global Dimming has nothing to do with the sun's radiation output,

it has to with aerosols, and particulates from air planes and such which fill our atmosphere and thus block some of the sunlight reaching the surface of Earth.

The affect actually masks the heat trapping characteristics of global warming, otherwise Earth would be hotter from than it is.

Of the two forces global warming is stronger than global dimming and we're still heating up but that's not to deny the adverse effects from global dimming on plant life as I proposed might be the case.

Edit for P.S. While .1% over an eleven year cycle may not be much, 4.% annually may be enough to cause effect.

[Ian David]

13. Aren't we at an all-time solar activity LOW? n/t

[rug]

7. Global Dimming was the main factor in the 2000 election.

[Uncle Joe]

9. I can agree with that, rug. n/t

[Union Yes]

10. Look across the horizon on a sunny day and I see more haze than anything else. knr nt