Outdoor Solar Lights

"An Open Letter to the Council of the American Physical Society
By webmaster | August 12, 2009 at 07:47 PM EDT

Regarding the National Policy Statement on Climate Change of the APS Council: An Open Letter to the Council of the American Physical Society

"As physicists who are familiar with the science issues, and as current and past members of the American Physical Society, we the undersigned urge the Council to revise its current statement on climate change as follows, so as to more accurately represent the current state of the science:

"Greenhouse gas emissions, such as carbon dioxide, methane, and nitrous oxide, accompany human industrial and agricultural activity. While substantial concern has been expressed that emissions may cause significant climate change, measured or reconstructed temperature records indicate that 20th 21st century changes are neither exceptional nor persistent, and the historical and geological records show many periods warmer than today. In addition, there is an extensive scientific literature that examines beneficial effects of increased levels of carbon dioxide for both plants and animals.
Studies of a variety of natural processes, including ocean cycles and solar variability, indicate that they can account for variations in the Earth’s climate on the time scale of decades and centuries. Current climate models appear insufficiently reliable to properly account for natural and anthropogenic contributions to past climate change, much less project future climate.

The APS supports an objective scientific effort to understand the effects of all processes – natural and human –on the Earth’s climate and the biosphere’s response to climate change, and promotes technological options for meeting challenges of future climate changes, regardless of cause."

["If APS reviews its statement in light of recent, more accurate research, its council may be inclined to adopt the revised statement on climate change from the open letter. But will APS leaders have the courage to do so in the face of intimidation by political leaders who don?t want to change their policies? It wouldn’t be the first time that political power trumped science."]

http://conservativebusinessnetwork.com/cbnblog.php?s=an-open-letter-to-the-council-of-the-american-physical-society

I doubt it. They will bend in the wind to the political pressure from the leftists. It is easier than trying to fight them and there are potential goodies in it for them if they exaggerate or allow the exaggeration of the effects.

In a microbrew induced haze I attempted this question a couple of nights ago but came across as coherent as a monkey, so…

My understanding of albedo is as a general unitless measurement for the reflectivity of a surface. With that in mind and with the following picture Dawei posted of my home town (ironic) at first glace it certainly appears that farms would have a higher albedo than forested land and thus the increase of farmland would lead to a negative forcing shown in the second link.

http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

However the darker color of the leaves absorbing more light and radiating heat can’t be compared to, say, dark rock because leaves convert the solar energy into chemical energy instead of simply storing and radiating heat. In fact a scant percentage of light absorbed by leaves is radiated as heat.

A cursory review of the literature shows no indication of this being taken into account in albedo measurements so is the negative forcing of land use changes truly accurate? Does the absorption of light and radiation of heat energy by land in fact play less of a negative role and potentially more of a positive one when the heat island effect of concrete, asphalt and steel is taken into account? What are your thoughts?
@Dana, maybe I’m misunderstanding your response, but my impression is that the land use albedo is more concerned with dark green forests converted to lighter colored farms causing more reflection and thus a negative forcing instead of absorbing radiation in excess of normal levels

@Dawei – I’m not comparing it to a rock, my point is that plant leaves (often darker colored) absorb light and convert it to chemical energy whereas a rock absorbs the light and immediately radiates heat to the surrounding environment which increases warming. Although virtual guys description of conversion of biomass to energy contradicts the idea. And I’m technically from Gainesville, just NW of city limits by a few miles.

Albedo is indeed a dimensionless number – it’s energy out divided by energy in. It doesn’t matter to the calculation what happens to the energy that stays with the planet.
Energy absorbed can show up as immediately or it can be bound in a chemical reaction, as in photosynthesis. When chemically bound, the energy is not detectable as heat, it will only show up that way if the chemical reaction is reversed – as in burning or metabolism.
About 1-2% of the light hitting a cornfield gets used photosynthetically to turn CO2 into biomass. That 1-2% of the light energy won’t show up as heat until the biomass is used for fuel or food. Meanwhile, the biomass came from sequestering atmospheric CO2, which is no longer in the atmosphere being a greenhouse gas until the biomass gets used. The albedo will be temporarily decreased.
The heat simply absorbed by a mass, however, remains heat. It is making a direct contribution to global warming whether it is absorbed by a parking lot or a tree.
The Hadley Center, mentioned in the reference, has done some studies relating to the effects of photosynthetic use vs absorption, including the carbon sequestration effects.

Edit. Our eyes are not well-suited to determining how much we’ve changed the reflectivity/texture of a surface when viewed from satellite distances. To change the picture of the earth so that you can see how we’ve changed it, look at the nighttime pictures.