(Totally OT) Re: DMD 0.175 release

[Sean Kelly]

Don Clugston wrote:
> 
> (1) It is clear that CO2 concentrations in the atmosphere are increasing 
> significantly as a result of human activity.
> (2) It is clear that, on its own, these increased CO2 levels will 
> increase global temperature by a couple of degrees.
> (3) It is known that global temperatures have risen over the last 
> hundred years, and particularly over the last 30.
> (4) What is completely unknown is, what feedback mechanisms are there in 
> the earths climate? Especially cloud formation. Feedback could be 
> positive or negative.
> (5) The contribution of solar activity is also unknown.
> 
> (human activity) + (other causes) + (feedback mechanisms) = (observed 
> climate change).

One issue I've never heard discussed is what impact urban development 
has had on climate.  In the past century, humanity has covered vast 
regions of the earth with stone (concrete and asphalt) that were 
previously forested, and has clear-cut other regions.  Both should have 
a measurable impact on heat absorption and reflection in affected areas, 
particularly in those areas where vegetation was replaced by concrete. 
And I suspect it's possible that the heat rising from some urban areas 
may be sufficient to affect local weather patterns, similar to the 
"artificial mountain" method of terraforming.  This may not contribute 
directly to a global temperature shift, but it could be enough to affect 
localized temperatures in some regions and possibly to affect local sea 
life from a corresponding shift in surface currents as well.


Sean