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Join Date: Nov 2011
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Relating Environmental Degradation / Poor Rains & Architecture

04/25/2013 2:59 AM

I am in Bangalore- a city whose population has grown phenomenally at over 40 to 50% every year. This year we have very little rains. City temperature has soared to nearly 39 Deg C. Water level in open wells is below 30 meters or 100 feet. In borewells - one needs to go below 1000 feet or 300 meters or lower. I understand that Bangalore which had over 200 lakes at one time has just about 4 lakes or so now- all others have been filled and converted to buildings.

Further buildings used to be constructed using burnt mud bricks. In remote towns olden day houses used to be built of huge bricks which were porous and houses used to be cooler. Now we use huge hollow cement blocks ( I do not know whether they use bricks from fly ash from thermal power stations) + glass paneled exteriors for huge commercial complexes. May be many are today air-conditioned for comfort of interiors- further adding to carbon emissions / pollution and environmental degradation.

My question is - is there a study showing heat storage capacity of burnt mud brick buildings, hollow cement blocks, glass paneled buildings - which could act as heat storage devices. This then leads to thermal convection upward currents driving away rain bearing clouds, thus reducing rains and aggravating the situation. Removal of huge old trees for road widening, and construction of buildings has further lead to lesser rains!!! I do not think the situation is anyway different in other cities across India/ other parts of the world- if architects use such modern materials in the name of aesthetics.

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Guru

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#1

Re: Relating Environmental Degradation / Poor Rains & Architecture

04/25/2013 10:56 AM

You can find discussion/ studies related to this topic by searching for 'Heat Island Effect'.

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Power-User

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#2
In reply to #1

Re: Relating Environmental Degradation / Poor Rains & Architecture

04/26/2013 4:22 AM

Thank you for that excellent reference. It answers all my queries. Are concerned urban planners, architects aware of this study and what action is being initiated? This last sentence puzzled me. But locally - we are able to feel the effect. Weathermen are just making postmortem report. Building sanctioning authorities now need to look into even materials and designs used - from UHI effect.

"Despite concerns raised about its possible contribution to global warming, comparisons between urban and rural areas show that the urban heat island effects have little influence on global mean temperature trends.[4]"

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Guru

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#3
In reply to #2

Re: Relating Environmental Degradation / Poor Rains & Architecture

04/26/2013 10:32 AM

I think what they are saying in the last sentence is that although there is a measurable effect locally, the changes in one area are offset by changes in another area....

.

It may rain less in the urban areas, but that is offset by more rain in certain directions a distance away from the urban area.\

or although temperatures may be higher in the urban areas, lower temperatures in some surrounding areas offset the effect on whole.

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Power-User

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#5
In reply to #3

Re: Relating Environmental Degradation / Poor Rains & Architecture

04/27/2013 5:40 AM

Your interpretation is right. Locally there are observed changes. Neighboring agricultural areas - nearby may have unwanted heavier rains leading loss of crop, flooding etc. So we have drought and heavy rains situations at the same time- in different parts. In the urban areas- butterflies, birds vanish (In Bangalore sparrows and butterflies have vanished long ago). Today our garden has little water and may be fewer flowering plans next year. Even in USA - you have hurricanes more regularly with devastating effects.

Old houses used to be of Laterite stones (http://en.wikipedia.org/wiki/Laterite) and later came mud bricks - both keep houses clean. But recently trend seems to be towards cement blocks, glass paneled buildings, asphalted roads - etc - which are all listed in the link on Urban Heat Islands (UHI) as they result in lower rainfall- locally.

Interesting if met department says - normal rainfall predicted fro the country as a whole - it can mean - undesired flooding in some regions, undesirable drought in some regions - but country as whole has normal average rainfall!!!!

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#4

Re: Relating Environmental Degradation / Poor Rains & Architecture

04/26/2013 4:05 PM

Investigate Trombe Walls

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Guru

Join Date: Jun 2010
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#6

Re: Relating Environmental Degradation / Poor Rains & Architecture

05/12/2013 11:23 AM

I noticed the other day while painting an aluminum spiral stairs outdoors that everything I touched that was not painted white yet was 25 degrees hotter than the white part of the stairs I had already painted.

This even included some scrap wood painted grey that I was using to prop up the stairs.

The natural as yet unpainted aluminum was too hot to touch but the white painted portions of the same piece of the stairs seemed cooler than the ambient air temperature after the paint had dried to the touch!

Paint the town including all the roof tops white!

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Guru

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#7
In reply to #6

Re: Relating Environmental Degradation / Poor Rains & Architecture

05/13/2013 5:37 PM

It's funny isn't it, that something like aluminum that is a decent reflector ends up heating up in the sun.

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The reason it happens is because aluminum in many forms is an effective selective surface..... even though it generally reflects much of the radiation, it tends to be a poor radiator compared to the portion it doesn't reflect.

.

The same thing can be true of white paint (though it isn't very common). The important thing to realize is that different white paints that look to be the same color, can have very different effects on the temperature of a surface exposed to the sun.

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