June 1, 2009

Putih menyejukkan bumi

Posted in Alam at 5:18 pm by kamilan

 1). Selepas membaca maklumbalas dalam blog-blog terhadap idea Steven Chu yang merupakan penasihat Obama mengenai penggunaan tenaga USA, supaya penduduk dunia serentak mengecat bumbung rumah kepada warna putih. Ada yang memandang idea tersebut lekeh. Ada yang mengatakan idea tersebut bukanlah idea asal Steven Chu.

2). Idea berteknologi-rendah tersebut, menurutnya jika dilakukan serentak seolah-olah telah mengurangkan kepanasan dunia (global warming) dengan tidak menggunakan kereta di seluruh dunia selama 11 tahun. Warna putih dapat menyejukkan ruang apabila menggunakan penghawa dingin dan seterusnya menjimatkan belanja penggunaan elektrik sebanyak 10 hingga 15 peratus.

3). Konsep idea iaitu warna putih membalikkan cahaya. Warna hitam menyerap haba. Jika bumi berwarna putih maka cahaya matahari akan dipancarkan semula ke langit dan menyebabkan bumi akan sejuk. Jika menggunakan warna gelap akan menyebabkan cahaya akan diserap dan haba akan terkumpul di bumi dan menyebabkan bertambah panas.

3). Jika bumi bertambah panas akan menyebabkan pencairan glasier di kutub.

4). Apakah bumi bertambah ceria apabila semua objek buatan manusia berwarna putih?

Sekian dulu. 01 Jun 2009 (08 Jamadilakhir 1430).



Now the man in the White House says paint your house white

By Fiona Macrae

Last updated at 8:45 AM on 28th May 2009

The solution to climate change could be as simple as a big bucket of whitewash, President Obama’s energy guru claimed yesterday.

Steven Chu believes that painting the world’s roofs, roads and pavements white would keep buildings cooler as temperatures rise and cut the need for air conditioning.

Dr Chu, the U.S. Secretary of Energy and a Nobel prize-winning scientist, said the low-tech solution would be as effective at reducing global warming as taking all the world’s cars off the road for 11 years.

His advice is the same as that issued by Britain’s Department of Health last week, although that was part of a package of health tips for coping with future heatwaves.

Visiting London for a climate change meeting hosted by Prince Charles and attended by 20 Nobel Laureates, he declared that the simple act of making roofs, pavements, roads and even cars white or light-coloured could have a dramatic effect.

Dr Chu said that when sunlight was reflected off a white or light-coloured surface it went straight through the atmosphere back into space, but when absorbed by darker surfaces it added to the warming of the planet.

Pale roofs reflect up to four times as much sunlight as dark ones, bouncing sunlight back into space and so making buildings cooler, and in turn cutting the need for air conditioning.

He said: ‘If that building is air-conditioned, it’s going to be a lot cooler (if painted white), so it can use 10 or 15 per cent less electricity.

Dr Chu said those who do not find white roofs pleasing could invest in ‘cool colours’ – pastel shades which also absorb less heat.

He added: ‘If all vehicles were light-coloured, there could be considerable savings because then you could downsize air conditioning … a considerable reduction in energy.

‘If you look at all the buildings and make all the roofs white, and if you make the pavement a more concrete type of colour rather than a black type of colour, and you do this uniformly, it’s the equivalent of reducing the carbon emissions due to all the cars in the world by 11 years.’

Other solutions being looked at by the U.S. energy department include requiring banks to assess a person’s gas and electricity use before approving a mortgage.

Calling for a revolution in energy generation, Dr Chu said: ‘The industrial revolution was a revolution in the use of energy. It offloaded from human and animal power into using fossil fuels.

‘We have to go to a different new revolution that can severely decrease the amount of carbon emissions in the generation of energy.’

The U.S. government forecast yesterday that without mandatory limits on greenhouse gases, the amount of heat-trapping carbon dioxide flowing into the atmosphere will increase by nearly 40 per cent by 2030 as energy consumption grows.

The Department of Health’s Heatwave Plan for England, which was unveiled last week, also recommends white paint.

Other advice for householders includes replacing carpets with tiles or wood, hanging curtains with white linings and installing ceiling fans.

High temperatures can put strain on the heart, while smog can make breathing problems worse. Heat-stroke, in which the body’s thermostat fails, can also be fatal.

Sir Liam Donaldson, the chief medical officer, said: ‘In contrast to deaths associated with cold snaps in winter, the rise in mortality as a result of very warm weather follows very sharply – within one or two days of the temperature rising.

‘This means that by the time a heatwave starts, the window of opportunity for effective action is very short indeed and therefore proper preparedness is of the essence.’ – DM

Mail Online: http://www.dailymail.co.uk/sciencetech/article-1188956/Now-Obamas-administration-agrees-Paint-houses-white-solve-global-warming.html



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