News24

Scientists foresee sun-reflecting cities

2012-04-13 13:30

Paris - Scientists sketched a vision on Friday of converting the world's cities into giant sunlight reflectors to help fight global warming but met with scepticism from fellow academics.

Gradually replacing traditional urban roofs and roads with white or lighter-coloured materials would yield a cooling benefit that, over 50 years, would be the equivalent of a reduction of between 25 and 150 billion tons of carbon dioxide (CO2), researchers in Canada said.

At the top end of the scale, this equals the emissions of all the world's cars over the same period, their study published in Britain's Institute of Physics' journal Environmental Research Letters stated.

Light-coloured materials help reflect the Sun's rays rather than absorb and convert them into heat, a phenomenon known as albedo in scientific terms.

Pavements and roofs make up more than 60% of urban surfaces and, by trapping solar energy, are largely to blame for "heat islands", where cities or districts become local hotspots.

Urban heat islands also gobble up energy in air conditioning and inflict health costs through smog.

The cost of reflectors need not be prohibitive as rooftops and paved surfaces need to be resurfaced every so often anyway, the scientists argued.

"All it means is that when the time comes, they would select a cool roof," Hashem Akbari of Concordia University in Montreal told AFP.

He conceded that some of the new materials may be slightly more expensive than before, but the cost would still be "lower than the ... savings they produce" in cooling.

French climate consultant Jean-Marc Jancovici, however, said the proposals would have only a localised effect.

People's choices

"If you decrease significantly the temperature in local places with something like painting the roofs in white, it doesn't ensure that you will have a decrease in the temperature in remote places," he said.

Alfredo Stein of the Global Urban Research Centre at Britain's University of Manchester also predicted practical difficulties, particularly for the world's sprawling slum areas.

"It will require very strong advocacy by whoever will be selling the roofs," he told AFP, especially considering that about 70 percent of houses worldwide are built by the owners themselves, mainly in informal settlements.

People's choices for roofing materials are largely determined by affordability and availability, Stein argued.

In a 2009 probe into so-called geo-engineering options to brake global warming, Britain's Royal Society gave low marks to "white roof" methods.

There would be benefits locally in hot countries, it said.

But only 0.05% to 1% of the world's land surface would be covered, which meant it would lack effectiveness on a global scale, the prestigious academy said.

And it estimated the cost at "about $300bn a year, making this one of the least effective and most expensive methods considered".

Comments
  • NrGx - 2012-04-13 14:04

    Am I not correct in saying the ozone / atmosphere lets heat in a traps it? So even if the cities are reflecting the heat, would it still not have the same effect?

      michael.a.devilliers - 2012-04-13 15:16

      Yes it does trap a certain percentage of the heat that IS reflected, so if more heat is reflected less will be trapped.

      michael.a.devilliers - 2012-04-13 15:16

      Yes it does trap a certain percentage of the heat that IS reflected, so if more heat is reflected less will be trapped.

      zane.blignaut - 2012-04-13 15:20

      the difference is reflective light and refracted light. when light is reflected its frequency stays the same and can escape our atmosphere, when light is refracted, its Hz change and therefore does not escape out ozone

      zane.blignaut - 2012-04-13 15:20

      the difference is reflective light and refracted light. when light is reflected its frequency stays the same and can escape our atmosphere, when light is refracted, its Hz change and therefore does not escape out ozone

      dave.ogier - 2012-04-13 15:22

      You are partly correct. Incoming solar radiation travels through the atmosphere/ozone and strikes the earth surface, if it is reflected, the wave length of the radiation don't change and can effectively travel back into space (no/little heat capture). If however the radiation is absorbed by the earth surface, it reradiates (as a function of temperature) at a different (longer) wave length. This terrestrial sourced radiation is captured particularly by CO2 in the atmosphere and heat is retained.

      dave.ogier - 2012-04-13 15:22

      You are partly correct. Incoming solar radiation travels through the atmosphere/ozone and strikes the earth surface, if it is reflected, the wave length of the radiation don't change and can effectively travel back into space (no/little heat capture). If however the radiation is absorbed by the earth surface, it reradiates (as a function of temperature) at a different (longer) wave length. This terrestrial sourced radiation is captured particularly by CO2 in the atmosphere and heat is retained.

  • robin.harriram - 2012-04-13 14:30

    It would be nice if the deserts can be cooled down, maybe all Mighty may send rain there and we can see green again.

      dave.ogier - 2012-04-13 15:30

      Ironically deserts have higher albedos (ie more reflective) than forests... so it's not always so cut and dry

      dave.ogier - 2012-04-13 15:30

      Ironically deserts have higher albedos (ie more reflective) than forests... so it's not always so cut and dry

  • revaro.winkler - 2012-04-13 15:26

    yip humans always gets a way out of s543455445

      marius.dumas - 2012-04-14 13:14

      @jgeorgiades I get what you are saying in a way. But there is a important law in nature, that is, that nature always strive to an equilibrium with or without humans. Although life supporting elements such as carbon, hydrogen, nitrogen, oxygen are in an abundance in nature, stars who's fusion processes produce them are in abundance in the universe, the life supporting conditions is unusual for us to observe but might not be as unusual in the universe. However it is irrelevant to our survival since we just cant get there or adapt that easily. However I agree that we are powerless to change natures collision causes with us on earth. I do feel that the support for life on earth is extremely likely and that the self regulating mechanisms of the eco system has protected life on earth for a more than a billion years. It might not protect humans in particular but it protects life. We can pollute, destroy and change all we want. if the eco system could survive ice ages then we know it can take a lot of beating and recover. Cont.

      marius.dumas - 2012-04-14 13:14

      @jgeorgiades I get what you are saying in a way. But there is a important law in nature, that is, that nature always strive to an equilibrium with or without humans. Although life supporting elements such as carbon, hydrogen, nitrogen, oxygen are in an abundance in nature, stars who's fusion processes produce them are in abundance in the universe, the life supporting conditions is unusual for us to observe but might not be as unusual in the universe. However it is irrelevant to our survival since we just cant get there or adapt that easily. However I agree that we are powerless to change natures collision causes with us on earth. I do feel that the support for life on earth is extremely likely and that the self regulating mechanisms of the eco system has protected life on earth for a more than a billion years. It might not protect humans in particular but it protects life. We can pollute, destroy and change all we want. if the eco system could survive ice ages then we know it can take a lot of beating and recover. Cont.

      marius.dumas - 2012-04-14 13:14

      To you the concrete building looks like a part of nature we destroyed, but for the bird that builds a nest in its roof it was a a perfect shelter and therefore the roof became part of nature. There are plants that are poisonous. we can see it as natures pollutions since it can kill. however life learn to adapt and not to eat from those plants. the same way nature always find a way to adapt around these obstacles and life will just keep on going and continue to adapt. What appears a distraction of nature to us, might in fact become a new habit for something else. We look at a dump as disgusting and the ultimate polluted area, have you ever seen how many birds, flies, maggots and other insects come to get their feast there and how a new eco system develop in the dump itself as a suitable habitat. These birds and insects just don’t see it the way we do. Average global temperature is some ware around 14.5°C, There was stages where temperatures was as low as 10 during ice ages, then as high as 25°C for about 60% of the last 560 million years. CO2 was 25 times more than now 500 million years ago still life continued as usual since life is busy evolving for more than 2 billion years. The fact is that we as modern humans have never experienced anything like 10 or 25°C global averages. It may be unusual for us but not for life on earth in general. The hot house effects is the stages where life progressed the most.

      marius.dumas - 2012-04-14 13:14

      To you the concrete building looks like a part of nature we destroyed, but for the bird that builds a nest in its roof it was a a perfect shelter and therefore the roof became part of nature. There are plants that are poisonous. we can see it as natures pollutions since it can kill. however life learn to adapt and not to eat from those plants. the same way nature always find a way to adapt around these obstacles and life will just keep on going and continue to adapt. What appears a distraction of nature to us, might in fact become a new habit for something else. We look at a dump as disgusting and the ultimate polluted area, have you ever seen how many birds, flies, maggots and other insects come to get their feast there and how a new eco system develop in the dump itself as a suitable habitat. These birds and insects just don’t see it the way we do. Average global temperature is some ware around 14.5°C, There was stages where temperatures was as low as 10 during ice ages, then as high as 25°C for about 60% of the last 560 million years. CO2 was 25 times more than now 500 million years ago still life continued as usual since life is busy evolving for more than 2 billion years. The fact is that we as modern humans have never experienced anything like 10 or 25°C global averages. It may be unusual for us but not for life on earth in general. The hot house effects is the stages where life progressed the most.

      marius.dumas - 2012-04-14 13:15

      Natural dynamics, (climate change, disasters, volcanoes…) are the main driving force behind evolution since the beginning of life. To the contrarily of your opinion, If not for them life on earth would have been fragile and simple. Every time the strong (most capable, or most likely) survive (law in biology, there are more offspring’s produce than what can survive) thus every time a disaster happens the strong survive, thus changing the biosphere to become stronger (biologically and mentally) and more resilient as it grows in complexity to adapt to the typical natural dynamics. Disasters are a very important part of successful evolution process and a fundamental part of the eco system. cont.

      marius.dumas - 2012-04-14 13:15

      Natural dynamics, (climate change, disasters, volcanoes…) are the main driving force behind evolution since the beginning of life. To the contrarily of your opinion, If not for them life on earth would have been fragile and simple. Every time the strong (most capable, or most likely) survive (law in biology, there are more offspring’s produce than what can survive) thus every time a disaster happens the strong survive, thus changing the biosphere to become stronger (biologically and mentally) and more resilient as it grows in complexity to adapt to the typical natural dynamics. Disasters are a very important part of successful evolution process and a fundamental part of the eco system. cont.

      marius.dumas - 2012-04-14 13:16

      Often it is hard for people to understand that the unwanted can become the most wanted or needed in a system. If you tell an a electronic engineer that you add noise or interference to the electronic circuit to improve precision of electronic measurements, the most experienced will at first look at you in total disbelief as every engineer strives to low noise, precision designs. I recently explained to a technologist how a low resolution analogue to digital converter (digitiser microchip) can be used to to perform extremely precise measurements, way beyond its design specification. This is to be done by adding sufficient random noise (interference) to the circuit, and then perform many samples before taking the arithmetic mean of the integers to produce a floating point value of great precision. This will result in a device capable of measuring 1024 divisions precise to become more precise to let say 10 000 divisions for its full scale capacity. But if a perfect signal is introduced that fall between to divisions it will be impossible to do this. It is most important to have a proper random deviation around the true value for the arithmetic mean to produce an increase in precision. This example show how nature allows us to use what is scientifically considered as most unwanted to be an important function in an ideal result.

      marius.dumas - 2012-04-14 13:16

      Often it is hard for people to understand that the unwanted can become the most wanted or needed in a system. If you tell an a electronic engineer that you add noise or interference to the electronic circuit to improve precision of electronic measurements, the most experienced will at first look at you in total disbelief as every engineer strives to low noise, precision designs. I recently explained to a technologist how a low resolution analogue to digital converter (digitiser microchip) can be used to to perform extremely precise measurements, way beyond its design specification. This is to be done by adding sufficient random noise (interference) to the circuit, and then perform many samples before taking the arithmetic mean of the integers to produce a floating point value of great precision. This will result in a device capable of measuring 1024 divisions precise to become more precise to let say 10 000 divisions for its full scale capacity. But if a perfect signal is introduced that fall between to divisions it will be impossible to do this. It is most important to have a proper random deviation around the true value for the arithmetic mean to produce an increase in precision. This example show how nature allows us to use what is scientifically considered as most unwanted to be an important function in an ideal result.

      marius.dumas - 2012-04-14 13:18

      In simple, we also know that field fires are very important to improve the quality of plant life in an area. Improving the plant life improves the entire biology of the area. By the above argument I reason that changes, disasters are fundamental parts of the eco system’s success and has no exact way they need to occur. We seen asteroids hitting the earth, CO2 25 times more than now, extreme heat and cold temperatures. All what happened as an result is that evolution progressed better than ever. Humans have weaken them selves by adapting to perfect environments, medicine, air-conditioned homes, cars and offices. We seek perfectly clean and hygienic food and water. While the strongest life on earth, has adapted to the hashes environments. The harshness is the fundamental reason their ability to survive is superior. Humans will become stronger if they learn to adapt rather than to control.

      marius.dumas - 2012-04-14 13:18

      In simple, we also know that field fires are very important to improve the quality of plant life in an area. Improving the plant life improves the entire biology of the area. By the above argument I reason that changes, disasters are fundamental parts of the eco system’s success and has no exact way they need to occur. We seen asteroids hitting the earth, CO2 25 times more than now, extreme heat and cold temperatures. All what happened as an result is that evolution progressed better than ever. Humans have weaken them selves by adapting to perfect environments, medicine, air-conditioned homes, cars and offices. We seek perfectly clean and hygienic food and water. While the strongest life on earth, has adapted to the hashes environments. The harshness is the fundamental reason their ability to survive is superior. Humans will become stronger if they learn to adapt rather than to control.

      marius.dumas - 2012-04-21 16:17

      jgeorgiades, what I say is, if conditions on the earth was static and ideal then life would not have evolved as much as it has under the dynamics of change and disaster. The law in biology that more offspring’s are born than what can possibly survive is a direct support to the theory that evolution progress at its best during the tightest of challenges for survival and not during ideal conditions. The ones that survive the harshest of conditions will lay the foundations of a more capable descendants. The asteroid that wiped out the dinosaurs made the greatest leap on evolution of life. The life that remained was extremely capable of survival. if you don't drink all your antibiotics, the bacteria becomes stronger not because of the ideal conditions for them but because of the antibiotic that cause difficulty for them and result in a mutation to a more resistant and more capable strain. Its not short sightedness. It is the basics of biology. Humans are part of this same biology. I have never suggested that the ones who are first to die are "weaker" I only suggested that they are less capable or less likely by nature. For instance the strongest man, who fight in front in the army might be one of the first to die while the scared weaker one might hide and survive. He might be the strongest but his position regarding intellect, size, strengths, confidence, social position made him less likely to survive.

      marius.dumas - 2012-04-21 16:17

      jgeorgiades, what I say is, if conditions on the earth was static and ideal then life would not have evolved as much as it has under the dynamics of change and disaster. The law in biology that more offspring’s are born than what can possibly survive is a direct support to the theory that evolution progress at its best during the tightest of challenges for survival and not during ideal conditions. The ones that survive the harshest of conditions will lay the foundations of a more capable descendants. The asteroid that wiped out the dinosaurs made the greatest leap on evolution of life. The life that remained was extremely capable of survival. if you don't drink all your antibiotics, the bacteria becomes stronger not because of the ideal conditions for them but because of the antibiotic that cause difficulty for them and result in a mutation to a more resistant and more capable strain. Its not short sightedness. It is the basics of biology. Humans are part of this same biology. I have never suggested that the ones who are first to die are "weaker" I only suggested that they are less capable or less likely by nature. For instance the strongest man, who fight in front in the army might be one of the first to die while the scared weaker one might hide and survive. He might be the strongest but his position regarding intellect, size, strengths, confidence, social position made him less likely to survive.

      marius.dumas - 2012-04-21 16:18

      I don’t know how involved you are with science since you have a few facts totally wrong. Firstly, the sun will not destroy us as a super nova. It will become a red giant and expand about 250 times it current radius and destroy the earth. A billion years from now the earth will be uninhabitable because of this. Another 4 billion years the earths fate will be sealed. Secondly to suggest that an asteroid will kill all life on earth is ludicrous. During the last billion years there were more asteroids than what we can expect for then next billion years. The solar system is cleaner now and more harmonious from such disturbances than before. The fact is that during the last billion years no asteroid has wiped away all life on earth or else we would not have been here. Then how can you reason it will necessarily happen in our future if the past has proven with great certainty that it has never happened that an asteroid took out all life. The chances is more than a million times less that it will happen in the next 1000 years. The asteroid that caused the Cretaceous–Paleogene extinction event killed most major dinosaur groups but did not kill all life on earth. There has never been an asteroid that killed all life on earth.

      marius.dumas - 2012-04-21 16:18

      I don’t know how involved you are with science since you have a few facts totally wrong. Firstly, the sun will not destroy us as a super nova. It will become a red giant and expand about 250 times it current radius and destroy the earth. A billion years from now the earth will be uninhabitable because of this. Another 4 billion years the earths fate will be sealed. Secondly to suggest that an asteroid will kill all life on earth is ludicrous. During the last billion years there were more asteroids than what we can expect for then next billion years. The solar system is cleaner now and more harmonious from such disturbances than before. The fact is that during the last billion years no asteroid has wiped away all life on earth or else we would not have been here. Then how can you reason it will necessarily happen in our future if the past has proven with great certainty that it has never happened that an asteroid took out all life. The chances is more than a million times less that it will happen in the next 1000 years. The asteroid that caused the Cretaceous–Paleogene extinction event killed most major dinosaur groups but did not kill all life on earth. There has never been an asteroid that killed all life on earth.

      marius.dumas - 2012-04-21 16:19

      Thirdly it will take 1 billion years before earth becomes hostile to life again. if the current conditions are not adversely disturbed. It is also not certain that the gradual collapse of the magnetosphere will in fact destroy all life. Or that it would only create another quantum leap in the evolution process. Many complex forms of life that cannot outsmart it might die but more primitive forms of life may evolve gradually to be better adapted to the new normal conditions, the same way it did during ice ages, hot houses and habitats of water, desert, land and air on earth. This will take millions of years and will not happen over night. It is extremely unlikely to find the earth in a condition where it cannot support life. This makes it extremely likely to support life. We might be the living proof of it. In fact, it will require an extremely rare situation to make life on earth unlikely. The eco-system always strive to recover, adapt and evolve life and it has succeeded doing it during the worst of conditions and it will be able to do it for more disastrous conditions beyond our imagination. The common belief that the eco-system I labial is inconsistent to the proven history of the biosphere.

      marius.dumas - 2012-04-21 16:19

      Thirdly it will take 1 billion years before earth becomes hostile to life again. if the current conditions are not adversely disturbed. It is also not certain that the gradual collapse of the magnetosphere will in fact destroy all life. Or that it would only create another quantum leap in the evolution process. Many complex forms of life that cannot outsmart it might die but more primitive forms of life may evolve gradually to be better adapted to the new normal conditions, the same way it did during ice ages, hot houses and habitats of water, desert, land and air on earth. This will take millions of years and will not happen over night. It is extremely unlikely to find the earth in a condition where it cannot support life. This makes it extremely likely to support life. We might be the living proof of it. In fact, it will require an extremely rare situation to make life on earth unlikely. The eco-system always strive to recover, adapt and evolve life and it has succeeded doing it during the worst of conditions and it will be able to do it for more disastrous conditions beyond our imagination. The common belief that the eco-system I labial is inconsistent to the proven history of the biosphere.

      marius.dumas - 2012-04-21 18:21

      Sorry with labial I actually meant labile Forth: Life supporting elements and conditions are in abundance in the universe. Carbon, oxygen, hydrogen, nitrogen are some of the most popular elements in the universe. It is a well known fact. The top popular elements in the known universe are Mass fraction part per million Hydrogen =739,000 Helium =240,000 Oxygen =10,400 Carbon =4,600 Neon =1,340 Iron =1,090 Nitrogen =960 Silicon =650 Magnesium =580 Sulfur =440 Life supporting elements are the most in abundance of amongst top most popular elements. Life supporting conditions are extremely likely when these elements and conditions are in a favourable condition. With the undiscovered boundaries of the universe it will be extremely unlikely that favourable conditions will not exist elsewhere. There might also be a major difference between favourable conditions for us to adapt too vs. favourable conditions for life in general. It is possible that life can form, adapt, evolve to conditions beyond our knowledge. Our own conditions are only a well known example of a life supporting condition. There is no rule to say that exactly the same conditions are required for life. The fact that life evolved on a tiny blue planet orbiting a star in some galaxy does by no mean or suggest that similar conditions is not in abundance throughout the rest of the universe. It is likely that there are more of those.

      marius.dumas - 2012-04-21 18:21

      Sorry with labial I actually meant labile Forth: Life supporting elements and conditions are in abundance in the universe. Carbon, oxygen, hydrogen, nitrogen are some of the most popular elements in the universe. It is a well known fact. The top popular elements in the known universe are Mass fraction part per million Hydrogen =739,000 Helium =240,000 Oxygen =10,400 Carbon =4,600 Neon =1,340 Iron =1,090 Nitrogen =960 Silicon =650 Magnesium =580 Sulfur =440 Life supporting elements are the most in abundance of amongst top most popular elements. Life supporting conditions are extremely likely when these elements and conditions are in a favourable condition. With the undiscovered boundaries of the universe it will be extremely unlikely that favourable conditions will not exist elsewhere. There might also be a major difference between favourable conditions for us to adapt too vs. favourable conditions for life in general. It is possible that life can form, adapt, evolve to conditions beyond our knowledge. Our own conditions are only a well known example of a life supporting condition. There is no rule to say that exactly the same conditions are required for life. The fact that life evolved on a tiny blue planet orbiting a star in some galaxy does by no mean or suggest that similar conditions is not in abundance throughout the rest of the universe. It is likely that there are more of those.

      marius.dumas - 2012-04-21 18:22

      If it is possible for the sun to have planets, then it is possible for other stars as well. If it is possible that one of the planets has life supporting elements, then it is possible that other planets may have those elements too. If it is possible that one of the plane to have an average temperature between 10 to 25°C , then it is possible that other plants which have life supporting elements might exits with nearly the same temperatures too. There is nothing abnormal to the conditions on earth. Infact there is no reason at all that the similar conditions are not in many other solar systems throughout the galaxy or other galaxies. Our current observations already proved that planets does exist in other solar systems. We are just to far to see what is going on in terms of life on them. The moon and mars is about as far as what we could get a real taste of.

      marius.dumas - 2012-04-21 18:22

      If it is possible for the sun to have planets, then it is possible for other stars as well. If it is possible that one of the planets has life supporting elements, then it is possible that other planets may have those elements too. If it is possible that one of the plane to have an average temperature between 10 to 25°C , then it is possible that other plants which have life supporting elements might exits with nearly the same temperatures too. There is nothing abnormal to the conditions on earth. Infact there is no reason at all that the similar conditions are not in many other solar systems throughout the galaxy or other galaxies. Our current observations already proved that planets does exist in other solar systems. We are just to far to see what is going on in terms of life on them. The moon and mars is about as far as what we could get a real taste of.

      marius.dumas - 2012-04-23 01:00

      jgeorgiades - the last correction I would like to make is, that the sun will not end in a supernova. You have that fact wrong. It is way too small for that. Secondly if a supernova should get closer to us than 3000 light years we will suffer the effect and possible death due to the secondary or primary impact of gamma radiation. So lets say Supernovae can kill us in that radius, but with supernovae only happening once every 50 years in our entire galaxy it is extremely unlikely for one to be a near earth supernova. Up to now it seem far more likely that supernova had a more constructive effect on life on earth than destructive. The reason being that all elements we know with atomic mass greater than oxygen’s (15.9g/mol) could only have been produced by the supernova that produced the elements we, the earth and sun is made off. Only the fusion at supernova level is capable of producing the rest of the elements. Therefore for us up to now supernovae was a bigger blessing than a curse.

      marius.dumas - 2012-04-23 01:00

      jgeorgiades - the last correction I would like to make is, that the sun will not end in a supernova. You have that fact wrong. It is way too small for that. Secondly if a supernova should get closer to us than 3000 light years we will suffer the effect and possible death due to the secondary or primary impact of gamma radiation. So lets say Supernovae can kill us in that radius, but with supernovae only happening once every 50 years in our entire galaxy it is extremely unlikely for one to be a near earth supernova. Up to now it seem far more likely that supernova had a more constructive effect on life on earth than destructive. The reason being that all elements we know with atomic mass greater than oxygen’s (15.9g/mol) could only have been produced by the supernova that produced the elements we, the earth and sun is made off. Only the fusion at supernova level is capable of producing the rest of the elements. Therefore for us up to now supernovae was a bigger blessing than a curse.

  • marius.dumas - 2012-04-14 11:57

    I am an sceptic of this idea. There is no proof that the earth will continue rapid heating as it showed and last resent years. The reason lies within the uncertainties of the global warming theory. Assuming that global warming projections from simulations are all true and accurate is as dangerous as assuming it is not. Simulations up to 2000 has already been proven wrong with our most resent data. The warming was less than predicted. For example. Europe has recently experienced some of the harshest winters in many years with great damages and risks to human life and food production. Do you really want to add things that cool them down during harsh winters even more? The uncertainties in the global warming theory allows the possibilities that cooling periods may lay ahead. Harsh winters may be more harmful to humans and food production than warmer weather. Plants, animals on earth needs heat, dinosaurs for example survived in mush warmer weather than this, while during some major ice ages scientists try to figure out how some bacteria’s could have possibly survived. If you must choose ice age, or hot house, please choose hot house, uncomfortable but life exceeds extremely well in such conditions. Doing anything to cool the planet artificially may be the most stupidest thing “a group” of scientist have ever came up with.

      marius.dumas - 2012-04-14 11:58

      Hysteresis phenomena in physics: Regulating the planet temperature may be extremely stupid due to hysteresis effects. This means you see a trend now, you compensate accordingly and when the natural reasons behind the trend changes, you are too late to realise that you over compensated. Thus you end up driving your own climate imbalances what you are trying to regulate. It will require many resources to create more chaos. Climatologist have reported many fields of uncertainty. The best is not to try anything stupid before you are really sure about the entire climate model. The fact is there are very few elements of climate change climatologist are sure about. The wise things is for people to plan to adapt to changes where necessary at this stage and don’t interfere. If they want to reduce pollution, at the worst we may benefit either way if it happens very gradually. Engineered artificial influences on climate is stupid and risky.

      marius.dumas - 2012-04-14 11:58

      Hysteresis phenomena in physics: Regulating the planet temperature may be extremely stupid due to hysteresis effects. This means you see a trend now, you compensate accordingly and when the natural reasons behind the trend changes, you are too late to realise that you over compensated. Thus you end up driving your own climate imbalances what you are trying to regulate. It will require many resources to create more chaos. Climatologist have reported many fields of uncertainty. The best is not to try anything stupid before you are really sure about the entire climate model. The fact is there are very few elements of climate change climatologist are sure about. The wise things is for people to plan to adapt to changes where necessary at this stage and don’t interfere. If they want to reduce pollution, at the worst we may benefit either way if it happens very gradually. Engineered artificial influences on climate is stupid and risky.

      marius.dumas - 2012-04-14 11:59

      Getting back to white roofs and roads White may absorb very little IR radiation but it lacks the ability to radiate whatever it has absorbed. However black bodies that absorb more IR radiation will also transmit more radiation at night. (See black body radiator theory) What I mean is, that back bodies absorb fast, but cools down fast as well. Therefore the total effect for let say 24 hrs average will not be as significant as the instantaneous observation. Most energy absorbed will at least find its way back into space, if not at night then during winters seasons. For those who still don’t get it. During the day you can see as the sun radiates energy to the earth, how the white roofs will reflect the energy back into space. But tonight very little radiation is measured from those white roofs. With black roofs. During the day you will see much of the energy absorbed and the earth seems to be holding on to the energy, but tonight and during winters you will observe how the earth continues to radiate the heat it has stored back into space as invisible infrared. This is due to the black body radiator effect. This is part of the advantage of using black heat sinks in electronics and using black radiators for motorcars and refrigerators. Black is more effective as a radiator.

      marius.dumas - 2012-04-14 11:59

      Getting back to white roofs and roads White may absorb very little IR radiation but it lacks the ability to radiate whatever it has absorbed. However black bodies that absorb more IR radiation will also transmit more radiation at night. (See black body radiator theory) What I mean is, that back bodies absorb fast, but cools down fast as well. Therefore the total effect for let say 24 hrs average will not be as significant as the instantaneous observation. Most energy absorbed will at least find its way back into space, if not at night then during winters seasons. For those who still don’t get it. During the day you can see as the sun radiates energy to the earth, how the white roofs will reflect the energy back into space. But tonight very little radiation is measured from those white roofs. With black roofs. During the day you will see much of the energy absorbed and the earth seems to be holding on to the energy, but tonight and during winters you will observe how the earth continues to radiate the heat it has stored back into space as invisible infrared. This is due to the black body radiator effect. This is part of the advantage of using black heat sinks in electronics and using black radiators for motorcars and refrigerators. Black is more effective as a radiator.

      marius.dumas - 2012-04-14 12:03

      If you have black pipes (solar heating) on your roof to heat your swimming pool water, if you continuously circulate the water though the pipes, then at day time it will heat the pool faster and at night it will cool the pool faster. It will tend to radiate the pools heat energy back into space as infrared at night having a greater cooling effect. Thus having almost the same, but only a delayed effect as a reflective surface over a period of time. Both will end up reflecting almost the same amount of infrared back into space. Thus pool water will heat up at a faster rate during the day, and cool down at a faster rate at night. The best is then not to circulate pool water through it at night if you want your pool to absorb more energy.

      marius.dumas - 2012-04-14 12:03

      If you have black pipes (solar heating) on your roof to heat your swimming pool water, if you continuously circulate the water though the pipes, then at day time it will heat the pool faster and at night it will cool the pool faster. It will tend to radiate the pools heat energy back into space as infrared at night having a greater cooling effect. Thus having almost the same, but only a delayed effect as a reflective surface over a period of time. Both will end up reflecting almost the same amount of infrared back into space. Thus pool water will heat up at a faster rate during the day, and cool down at a faster rate at night. The best is then not to circulate pool water through it at night if you want your pool to absorb more energy.

      marius.dumas - 2012-04-14 13:49

      Earths heating or cooling is determined by the amount of infrared in the solar irradiance entering the atmosphere, compared to the amount of infra red leaving the atmosphere back into space. If less goes back into space, the earth heats, if more goes back into space the earth cools. The fact is that in an instant of time during a sunny day the white roofs will appear to radiate more energy back into space but may have little effect at night or winter in comparison to black roofs. The result is that over a period of time, the black roofs and the white roofs will eventually put the same amount of energy back into space. At night when white roofs reflect nothing, black roofs will act as black body radiators. (ideal heat sinks)

      marius.dumas - 2012-04-14 13:49

      Earths heating or cooling is determined by the amount of infrared in the solar irradiance entering the atmosphere, compared to the amount of infra red leaving the atmosphere back into space. If less goes back into space, the earth heats, if more goes back into space the earth cools. The fact is that in an instant of time during a sunny day the white roofs will appear to radiate more energy back into space but may have little effect at night or winter in comparison to black roofs. The result is that over a period of time, the black roofs and the white roofs will eventually put the same amount of energy back into space. At night when white roofs reflect nothing, black roofs will act as black body radiators. (ideal heat sinks)

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