Akbari Hashem, researcher of the Lawrence Berkley National Laboratory, in United States, affirmed in a recent study that painting the roofs with a white color can help to combat the global warming, decreasing the temperature of the urban heat islands at the great urban centers. As the dark covers absorb 80% of the extreme heat, the clear ones reflect until 90% of the solar light.
The fact is: if we do not do something to change the gas emissions panorama of the green effect, the price of the global warming to the world economy -- today, US$ 125 billion per year (more than the Gross Domestic Product of 73% of the countries of the world) -- can increase to US$ 340 billion. Of course, this is the mainly reason for finding solutions at middle date to ease the problem -- even if they are curious and strange at first sight, as the "green roofs" and now the "white roofs" suggestions.
The second idea has more chances to succeed because it conquered the sympathy of the Obama Govern "climate guru", the Energy Secretary Steven Chu. He is excitedly suggesting to paint the world with a white color.
Based on the Akbari studies, the Nobel Steven believes that, reflecting the solar rays back to space, the roofs, pavements and roads painted in white can generate the same economy produced if all the cars of the world were taken off the circulation through eleven years. It would decrease also the air-conditioned use on edifications, as a white roof of 100 m2 can balance about 10 tons of carbonic gas -- the annual emission of an average residential house in Europe or United States.
This solution will have a bigger effect if we include, at this general "whitewashing", whole properties, as the people do at the Mediterranean Coast for centuries.
Steven, based on the Akbari studies, also wants that the communities, authorities and families -- like California, where there is already a law which demands that the commercial buildings have their roof painted in white -- use more reflecting materials in eventual maintenances and repairs, defending even big fields of agricultural cultures which shine at sunlight, like soy, barley, wheat, etc.
Without mentioning what would be the emission of CO2 amount necessary to produce and apply the white ink in all the world edifications, Akbari and Steven want that United States turn words into action. Then, the countries with a big emission of CO2 amount -- like China -- would follow this example.
Let's put polemics and practical results apart: this idea would be very interesting to increase the tourism of the city where I was born -- Salvador, Bahia, Brazil, South America. Under the influence of a strong mysticism, major part of the people are dressed in white on Fridays and on each 2nd Thursday of every year, following the baianas on typical suits. One million devoted people arising the sacred hill to wash with essences the stairs of the Nosso Senhor do Bomfim Church.