Spain: Cooling trend in Almería by its greenhouses surface

This is an update of the research on albedo or reflectance, which, 12 years ago, meant the characterization of a buffer effect of global warming by urban settlements, specifically in the horticultural area of Almería.

The high albedo or reflectance of Almería’s greenhouses is the reason why it is the only human settlement visible to the naked eye from space.

Albedo is the cooling effect produced in the temperatures of an area by the increase of solar reflectance due to changes in the surface cover, more intense, the greater the surface is covered with light colors or bleached, as the case of greenhouse building or whitewashing of building roofs or urban pavements is.

Greenhouse horticulture has experienced in recent decades a dramatic spatial expansion in the semiarid province of Almería, in southeastern Spain, reaching a continuous area of about 30,000 ha, the widest greenhouse area in the world.

It had a great impact on the media and especially on scientists investigating, through climatic simulations, different viable options for adaptation to expected global warming, mainly in urban areas.

The results showed that 45% of the total carbon footprint of the greenhouse horticulture could be considered offset by albedo. It can therefore concluded that the Almería greenhouse covers have two complementary positive effects on climate change: one local, neutralizing global warming in the area, and another on a planetary scale, partially offsetting of the total carbon footprint.

This indirect effect is called high yield conservation. In Almería, only 30,000 ha, 3% of the provincial surface is covered by greenhouse irrigated farming. 3.5 billion tons of fruit and vegetables worth €2.5 billion come out of it, a huge source of food and income. Thanks to this alternative income (along with the marble sector and tourism) hundreds of thousands of hectares of traditional agriculture, with high erosive and superficial impact, were abandoned and now constitute a green lung, where the Mediterranean scrub in spontaneous expansion is fixing million tons of CO2.

  • They currently consider that this research line is closed, although they remain open to establishing collaboration with anyone whose interest would be applying albedo as the only geo-engineering strategy, feasible today, which has proven its effectiveness in urban adaptation to global warming.