Did you know that our greenhouses help regulate the climate?
Towards an essay made at Almería’s University and published in the Journal of geophysical Research, the plastics on top of the greenhouses makes solar light reflect to space in the same way as glaciers do in the poles, contributing to make a cooling effect, 12 times stronger than in another parts of the globe.
As the essay shows up, in the last 30 years, the average temperature has been reduced almost 1ºC. This reflect effect is known as Albedo Effect.
But, what exactly is Albedo Effect?
The word albedo comes from the latin “albus”, which means white light. Although it can also mean Earth surface light property and its atmosphere. Mainly, last definition is the one that we are more interested in.
Earth reflects part of the radiation than comes from the sun is three different ways: by the atmosphere its own, by the clouds and by the Earth’s surface. The radiation reflected by this surface is what we call Albedo. Therefore, we can define this effect as the percent of solar radiation that is sent back to the atmosphere, after being on the Earth’s surface.
The albedo radiation, can cause two different effects: the cooling effect (when the light is reflected back to space), and the warming effect (where the light stays on the Earth’s surface). All these effects, are also in relation with the color of the materials that the light applies. The lighter colors have a higher percent of albedo than the dark ones. In the following chart, we can see a comparison between main materials that appear in the nature and its percent of albedo effect.
So, coming back to Almeria’s scenario, the almost 30,000 hectares of fruit and vegetable greenhouses that have been expanding since the 80’s in the whole region, have created an unexpected cooling effect in the local climate. While the temperaturas are rising all over the world, at Almería’s meteorologic observatories the opposite happens, decreasing temperatures 0.3 degrees per decade.
The strange phenomenon has not gone unnoticed by the scientific media, but now, a formed essay has done a reliable explication about the climate changes in the area: acting like a mirror, the plastic’s white color reflects the solar lights to the atmosphere, stopping the warming effect for Earth’s surface. In some ways, the local greenhouses “fight” against the global greenhouse-effect.
The essay published in the science Journal of Geophysical Research, has been coordinated by a research group headed by Pablo Campra, an Almeria’s University (UAL) professor.
During the first stage of the essay, the researchers analyse the temperatures of the two main observatories in Almeria, located in Las Palmerillas-Cajamar y La Mojonera, and they had been compared with the other close stations
The result was that the temperatures have decreased 0.9 degrees since 1980, when the expansion of greenhouses started, while in Malaga, Granada and Murcia-San Javier, the temperaturas have increase around 1.3 degrees. So, it makes a difference of more than 2 degrees centigrade.
The amount of rainfall however has not changed significantly.
Almeria’s aeroport observatory has in-between results: the temperatures had increased since 1980, but in the 90’s they started to decreased and then stablished a nule balance. “You can observed every year how the greenhouses get closer the city”, Campra said.
In the second part of the essay, the researchers analised if there were any changes in the light reflectivity and the results were incredible: since 1983, the Aldebo effect in Almeria has increased in a 9%, which means that, there is 9% more of radiation gets reflected back to space.
All this, supposed indirectly, an improvement in comfort for the citizens and a decrease of energetic use for the climated systems at homes and greenhouses.
From AgroInver, we would like to encourage our readers to fight against the climate change in a sustainable way, giving our grandchildren the chance to grow plants in the lands we are growing today.