Greenhouses with sparkling roofs help fight global warming, according to recent studies.

As the use of greenhouse areas around the world becomes more widespread, researchers have found that plastic and glass roofs of greenhouses have a cooling effect. Such roofs reflect solar radiation, contributing to lowering the temperature inside the greenhouse, even if surrounding areas are still heating up due to climate change. Fred Pierce reports this in an article published on the Yale School of the Environment portal.

The use of greenhouses continues to expand, and satellite image analysis allows us to estimate the total area occupied by greenhouses worldwide. From Spain to China, and from East Africa to Mexico, millions of hectares of shrubland and abandoned agricultural lands are being replaced by greenhouse giants with shiny reflective surfaces.

These reflective surfaces increase the albedo - the Earth's ability to reflect solar radiation - leading to reduced solar heating in the lower layers of the atmosphere. Various studies have already shown that such greenhouses lead to a decrease in temperature inside them by several degrees.

As a result of new satellite mapping, the area under greenhouses was found to be equivalent to the area of the U.S. state of Connecticut, with more than half located in China. This is much larger than previous estimates and several tens of times higher than estimates made decades ago. However, these figures are only a small part of the picture. The lead author of the study, geographer Xiaoye Tong, says that if temporary coverings of fields with light-reflecting plastic film are taken into account, the total area under greenhouses will increase by about 10 times - roughly equivalent to the size of New York State.

The proliferation of greenhouses and the use of plastic film on agricultural crops represent a huge climate experiment that could have significant implications for cooling urban areas and even mitigating global climate change. Researchers note that the greenhouse effect can already be considered a potential geoengineering project. One detailed analysis of the impact of this land use change on local temperatures is being conducted in the Spanish province of Almeria.

Previously, this area was one of the driest in Europe and was known for being the setting for Western movies. Now it has become the largest producer of fruits and vegetables in the European Union. Plastic greenhouses occupy more than two-thirds of the total area, and around 3 million tons of agricultural products are produced here annually. Agronomists from the University of Almeria conducted an analysis of the impact of greenhouses and found that the albedo inside them increases by 9 percent compared to previous areas.

This means that the reflection of solar radiation leads to a reduction in heating by 20 watts per square meter. Temperature observations have shown an average cooling of 1.3 degrees Fahrenheit (0.7 degrees Celsius) inside the greenhouses over 23 years, while temperatures in surrounding areas continued to rise by 1.8 degrees Fahrenheit (1 degree Celsius).

Thus, the cooling efficiency from the use of greenhouses amounted to at least 1.7 degrees Celsius. Shandong, a province in northeastern China, where there are also significant areas with greenhouses, shows a different situation. Unlike Almeria, there is no cooling effect observed here. Possible reasons include a reduction in precipitation and an increase in air pollution in the past. However, experts claim that greenhouse crops, overall, more efficiently utilize resources such as land and help reduce environmental impact.