In this paper entitled "Invisible Impact of Deforestation on Climate", the authors explain that their analysis compares the biophysical and carbon dioxide impacts of deforestation in a regional scale for the first time.
Biophysical influence
Deborah Deborah Lawrence, the first author of this paper and a professor at the University of Virginia, pointed out that although climate models do include biophysical effects of deforestation, decision makers do not always take this into account when making land use decisions.
One of the main biophysical effects of deforestation studied by researchers is how the loss of forest cover affects the heat distribution. The tall canopy takes heat away from the ground strap and distributes it in a higher position in the atmosphere.
"Imagine a smooth surface, the wind just flows directly, and the heat of the sun comes down directly. But with the canopy, its surface is like a cauliflower, and these airbags will bounce back and the heat will be dispersed, "Lawrence said."
Just as an umbrella scatters a lot of water droplets to keep people dry under the umbrella, the forest also plays this biophysical role in hot weather.
"It is very important to keep the heat away from the ground because we live here. The temperature rise is measured on the ground, "Lawrence said.
Louis Verchot, chief scientist of the International Biodiversity Union and CIAT in Cali, Colombia, pointed out that another important biophysical factor is the water cycle. "Forests are also very important to the regional hydrological cycle; Once you cut down trees, you remove the pump that transfers water from the surface to the atmosphere, which will affect the downwind rainfall. "
Forests are also the main source of bio-volatile organic compounds, and bio-volatile organic compounds are one of the many factors that cause cloud formation. Verchot pointed out: "BVOCs produced by forests increase the concentration of water droplets in clouds, which makes clouds brighter, so they reflect more energy back into space."
Verchot said that although the interaction of condensation nuclei (around the formation of clouds) is very complicated, it is increasingly clear that the changes of BVOCs related to deforestation have an indirect and direct impact on clouds. "We used to think that biophysical effects cancel each other out, but now we know that removing forests will greatly reduce the cooling effect of clouds."
From the perspective of "landscape system"
Verchot said that although CIAT, as an international tropical agricultural center, has agronomists and plant breeders, they also use the method of landscape system to understand the importance of other types of ecosystems in the landscape, their functions and services to society.
"My team pays attention to Amazon and studies fires, deforestation and wetland loss in Latin America ... from the perspective of carbon cycle and hydrological cycle," Verchot added, adding that the alliance is an applied research center to study the impact of these things on human well-being.
"We are helping to explain to the government and policy makers that preventing deforestation has economic advantages, and owning forests in these areas can provide an economic safety net because we don't just look at it from the perspective of carbon," Verchot said.
In fact, it is not only the decision makers in the tropics who should take this into account. Lawrence said: "If we are seeking local and global overall climate benefits, then we should work very hard to plant and maintain forests in tropical areas and seek sustainable management of forests outside tropical areas."