August 28, 2019

Andrew Campbell 

The phenomenon of global greening initiates by the rising concentration of CO2 to cause the growth of plants globally. The findings revealed that the stress of lacking water resources might offset the phenomenon of global greening.

Since industrial revolution, both the growth of plants and the vegetated regions were increased. The major reason to cause the effect of global greening is that the increasing of CO2 concentration in the atmosphere. Plants will use CO2 in the photosynthesis. When human beings emit more CO2, the higher concentration of CO2 will cause the rapid growth for plants. 

Recently, a paper published in the journal Science Advances to reveal the reasons to cause the rapid growth of plants. The paper was written by Mr. Yuan. In this research, vapor pressure deficit (VPD) was the variables to access the function of ecosystems. VPD, by definition, is the difference between water vapor pressure at saturation in the air and the actual water vapor pressure for a given temperature. According to the research, Mr. Yuan stated that the differences could explain the water potential in the atmosphere. In general, if the water potential is larger in the atmosphere, the VPD is larger so the water evaporates rapidly from soil and plants.

Mr. Yuan analyzed several climate change databases to understand the variations of VPD, especially for the vegetation regions. The study indicated that the global greening effect tended to decrease slow and steady at the late 1990s. Researchers concluded that the increase of VPD was the major reason to hinder the growth of plants after they analyzed with several models.

Professor Ranga Myneni is a researcher of global greening from Boston University, who was not participated in this research. He stated that the conclusion of this research emphasized the threat to plants and soils based on water stress. The water stress would lead browning, especially in tropical and boreal forests. During the past 20 years, researchers were already known that climate change would cause fires and insects outbreak in forest. The study of Mr. Yuan reminded us to notice the increase of water stress for plants.

Photo:Webshot.