This study is led by Dr. Bin He (College of Global Change and Earth System Science, Beijing Normal University) and Dr. Wenping Yuan (School of Atmospheric Sciences, Sun Yat-sen University). Terrestrial ecosystem, as a major carbon sink, plays an important role in regulating the global carbon cycle and atmospheric CO2 mixing ratio. Traditionally, atmospheric temperature or land water availability have been considered as the two dominant drivers of interannual variability of global terrestrial carbon sink. In 2019, Wenping Yuan's group observed an apparent shift in global vegetation growth from greening to browning in the 1990s, and attributed this shift to the sharp increase in vapor pressure deficit (VPD). Inspired by this study, Bin He proposed that VPD should regulate the global terrestrial carbon cycle to a significant extent, which has been ignored by previous studies. "When I found the strong correlation between VPD and atmospheric CO2 growth rate, and the latter is an integrated measurement of global land carbon sink, I realized this finding may bring a completely new research objective in the field of global carbon cycle and climate change" Bin He says.
source https://phys.org/news/2021-10-underestimated-impact-vapor-pressure-deficit.html