New research utilizing long-term satellite data has revealed a significant cooling effect of vegetation on land surface temperature, offering insights into potential climate change mitigation strategies for arid regions, particularly the Arabian Peninsula. The study, published in Ecological Indicators, emphasizes the importance of effective strategies as the region faces increasing vulnerability to heat stress due to rising temperatures.
Climatologist Matteo Zampieri from the King Abdullah University of Science and Technology (KAUST) highlights the impact of vegetation on surface temperature, explaining, “As vegetation absorbs more solar energy compared to the desert, it reduces the reflectivity (albedo) of the land surface. This, in turn, increases the temperature of the land surface in water-limited areas. The balance between increased evapotranspiration and reduced albedo determines the outcome of greening efforts.”
Zampieri cautions that the outcomes of desert greening efforts can vary, depending on factors such as water availability for plants and specific physiological processes of drought-adapted plant species. While some instances of desert greening may lead to surface cooling, others can result in surface warming.
To investigate the impact of managed vegetation, researchers used satellite data to compare surface temperature differences between planted areas and bare soil at various sites representing Saudi Arabia’s main agricultural regions. The study focused on Al-Qirw, where temperature differences between vegetated and bare soil are not influenced by differences in elevation.
The findings show a considerable difference in the annual mean land surface temperature (LST) between planted areas and bare soil at Al-Qirw. Between 2010 and 2017, the daytime LST inside the vegetated area was approximately 4°C cooler than the surrounding bare soil. This cooling effect was more pronounced on hotter days, corresponding with an increase in the normalized difference vegetation index (NDVI) in the vegetated area.
Ibrahim Hoteit, leader of the research team at KAUST, underscores the study’s significance in supporting evidence that managed vegetation and effective water management practices can mitigate high temperatures in arid regions. However, he emphasizes the importance of sustainability, noting that the collapse of vegetation can diminish the cooling effect and accelerate local warming trends.
“Our study shows that managed vegetation plays a crucial role in mitigating the impacts of climate change, especially heat waves,” says Hoteit. “However, it also highlights the importance of sustainability factors because the collapse of vegetation can diminish the cooling effect and accelerate local warming trends,” he warns.