Lixin Wang (Science)
Lixin Wang: Earth Scientist
Tackling SDGs 2, 6, 12 and 13
Dr. Lixin Wang’s passion for hydrology, geochemistry, and soils earned him the 2020 Research Frontiers Trailblazer Award and the 2021 President’s Bicentennial Medal. A professor of earth sciences in the IUPUI School of Science, Dr. Wang’s cutting-edge work on the UN Sustainable Development Goals has also resulted in grant funding in excess of $3 million. In addition, he is a reviewer and editor of major international journals including Hydrology and Earth System Sciences, Nature, Nature Climate Change, Nature Geoscience, and Journal of Hydrology.
Water and vegetation are critical to the Earth’s natural processes, and Dr. Wang’s research involves studying spatial and temporal patterns of water and nutrient availability, how vegetation adapts to and affects these patterns, and how future climate/land use changes affect vegetation-resources interactions. This research directly contributes to SDG 2: Zero Hunger, SDG 6: Clean Water and Sanitation, SDG 12: Responsible Production and Consumption, and SDG 13: Climate Action.
Drivers of Ecological Change in Drylands
Drylands are land with limited natural water supply and can include deserts, parched land, and dry non-desert areas. About 40% of the Earth’s land surface is classified as drylands and this environment is home to approximately 2.5 billion people. A key aspect of Dr. Wang’s work is to investigate the effect of non-rainfall water sources in dryland ecosystems, especially contributions from fog and dew.
Dr. Wang’s research used stable isotope techniques to show the surprisingly numerous origins of source water for fog and dew formation in deserts and that these have important implications for future changes of fog and dew dynamics. It also shown that it is possible to use satellite data to study the impact of fog levels on vegetation health in drylands. The Redwood Forests in California, the Atacama Desert in Chile, and the Namib Desert in Namibia all depend on fog as one major water source. The novel technique of studying climate factors using stable isotopes and satellite data has greatly improved the efficiency and accuracy of investigations. These research studies and their subsequent findings allow us to understand and mitigate climate change impacts, thus making them significant for SDG 13.
Impact of Environmental Changes on Vegetation
Global climate change, including a rise in atmospheric CO2 levels and reductions in water levels, have crucial implications for vegetation across the globe. Dr. Wang’s research into the effects that global climatic deviations have had on plant life in the past allows researchers to build accurate models of future vegetation growth.
One study by Dr. Wang’s group analyzed greening of areas traditionally classified as drylands in the Mediterranean, Middle East, Mongolia and South America. After considering other factors such as increased rainfall and altered agricultural practices, Dr. Wang concluded that increasing atmospheric CO2 concentrations provide the key explanation for global dryland greening. Between 1960 and 2015, carbon dioxide levels have risen approximately 27%. The increased CO2 levels augment soil water levels through higher efficiency in water use by plants, thus causing greening, but further investigation is necessary to understand the long-term effects of dryland greening. Dr. Wang reports that determining whether the greening of drylands is good or bad, also requires further investigation.
Another study conducted by Dr. Wang’s group investigated the effect that rising global temperatures and CO2 levels have on vegetation water needs in the northern hemisphere. This novel and large-scale research used satellite remote sensing data to show that increased atmospheric temperatures and CO2 levels are reducing water availability to vegetation, thereby stunting the growth of plants. While general increases in carbon dioxide promote vegetation growth, this study indicates that water limitations arising from temperature changes are hampering plant growth. Therefore, Dr. Wang and his colleagues see an urgent need to significantly reduce CO2 emissions in a bid to reduce warmer temperatures. The results make these objectives significant for SDG 12 and 13.
Climate Change and Agriculture
Agriculture is a significant source of human and animal food. Projected demand for food over the next few decades is astronomical, making food supply chains and production systems paramount. In recent history, climate change has caused extreme weather events, such as droughts, that severely impact crop yields. Furthermore, agricultural practices can also exacerbate climate change through greenhouse gas emissions and water pollution. Dr. Wang’s research delves into both these aspects in a bid to produce knowledge which can help mitigate the effects that they have on each other.
One study provided insight on the factors which affect legume yield during drought. The study showed a positive correlation between yield reduction and water availability reduction, but the magnitude of the impact depended on the legume and the stage of the crop’s life cycle. Soil textures were also found to have an effect on legume yield, revealing subtle nuances which must be considered to minimize loss of legume yield during drought conditions.
Agriculture contributes significantly to greenhouse gas emissions and runoffs that affect aquatic ecosystems. One technique which has become increasingly common is no-till farming: Soil is left undisturbed without tilling, allowing organic matter to build up in the soil. The technique is touted for its ability to reduce soil erosion and nutrient contamination of water. However, Dr. Wang’s research has discovered that this technique in fact increases nitrate leaching, a common cause of water pollution. This study is critical as it highlights the need to understand agricultural practices and implement them in a manner which minimizes environmental effects. Building on these findings, Dr. Wang and his colleagues have received a $500K United States Department of Agriculture (USDA) grant in 2021 to study the impact of combining no-till and cover cropping on greenhouse gas emissions and nutrient leaching. Such studies are critical to SDGs 2, 6, 12, and 13.