AUBURN, Ala. (EETV)- Professors Hanquin Tian and Susan Pan, of Auburn’s School of Forestry and Wildlife Sciences, in addition to Hao Shi, an Auburn University postdoctoral fellow at the International Center for Climate and Global Change Research, have accomplished breakthrough climate research regarding global aridity. The Proceedings of the National Academy of Sciences of the United States of America (PNAS) published this predictive understanding, of how increasing global aridity velocity impacts species range, online on August 30th and in issue September 7th, 2021. PNAS is a multidisciplinary scientific journal, publishing research papers globally which broadly span all the way from biological nuances to physical and social scientific contributions in the field.

This astounding team of researchers calculated the speeds and directions of aridity shifts across the globe to approximate species migration, based upon where water will be available in the future. Professor Hanquin Tian explains how, “this study was inspired by animal and human behaviors in response to water deficits,” since, “just as nomadic people throughout history have migrated, animals continue to migrate to find food and water in dry seasons.” Terrestrial biodiversity is threatened by increasing global aridity velocity. The regions which currently have a high aridity speed will experience the greatest migration of species. Species in these environments will be required to adapt to droughts. Furthermore, global drying will accelerate unevenly, speeding up tremendously in terrestrial areas without mitigation and thus leaving some species unable to adapt in a timely manner, especially amphibians who will suffer the greatest. This research is significant in that it requires strong climate mitigation to be developed. Christopher Reyer, a contributing  co-author from the Potsdam Institute for Climate Impact Research, emphasized how, “changes in aridity velocity are more variable than shifts in temperature velocity." Species have had to be ‘running to stand still’ to remain in suitable climates under future temperature changes. However, taking into account the speed of aridity, species will now be required to ‘run faster and into different directions’.

This study is unique in that it not only investigated the global aridity velocity from past decades, 1979 to 2016, but also into the foreseeable future, 2050 to 2099. Access to satellite imagery made this possible, providing the ability to calculate spatial shifts in vegetation greenness and project upcoming trends to follow. 

While this research focused on future global aridity velocity, it also concentrated on its overlap with the three most common sectors: agricultural areas, natural protected areas, and urban areas. Therefore, this research can be used to inform the design of predicted hotspot areas on how to prepare for exposure to high drying speed. Auburn University postdoctoral fellow, Hao Shi, explained how, “the majority of the globe is projected to experience drying, especially in the Amazon region, which is the Earth’s biodiversity champion.” Some predicted hotspots of aridity velocity include the southeastern United States and Europe, tropical Asia, southern Africa, and North America. These areas now receive an abundance of annual precipitation, yet will become increasingly susceptible  to extreme droughts in the future. 

This research is a call to action. It acknowledges both the inevitable trends we will face and how we can start preparing to combat these adjustments, especially in areas which will suffer a higher aridity velocity. Breeding and management should be improved to correspond to water stress. Additionally, for cities that would experience long-term drying, infrastructure which sustains water supply to both humans and urban vegetation must be implemented. On a wider scope, significant change requires civic engagement, and there is a dire need to push for water-saving policies to be enacted.