Oases are vital habitats and water sources for dryland regions, supporting 10% of the world’s population while occupying only about 1.5% of the land area. However, these wet refuges face threats from climate change and human activities that can compromise their fragile existence. New research has shown how the world’s oases have changed in size over the past 25 years due to shifts in water availability and encroaching desertification.
A study led by Dongwei Gui from the Chinese Academy of Science revealed that global oases expanded by more than 220,000 square kilometers from 1995 to 2020, primarily due to intentional oasis expansion projects in Asia. However, desertification resulted in the loss of over 134,000 square kilometers of oasis land during the same period, mostly in Asia. This led to a net growth of 86,500 square kilometers over the study period, emphasizing the risks posed by climate change and human stressors on these crucial habitats.
The findings underscore the importance of understanding and monitoring oases to inform water resource management and sustainable development in arid regions. Oases provide water for humans, plants, and animals in drylands, supporting productivity and life in deserts. Their existence depends on reliable water sources distinct from rainfall, and today they are found in 37 countries, with 77% located in Asia and 13% in Australia.
Using satellite data, researchers tracked changes in oasis area and health by monitoring vegetation greenness within dryland areas over 25 years. They found that human efforts to convert desert land into oases contributed to the overall increase in oasis size, especially in China where conservation efforts and management have driven growth. However, desertification has led to significant oasis losses globally, affecting approximately 34 million people worldwide.
To ensure the long-term sustainability of oases, researchers suggest improving water resource management, promoting sustainable land use, and encouraging water conservation and efficient use. With climate change affecting glacier melt and water supplies, overexploitation of groundwater and glacier loss may limit the sustainability of oases. International cooperation is crucial for addressing water scarcity and promoting sustainable development, given that river basins often nurture multiple oases across different countries.
Overall, oases gained a net area of about 33,400 square miles from 1995 to 2020, with most of the growth stemming from artificial expansion projects that may not be sustainable in the long run. Thus, efforts to preserve and protect these vital wet habitats are essential to ensure their continued support for human and ecological communities in arid regions. The study’s findings provide valuable insights into the dynamics of oases and the challenges they face, highlighting the need for proactive measures to safeguard these critical landscapes.
