 Drylands cover around 40 percent of the Earth's land surface and are responsible for producing around 40 percent of the world's net primary productivity. Water is essential for maintaining ecosystem health and food production in drylands, which are especially vulnerable to climate change due to their close relationship with water resources. This paper summarizes the current state of knowledge regarding dryland ecology and its response to climate change, focusing on the role of water in dryland ecosystems. Technological advancements have provided new tools to monitor dryland water dynamics, water budgets, and vegetation water use, including the use of stable isotopes and remote sensing. These tools can help us better understand the impacts of climate change on dryland ecosystems and inform future research efforts. This article was authored by L. Wang, P. Diodorico, J. P. Evans, and others.