The surface water and ocean topography mission, known as SWOT tracks Earth’s surface water with unprecedented accuracy and completeness, improving our understanding of water under the changing climate. Nadya Vinogradova Shiffer is program manager of Ocean Physics, lead of Climate Variability and Change at NASA headquarters, program scientist of SWOT and co-founder of a non-profit organization for research in Earth science. In her conversation with Nature Water, she speaks about what SWOT will bring and why SWOT matters.