Changes in land surface water dynamics since the 1990s and relation to population pressure

Abstract

We developed a remote sensing approach based on multi‐satellite observations, which provides an unprecedented estimate of monthly distribution and area of land‐surface open water over the whole globe. Results for 1993 to 2007 exhibit a large seasonal and inter‐annual variability of the inundation extent with an overall decline in global average maximum inundated area of 6% during the fifteen‐year period, primarily in tropical and subtropical South America and South Asia. The largest declines of open water are found where large increases in population have occurred over the last two decades, suggesting a global scale effect of human activities on continental surface freshwater: denser population can impact local hydrology by reducing freshwater extent, by draining marshes and wetlands, and by increasing water withdrawals.