Featured collection introduction: Water for megacities - challenges and solutions

摘要: The Earth has entered into Anthropocene, a new epoch dominated by people. world’s urban population grown more than four times during the past 60 years to 3.9 billion. Today, people are living in cities countryside most nations. Cities growing bigger and faster ever before (United Nations, 2014). that have >10 million commonly considered as megacities defined UN-HABITAT (Li et al., 2015b). Globally, there about 28 with approximately 13% of Most these found Asia. By 2030 world is projected 41 Africa Asia fastest Megacities face many emerging challenges, from economic development social stability environmental changes 21st Century. Obviously, water resource challenges rooted rapid rise competing demands for multiple uses. Water problems arise when demand cannot be met supply due either natural (e.g., surface or groundwater exhaustion), socioeconomic financial governance), quality, constraints. Meeting rapidly often means sacrificing environment such quality degradation, ecosystem damage, and/or unsustainable use depletion salt intrusion. Competing irrigated agriculture, thermoelectric power generation, industrial residential common causes shortages megacities, especially arid semiarid regions extreme drought years. pollution alone can turn “water rich” city poor” one demonstrated developing countries. Climate change affects availability everywhere, but vulnerable simply because large 2015a, b). Growing weather events hurricane, droughts, floods) associated climate variability pose some biggest infrastructures megacities. It