为什么现在洪水、暴雨、干旱越来越多了？

Core Viewpoint - The article discusses the urgent state of global water systems, highlighting the impact of human activities and climate change on water cycles, leading to increased water-related disasters and a looming water crisis that threatens food security and economic stability [3][4][10]. Group 1: Water Crisis and Its Implications - Thailand's recent flooding in Chiang Mai, attributed to heavy rainfall and exacerbated by deforestation and land use changes, reflects a broader trend of increasing water-related disasters globally [3][4]. - The Global Water Economy Commission (GCEW) report indicates that human activities have disrupted the global hydrological cycle for the first time in history, making natural rainfall less reliable as a freshwater source [4][9]. - By 2050, the water crisis is projected to threaten over half of global food production, with potential GDP losses averaging 8% worldwide, and up to 15% in low-income countries [12][18]. Group 2: Green Water and Its Role - Green water, which constitutes nearly half of terrestrial rainfall, is often overlooked in water management policies that focus primarily on blue water (surface and groundwater) [6][12]. - The report emphasizes the need for a holistic approach to water management that includes both blue and green water, as changes in land use can significantly affect rainfall patterns in other regions [8][13]. - In China, the disparity in water distribution, with 80% of water resources in the south but half the population and two-thirds of arable land in the north, highlights the urgent need for improved water management strategies [12][14]. Group 3: Economic and Policy Recommendations - The GCEW report advocates for viewing water as a public good and integrating economic, social, and environmental sustainability in water resource management [17][18]. - Recommendations include reforming water pricing, investing in public goods for better water data transparency, and promoting sustainable water resource allocation [18]. - The report calls for a revolution in food systems, protection of natural habitats, and the reuse of water to address the impending water crisis effectively [18].