The coronavirus that is currently causing severe respiratory illness worldwide has now been named SARS-CoV-2, and the disease is COVID-19. When the virus first emerged last December, it was generally described in medical journals as the ‘2019 novel coronavirus’.
Your view that China’s re-vegetation of its deserts could exacerbate water shortages risks oversimplifying an incredibly complex eco-restoration problem (Nature 573, 474–475; 2019). Far from just planting trees in arid areas, China’s re-vegetation codes vary for different regions and greening programmes.
In this study we applied two spatially explicit models to the problem. One is the Penn State Integrated Hydrologic Model (PIHM), a hydrologic model that partitions the water balance in space and time over the urban catchment. The other is the Cellular Automata Land Use Change Model (CALUC), a land use change model, which simulates the evolution of land use classes based on physical measures associated with population change and land use demand factors. We selected two study sites, one modern and one ancient, to highlight the capability of coupling catchment hydrology with land use change models. The goal is to assess the role of hydrologic change in urbanizing watersheds and to evaluate the contemporaneous impacts of climate change. The modern sites are the Conestoga watershed and the Lancaster PA urban center; the historical site is the ancient Maya city of Tikal in Peten region of Guatemala. In each setting, the essential data was developed and the models were used to evaluate how urbanization and land use change gradually altered the entire water balance often in unexpected ways.