Mitigating Human Enhanced Water Emission Impacts on Climate Change

Water is the most significant GHG, yet climate modelers appear to have ignored human activities that directly add to the concentration of water vapour in the atmosphere. Concentrated water emissions from irrigation, industrial cooling, power generation and hydroelectric reservoirs, add large amounts of water and energy to the atmosphere in dry, and/or heavily populated regions, and this water must come out as precipitation in cooler regions. The magnitude of these emissions is significant, and is estimated to be 4-5 Tt/yr, which is a 4-5% increase in land/atmosphere water flux, over the last century. Evaporating this volume of water requires an incremental 9,000+ ExaJoules/yr, and is all emitted from less than 1% of the earth's surface, mainly in the northern hemisphere. Reduced river flows, and reduced fresh water flow to ocean areas, should be a factor in warming of southern ocean areas, while also causing increased precipitation in cold northern areas. Engineers should be working to mitigate the potential climate impacts of water emissions through increased energy efficiency, and avoiding water emissions from industrial and agricultural operations.