Inadvertent—may change local weather and long-term climate.

Cloud seeding can induce rain or disperse fog under the right atmospheric conditions. Improving the local situation, however, often makes things worse somewhere else. It is not yet clear what the future of our weather and climate will be. Some scientists warn that the gaseous pollutants we release into the atmosphere may trap radiant energy and cause a global warming trend that could drastically disrupt human activities and natural ecosystems. Understanding and protecting this complex, vital aspect of our world is clearly essential.