How is the global Earth system changing? This is one of the big questions that NASA Earth science addresses. Some changes are well documented and quantified, such as the average global temperature rise of 1.1 degrees Fahrenheit over the past century. Other changes are more subtle and not easily measured, but still have far reaching effects. For example, human impact on the environment can influence rainfall or drought.
Another big question that NASA Earth scientists are addressing is: “How will the Earth system change in the future?” For instance, scientists predict changes in precipitation patterns. High latitudes and wet regions are predicted to get wetter. At the same time, tropical areas and dry places are expected to get dryer.
The availability of freshwater has always been a determining factor in the success of human civilizations. Only 2.5 percent of all the water on Earth is freshwater. Most of the freshwater is frozen on the surface in glaciers and ice caps. Very little of Earth’s freshwater is contained in rivers, lakes and streams, and in the atmosphere. Much more of it is stored in the ground in aquifers that feed rivers and streams.
Given the importance of water, drought is a major issue in the United States and across the world. In 2013, 57.4 percent of land in the lower 48 states was experiencing drought. Many states in the southwest depend on snow pack in the Colorado Rockies for water. Southern Colorado, northern Texas and Oklahoma have experienced drought since 2011. Around the world, Australia, the Sahel region of Africa, southern Asia, and the Mediterranean are also experiencing drier conditions.Back to NASA VizApps