Volume 8, Number 3     May/June 2000

Earth Science in the New Decade

By Dr. Ghassem R. Asrar
Associate Administrator for Earth Science
NASA Headquarters

If we could extend practical weather forcasts to 7 to 10 days, the benefits to companies and to building contractors—to just about everyone—would be enormous. If we knew how much rainfall to expect next season, farmers could make better decisions about planting drought-resistant crops or more thirsty ones. If we understood the true shape of Earth's surface, and how the motions of Earth's interior affected it, we could begin to predict volcanic eruptions, earthquakes and floods. How will we get there? The same way the nation achieved the current three-to five-day forecasts—by linking NASA's satellite technology to the National Oceanic and Atmospheric Administration's operational weather forecasting capability, to the U.S. Department of Agriculture's agricultural extension programs and to the U.S. Geological Survey and Federal Emergency Management Agency's floodplain mapping, natural hazard preparedness and emergency warning products.

NASA's Earth Science Enterprise aims to obtain a scientific understanding of the entire Earth system on a global scale by describing how its component parts and their interactions function, and how they may be expected to change in both the near and distant futures. The challenge is to develop the capability to predict those changes that will occur in the next year, decade and century, both naturally and in response to human activity. The strategic objective of the Enterprise is to provide scientific answers to the overarching question: How is Earth changing, and what are the consequences for life on Earth?

The view of Earth from space afforded by NASA's research satellites over the past 40 years has led scientists to see Earth as a complex and dynamic system. Its varied components of land, atmosphere, oceans, ice and life are highly interactive. Incoming energy from the Sun and the motions of Earth's interior drive these interactions. Especially in the last few millennia, and accelerating in recent centuries, human activities have constituted additional forces acting on the Earth system. These forces elicit a wide variety of responses in the Earth system. These include large-scale changes in ecosystems over time (for example, when "ice ages" expand and recede, or when forested lands are converted to agricultural or residential use), or even frequent, severe storms. By examining Earth as a system, as the view from space enables us, NASA aims to understand the forces acting on Earth, their resulting responses and feedbacks and what their impacts are on agriculture, industry and other societal activities.

The Earth Science Enterprise is deploying the Earth Observing System (EOS), a constellation of satellites, to probe these key Earth system interactions. The first four EOS satellites were launched in 1999, and the remaining nine will be launched through 2003. Over the next few years, NASA is investing in building and launching more than 26 satellites to examine practically every aspect of our home planet from space. The Enterprise is also planning its research priorities and missions for the next decade. We are investing in advanced instrument technologies, including active sensors (radar and lidar) to resolve three-dimensional structures of the atmosphere and land surface, and improved passive sensors to extend long-term data records at reduced cost. We are investing in advanced computing and communications technologies to enable on-board information product generation and distribution and to create visualizations that allow for the understanding of massive quantities of data.

The next decade promises to be an exciting one. We will move beyond characterizing the Earth system to genuinely understanding how it works, so that we can begin to predict future change. New scientific knowledge and practical applications will be streaming from NASA's Earth-observing satellites. Advanced technology and lower cost missions will be developed to assure the continuity of essential scientific data and information while enabling new and innovative applications. Small, innovative missions will discover facets of the Earth system that we can only guess at today. An information management system will ensure affordable and timely delivery and access to data products by scientists, practitioners and policymakers. New ways of combining geospatial data into innovative, useful information products will engage a broader range of users to multiply the return on the national investment in Earth science. And the result will enable a robust climate, weather and natural hazard assessment and prediction capability, support for the efficient production of food and fiber, effective management of natural resources, and enhancement of the quality of life on Earth.