that are related to climate events, are extremely inadequate. Soil moisture, for example, is important for monitoring drought as well as for estimating the potential for flooding. Streamflow is a good large-area integrator of short- and longer-term moisture conditions for a basin, a region, or even a continent. Sea surface temperature is especially important for tracking El Niño–Southern Oscillation events.
The white paper found that such data, as well as detailed hourly information on variables such as precipitation intensity, distribution, frequency, and amount of precipitation, are necessary for predicting extreme events on regional scales. Because there are not yet adequate data in these areas, it may be necessary to develop global indicators in an incremental fashion—for instance, by adding one or two parameters at a time or by beginning with specific regions that allow early development, such as Europe or Australia.
Numerous analyses have documented the linkages between global climate change and environmental sustainability (e.g., National Research Council, 2010a, 2010b, 2010c). One example is the way in which changes in ocean and atmospheric circulation force corresponding changes in ocean temperatures, which reach the ice shelves, resulting in land ice loss, sea level rise, and, ultimately, coastal erosion. Likewise, changes in precipitation patterns can affect the snowpack and surface hydrology, thereby affecting agricultural productivity. And increased carbon dioxide emissions absorbed by the ocean lead to increased ocean acidity, which destroys the marine organisms that provide food sources for other marine life and thus negatively affects fisheries. To understand these relationships it is necessary to measure a broad and diverse set of the variables that connect global climate change with human life-supporting systems such as those providing for food, energy, water, and health. Global-scale indicators and metrics based on a broad spectrum of observations can provide some advance warning of the impacts of global climate change (National Research Council, 2010b). Sea level rise is one such indicator, for example, because it is a function of oceanic, land ice, and hydrologic processes. However, to obtain better estimates and projections of rising sea levels it will be necessary to make better sustained observations of such variables as sea state, atmospheric wind speed and direction, sea-ice extent, the mass balance of mountain glaciers and ice sheets, and river discharge.
The United States and other countries do not currently have national strategies for sustaining long-term environmental observations. Joint efforts in support of the UNFCCC and IPCC are encouraging international collaboration, and many nations have recognized the need for a fully implemented observing system. However, funding is a major obstacle. Major gaps in satellite and in-situ observations are developing because of the loss of several key satellites, such as Cryosat, the Orbiting Carbon Observa-