This Week’s Earth Indicator: 90

We bring you this week’s indicator—90—with a sigh.

Ninety is the combined number of Earth-observing instruments on NASA and NOAA satellites that are currently monitoring our planet. And that number is about to plunge, according to a National Research Council report released in May 2012. By 2020, there could be less than 20 instruments in orbit, and the total number of missions is expected to fall from 23 to just 6.

Many of the these space-based instruments aren’t exactly household names. (MODIS, anyone? ASTER or ALI? AMSU-A or SORCE?) Still, they are our eyes and and ears on the planet, as indispensable to understanding how it works and changes as our human senses are to navigating life on the surface. Without these satellites, the United States would be blind to most Earth systems, unable to effectively monitor the effects of global warming and the constant parade of volcanic eruptions, wildfires, droughts, dust storms, hurricanes, crop health, air pollution.

The NRC study authors mince few words in explaining what the reduction would mean:
These precipitous decreases warn of a coming crisis in Earth observations from space, in which our ability to observe and understand the Earth system will decline just as Earth observations are critically needed to underpin important decisions facing our nation and the world. Advances in weather forecast accuracy may slow or even reverse, and gaps in time series of climate and other critical Earth observations are almost certain to occur. When these long-running data streams fall silent, users requiring these observations will go unsupported, and progress toward understanding the Earth system and how it supports life may stagnate.

It’s worth noting that the committee only counted missions that have been officially proposed, funded, and given a launch date. It did not include missions that will likely come to fruition but have not yet been fully funded (the successor mission to GRACE, for example). That means the future fleet might not be quite as small as feared, but even the most optimistic estimates indicate a major decline in observing capability.

Media outlets including Wired and EarthSky have more details. The Washington Post wrote an editorial on the subject. NASA Chief Scientist Waleed Abdalati (video below) explains the importance of Earth-observing satellites and points out that most of those in orbit are already past their design lives and living on “borrowed time.”

- NASA