...the world is changing. How will we observe these changes if we're flying blind? That's what Loarie et al. are worried about - and with good reason.
Let me explain... Imagine you're a scientist monitoring the planet from space using satellite imagery. You depend on these pictures to understand climate change, asses deforestation, and track the loss of biodiversity. These images allow you to observe many different processes from shrinking tropical forests to melting icecaps and this information is useful in policy and raising public awareness on critical issues.
If you're that scientist, and in reality, even if you're not - the latest from Trends in Ecology and Evolution comes as bad news:
As a result of battery failure on October 6th, 2007, the United States government's Landsat mission which had imaged the globe continuously since 1972 stopped functioning. The thirty-five year sequence of Landsat images has allowed scientists to monitor long term changes to the environment. The private sector is launching high resolution satellites and is doing an excellent job making images available to scientists. But these images under represent places most threatened by environmental changes. The scientific community must find ways to work with the government and the private sector to ensure that we monitor these processes.
What does that mean? Well the private sector has the ability to fill the gap and provide data to climate scientists. The thing is we need to be watching tropical forests and the poles, yet most high resolution images are of cities and roads. As the Pimm group suggests:
The scientific community must find ways to work with the government and the private sector to ensure that we keep a vigilant eye on our environment through our satellite network.
This was a failure of Landsat 5, a venerable satellite. Landsat 7 is still working, but had the early scan line collector failure. (Read about it on Wikipedia.) Result: "The net effect is that approximately one-fourth of the data in a Landsat 7 scene is missing when acquired without a functional SLC." So the Landsat mission(s) isn't over yet. But this underscores the need for overlapping sequential mission planning on a much tighter timeframe.
Miss Sheril,
True, the private sector can provide data, but if the data comes from China or the EU, there are actually complex agreements that have to executed governement ot government before the federal, state, and local community can use the non-US data. Lack of one of those agreements almost derailed satellite data use during Katrina, when US satellite feeds were knocked out in Louisiana, and the EU wouldn't let us havetheir data stream (see Ivar Van Heerdon's recent book on Katrina for more on this).
Of equal worry to many of us in the ocean community is the impending end of satellite coverage, or the downgrading of coverage, from a variety of ocean related sensors. the loss of LandSat5 may be the first of many such happenings inthe next few years.