The U.S. government’s reinstatement of the Total Solar Irradiance Sensor, an important climate research capability, aboard its next generation of polar-orbiting weather satellites is a small but noteworthy step toward re-energizing a critical scientific endeavor that had lost momentum due to
funding problems
and White House indifference.


The instrument, which measures solar radiation coming into the atmosphere, was one of several that became expendable in the eyes of the government when massive cost overruns forced a restructuring of the civil-military National Polar-orbiting Operational Environmental Satellite System (NPOESS) in 2006. The restructuring, which pared the NPOESS payload to those instruments necessary for near-term weather forecasting, sparked outcry among climatologists, who have argued – justifiably – that with global temperatures on the rise, and human activity strongly implicated as a contributing factor, now is not the time to curtail climate-research measurements from space.


Scientists fighting for more government funding for their particular field of study is an annual ritual in Washington, especially at a time when just about every research-oriented activity at NASA and its sister agency, the U.S. National Oceanic and Atmospheric Administration (NOAA), is getting squeezed by tight budgets. But given the economic and geopolitical implications of global warming, and the growing potential for gaps in key data sets as NASA’s Earth Observing System satellites age, climatologists can invoke urgency in making their case. To cite one just example, a team of NASA-led researchers recently concluded that human-induced climate change already is having a measurable impact on Earth’s environment and biology.


During its first six to seven years in office, the administration of U.S. President George W. Bush seemed at best disinterested, at worst flat-out hostile, to climate-change research. In recent months, however, the White House seems to have changed its tune. In February, for instance, NASA announced plans to spend $910 million – more than half of which would be drawn from other space science activities – over the next six years to begin work on five of the 15 missions identified by the U.S. National Research Council as priorities in its Earth science decadal survey, released last year. NOAA, meanwhile, requested $74 million for 2009 to restore climate-change instruments that had been eliminated from NPOESS.


The first move actually occurred last year, when the Ozone Mapping and Profiler Suite-Limb was added back to the NPOESS Preparatory Project, a NASA-led precursor mission slated to launch around 2010. That was followed early this year by news that the Clouds and Earth Radiant Energy System instrument was being added to the satellite, providing a bridge for that measurement – solar radiation reflected from Earth – between the Earth Observing System and the first NPOESS satellite. The addition of the Total Solar Irradiance Sensor to the first NPOESS satellite is the latest development, and represents a retreat from previous plans to freeze that spacecraft’s instrument payload to reduce risk.


The trend is positive and encouraging, but there is still much to be concerned about: other important climate monitoring capabilities aboard NPOESS have been watered down, some have not been restored, and even for those that have, the fix is temporary.


Scientists have identified 26 climate variables for which continuous monitoring is essential to understanding the phenomenon of climate change and its causes. Unfortunately, the U.S. government lacks a coherent, long-term strategy for climate-change monitoring that is realistic and sustainable from a budgetary point of view. Compounding the problem is the lack of a clear mechanism for transferring measurements that are deemed experimental or research-oriented, traditionally a NASA responsibility, to operational status, which is NOAA’s domain.

The White House Office of Science and Technology Policy recently launched a study by the interagency U.S. Group on Earth Observations – led by that office, NASA and NOAA – on a future strategy for making critical Earth observations, including those relevant to climate change. This was too long in coming, however; it is very difficult to imagine there being enough time left in this administration to devise – much less begin to implement – a coherent, long-term strategy that takes into account not just NPOESS and successor systems but also contributions that can realistically be counted on from other countries. This is a task that will have to be taken up by the next administration, which based on what is now known about climate change, will have little excuse to not make this an early priority.