Climate Change, Health, and National Security


The graceful swirls of the meandering Mississippi River are surrounded by small, boxy shapes of towns, fields and pastures. Countless oxbow lakes and cutoffs accompany the river south of Memphis, Tennessee, on the border between Arkansas and Mississippi. The “Mighty Mississippi” is the largest river system in North America. Landsat 7 data acquired May 28, 2003, courtesy of USGS.

, is editor of Imaging Notes and Senior Advisor of the Secure World Foundation, an organization devoted to the promotion of cooperative approaches to space security.

This July will mark the 40th anniversary of the launch of the first satellite in the Landsat system, a system that miraculously survived years of policy indecision, budget turmoil, technological challenges and interagency warfare to emerge today as the longest operating and most widely used electro-optical land remote sensing system in the world. Developed by NASA and now operated by the U.S. Geological Survey (USGS), the medium-resolution multispectral Landsat dataset constitutes the longest and most complete space-based global record of environmental change the world has. Landsat data, available for free download, are widely used throughout the world to tackle a broad variety of environmental issues.

The experience with Landsat data has paved the way for the operation of literally tens of other Earth observing satellites operating today, providing specialized data for a wide range of beneficial uses in support of human and environmental security. (A later column this year will review the long history of Landsat and future prospects for the Landsat Data Continuity Mission, scheduled to launch in December this year.)

As we move into 2012, I thought it worthwhile to review two quite different but important 2011 reports on the benefits of Earth observation systems that in my view have not received sufficient attention. The first is space policy analyst Lyn Wigbel’s enlightening CSIS report, Using Earth Observation Data to Improve Health in the United States: Accomplishments and Future Challenges. This report reviews the utility of satellite Earth observing systems in combating disease and promoting health, and also warns that capitalizing on the gains made over the years is becoming more difficult.

The second report, a thoughtful product of the Center for a New American Security (CNAS), explores the role of Earth observing systems in supporting U.S. national security. In Blinded: The Decline of U.S. Earth Monitoring Capabilities and Its Consequences for National Security, national security experts Christine Parthemore and Will Rogers focus on the security risks we now face as those capabilities decline.

Although these two reports focus on quite different applications of Earth observing systems, they are nevertheless closely linked. Both illustrate the increasing utility of Earth observing satellites in support of human and environmental security, and both highlight the challenges faced by policymakers in continuing to operate these highly beneficial systems into the future.

The use of satellite systems to support public health is a subject that receives relatively little attention, but one that is likely to become increasingly important as climate change brings substantial environmental change to the United States and to the world, and as analytical models based on satellite data become more sophisticated. For example, changes in surface temperature, rainfall and other environmental factors have a significant role in the geographic spread of certain environmentally sensitive diseases such as malaria and West Nile virus.

In the United States, the incidence of Lyme disease, endemic in the Northeast, and Hanta Virus, more common in parts of the Southwest, are both affected by changing weather patterns. Although the mechanism of disease transmission is different in each, they share the characteristic that additional rainfall helps in promoting growth of animal populations that carry the diseases to humans.

Doctors in these regions often have trouble interpreting the symptoms these serious diseases exhibit in patients because they closely mimic other, less virulent ones. Observations from orbit of sharply increased vegetation growth in affected localities can assist public health officials in providing advance warning to local hospitals and doctors. This information can alert local doctors ahead of time to look for telltale signs of these diseases, thus saving lives.

Citing the Department of Defense’s (DoD’s) 2010 Quadrennial Review, the CNAS report reminds us that the department takes global environmental trends extremely seriously: they ‘will shape the operating environment, roles, and missions’ and ‘may act as an accelerant of instability or conflict.’ This is a theme that was first studied in detail in the 1990s in a series of detailed studies by Thomas Homer-Dixon of the University of Toronto and his colleagues, who examined the linkages among population growth, renewable resource scarcities, migration and violent conflict. Those studies made a persuasive case that although environmental degradation may not trigger violent conflict, it can exacerbate conflict and hasten outmigration from conflict regions.

Analysis based on satellite data provides an effective way to detect deleterious environmental changes that could lead to or aggravate conflict in a region. Since at least the Gulf War, military analysts have used both medium- and high-resolution data from a range of Earth observing satellites to understand real-time battlefield environmental conditions and long-term trends in order to fight more efficiently and to protect the troops from harm.

The CSIS report highlights a familiar problem in the structure of U.S. Earth observation technology development and use – the existence of a so-called ‘valley of death’ between the development and testing of an EO capability by NASA and its long term operation by NOAA or other agency focused on the operational utility of that capability. For decades, policymakers have insisted that NASA’s proper role in the process is to develop space-based instrumentation in support of advancing science. According to this institutional model, if some of the sensors developed by NASA later prove successful in tackling societal needs such as public health or climate change, then they should be developed and operated by operational agencies like NOAA or USGS. This model has been much more successful in promoting leading edge Earth science than in bringing benefits to the public.

In reality, the money needed by the operational agencies for developing and operating new satellite sensors is seldom available to them, despite the clear utility of the collected data for their mission. As a result, the United States often cannot take advantage of the benefits such sensors would provide. For example, both reports cite the enormous utility of NASA’s MODIS sensors for monitoring broad-scale environmental conditions in the United States and around the world. Data from these sensors are being widely used operationally by thousands of researchers to provide early warning of harmful environmental changes.

Yet, once these workhorse research sensors begin to fail, there are no planned replacements, despite years of effort to provide the funding for follow-on operational instruments. The VIIRS sensor on the recently launched NPOESS Preparatory Project (NPP) satellite will provide some of the needed data, but tradeoffs made in its design mean that some operational users will lose some of the MODIS capability they have depended on and will have to develop new algorithms to make effective use of the VIIRS data for their applications.

As we look ahead in 2012, we can hope that the continuing budget battles will not completely gut the U.S. Earth monitoring capability. Now more than ever, as these two reports illustrate, we need the ability to monitor Earth’s environment from orbit to make use of the synoptic view that such observations provide.

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