« Back

Non-stationarity: New vocabulary for a changing climate


Blog originally posted on The GLOBE Scientists' Blog: http://blog.globe.gov/sciblog/2012/11/08/non-stationarity-new-vocabulary-for-a-changing-climate/

A few years ago I attended a workshop for early career scientists to discuss frontiers in integrated water-climate-society vulnerability and adaptation science. This interdisciplinary area of science focuses on the need for using scientific information to not only identify communities that are vulnerable to climate change, but to also help create effective approaches for communities to adapt to climate change. Since every society needs water to survive, the focus was on water and climate.Thus, the workshop brought together emerging scientists in the physical sciences (e.g., atmospheric and climate scientists, hydrologists) and the social sciences (e.g., anthropologists, sociologists). I attended the workshop representing atmospheric scientists who study the water cycle, and I learned a lot about the need for interdisciplinary efforts to address problems in the water-climate-society nexus. One of the things I learned was a new term: non-stationarity.Non-stationarity means that what used to be normal is not normal anymore. It means that our climate system can no longer be considered stationary. The extremes in our climate system of the past, can no longer be considered the outer limits of what our current and future climate system can exceed. For example, a 100-year flood could now be expected to happen more frequently than once in a 100-year period; thus it may become a 50-year flood, or less.

Image looking at the magnitude and frequency of 100 year floods
Image looking at the magnitude and frequency of 100 year floods.
From Ohio Department of Natural Resources.

The principle of non-stationarity has broad implications. Insurance companies, that base their rates on the likelihood that extreme events will or will not occur, are now having an even harder time doing their risk analyses. Engineers that build dams, levees, and bridges are challenged to build structures that can withstand extreme conditions that we used to not think possible. And communities, especially those in areas vulnerable to sea level rise, drought, or floods, are faced with even tougher potential conditions to adapt to. While the term is just becoming part of my vocabulary, the effects of non-stationarity will be felt for years to come. Thus, accepting this new concept and starting to frame our adaptation solutions around it is crucial as our communities respond to the changing climate.

Future drought. These four maps illustrate the potential for future drought worldwide over the decades indicated, based on current projections of future greenhouse gas emissions.
Future drought. These four maps illustrate the potential for future
drought worldwide over the decades indicated based on
current projections of future greenhouse gas emissions.
From Aiguo Dai, NCAR.

Suggested GLOBE activity: Taking climate measurements regularly, for many years to come, will help provide data to establish climate baselines (or “normals”), and over a long enough period of time will help monitor if these baselines are shifting. You can contribute to these climate data sets by participating in the Great Global Investigation of Climate, the Climate and Land Cover project, and/or the Phenology and Climate project.

If you are interested in interdisciplinary science related to the water-climate-society interface, please see a resource list that was compiled by workshop participants to learn more about programs to get involved in.

Comments
Please log-in to post comments