Impacts of Climate Change

What is climate change?

Climate change is an alteration in the pattern of climate over a long period of time due to a combination of natural and human induced causes. Global climate has varied greatly throughout Earth’s history but not at same rate of warming as the final decades of the 20th century (Figure 1), which is unprecedented for thousands of years.  The observed global warming mostly caused by human activities (IPCC, 2014) that increase the greenhouse gas concentrations in the atmosphere (Figure 2). Global average temperature rise has been accompanied by ocean temperature increase, and sea levels rise (Figure 3) due to melting ice sheets and most glaciers.  

Figure 1. Global Temperature Trend 1880-2015 – This graph shows the global temperature anomaly from 1880 to 2015. (Credit: NASA/JPL-Caltech)
Figure 2. Atmospheric CO2 trend for centuries – This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)
Figure 3. Sea level rise: 1880-2013 (Credit: CSIRO, updated Church and White, 2011)

Since the mid-20th century, climate change has resulted in increases in the very hot days and decreases in frost free days (Alexander et al., 2006). These trends will continue with further global warming. Heavy rainfall events have intensified over most land areas and will likely continue to do so, but changes are expected to vary by region.

What are projected future impacts on installations?

During the next few decades and beyond, global warming is expected to cause further increases in atmospheric moisture content, more extreme heatwaves, fewer frosts, further decreases in the extent and thickness of sea ice, further melting of mountain glaciers and ice sheets, shifts in rainfall (increases in most tropical and high-latitude regions and decreases in many subtropical and mid-latitude regions), further ocean warming, and further rises in sea levels. The magnitude of expected change depends on future greenhouse gas emissions and climate feedbacks (AAS, 2019). Climate Change and Carbon Tools can be found from the USDA and USFS webpage at

DoD highlights the climate change impacts on its infrastructure and operations that are occurring and expected to occur, stressing the importance of adapting to these impacts in order to accomplish the department’s mission (GAO, 2017). Climate change can have cascading impacts on military missions through the following impacts on natural resources:

  • Effects on the suitability of training and testing sites due to land loss or alteration of natural ecosystems;
  • Limitations on the timing of training and other activities due to increases in wildfires, floods, and other natural hazards;
  • Increased damage to facilities and operational assets due to loss in protective functions offered by wetlands, dunes, and other natural systems; and 
  • Higher regulatory compliance costs and restrictions due to declines in protected species or habitats (Stein, Lawson, Glick, Wolf, & Enquist, 2019). 
  • AAS (Australian Academy of Sciences). (2019). Summary | Australian Academy of Science. Retrieved May 8, 2019, from
  • Alexander, L. V., Zhang, X., Peterson, T. C. et al. (2006). Global observed changes in daily climate extremes of temperature and precipitation. Journal of Geophysical Research111, 1-22.
  • GAO, (Government Accountability Office). (2017). Climate change adaptation: DoD needs to better incorporate adaptation into planning and collaboration at overseas installations. Retrieved from
  • IPCC, (Intergovernmental Panel on Climate Change). (2014). Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. Geneva, Switzerland. Retrieved from
  • Stein, B. A., Staudt, A. Cross, M.S. et al. (2013). Preparing for and managing change: Climate adaptation for biodiversity and ecosystems. Frontiers in Ecology and the Environment, 11(9), 502–510.

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