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Biome Shifts Due to Climate Change Creates Increased Vulnerabilities for Military Installations

Tyndall Air Force Base Grounds Depicting Damage from Hurricane Michael, the Center for Climate and Security, April 30, 2019

By Dr. Marc Kodack

Supporting sustainable range management and training activities on military installations will be challenged by climate change, both in the near term and many years into the future. Odom and Ford (2020) modelled possible changes to biomes located on military lands from climate change to assess installation vulnerability to these shifts. Based on their modelling they found that the Northeast, the Great Lakes states, and western Great Plains will have the largest increases in temperature. These increased temperatures may adversely affect both forest and grasslands which are managed by installations to support training and natural resource management requirements, e.g., Clean Water Act; Endangered Species Act; Sikes Act. Adverse effects may include changed disturbance patterns–e.g., increased erosion in areas where heavy tactical vehicles are used in the winter when less snow occurs– as well as heat, and water stress to natural communities which, in turn, can disrupt scheduled training activities. The modelling results also forecast increased rainfall for the Northeast and Great Lakes. Disruptions to training may affect readiness of both personnel and equipment. These disruptions may then affect planned deployments.

Odom and Ford (2020) included 595 military installations in the coterminous U.S. in their study of potential biome shifts. A biome is “large community of vegetation and wildlife adapted to a specific climate. The five major types of biomes are aquatic, grassland, forest, desert, and tundra.” The began by using a biome system that incorporates mean annual temperature and potential evapotranspiration (PET) to differentiate biomes in the U.S. These two variables were selected because they are included in the 16 global circulation models (GCM) that Odom and Ford used to model climate change across three emission scenarios for three time periods–current, 2055, and 2085.

The results of the analysis showed that under all three emission scenarios, by 2085 most of the current biomes in the eastern U.S. will shift north/northeast by approximately 600 km (373 miles), about 8 km (5 miles) annually. For example, the warm temperate humid forest of the southeastern U.S. will shift to the northeastern U.S. The subtropical humid forest that currently encompasses all of Florida and runs along the Gulf Coast will become dominant throughout the interior Southeast. Species will map to these changes with some changing their geographic distributions. Others may be able to tolerate higher mean annual temperatures and remain in place. These shifts will reduce the spatial extent of existing boreal and temperate biomes. Other biogeographic shifts are projected to occur elsewhere in the U.S. (Figure 3, 2020).

Fort Drum located in upstate New York is an example of what a biogeographic change might mean for a specific installation in the Northeast. Fort Drum obtains 100% of its electricity from a biomass plant located on the installation (here). If the fast-growing aspen-birch stands that are now harvested for their biomass are succeeded by slower growing red maple or black cherry, this could decrease the volume of biomass available for electricity generation. Tracking the decade-in-the-making shift will be important to avoid disruptions if biomass continues to be the main source of power for the installation over the next 65 years.

For some installations in the Northeast and upper Midwest, endangered species may be affected by the modelled changes in climate. For example, at the Michigan National Guard’s Camp Graying in northern Michigan, the endangered Kirtland warbler may be negatively affected as the climate warms and rainfall increases in the Jack pine forests, its’ native habitat.

Other regional shifts in temperature and precipitation from climate change will affect the frequency of wildfires, drought, and humidity, which will differentially affect the distribution of endangered/threatened and game species. For example, in the western U.S. some species may seek higher elevations to escape increased temperatures, whereas others may shift downslope.

Odom and Ford conclude that changes in temperature and precipitation under the different emission scenarios across the three time periods will affect military installations differently depending on where they are located. When the modelled changes in temperature and precipitation are mapped onto the shifts in biomes boundaries, species diversity, distribution, and abundance will occur. There will be a mixture of possible responses by these species and the natural resource managers on military installations out to the end of the century. One result may be that training activities are negatively affected, whether from expansion or migration of endangered/threatened species from increases in temperature and precipitation. Elevated temperature coupled with increased humidity directly degrades human health when performing strenuous activities outside such as occurs in training. 

Managing natural resources under climate change requires comprehensive planning, flexibility, and foresight if the end goal is to ensure that installation missions can be performed with a minimal amount of disruption.

Dr. Marc Kodack is Senior Fellow at the Center for Climate and Security and former Sustainability and Water Program Manager in the Office of the Deputy Assistant Secretary of the Army for Energy and Sustainability.

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