Meredith Muth, National Oceanic and Atmospheric Administration
Joel B. Smith, Abt Associates
Alice Alpert, U.S. Department of State
James L. Buizer, University of Arizona
Jonathan Cook, World Resources Institute (formerly U.S. Agency for International Development)
Apurva Dave, U.S. Global Change Research Program/ICF
John Furlow, International Research Institute for Climate and Society, Columbia University
Kurt Preston, U.S. Department of Defense
Peter Schultz, ICF
Lisa Vaughan, National Oceanic and Atmospheric Administration
Diana Liverman, University of Arizona
Apurva Dave, International Coordinator and Senior Analyst
<b>Smith</b>, J.B., M. Muth, A. Alpert, J.L. Buizer, J. Cook, A. Dave, J. Furlow, K. Preston, P. Schultz, and L. Vaughan, 2018: Climate Effects on U.S. International Interests. In <i>Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II</i> [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 604–637. doi: 10.7930/NCA4.2018.CH16
Climate Effects on U.S. International Interests
Shared resources along U.S. land and maritime borders provide direct benefits to Americans and are vulnerable to impacts from a changing climate, variability, and extremes. Multinational frameworks that manage shared resources are increasingly incorporating climate risk in their transboundary decision-making processes.
The shared borders of the United States are extensive. Land borders with Canada (13 states) and Mexico (4 states) include shared rivers and lakes. Maritime borders are shared with 21 countries by Hawai‘i and other island areas, including the U.S. Caribbean, the U.S.-Affiliated Pacific Islands, and the Arctic region.92,93
Climate variability and change, as well as related extreme events across shared U.S. borders, can have direct and indirect impacts on those living in the United States. For example, increased temperatures coupled with decreased precipitation in northern Mexico can lead to an increase in the intensity of dust storms and wildfires, which can cross the border into the United States.94,95,96,97,98,99 Similarly, transport of smoke from wildfires across the Canadian borders can lead to air quality and health concerns in the United States (Figure 16.4) (see also Ch. 24: Northwest, Box 24.7). Movement of fish species is affected by changes in water temperature (Ch. 9: Oceans, KM 2; Ch. 20: U.S. Caribbean, KM 2) as illustrated by the migration of Pacific hake, an economically important fish species that migrated northward from the United States to Canadian waters due to warmer ocean temperatures during the 2015 El Niño.100 Additionally, climate impacts are likely to exacerbate cross-border issues related to water, wildlife, trade, transportation, health (Box 16.1) (see also Ch. 14: Human Health), infrastructure, energy, natural resources (such as biodiversity and forests), food security, human migration, and cultural resources. Shared water resources such as rivers and lakes are particularly sensitive to changes in precipitation (Figure 16.4). In the U.S.–Mexico drylands region, large areas are projected to become drier (Ch. 23: S. Great Plains),101,102 which is expected to present increasing demands for water resources on top of existing stresses associated with population growth.103,104 Along the U.S.–Canada border, changing weather patterns along the Columbia River, which originates in Canada, affect the amount of water available for irrigation, drinking water supplies, and hydroelectric power generation.105
Figure 16.4: Shown here are examples of climate-related impacts spanning U.S. national borders. (left) The North American Drought Monitor map for June 2011 shows drought conditions along the US–Mexico border. Darker colors indicate greater intensity of drought (the letters A and H indicate agricultural and hydrological drought, respectively). (right) Smoke from Canadian wildfires in 2017 was detected by satellite sensors built to detect aerosols in the atmosphere. The darker orange areas indicate higher concentrations of smoke and hazy conditions moving south from British Columbia to the United States. Sources: (left) adapted from NOAA 2018,114 (right) adapted from NOAA 2018115.
The management process of shared water resources is increasingly incorporating climate information into the decision-making process. Several agreements between countries have recently been restructured to consider changing weather patterns and related management challenges to include climate risk and adaptive management into their near- and long-term strategies. Along the Mexican border, the International Boundary and Water Commission, which implements water treaties between the United States and Mexico, is exploring an array of adaptive water management strategies (Ch. 25: Southwest, Box 25.1)106 and utilizes an adaptive approach that can help with managing climate-related impacts on Colorado River water.107 An example of this adaptive management approach is the design of flexible surface water and groundwater storage facilities, coupled with governance mechanisms that continuously account for changing climate conditions and water demand.
The International Joint Commission is also using adaptive management to address climate risks to U.S.–Canadian waters.108 At the subnational level, the U.S.–Canada Great Lakes Water Quality Agreement incorporated a new annex in 2012 to identify, quantify, understand, and predict the impacts of climate change on Great Lakes water quality,109 which has helped foster the binational development of new climate products for the Great Lakes (Ch. 21: Midwest, KM 3). Researchers are incorporating climate information into computer models of streamflow and reservoirs along the U.S.–Canada border to help decision-makers understand the long-term potential impacts to flood risk management, hydropower generation, and water availability in the Columbia River Basin.110 This work is led by U.S. and Canadian agencies in partnerships with academic institutions and regional entities and can be utilized to inform management over long periods of time. These examples of including climate risk into the management of shared river and lake resources can be a model for improving resilience of other shared resources, such as fisheries.
In addition to government-to-government management of transboundary resources, public–private partnerships are increasingly helping to manage climate risks associated with these resources. For example, numerous efforts exist of transboundary collaboration in the Rio Grande–Rio Bravo Basin (Ch. 23: S. Great Plains, Case Study “Rio Grande Valley and Transboundary Issues”), including a bilateral public–private partnership that has implemented collaborative science, restoration, and monitoring actions to restore the river, with climate adaptation as one of the objectives. The partnership consists of businesses, nongovernmental conservation organizations, federal and state agencies, academic institutions, private foundations, and the public from both Mexico and the United States.104,111,112,113 The U.S. Caribbean (Ch. 20: U.S. Caribbean, KM 6) and Hawai‘i and the Pacific Islands (Ch. 27: Hawaiʻi & Pacific Islands) are actively engaged with international partners to build adaptive capacity and reduce risks associated with climate change uncertainty at the regional level. Such international engagement may be more in demand in the future to address increasing vulnerabilities of transboundary resources.