Records of past climate show that the Southwest’s climate has been highly variable over time, but now human activity is altering that climate to an unprecedented state. Climate models project that the Southwest will become even warmer and more arid than it is today. Because water is such a limiting resource for life in desert environments, a more arid climate could profoundly impact southwestern ecosystems and human society. This overview describes only some of those potential impacts to ecosystems in the Southwest. Because any impact to a part of an ecosystem can affect the whole, climate change impacts can cascade, indirectly affecting the biological processes of many different organisms. In addition, different impacts can interact with each other and compound the effects of climate change. For example, in the Sonoran desert, the combination of grasses invading the desert and an increased frequency of fires could devastate saguaro cacti. While scientists may not be able to forecast the exact impacts of climate change, human-induced climate change will clearly have consequences for the arid Southwest.
Climate Change in the Southwest - Conclusions and Literature Cited
Climate models project an even warmer, drier Southwest. As water is life in the desert, these projected changes may profoundly impact southwestern ecosystems and human society.
Allen, C. D., and D. D. Breshears. 1998. Drought-induced shift of a forest-woodland ecotone: rapid landscape response to climate variation. Proceedings of the National Academy of Science 95: 14839-14842.
Barnett, T. P., D. W. Pierce, H. G. Hidalgo, C. Bonfils, B. D. Santer, T. Das, G. Bala, A. W. Wood, T. Nozawa, A. A. Mirin, D. R. Cayan, and M. D. Dettinger. 2008. Human-induced changes in the hydrology of the western United States. Science 319: 1080-1083.
Bonfils, C., B. D. Santer, D. W. Pierce, H. G. Hidalgo, G. Bala, T. Das, T. P. Barnett, D. R. Cayan, C. Doutriaux, A. W. Wood, A. Mirin, and T. Nozawa. 2008. Detection and attribution of temperature changes in the mountainous western United States. Journal of Climate 21: 6404-6424.
Breshears, D. D., N. S. Cobb, P. M. Rich, K. P. Prices, C. D. Allen, R. G. Balice, W. H. Romme, J. H. Kastens, M. L. Floyd, J. Belnap, J. J. Anderson, O. B. Myers, and C. W. Meyer. 2005. Regional vegetation die-off in response to globalchange- type drought. Proceedings of the National Academy of Science 102(42): 15144-15148.
Brown, J. H., T. J. Valone, and C. G. Curtin. 1997. Reorganization of an arid ecosystem in response to recent climate change. Proceedings of the National Academy of Science 94: 9729-9733.
Cayan, D. R., S. A. Kammerdiener, M. D. Dettinger, J. M. Caprio, and D. H. Peterson. Changes in the onset of spring in the western United States. Bulletin of the American Meteorological Society 82(3): 399-415.
Christensen, J. H., B. Hewitson, A. Busuioc, A. Chen, X. Gao, I. Held, R. Jones, R. K. Kolli, W.-T. Kwon, R. Laprise, V. Magaña Rueda, L. Mearns, C. G. Menéndez, J. Räisänen, A. Rinke, A. Sarr, and P. Whetton. 2007. Regional climate projections. Pages 847-940 in Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H. L. Miller, editors. Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Comrie, A. C., and E. C. Glenn. 1998. Principal componentsbased regionalization of precipitation regimes across the southwest United States and northern Mexico, with an application to monsoon precipitation variability. Climate Research 10: 201-215.
Cook, E. R., C. A. Woodhouse, C. M. Eakin, D. M. Meko, and D. W. Stahle. 2004. Long-term aridity changes in the western United States. Science 306: 1015-1018. Diffenbaugh, N. S., F. Giorgi, and J.S. Pal. 2008. Climate change hotspots in the United States. Geophysical Research Letters 35: L16709.
Diffenbaugh, N. S., J. S. Pal, R. J. Trapp, F. Giorgi, and S. H. Schneider. 2005. Fine-scale processes regulate the response of extreme events to global climate change. Proceedings of the National Academy of the United States of America 102(44): 15774-15778.
Dominguez, F., J. Cañon, and J. Valdes. 2009. IPCC-AR4 climate simulations for the Southwestern US: the importance of future ENSO projections. Climatic Change: published online October 10, 2009.
Douglas, M. W., R. A. Maddox, and K. Howard. 1993. The Mexican monsoon. Journal of Climate 6: 1665-1677. Goodrich, G. B., and A. W. Ellis. 2008. Climatic controls and hydrologic impacts of a recent extreme seasonal precipitation reversal in Arizona. Journal of Applied Meteorology and Climatology 47: 498-508.
Grimm, N. B., A. Chacon, C. N. Dahm, S. W. Hostetler, O. T. Lind, P. L. Starkweather, and W. W. Wurtsbaugh. 1997. Sensitivity of aquatic ecosystems to climatic and anthropogenic changes: the Basin and Range, American Southwest and Mexico. Hydrological Processes 11: 1023-1041. Herweijer, C., R. Seager, E. R. Cook, and J. Emile-Geay. 2007. North American droughts of the last millennium. Journal of Climate 20: 1353-1376.
Intergovernmental Panel on Climate Change (IPCC). 2007. Summary for policymakers in Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H. L. Miller, editors. Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Jansen, E., J. Overpeck, K. R. Briffa, J.-C. Duplessy, F. Joos, V. Masson-Delmotte, D. Olago, B. Otto-Bliesner, W.R. Peltier, S. Rahmstorf, R. Ramesh, D. Raynaud, D. Rind, O. Solomina, R. Villalba and D. Zhang. 2007. Pages 434-497 in Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H. L. Miller, editors. Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Karl, T .R., J. M. Melillo, and T. C. Peterson, editors. 2009. Global change impacts in the United States. United States Global Change Research Program. Cambridge University Press, New York, NY, USA.
Kelly, A. E., and M. L. Goulden. 2008. Rapid shifts in plant distribution with recent climate change. Proceedings of the National Academy of Science 105(33) 11823-11826. Knowles, N., M. D. Dettinger, and D. R. Cayan. 2006. Trends in snowfall versus rainfall in the western United States. Journal of Climate 19: 4545-4559.
Lenart, M. 2007. Global warming in the Southwest: projections, observations and impacts. Climate Assessment for the Southwest, Institute for the Study of Planet Earth, Tucson, AZ. Littell, J. S., D. McKenzie, D. L. Peterson, and A. L. Westerling. 2009. Climate and wildfire area burned in western U.S. ecoprovinces, 1916-2003. Ecological Applications 19(4): 1003-1021.
McAfee, S. A., and J. L. Russell. 2008. Northern Annular Mode impact on spring climate in the western United States. Geophysical Research Letters 35: L17701. Mitchell, V. L. 1976. The regionalization of climate in the western United States. Journal of Applied Meteorology 15(9): 920-927.
Mote, P. W., A. F. Hamlet, M. P. Clark, and D. Lettenmaier. 2005. Declining mountain snowpack in western North America. Bulletin of the American Meteorological Society 86(1): 39-49.
Ni, F., T. Cavazos, M. K. Hughes, A. C. Comrie, and G. Funkhouser. 2002. Cool-season precipitation in the southwestern USA since A. D. 1000: comparison of linear and nonlinear techniques. International Journal of Climatology 22: 1645- 1662.
Pierce, D. W., T. P. Barnett, H. G. Hidalgo, T. Das, C. Bonfils, B. D. Santer, G. Bala, M. D. Dettinger, D. R. Cayan, A. Mirin, A. W. Wood, and T. Nozawa. 2008. Attribution of declining western U.S. snowpack to human effects. Journal of Climate 21: 6425-6444.
Rahel, F. J., and J. D. Olden. 2008. Assessing the effects of climate change on aquatic invasive species. Conservation Biology 22(3): 521-533.
Regonda, S. K., B. Rajagopalan, M. Clark, and J. Pitlick. 2005. Seasonal cycle shifts in hydroclimatology over the western United States. Journal of Climate 18: 372-384.
Rehfeldt, G. E., N. L. Crookston, M. V. Warwell, and J. S. Evans. 2006. Empirical analyses of plant-climate relationships for the western United States. International Journal of Plant Sciences 167(6): 1123-1150.
Salzer, M. W., and K. F. Kipfmueller. 2005. Reconstructed temperature and precipitation on a millennial timescale from tree-rings in the southern Colorado Plateau, U.S.A. Climatic Change 70: 465-487.
Schoennagel, T., T. T. Veblen, and W. H. Romme. 2004. The interaction of fire, fuels, and climate across Rocky Mountain forests. BioScience 54(7): 661-676.
Seager, R., M. Ting, I. Held, Y. Kushnir, J. Lu, G. Vecchi, H. Huang, N. Harnik, A. Leetmaa, N. Lau, C. Li, J. Velez, and N. Naik. 2007. Model projections of an imminent transition to a more arid climate in southwestern North America. Science 316: 1181-1184.
Sheppard, P. R., A. C. Comrie, G. D. Packin, K. Angersbach, and M. K. Hughes. 2002. The climate of the US Southwest. Climate Research 21: 219-238.
Swetnan, T., and J. L. Betancourt. 1990. Fire-southern oscillation relations in the southwestern United States. Science 249: 1017-1020.
Swetnam, T., and J. L. Betancourt. 1998. Mesoscale disturbance and ecological response to decadal climatic variability in the American Southwest. Journal of Climate 11: 3128-3147. Stewart, I. T., D. R. Cayan, and M. D. Dettinger. 2004. Changes in snowmelt runoff timing in western North America under a ‘business as usual’ climate change scenario. Climatic Change 62: 217-232.
van Mantgem, P. J., N. L. Stephenson, J. C. Byrne, L. D. Daniels, J. F. Franklin, P. Z. Fule, M. E. Harmon, A. J. Larson, J. M. Smith, A. H. Taylor, and T. T. Veblen. 2009. Widespread increase of tree mortality rates in the western United States. Science 323: 521-524.
Weiss, J. L., and J. T. Overpeck. 2005. Is the Sonoran Desert losing its cool? Global Change Biology 11: 2065-2077.
Westerling, A. L., A. Gershunov, T. J. Brown, D. R. Cayan, and M. D. Dettinger. 2003. Climate and wildfire in the western United States. Bulletin of the American Meteorological Society 595-604.
Westerling, A. L., H. G. Hildalgo, D. R. Cayan, and T. W. Swetnam. 2006. Warming and earlier spring increase western U.S. forest wildfire activity. Science 313: 940-943.
Last updated: February 3, 2015