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Separating Human and Natural Influences on Climate
The blue band shows how global average temperatures would have changed due to natural forces only, as simulated by climate models. The red band shows model projections of the effects of human and natural forces combined. The black line shows actual observed global average temperatures. As the blue band indicates, without human influences, temperature over the past century would actually have first warmed and then cooled slightly over recent decades.1 Image Reference: Hegerl et al.2
References
- 1. [58] Dole, R., and M. Hoerling. "Introduction." In Reanalysis of Historical Climate Data for Key Atmospheric Features: Implications for Attribution of Causes of Observed Change, edited by R. Dole, M. Hoerling and S. D. Schubert, 5-10. Vol. Synthesis and Assessment Product 1.3. Asheville, NC: NOAA's National Climatic Data Center, 2008.
- 2. [49] Hegerl, G. C., F. W. Zwiers, P. Braconnot, N. Gillett, Y. Luo, J. A. Marengo Orsini, N. Nicholls, J. E. Penner, and P. A. Stott. "Understanding and Attributing Climate Change." In Climate Change 2007: The Physical Science Basis, edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor and H. L. Miller, 663-745. Vol. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK and New York, NY: Cambridge University Press, 2007.
Summary
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