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World Bank Study
models7 that form part of the CMIP3 dataset prepared under the IPCC AR4, 15 are used for this analysis. A description of these models, together with caveats about the results, can be found in Appendix B. Projected Changes in Surface Temperature
It is evident that all land regions are very likely to warm during the 21st century. Geographical pa erns of projected warming of surface temperatures are scenario-independent, with the greatest temperature increases over land and at most high northern latitudes, and least over the Southern Ocean and parts of the North Atlantic Ocean, consistent with the observed changes during the la er part of 20th century, as well as over mountain regions. Appendix D provides detailed regional information for the likely changes in climate between the 1980 to 1999 period and the 2080 to 2099 period from a set of 21 global models in the multi-model data set for the A1B scenario for all geographic regions (IPCC 2007a, Chapters 10, 11). To complement this, expected changes in inter-annual temperature variability are presented in Figure 2.4 based on an assessment of the standard deviation for the A2 and B1 scenarios. The western part of Europe and Central Asia, West Africa, and several parts of Latin America and the Caribbean are projected to experience increasing levels of temperature variability; in excess of 0.2°C in B1 and 0.4°C in A2. Note the different color scales in Figure 2.4. These changes correspond to a projected variability of more than 10 percent when compared to the observed variability (see Figure 2.4, right), therefore adding additional strain to ecosystems, water resources, and energy systems and in general to all economic activities, including transport and agriculture. It would therefore appear sensible to put in place measures to manage this expected increased variability, notwithstanding the fact that current variability may already warrant a ention. The derived quantities of heating/cooling degree days (HDDs/CDDs) are closely related to temperature. These quantitative indices reflect the demand for energy to heat/
Figure 2.4. Projected Changes in the Standard Deviation of Two-Meter Temperature for JJA
Source: Generated by authors. Note: Changes are computed as differences with respect to the 1970−1999 climate run results, for scenarios B1 (left) and A2 (right). White areas indicate near-zero differences. Numbers in parenthesis in the title indicate the number of models used for the averaging of each individual period (that is, before computing the differences). Note the different color scales in the two plots.