and they also project drying in the dry season in the south and southwest United States and Mexico (see Figure O.1). {4.2}

Streamflow Changes

Widespread changes in streamflow are expected in a warmer world, with many regions experiencing changes of the order of 5-15% per degree of warming. Streamflow is a key index of the availability of freshwater, a quantity that is essential for human and natural systems. Changes in streamflow depend upon both evaporation (and hence warming) as well as precipitation. In regions where decreases in precipitation are predicted, these decreases usually will be accompanied by larger decreases in streamflow.

FIGURE O.1 Estimated changes in precipitation per degree of global warming in the three driest consecutive months at each grid point from a multi-model analysis using 22 models (relative to 1900-1950 as the baseline period). White is used where fewer than 16 of 22 models agree on the sign of the change. One ensemble member from each model is averaged over the dry season and decadally in several indicated regions including southwestern North America and Alaska, as shown in the inset plots. Adapted from Solomon et al. (2009), with additional inset panel for Alaska (courtesy R. Knutti) provided using the same datasets and methods as in that work. {4.2}

FIGURE O.1 Estimated changes in precipitation per degree of global warming in the three driest consecutive months at each grid point from a multi-model analysis using 22 models (relative to 1900-1950 as the baseline period). White is used where fewer than 16 of 22 models agree on the sign of the change. One ensemble member from each model is averaged over the dry season and decadally in several indicated regions including southwestern North America and Alaska, as shown in the inset plots. Adapted from Solomon et al. (2009), with additional inset panel for Alaska (courtesy R. Knutti) provided using the same datasets and methods as in that work. {4.2}



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