BOX S.1 INFORMATION FROM CLIMATE MODELS
Climate models skillfully reproduce important, global- to continental-scale features of the present climate, including the simulated seasonal-mean surface air temperature (within 3°C of observed [IPCC, 2007c], compared to an annual cycle that can exceed 50°C in places), the simulated seasonal-mean precipitation (typical errors are 50 percent or less on regional scales of 1,000 km or larger that are well resolved by these models [Pincus et al., 2008]), and representations of major climate features such as major ocean current systems like the Gulf Stream (IPCC, 2007c) or the swings in Pacific sea-surface temperature, winds, and rainfall associated with El Niño (AchutaRao and Sperber, 2006; Neale et al., 2008). Climate modeling also delivers useful forecasts for some phenomena from a month to several seasons ahead, such as seasonal flood risks (Figure 1).
FIGURE 1 Climate models can deliver useful forecasts for some phenomena a month to several seasons ahead, such as this spring flood risk outlook from NOAA’s National Weather Service for 2011. See Chapter 1 for more details. SOURCE: http://www.noaa.gov/extreme2011/mississippi_flood.html (accessed October 11, 2012).