in their distribution. Furthermore, the response
to forcings is partly governed by feedback processes that may operate in different regions
from those in which the forcing is greatest. Thus, the projected changes in climate will also
vary from region to region.
Latitude is a good starting point for considering how changes in climate will affect a region.
For example, while warming is expected everywhere on Earth, the amount of projected warming
generally increases from the tropics to the poles in the Northern Hemisphere. Precipitation is
more complex, but also has some latitude-dependent features. At latitudes adjacent to the polar
regions, precipitation is projected to increase, while decreases are projected in many regions
adjacent to the tropics (see Figure 1). Increases in tropical precipitation are projected during
rainy seasons (e.g., monsoons), and over the tropical Pacific in particular.
Location with respect to oceans and mountain ranges is also an important factor. Generally, the
interiors of continents are projected to warm more than the coastal areas. Precipitation responses
are especially sensitive not only to the continental geometry, but to the shape of nearby mountain
ranges and wind flow direction. Monsoons, extratropical cyclones and hurricanes/typhoons are all
influenced in different ways by these region-specific features.
Some of the most difficult aspects of understanding and projecting changes in regional climate
relate to possible changes in the circulation of the atmosphere and oceans, and their patterns
of variability. Although general statements covering a variety of regions with qualitatively
similar climates can be made in
FAQ 11.1, Figure 1. Blue and green areas on the map are by the end of the century projected to experience increases
in precipitation, while areas in yellow and pink are projected to have decreases. The top panel
shows projections for the period covering December, January and February, while the bottom panel
shows projections for the period covering June, July and August.