1.3 Observed changes in natural and managed systems related to regional climate changes

The following sections assess studies that have been published since the TAR of observed changes and their effects related to the cryosphere, hydrology and water resources, coastal processes and zones, freshwater and marine biological systems, terrestrial biological systems, agriculture and forestry, human health, and disasters and hazards related to regional warming. More detailed descriptions of these effects are provided in subsequent chapters of the WGII Fourth Assessment Report (AR4).

In some cases, studies published before the TAR have been included, either because they were not cited in the TAR or because they have been considered to contain relevant information. The sections describe regional climate and non-climate driving forces for the systems, assess the evidence regarding observed changes in key processes, and highlight issues regarding the absence of observed changes and conflicting evidence. An assessment of how the observed changes contribute to understanding of adaptation and vulnerability is found in Sections 1.3.9 and 1.5.