TS.4 Current knowledge about future impacts
This section summarises the main projected impacts in each system and sector (Section TS.4.1) and region (Section TS.4.2) over this century, judged in terms of relevance for people and the environment. It assumes that climate change is not mitigated, and that adaptive capacity has not been enhanced by climate policy. All global temperature changes are expressed relative to 1990 unless otherwise stated. The impacts stem from changes in climate and sea-level changes associated with global temperature change, and frequently reflect projected changes in precipitation and other climate variables in addition to temperature.