ABSTRACT
This chapter reviews the instrumental climate record considering the homogeneity of the basic data, the hemispheric and global temperature series and some of the longest temperature, precipitation and pressure records from each of the continents. Instrumental records are not only essential to all aspects of climatology, but are the observational data against which all palaeoclimatic evidence must be calibrated. Calibration, and verification with independent data withheld, proves the usefulness of the indicator as a proxy for past periods. The strong spatial coherence of most climatic series shows that observational data does not have to be adjacent to the proxy source, but can be some distance due to the typical 400–1300 km correlation decay lengths. This coherence also applies to climate observations from different elevations, allowing remote, often high-elevation proxy information to be calibrated against nearby low-elevation sites with long records. The chapter concludes by discussing our present knowledge of the last thousand years, placing the 150-year instrumental record in a much longer context.
