High Quality Content by WIKIPEDIA articles! The temperature record of the past 1,000 years describes the reconstruction of temperature for the last 1000 years on the Northern Hemisphere, later extended back to 2000 years and also to cover the southern hemisphere. A reconstruction is needed because a reliable surface temperature record exists only since about 1850. Studying past climate is of interest for scientists in order to improve the understanding of current climate variability and, relatedly, providing a better basis for future climate projections. In particular, if the nature and magnitude of natural climate variability can be established, scientists will be able to better detect and attribute anthropogenic global warming.