The description of the Medieval Warm Period and Little Ice Age in IPCC reports has changed since the first report in 1990 as scientific understanding of the temperature record of the past 1000 years has improved. The Medieval Warm Period (MWP) and Little Ice Age (LIA) are the best-known temperature fluctuations in the last millennium. Critics of the "hockey stick graph" of all subsequent reports have claimed that the record of the MWP and LIA were suppressed in the IPCC Third Assessment Report although every report discussed the phenomena.