prefers the term "Medieval Climate Anomaly" (MCA) to "Medieval Warm Period". Chapter 5, section 5.3.5.1 discussed work since AR4 on the MCA and LIA. It notes that the timing and spatial structure of the MCA and LIA are complex, with different reconstructions exhibiting warm and cold conditions at different times for different regions and seasons. A combination of Northern Hemisphere temperature reconstructions shows mostly warm conditions from about 950 to about 1250 and colder conditions from about 1450 to about 1850, which are taken to represent the times of the MCA and LIA. They express high confidence that the mean Northern Hemisphere temperature of the last 30 or 50 years exceed 30- or 50-year means of the past 800 years, and medium confidence that the last 30 years were likely the warmest 30-year period of the last 1400 years. See also Intergovernmental Panel on Climate Change References . . . . . . Climate change assessment and attribution Intergovernmental Panel on Climate Change Hockey stick controversy