Read here. The Climategate scandal was the door opening that revealed a cadre of IPCC "scientists" conspiring to push their rendition of crop circle pseudoscience. A key component of that effort was the infamous "hockey-stick" that purported to show modern era temperatures to be unprecedented, and the climates of the Medieval Warming (MWP) and Little Ice Age (LIA) to be minor blips of no significance. The IPCC's crop circle scientists also claimed that the MWP and LIA only existed in the small regional area of the north Atlantic/European geography. Subsequent studies and a mountain of empirical evidence refutes the IPCC pseudoscience.
A new peer-reviewed paper by Bertler et al., using the latest deuterium and temperature-isotope science, constructed temperatures going back 1,100 years. The new temperature dataset (see adjacent chart - click to enlarge) clearly shows the LIA in Antarctica to be massively cooler than modern temperatures; the dataset establishes that the modern warming is not "unprecedented" as the MWP is slightly warmer.
"The researchers obtained new deuterium (δD) data from the Ross Sea region of Antarctica that they acquired via analysis of the top fifty meters of a 180-meter-long ice core that had been extracted from the ice divide of Victoria Lower Glacier...work revealed three climatically-distinct time periods: the last 150 years of the Medieval Warm Period (MWP, AD 1140 to 1287), the Little Ice Age (LIA, AD 1288 to 1807), and the Modern Era (ME, AD 1808 to 2000)...authors report that "the final 150 yrs of the MWP were ... about 0.35 °C warmer than the ME,"" [N.A.N. Bertler, P.A. Mayewski, L. Carter 2011: Earth and Planetary Science Letters]