Latest scientific research completely debunks Michael Mann's bogus hockey stick chart - North Atlantic ocean temperatures warmer during Medieval Warming
Read here. As the adjacent chart reveals, both the Roman and Medieval periods included significantly warmer sea surface temperatures in the North Atlantic region.
Around 1250 AD, the Little Ice Age started a cooling process of the sea surface temperatures, which modern warming has yet to recover from.
There is no hockey stick as claimed by Michael Mann. There is no "unprecedented" and "accelerating" warming as claimed by the IPCC. The empirical evidence does not support the left / liberal / progressive / Democrat claim of dangerous climate change due to CO2 warming.
"A paper published today in the journal Paleoceanography finds that Atlantic Ocean surface temperatures have significantly cooled over the past millennium, since the Medieval Warming Period from about 950-1200 AD...Cooling by ∼0.5°C takes place between about AD 1250 and AD 1500; while this corresponds to the inception of the Little Ice Age (LIA), the end of the LIA is not reflected in our record and SST remains relatively low. This transition to cooler SSTs parallels the previously reconstructed shift in the North Atlantic Oscillation toward a low pre-20th century mean state and possibly reflects common solar forcing." [Henning Kuhnert, Stefan Mulitza 2011: Paleoceanography]