How does one erase 300 years of inconvenient warming?
From the Climategate 2.0 e-mail collection, someone named Pollack (possibly alarmist Henry Pollack)
But it will be very difficult to make the MWP [Medieval Warm Period] go away in Greenland.
The chart below from the IPCC First Assessment Report in 1990 shows why alarmists want to erase the MWP.
The chimney was invented in the late 13th century. It was not invented earlier simply because the warm climate of the MWP meant that only food needed to be heated.