The climate has been much warmer in the recent past. The medieval warming period made Greenland warmer than it is now. from about 700 AD to 1300 AD it was good farm and grazing land. About 1200 AD it started to get colder and by 1300 AD the farms were abandoned. That is a 500 year period with warmer climate than now and negligible burning of fossil fuels. These climate scientists see a 15 or 30 year rise and think it means something. They keep twisting the data to match their theories but facts are stubborn things and keep coming back no matter how many time they are dismissed.