Please explain how they know the average temperature of the earth back further than the past 100 years or so?
Shoot the thermometer wasn't invented until the early 1500's and the Farenheit, Celcius thermomters weren't available until the 1600's.
Bogus data equals bogus forecast......
Hell, they can't predict the weather for the next 15 minutes let alone the next 15 years. Anyone remember Ted Danson in 1990 stating that we had maybe 10 years left before global flooding from melting glaciers?
Last time I checked is that we are still above the water line...........
Oxygen-18 isotope ratios with oxygen-16 are a reliable paleothermometer that is used to determine temperature records from ice cores. The 018/016 ratio varies with temperature due to the different kinetic rates for evaporation and precipitation for water with 018 atoms and water with 016 atoms.