I don't agree. Human beings are the front runner in opening the doors for the global warming. Ya it's true global warming is not a recent issue. There were great ice age in the past like cenozoic era- pleistocene epoch. It has been melting since then. National Bureau of science recorded that atmospheric temperature is 3 centrigade warmer over all and is 1 centrigade warmer in arctic right now and is increasing with the carbondioxide input in the air.