From a press release entitled (not so alarmingly), NASA STUDY FINDS WORLD WARMTH EDGING ANCIENT LEVELS
The most important result found by these researchers is that the warming in recent decades has brought global temperature to a level within about one degree Celsius (1.8° F) of the maximum temperature of the past million years. According to [NASA scientist James] Hansen, "That means that further global warming of 1 degree Celsius defines a critical level. If warming is kept less than that, effects of global warming may be relatively manageable. During the warmest interglacial periods the Earth was reasonably similar to today. But if further global warming reaches 2 or 3 degrees Celsius, we will likely see changes that make Earth a different planet than the one we know. The last time it was that warm was in the middle Pliocene, about three million years ago, when sea level was estimated to have been about 25 meters (80 feet) higher than today."
N.B.: This is the country's preeminent climate expert talking, not some hack journalist struggling to meet deadline.