http://www.earth-policy.org/Indicators/Temp/2008.htm

2007 SECOND WARMEST YEAR ON RECORD
Northern Hemisphere Temperature Highest Ever

With the record for 2007 now complete, it is clear that temperatures around the world are continuing their upward climb. The global average in 2007 was 14.73 degrees Celsius (58.5 degrees Fahrenheit)—the second warmest year on record, only 0.03 degrees Celsius behind the 2005 maximum. January 2007 was the hottest January ever measured, a full 0.23 degrees Celsius warmer than the previous record. August was also a record for that month and September was the second warmest September recorded.

Looking at the northern hemisphere alone, 2007 temperatures averaged 15.04 degrees Celsius (59.1 degrees Fahrenheit)—easily the hottest year in the northern half of the globe since the record began in 1880, and more than a degree warmer than the 1951–80 average. Paleo-temperature records from ancient tree rings suggest that the northern hemisphere is now warmer than at any time in at least the last 1,200 years.

The year 2007 fits into a pattern of steadily increasing global average temperature, with the eight warmest years on record all occurring in the last decade................

..............In 2007, the Intergovernmental Panel on Climate Change (IPCC), the Nobel prize–winning body of more than 1,250 scientists, released its Fourth Assessment Report, which detailed the likely climatic consequences if human beings continue to pump greenhouse gases into the atmosphere. It reported that unabated emissions would result in a temperature rise of between 1.1 and 6.4 degrees Celsius (2 to 12 degrees Fahrenheit) during the twenty-first century.

To put this in perspective, temperatures over the last 100 years rose by a comparably small 0.74 degrees Celsius, and yet this appears to have already contributed to trends of more heat waves, longer and more intense droughts, higher sea level, more frequent heavy rain events, and stronger hurricanes. Future warming on the scale projected by the IPCC will bring with it a multitude of outcomes that can only be described as disastrous. These include hundreds of millions of people exposed to increased water stress, a third of species at increasing risk of extinction, widespread coral mortality, grain yield declines at low latitudes, the loss of 30 percent of remaining coastal wetlands, and the disappearance of glaciers feed some of the world’s major rivers.

The temperature record for 2007 shows that we have now fully entered into what some are calling a new geological epoch, the Anthropocene, in which human activities are the main driver of the global climate system. The many effects of warmer temperature, which we are already beginning to see, will only become more severe and more costly to society if greenhouse gas emissions are not cut quickly and dramatically. Our future now depends on what we do to limit warming by moving away from climate-disrupting fossil fuels and toward renewable energy and energy-efficient technologies...............