This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.
The results are in for 2007, and it was a warm one. How warm? It depends who you ask. According to NASA, 2007 was the second warmest year on record. NOAA’s analysis put it in fifth place. The University of East Anglia’s Climatic Research Unit (CRU) ranked it eighth.
The results differ because it’s not as straightforward as you might think to take the temperature of the globe. There are many subtleties to consider.