Well that depends on where you start measuring from. Was it the warmest since the National Weather Service started keeping records in the 1800s, or was it uncovered in NASA/GISS adjusted surface temperature data bases? Or, perhaps we need to take a long view and ask, was this year the warmest in the last 10,000 years?
Taking the longer view we find that over the past 10,000 years, 9,100 were warmer than 1934, 1998 or 2010. Regardless of which year (1934, 1998, or 2010) is declare the warmest year by some rent seeking environmentalist, or government agency like NOAA or NASA, it is clear the warmest of the past century will only rank number 9,099 in on our long-term list of warm years.
More details can be found Guest post by Dr. Don J. Easterbrook, “2010 – where does it fit in the warmest year list?“, at Watts Up With That.
Exit Questions: How did it get so warm over the last 10,000 years without humans driving SUV's and burning coal to keep warm? I think a really more important questions would be what caused the plunge into a Little Ice Age that we are just recovering from? Is this just a signal the interglacial is about to come to an end? Your thoughts on these questions are most welcome.
H/T to Heliogenic Warming for the link and Dr. Easterbrook’s fine work at WUWT.