Every year NASA’s Goddard Institute for Space Studies (GISS) release their analysis of annual global temperatures. The results for 2013, published yesterday, conform to a sustained long term climate warming trend.
The average global temperature last year was 14.6 degrees Celsius which is 0.8 C warmer than temperatures in 1880. Most of this warming (about 0.6 C) occurred in the last 60 years. The results unequivocally show that the climate is indeed experiencing a long term warming trend. Nine of the top 10 warmest years in the 134-year meteorological record have occurred since the year 2000. 2010 and 2005 were jointly the warmest years on record.
The IPCC Fifth Assessment Report (AR5): Working Group 1 (WG1) report published last year states with very high certainty that this warming trend is mostly due to the affects of human induced greenhouse gas emissions.
NASA scientists stressed the difference between a long term warming trend and differences in short term temperatures. Annual/seasonal differences occur due to random weather variations while long term trends indicate changes in the global average climate.
The greatest magnitude of warming is occurring in the northern latitudes around the arctic circle. These observations closely tie-in with measurements of annual average arctic sea ice extent.
The GISS temperature record is one of several global temperature analyses, along with those produced by the Met Office Hadley Centre in the United Kingdom and NOAA’s National Climatic Data Center in Asheville, N.C. These three primary records use slightly different methods, but overall, their trends show close agreement.