January 19, 2011
Four different global temperature records show the Earth is warming. Graph courtesy of NASA. Click to enlarge.
"The official records vary slightly because of subtle differences in the way we analyze the data, but they also agree extraordinarily well," said Reto Ruedy with NASA’s GISS.
For example, both NASA and the NOAA has found that last year, 2010, was tied for the warmest on record. In contrast, the Japanese Meteorological Agency found that last year was the second warmest year on record. While this may confuse the public and sow doubt about climate change findings, for scientists it’s the trend—not annual records—that really count. The fact that these four different records all show extremely similar warming trends actually boosts rather than undercuts climatologists’ confidence in regard to global warming.
Changes in year-to-year findings are often due to how different organizations measure areas where temperature records are few and far between. For example NASA GISS’s fills in the blank spots with data from the nearest temperature station, while the UK’s Met Office leaves some of these areas out, such as parts of the Arctic Ocean.
"There’s no doubt that estimates of Arctic warming are uncertain, and should be regarded with caution," explains James Hansen, head of NASA GISS. "Still, the rapid pace of Arctic ice retreat leaves little question that temperatures in the region are rising fast, perhaps faster than we assume in our analysis."
Overall the different data sets agree: the world is warming rapidly.
NASA GISS data from November 2010. Image courtesy of NASA. Click to enlarge.
Met Office Hadley Center’s Climatic Research Unit data from November 2010. Image courtesy of NASA. Click to enlarge.