- 2009 was the second equal warmest year in the past 130 years, (since the instrumental record began) according to NASA scientists at the Goddard Institute for Space Studies.
- There is year-to-year variability in global temperatures due to factors like El Nino. This means not every year will be the hottest on record.
- Global temperature shows "a term warming trend that has become strong and persistent over the past three decades", despite year-to-year natural variability reports NASA scientist Dr James Hansen one of the world leading climatologists.
- According to NASA, the warmest year on record is 2005, then 2009, 2007, 1998, 2002 and so on. In fact 9 of the 10 hottest years on record occured from 2000-2009.
- Climate scienists say we must keep warming under 2 degrees Celcuis to prevent the worst effects of climate change, however since the late 19th century the world has warmed by ~0.8 dC, meaning almost half our warming "safe zone" is already gone.
This is what global warming looks like when you graph it:
Graph of global temperature change from NASA GISS (Goddard Institute for Space Studies)
Explanation of the graph
The worldwide average temperature anomaly for each year is shown by the black squares (surface temperature of both the land and oceans) and the solid red line is the five-year average. Following the red line shows the temperature trend. The graph uses a base period from 1951-1980, and hence shows the temperature change/anomaly compared to the base period. Green bars show the uncertainty in the temperature measurement. Yearly temperatures are more certain now because of better measurements ie: the use of satellites to measure sea surface temperature.
For more information
NASA news release about 2009 temperatures
Dr Hansen explains 2009 temperatures in more detail on his website
NASA GISSTEMP web-page with all their graphs, data and more detailed explanations
See our Transition Kenmore climate science resources parts 1 and 2.