In his landmark testimony (PDF) before the US Senate Committee on Energy and Natural Resources on June 28, 1988, Dr. James Hansen, then director of the NASA Goddard Institute for Space Studies said,
The present temperature is the highest in the period of record…The four warmest years, as the Senator mentioned, have all been in the 1980s. And 1988 so far is so much warmer than 1987, that barring a remarkable and improbable cooling, 1988 will be the warmest year on record.
Hansen’s testimony proved to be accurate. 1988 ended up as the warmest year on record at that time, dating back to 1880, according to data from NOAA. The average global temperature in 1988 was 0.34ºC above the 20th century average, just edging out the 0.33ºC temperature anomaly from 1987.
Flash forward to today. Yesterday, NOAA reported that, globally, 2013 tied 2003 as the fourth warmest year on record. Despite abnormally cool temperatures in the continental US during November and December, those months proved to be the warmest and third warmest on record worldwide, respectively. Overall, 2013 was 0.62ºC above the 20th century average. Accordingly, the temperature anomaly for 2013 was 82% larger than that for 1988.
Seth Borenstein, the great AP reporter on weather/climate issues, made a remarkable observation on Twitter yesterday after NOAA released its data.
In 1988, Hansen testimony put global warming in news: ’88 was hottest year on record at time. Now 2013 just pushed 1988 out of top 20
— seth borenstein (@borenbears) January 21, 2014
The great warming of 1988, which sparked Hansen’s testimony and put climate change on the map as a political issue, is now so ordinary that it no longer ranks among the 20 warmest years on record. The rate of warming may have slowed slightly since 1988, but the total warming trend continues to plow ahead. It took all of 25 years to push 1988 out of the top 20.
Looking at the overall trend, you can really get a sense of how quickly warming has increased since the 1940s. Due to a string of cooler than normal years from the 1880s-1930s, the average temperature anomaly from 1880 (when record keeping began) and 1988 was actually -0.08ºC. Since 1988, that warming anomaly has skyrocketed to an average of 0.49ºC.
Twenty five years ago, 1988 stood out for its searing, abnormal heat. Unless we take action, 25 years from now we may end up looking back nostalgically at that year and praying for temperatures that cool.