I wanted to write a post about some datasets that encompass 2008 to put my recent discussions and future posts on climate in perspective. First up, the World Meteorological Organization’s global temperature dataset. In a preliminary report issued on 16 Dec, 2008’s global mean temperature was 14.3 °C, making it the 10th warmest year on record going back to 1850. Despite a lingering La Nina, which is characterized by cooler than normal temperatures, 2008 was warmer than the 1990’s average temperature. It was almost as warm as 1997, in the runup to the strongest El Nino on record. It was only 0.2 °C cooler than the 1998 record temperature anomaly. Those 10 warmest years on record? All have occurred since 1997.
The La Nina that developed during 2007 and hung around through 2008 was easing back by the end of the year. November was the 4th warmest all-time (land and ocean combined), as measured by NOAA’s National Climatic Data Center.
- The November combined global land and ocean surface temperature was 1.06 degrees F (0.59 degree C) above the 20th century mean of 55.2 degrees F (12.9 degrees C).
- Separately, the November 2008 global land surface temperature was fourth warmest on record and was 2.11 degrees F (1.17 degrees C) above the 20th century mean of 42.6 degrees F (5.9 degrees C).
How much did the La Nina affect global temperatures? According to NASA, the 2008 meteorological year (Dec 2007 – Nov 2008) was the coolest year since 2000, yet was still the 9th warmest on record (dating back to 1880). So the coolest year since 2000 is a good thing, right? Well, until the La Nina subsides. 2003, 2005, 2006 and 2007 were as anomalously warm as the record 1998 year, which had an extreme El Nino event. How anomalously warm will the next El Nino year be?
More importantly, the trend in the Met Office/WMO and the NASA data continue to show a large and rapidly increasing warm anomaly. Of particuar worry is the very large warm anomaly found over the Antarctic peninsula and eastern Russia. The former has seen massive ice sheet calving episodes in recent years and increased ice flow toward the ocean from land as a result. The latter has seen increasing emissions of methane as the permafrost thaws. The former will lead to rising sea levels if trends don’t change. The latter will release a greenhouse gas 20x as effective as CO2 is in energy absorption. There is a lot of methane trapped in the permafrost. Thawing the permafrost could initiate a positive feedback loop in which even more methane is released from the ground, which would warm the region and the globe even more.
The above temperature record also occurred in a period of low solar activity, which many climate change deniers claim is the most important factor driving our climate. Most climatologists acknowledge the sun’s activity as being one input into our climate system, but also recognize that human forcing has likely become a more important climate driver.
NOAA’s 2008 Atlantic Hurricane Report details some of the noteworthy accomplishments of the season:
- Bertha was a tropical cyclone for 17 days (July 3-20), making it the longest-lived July storm on record in the Atlantic Basin.
- Fay is the only storm on record to make landfall four times in the state of Florida, and to prompt tropical storm and hurricane watches and warnings for the state’s entire coastline (at various times during its August lifespan).
- Paloma, reaching Category 4 status with top winds of 145 mph, is the second strongest November hurricane on record behind Lenny in 1999 with top winds of 155 mph).
More items of interest:
Overall, the season is tied as the fourth most active in terms of named storms (16) and major hurricanes (five), and is tied as the fifth most active in terms of hurricanes (eight) since 1944, which was the first year aircraft missions flew into tropical storms and hurricanes.
For the first time on record, six consecutive tropical cyclones (Dolly, Edouard, Fay, Gustav, Hanna and Ike) made landfall on the U.S. mainland and a record three major hurricanes (Gustav, Ike and Paloma) struck Cuba. This is also the first Atlantic season to have a major hurricane (Category 3) form in five consecutive months (July: Bertha, August: Gustav, September: Ike, October: Omar, November: Paloma).