Unfortunately, the greatest warming in 2008 came in the worst possible place for humanity — the Siberian tundra. That’s clear from NASA’s Goddard Institute for Space Studies report on the meteorological year, December 2007 through November 2008:
The remarkably widespread warming in the land of the permafrost permamelt should be the big global warming story because:
- The permafrost contains as much carbon as the atmosphere, and it is increasingly not so perma (see Tundra, Part 1).
- Siberian tundra contains probably the world’s largest amount of carbon locked away in the permafrost.
- As it defrosts, much of the tundra’s carbon would be released as methane, which is twenty times more potent a greenhouse gas than carbon dioxide.
- “The year 2007 was the warmest on record for the Arctic,” according to NOAA.
- NOAA reported that methane levels rose in 2007 for the first time since 1998 (see here).
- Scientific analysis suggests the rise in 2007 methane levels came from Arctic wetlands (see here).
- The tundra feedback, coupled with the climate-carbon-cycle feedbacks that the IPCC models, could easily take us to the unmitigated catastrophe of 1000 ppm (see Tundra, Part 2: The point of no return).
While the permafrost warming may well be the biggest story to come out of the annual global temperature reports, needless to say the media have ignored that story as far as I can tell. They have also ignored the now clear evidence that the 2000s are easily the hottest decade in recorded history and instead focused has been almost exclusively on where 2008 ranks among recent years temperature-wise. NASA did weigh in on that with this figure:
So 2008 is warmer than any year last century but the El Ni±o-enhanced 1998, and about 0.1°C warmer than the 1990s as a whole. NASA adds:
Finally, we note that we provide the rank of global temperature for individual years because there is a high demand for it from journalists and the public. The rank has scientific significance in some cases, e.g., when a new record is established. However, otherwise rank has limited value and can be misleading. Note that, given our estimated error bar in Figure 1, we can only say that 2008 probably ranks as somewhere between the 7th and 12th warmest year.
NASA explains the 2008 temperature was “a bit cooler” (about 0.1°C) than the 2001–2007 mean because of the La Ni±a in the first half of the year, which is clearly seen in the figure at the top of this post. For ENSO junkies (you know who you are), NASA provides this figure (click to enlarge):
Figure 2, at right. Top: Seasonal-mean global and low latitude temperature anomalies relative to 1951–1980 base period. (Click for large GIF or PDF.) Bottom: Monthly-mean global-ocean surface temperature anomaly, based on satellite temperature analyses of Reynolds et al. (Click for large GIF or PDF.)
Figure 2 (top) provides seasonal resolution of global and low latitude surface temperature, and an index that measures the state of the natural tropical temperature oscillation. The figure indicates that the La Ni±a cool cycle peaked in early 2008. The global effect of the tropical oscillation is made clear by the average temperature anomaly over the global ocean (Figure 2, bottom). The “El Ni±o of the century”, in 1997–98, stands out, as well as the recent La Ni±a.
Enough data for you?