Het blijkt toch moeilijk de jaren 1998 en 2005 te verslaan. Alleen in de GISS-reeks is het record scherper gesteld maar de bij andere reeksen net niet. De verschillen zijn te klein om naam te hebben.
Dit bevestigd de indruk dat de opwarming achterblijft op de prognoses. Veel klimatologen zitten al een paar jaar te wachten totdat het wereldwijde temperatuurrecord wordt verbroken.
Bij de eerste de beste El Nino zou het zo ver zijn.
2010 was dé kanshebber...
Hieronder een stuk uit het jaarverslag van de NASA van drie jaar terug. Daaruit blijkt dat James Hansens' verwachtingen te hoog gespannen waren.
Met dit tempo van opwarming halen we de 3 graden opwarming, gemiddelde voorspeld door het IPCC, in 2100 niet. Gelukkig maar.
"Global Predictions
The quasi-regularity of some natural climate forcing mechanisms, combined with knowledge of human-made forcings, allows projection of near-term global temperature trends with reasonably high confidence. Prediction for a specific year is a bit hazardous, as evidenced by an incorrect prediction of record global warmth made by the British climate analysis group for 2007. Such speculations are useful, as they draw attention to the mechanisms, and allow testing of understanding. Presumably part of the basis for their prediction was an assumption of a continued warming contribution from the 2006 El Niño. However, evidence of El Niño warmth disappeared very early in 2007.
Solar irradiance will still be on or near its flat-bottomed minimum in 2008. Temperature tendency associated with the solar cycle, because of the Earth's thermal inertia, has its minimum delayed by almost a quarter cycle, i.e., about two years. Thus solar change should not contribute significantly to temperature change in 2008.
La Niña cooling in the second half of 2007 (Figure 2) is about as intense as the regional cooling associated with any La Niña of the past half century, as shown by comparison to Plate 9 in Hansen et al. (Hansen et al. 1999) and updates to Plate 9 on the GISS web site. Effect of the current La Niña on global surface temperature is likely to continue for at least the first several months of 2008. Based on sequences of Pacific Ocean surface temperature patterns in Plate 9, a next El Niño in 2009 or 2010 is perhaps the most likely timing. But whatever year it occurs, it is a pretty safe bet that the next El Niño will help carry global temperature to a significantly higher level.
Competing with the short-term solar and La Niña cooling effects is the long-term global warming effect of human-made GHGs. The latter includes the trend toward less Arctic sea ice that markedly increases high latitude Northern Hemisphere temperatures. Although sea ice cover fluctuates from year to year, the large recent loss of thick multi-year ice implies that this warming effect at high latitudes should persist.
Based on these considerations, it is unlikely that 2008 will be a year with truly exceptional global mean temperature. These considerations also suggest that, barring the unlikely event of a large volcanic eruption, a
record global temperature clearly exceeding that of 2005 can be expected
within the next 2-3 years. "
Victor
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