Wednesday, October 05, 2011

UAH AMSU, Jan-Sep: 2011 sixth warmest on record

This text is just an update of what I wrote one month ago and two months ago. The results have changed partly because I used UAH AMSU instead of RSS AMSU. The La Niña odds have considerably strengthened. However, the competing years had cooler Septembers than 2011 so this year jumped from 12th to 6th place.

According to UAH AMSU together with Roy Spencer's newest figure which I used instead of RSS AMSU because UAH was faster than RSS this time, the first 9 months made the January-August period of this year 6th warmest on the UAH AMSU satellite record.

The top 15 ranking of the years 1979-2011 according to the average UAH temperature during the first nine months is as follows:
  1. 1998: 0.51
  2. 2010: 0.47
  3. 2005: 0.24
  4. 2002: 0.24
  5. 2007: 0.21
  6. 2011: 0.16
  7. 2009: 0.16
  8. 2006: 0.16
  9. 2003: 0.15
  10. 1991: 0.10
  11. 2001: 0.09
  12. 2004: 0.09
  13. 1988: 0.07
  14. 1995: 0.05
  15. 1980: 0.02
The El Niño year 1998 remains the leader of the league: its first 9 months were 0.35 °C warmer than the same months of 2011. Despite the jump in the direction up, 2011 is still helping to make the preliminary 21st century temperature trend smaller than before: the UAH trend since Jan 2001 is about +0.5 °C/per century while the RSS trend is about -0.1 °C/century (negative); this is no bulšit, angry Al.

In spite of the month-on-month cooling between August and September 2011, some warming may have been taking place in previous months – because of the delayed effect of the disappearing (previous) La Niña a few months ago. But it may be replaced by another cooling in the coming months.

As we already noticed a month ago, the ENSO oscillations have returned to the negative, La Niña territory after a few months in the neutral interval. For example, the latest weekly ENSO report says that the ONI 3.4 anomaly is at –0.7 °C (and similarly other regions) – it went down from –0.6 °C a month ago and –0.4 °C two months ago and has slipped below –0.5 °C, the boundary of the La Niña conditions.

The newest update a month ago was still showing "equal odds of La Niña and neutral conditions" but it was quickly replaced by an unequivocal La Niña and the ENSO models now speak a clear language. The picture from Monday shows a nice blue spot near the South American Western beaches:

I think that the blue spot sits at an important place – and is already big enough – and could help to decide that La Niña conditions will survive during the winter. Just to be sure, that is going to be the second consecutive La Niña episode.

Whatever will happen to ENSO in the Fall, I think that it will only substantially influence the global temperatures in 2012.

In the rest of 2011, we will see comparable temperature anomalies as in the first half of 2011 which may be smaller than the anomalies from July and August (and even September). According to my calculations and estimates, UAH AMSU will see 2011 as 5th-9th warmest year on their record; the anomalies of these five years are almost equal:
  1. 1998: 0.43
  2. 2010: 0.41
  3. 2005: 0.25
  4. 2002: 0.22
  5. 2009: 0.19
  6. 2003: 0.19
  7. 2011: 0.18 ± 0.03
  8. 2006: 0.18
  9. 2007: 0.17
  10. 2001: 0.11
It's more likely than not that during 2012 or at the beginning of 2013, we will actually see an RSS and/or UAH climate record that will display a cooling trend during the most recent 15 years – partly because of the expected 2011/2012 La Niña, partly because the warm 1998 year will emerge at the beginning of the 15-year interval. Recent years increasingly paint the story that the "global warming" stopped more than a decade ago.

The first 11 years of this century display a cooling trend. One may believe that during the century (e.g. in 2040), the sign of the slope will be reverted but it doesn't have to be. There doesn't exist any convincing scientific evidence that it has to.

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