Uah Ranks 2014 Third Warmest Year Just

Satellite measurements of the temperature of the atmosphere rank 2014 as the third warmest year in the satellite record, according to the University of Alabama in Huntsville (UAH).

The global average temperature anomaly – that is, the variance to the long term average global temperature between 1981 and 2010 – for the layer of the atmosphere from the surface up to around 8km in altitude known as the lower troposphere during 2014 was 0.27oC, according to UAH data.

This was just 0.01oC warmer than 2005 and just a few hundredths of a degree warmer than 2013 and 2002 – such small differences as to make the 2014 result statistically indistinguishable from these other years. This suggests that the so called pause or hiatus in global warming continued through 2014, at least in the satellite record.

The UAH analysis shows that the global temperature trend from 2002 through 2014 was a warming at the rate of +0.05oC per decade which is statistically insignificant. However, it is also the case that global temperatures have remained elevated throughout this period and that these years have averaged some 0.18oC above the baseline provided by the 30-year long term average and contain nine of the 10 warmest years – the warmest of all being 1998.

Dr. John Christy, professor of atmospheric science and director of the Earth System Science Center at UAH is quoted by the UAH press release issued today as saying: “2014 was warm, but not special. The 0.01oC difference between 2014 and 2005, or the 0.02 difference with 2013 are not statistically different from zero. That might not be a very satisfying conclusion, but it is at least accurate”.

An analysis of essentially – but not quite – the same satellite data by US firm Remote Sensing Systems (RSS) shows that 2014 was the sixth warmest year on record.

The global average temperature anomaly for the lower troposphere in December was 0.32oC making it the second warmest December in the UAH dataset. RSS data ranks December 2014 as seventh warmest December since 1979 when satellite measurements began.

RSS tends to report data that is cooler than UAH.

It is likely that 2014 will rank higher in the surface temperature data sets managed by the National Oceanic and Atmospheric Administration (NOAA) of the US, by US space agency NASA and by the UK Meteorological Office, among others. These are expected to show that 2014 was either the warmest year on record or one of the warmest years on record.

If this is the case then the apparent divergence between the relative warmth of 2014 in terms of atmosphere temperatures and in terms of surface temperature data will prompt questions into the relative merits of satellite and ground based temperature observations and also fuel debate among climate sceptics. There is no widely agreed explanation for the divergence.

UAH ranks the top 10 warmest years with their respective temperature anomalies as follows:

1    1998     0.42
2    2010     0.40
3    2014    0.27
4    2005     0.26
5    2013     0.24
6    2002     0.22
7    2009     0.21
8    2007     0.20
9    2003     0.19
10    2006     0.19

RSS data ranks the top 10 warmest years with their respective temperature anomalies as follows:

1 1998 0.55

2 2010 0.47

3 2005 0.33

4 2003 0.32

5 2002 0.31

6 2014 0.26

7 2007 0.25

8 2001 0.25

9 2006 0.23

10 2009 0.22

Note that RSS uses a different baseline to UAH so although the anomalies agree not comparable the trends and ranks should be.

Here is the text of a news release issued by UAH today (Tuesday 6 January 2015):

2014 was third warmest, but barely

Global climate trend since Nov. 16, 1978: +0.14 C per decade

December temperatures (preliminary)

Global composite temp.: +0.32 C (about 0.58 degrees Fahrenheit) above 30-year average for December.

Northern Hemisphere: +0.46 C (about 0.83 degrees Fahrenheit) above 30-year average for December.

Southern Hemisphere: +0.18 C (about 0.32 degrees Fahrenheit) above 30-year average for December.

Tropics: +0.30 C (about 0.54 degrees Fahrenheit) above 30-year average for December.

November temperatures (revised):

Global Composite: +0.33 C above 30-year average

Northern Hemisphere: +0.35 C above 30-year average

Southern Hemisphere: +0.30 C above 30-year average

Tropics: +0.25 C above 30-year average

(All temperature anomalies are based on a 30-year average (1981-2010) for the month reported.)

Notes on data released Jan. 3, 2015:

2014 was the third warmest year in the 36-year global satellite temperature record, but by such a small margin (0.01 C) as to be statistically similar to other recent years, according to Dr. John Christy, a professor of atmospheric science and director of the Earth System Science Center at The University of Alabama in Huntsville. “2014 was warm, but not special. The 0.01 C difference between 2014 and 2005, or the 0.02 difference with 2013 are not statistically different from zero. That might not be a very satisfying conclusion, but it is at least accurate.”

The 2014 average temperature anomaly also is in keeping with temperatures since late 2001, when the global average temperature rose to a level that is generally warmer than the 30-year baseline average. The most recent 13 complete calendar years, from 2002 through 2014, have averaged 0.18 C (about 0.33 degrees Fahrenheit) warmer than the 30-year baseline average, while the global temperature trend during that span was a warming trend at the rate of +0.05 C per decade — which is also statistically insignificant.

Compared to seasonal norms, the coldest annual average temperature on Earth throughout 2014 was just south of Wilmar, Minnesota. The average 2014 temperature there was –1.27 C (about 2.29 degrees F) colder than normal. The ‘warmest’ place throughout 2014 was just south of the North Pole along the International Date Line. Temperatures there averaged 1.65 C (about 2.97 degrees F) warmer than normal for the year.

Annual Global Temperature Anomalies, ranked

1.    1998     0.42
2.    2010     0.40
3.    2014    0.27
4.    2005     0.26
5.    2013     0.24
6.    2002     0.22
7.    2009     0.21
8.    2007     0.20
9.    2003     0.19
10.    2006     0.19
11.    2012     0.17
12.    2011     0.13
13.    2004     0.11
14.    2001     0.11
15.    1991     0.02
16.    1987     0.01
17.    1995     0.01
18.    1988     0.01
19.    1980    -0.01
20.    2008    -0.01
21.    1990    -0.02
22.    1981    -0.05
23.    1997    -0.05
24.    1999    -0.06
25.    1983    -0.06
26.    2000    -0.06
27.    1996    -0.08
28.    1994    -0.11
29.    1979    -0.17
30.    1989    -0.21
31.    1986    -0.24
32.    1993    -0.25
33.    1982    -0.25
34.    1992    -0.29
36.    1985    -0.31
37.    1984    -0.35

With a global average temperature that was 0.32 C (about 0.58 degrees Fahrenheit) warmer than seasonal norms, December 2014 trailed only December 2003, which averaged 0.37 C (about 0.67 degrees Fahrenheit) warmer than seasonal norms, among the warmest Decembers in the satellite temperature record. While December 2014 ranked second warmest for both the globe and the Northern Hemisphere, it was only the sixth warmest December in the tropics despite an El Niño Pacific Ocean warming event that seems to be forming there.

Warmest Decembers (1979-2014)
(Global average, warmer than seasonal norms)

1.   2003    +0.37 C
2.   2014   +0.32 C
3.   1987    +0.27 C
2013    +0.27 C
5.   2009    +0.24 C
6.   2012    +0.23 C
7.   1997    +0.22 C
2006    +0.22 C
9.   1998    +0.19 C
2005    +0.19 C

Compared to seasonal norms, the coldest place in Earth’s atmosphere in December was in northwestern Greenland, where temperatures were as much as 2.70 C (about 4.86 degrees Fahrenheit) colder than seasonal norms. Compared to seasonal norms, the warmest departure from average in December was in central Russia, north of the town of Yeniseysk. Temperatures there were as much as 2.75 C (about 4.86 degrees Fahrenheit) warmer than seasonal norms.

Archived color maps of local temperature anomalies are available on-line at:

As part of an ongoing joint project between UAHuntsville, NOAA and NASA, Christy and Dr. Roy Spencer, an ESSC principal scientist, use data gathered by advanced microwave sounding units on NOAA and NASA satellites to get accurate temperature readings for almost all regions of the Earth. This includes remote desert, ocean and rain forest areas where reliable climate data are not otherwise available.

The satellite-based instruments measure the temperature of the atmosphere from the surface up to an altitude of about eight kilometers above sea level. Once the monthly temperature data is collected and processed, it is placed in a “public” computer file for immediate access by atmospheric scientists in the U.S. and abroad.

Neither Christy nor Spencer receives any research support or funding from oil, coal or industrial companies or organizations, or from any private or special interest groups. All of their climate research funding comes from federal and state grants or contracts.

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