Guest Post by Werner Brozek, Extended Comments from Barry and Edited by Just The Facts
UAH (University of Alabama in Huntsville) and RSS (Remote Sensing Systems) are two major satellite groups that provide monthly climate anomalies. From January 1998 to January 2016, the slope was slightly negative, a period which many have referred to as a “pause”, although some prefer other names. Since a huge anomaly spike in February 2016 due to a very strong El Nino, the so called pause is gone.
Last month, Barry wrote about several things that must happen for the pause to return for UAH, which I excerpted in an article titled How Imminent is the UAH Pause? (Now Includes Some January Data) This month, Barry has written about what must happen for the pause to return for RSS, as well as provided additional information with respect to the UAH pause.
Barry’s comments follow:
This RSS analysis leverages the RSSv3 TLT global data set. The following plot contains the full record with 12 month averages for visual accompaniment:
Ordinary least squares linear regression, trends in degrees Celsius, the mean trend from January 1998 to:
Feb 2016: 0.019 /decade
Mar 2016: 0.028 /decade
Apr 2016: 0.035 /decade
May 2016: 0.038 /decade
Jun 2016: 0.041 /decade
Jul 2016: 0.043 /decade
Aug 2016: 0.045 /decade
Sep 2016: 0.049 /decade
Oct 2016: 0.049 /decade (higher to 4 decimal places than Sep)
Nov 2016: 0.050 /decade
Dec 2016: 0.048 /decade
Jan 2017: 0.052 /decade
Feb 2017: 0.053 /decade
Unlike UAHv6, there is one month (Dec 2016) that lowered the then warming trend slightly. I’ve plotted monthly data and the trend to Nov 2016, and you can see the Dec 2016 anomaly is below the trend line. That’s why December lowered the then trend slightly:
Otherwise, every other month after the peak warm month of Feb 2016 increased the trend, even though they were all cooler than February. The trend rose because subsequent months were warmer than the trend itself, except December 2016. For the ‘pause’ from 1998 to resume next month, the March anomaly would have to be -3.6C. For the pause to resume by December 2017, the annual average anomaly for 2017 would have to be -0.02C. The last time an annual temperature anomaly was this cool or cooler in the RSSv3 TLT dataset was 1993 (-0.118C). However, January and February 2017 have been 0.41 and 0.44 respectively, so for the pause to resume by December, the average of the next 10 months would have to be -0.12C. The last time this happened was in 1992 (-0.19C).
For a pause to resume by 2020 (Dec 2019), the three year averaged anomaly 2017 to 2019 for RSS would have to be -0.04C. The last time a 3 year average was that cool or cooler was 1992 through 1994 (-0.09). For the pause to resume by 2020, we’d need to see temps of the next three years similar to those of the early 1990s. Check the graph above to see what that looks like.
The section below provides some additional updates for UAH.
Next month’s anomaly would have to be lower than 0.2C to reduce the trend slightly. To get a flat or negative trend since 1998, the March anomaly would have to be -3.8C. The decimal point is in the correct place!
For the 1998 trend to return to flat or negative values by the end of this year, the annual average anomaly for 2017 would have to be -0.16C. We have 2 months data already, at around 0.5C warmer than that, so what would the average temperature anomaly for the rest of 2017 have to be to get a flat/negative trend since 1998? -0.26C (Mar-Dec)
The most recent year the annual average anomaly was that cool was in 1985. The annual average then was -0.35C. With 2017 predicted to be an el Nino or ENSO neutral year the chances of a flat trend by December are very slim. As I expect some warming with atmospheric CO2 increase, however one may argue the magnitude, I think it is unlikely we will see a year as cold as 1985, barring a volcanic eruption of greater magnitude than the 1991 Pinatubo eruption. Consequently, I think it is unlikely the ‘pause’ will return at all if 1998 is used as the start date.
In comments last month Werner asked how cool the annual anomalies would have to be to get a flat trend if there were a succession of cool years. For the trend since 1998 to go flat by 2020 (December 2019) the annual average temperature anomaly for the three years Jan 2017 to Dec 2019 would have to be: 0.05C
When did we last have 3 consecutive years as cool or cooler than that?
2007 to 2009: 0.05C However, January and February 2017, being 0.30 and 0.35C respectively, would raise the three year average to
0.6 0.065 if the rest of the months through 2019 were 0.05C. So we have to go further back in time to get a cooler 3-year average. Most recent is: 1994 to 1996: 0.0C
Those predicting imminent cooling from lower solar ebb or ocean-atmosphere oscillations may expect to see annual temperatures like the early 1990s sometime soon. I am less confident of that. Time will tell.
Written by Barry
In the sections below, we will present you with the latest facts. The information will be presented in two sections and an appendix. The first section will show for how long there has been no statistically significant warming on several data sets. The second section will show how 2017 compares with 2016, the warmest year so far, and the warmest months on record so far. The appendix will illustrate sections 1 and 2 in a different way. Graphs and a table will be used to illustrate the data.
For this analysis, data was retrieved from Nick Stokes’ Trendviewer available on his website. This analysis indicates for how long there has not been statistically significant warming according to Nick’s criteria. Data go to their latest update for each set. In every case, note that the lower error bar is negative so a slope of 0 cannot be ruled out from the month indicated.
On several different data sets, there has been no statistically significant warming for between 0 and 23 years according to Nick’s criteria. Cl stands for the confidence limits at the 95% level.
The details for several sets are below.
For UAH6.0: Since December 1993: Cl from -0.009 to 1.776
This is 23 years and 3 months.
For RSS: Since October 1994: Cl from -0.006 to 1.768 This is 22 years and 5 months.
For Hadcrut4.5: The warming is statistically significant for all periods above four years.
For Hadsst3: Since May 1997: Cl from -0.031 to 2.083 This is 19 years and 9 months.
For GISS: The warming is statistically significant for all periods above four years.
This section shows data about 2017 and other information in the form of a table. The table shows the five data sources along the top and other places so they should be visible at all times. The sources are UAH, RSS, Hadcrut4, Hadsst3, and GISS.
Down the column, are the following:
1. 16ra: This is the final ranking for 2016 on each data set. On all data sets, 2016 set a new record. How statistically significant the records were was covered in an earlier post here: https://wattsupwiththat.com/2017/01/26/warmest-ten-years-on-record-now-includes-all-december-data/
2. 16a: Here I give the average anomaly for 2016.
3. mon: This is the month where that particular data set showed the highest anomaly. The months are identified by the first three letters of the month and the last two numbers of the year.
4. ano: This is the anomaly of the month just above.
5. sig: This the first month for which warming is not statistically significant according to Nick’s criteria. The first three letters of the month are followed by the last two numbers of the year.
6. sy/m: This is the years and months for row 5.
7. Jan: This is the January 2017 anomaly for that particular data set.
8. Feb: This is the February 2017 anomaly for that particular data set if available.
9. ave: This is the average anomaly of all available months with at least two months of data.
10. rnk: This is the 2017 rank for each particular data set assuming the average of the anomalies stay that way all year. Of course they won’t, but think of it as an update 5 minutes into a game.
If you wish to verify all of the latest anomalies, go to the following:
For UAH, version 6.0beta5 was used.
For RSS, see: ftp://ftp.ssmi.com/msu/monthly_time_series/rss_monthly_msu_amsu_channel_tlt_anomalies_land_and_ocean_v03_3.txt
For Hadcrut4, see: http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.18.104.22.168.monthly_ns_avg.txt
For Hadsst3, see: https://crudata.uea.ac.uk/cru/data/temperature/HadSST3-gl.dat
For GISS, see:
To see all points since January 2016 in the form of a graph, see the WFT graph below.
As you can see, all lines have been offset so they all start at the same place in January 2016. This makes it easy to compare January 2016 with the latest anomaly.
The thick double line is the WTI which shows the average of RSS, UAH, HadCRUT4.5 and GISS.
In this part, we are summarizing data for each set separately.
For UAH: There is no statistically significant warming since December 1993: Cl from -0.009 to 1.776. (This is using version 6.0 according to Nick’s program.)
The UAH average anomaly so far is 0.324. This would rank in fourth place if it stayed this way. 2016 was the warmest year at 0.503. The highest ever monthly anomaly was in February of 2016 when it reached 0.829.
For RSS: There is no statistically significant warming since October 1994: Cl from -0.006 to 1.768.
The RSS average anomaly so far is 0.425. This would rank in fourth place if it stayed this way. 2016 was the warmest year at 0.574. The highest ever monthly anomaly was in February of 2016 when it reached 0.996.
For Hadcrut4.5: The warming is significant for all periods above four years.
The Hadcrut4.5 average anomaly for 2016 was 0.773. This set a new record. The highest ever monthly anomaly was in February of 2016 when it reached 1.070. The January anomaly was 0.741 which would rank 2017 in third place if it stayed this way.
For Hadsst3: There is no statistically significant warming since May 1997: Cl from -0.031 to 2.083.
The Hadsst3 January anomaly is 0.488. This would rank third if it stayed this way. The highest ever monthly anomaly was in January of 2016 when it reached 0.732.
For GISS: The warming is significant for all periods above four years.
The GISS average anomaly for 2016 was 0.98. This set a new record. The highest ever monthly anomaly was in February of 2016 when it reached 1.30. The January anomaly was 0.92 which would rank 2017 in second place if it stayed this way.
Do you think RSS will ever have a pause of over 18 years again? Why or why not?