## Are we presently in a global warming pause or in a decline or neither?

WoodForTrees.org – Paul Clark – Click the pic to view at source. Image Credit: WoodForTrees.org

**Guest Post By Werner Brozek, Edited By Just The Facts**

*At least April data was my intention. However as of June 8, HadCRUT3 for April is still not up! Could it be because as of the end of March, the slope of 0 lasted 16 years and 1 month and they do not want to add another month or two? What do you think? WoodForTrees (WFT) is up to date however, thank you very much Paul!

The graph above shows a few different things for three data sets where there has been no warming for at least 16 years. WFT only allows one to draw straight lines between two points, however climate does not go in straight lines. Often, temperatures vary in a sinusoidal fashion which cannot yet be shown using WFT. However we can do the next best thing and show what is happening over the first half of the 16 years and what is happening over the last half. As shown, the first half shows a small rise and the last half shows a small decline. Note that neither the rise in the first half nor the drop in the last half is statistically significant. However the lines do suggest that we are just continuing a 60 year sine wave that was started in 1880 according to the following graphic:

Do you agree? What are your views on the question in the title? Do you think we are presently in a pause or in a decline or neither?

In the sections below, we will present you with the latest facts. The information will be presented in three sections and an appendix. The first section will show the period that there has been no warming for various data sets. The second section will show the period that there has been no “significant” warming on several data sets. The third section will show how 2013 to date compares with 2012 and the warmest years and months on record. The appendix illustrate sections 1 and 2 in a different format. Graphs and a table will be used to illustrate the data.

**Section 1**

This analysis uses the latest month for which data is available on WoodForTrees.com (WFT). All of the data on WFT is also available at the specific sources as outlined below. We start with the present date and go to the furthest month in the past where the slope is a least slightly negative. So if the slope from September is 4 x 10^-4 but it is – 4 x 10^-4 from October, we give the time from October so no one can accuse us of being less than honest if we say the slope is flat from a certain month.

On all data sets below, the different times for a slope that is at least very slightly negative ranges from 8 years and 5 months to 16 years and 6 months.

1. For GISS, the slope is flat since January 2001 or 12 years, 4 months. (goes to April)

2. For Hadcrut3, the slope is flat since March 1, 1997 or 16 years, 1 month. (goes to March 31, 2013)

3. For a combination of GISS, Hadcrut3, UAH and RSS, the slope is flat since December 2000 or 12 years, 6 months. (This goes to May. I realize that Hadcrut3 is not up to date, but on the basis of its present slope and the latest numbers that I do have from the other three sets. I am confident that I can make this prediction.)

4. For Hadcrut4, the slope is flat since November 2000 or 12 years, 6 months. (goes to April)

5. For Hadsst2, the slope is flat from March 1, 1997 to April 30, 2013, or 16 years, 2 months.

6. For UAH, the slope is flat since January 2005 or 8 years, 5 months. (goes to May)

7. For RSS, the slope is flat since December 1996 or 16 years and 6 months. (goes to May) RSS is 198/204 or 97% of the way to Ben Santer’s 17 years. This 97% is real!

The next graph shows just the lines to illustrate the above for what can be shown. Think of it as a sideways bar graph where the lengths of the lines indicate the relative times where the slope is 0. In addition, the sloped wiggly line shows how CO2 has increased over this period.

When two things are plotted as I have done, the left only shows a temperature anomaly. It goes from 0.1 C to 0.6 C. A change of 0.5 C over 16 years is about 3.0 C over 100 years. And 3.0 C is about the average of what the IPCC says may be the temperature increase by 2100.

So for this to be the case, the slope for all of the data sets would have to be as steep as the CO2 slope. Hopefully the graphs show that this is totally untenable.

The next graph shows the above, but this time, the actual plotted points are shown along with the slope lines and the CO2 is omitted.

**Section 2**

For this analysis, data was retrieved from SkepticalScience.com. This analysis indicates for how long there has not been significant warming according to their criteria. The numbers below start from January of the year indicated. Data go to their latest update for each set. In every case, note that the magnitude of the second number is larger than the first number so a slope of 0 cannot be ruled out. (To the best of my knowledge, SkS uses the same criteria that Phil Jones uses to determine significance.)

The situation with GISS, which used to have no statistically significant warming for 17 years, has now been changed with new data. GISS now has over 18 years of no statistically significant warming. As a result, we can now say the following: On six different data sets, there has been no statistically significant warming for between 18 and 23 years.

The details are below and are based on the SkS site:

For RSS the warming is not significant for over 23 years.

For RSS: +0.123 +/-0.131 C/decade at the two sigma level from 1990

For UAH the warming is not significant for over 19 years.

For UAH: 0.142 +/- 0.166 C/decade at the two sigma level from 1994

For Hadcrut3 the warming is not significant for over 19 years.

For Hadcrut3: 0.092 +/- 0.112 C/decade at the two sigma level from 1994

For Hadcrut4 the warming is not significant for over 18 years.

For Hadcrut4: 0.093 +/- 0.108 C/decade at the two sigma level from 1995

For GISS the warming is not significant for over 18 years.

For GISS: 0.103 +/- 0.111 C/decade at the two sigma level from 1995

For NOAA the warming is not significant for over 18 years.

For NOAA: 0.085 +/- 0.104 C/decade at the two sigma level from 1995

If you want to know the times to the nearest month that the warming is not significant for each set to their latest update, they are as follows:

RSS since August 1989;

UAH since June 1993;

Hadcrut3 since July 1993;

Hadcrut4 since July 1994;

GISS since October 1994 and

NOAA since May 1994.