Agree to Disagree
Debate in a non-hostile environment
How “special” was the recent slowdown?
Warmists and Alarmists are still fighting the idea, that there was a recent slowdown. In order to show just how “special” the recent slowdown was, I have created a new type of graph, which shows the warming rate plotted against the date range which was used to calculate the warming rate.
That may sound confusing, but when you look at the graph, it will become clear. The graph is based on very simple principles. A quick numerical example will show how the graph was made.
The warming rate (calculated using a linear regression), for the date range from 2002 to 2012, was 0.12 degrees Celsius per century. The graph is an X-Y graph. This calculated warming rate is plotted as a line, which runs from (2002, 0.12) to (2012, 0.12).
This is a horizontal line, which runs from 2002 to 2012 on the X-axis, at a height of 0.12 (the warming rate), on the Y-axis. Now just add more horizontal lines, for all of the other calculated warming rates, and you will have the finished graph.
Note that only date ranges which are greater than or equal to 10 years, have been used. Short date ranges tend to have very variable warming rates, so these have been ignored.
Have a look at the graph, and see what you think. I will give you my interpretation of the graph, after you have had a chance to look at it. Note that I have coloured the warming rate that I used as a numerical example above, in red. This is the lowest warming rate from 1980 to 2017, and it is therefore the strongest slowdown. All of the other warming rates are coloured blue.
A number of the lines have been labelled with the warming rate, in degrees Celsius per century, at the right-hand end of the line. This means that you can see what the warming rate is, without having to guess it from the Y-axis. There were too many lines to label them all, so I have tried to label the ones that are the most useful.
Note the red line near the bottom of the graph, which runs from 2002 to 2012 on the X-axis, at a height of 0.12 (the warming rate), on the Y-axis. This is the lowest warming rate, which is also the strongest slowdown.
The strongest slowdown is not all alone. It has some neighbours nearby. The closest is 2002 to 2013, with a warming rate of 0.22 (all warming rates are in degrees Celsius per century, I will not specify this each time that I give a warming rate).
Also nearby, is 2003 to 2013, with a warming rate of 0.35. As you might expect, warming rates which share a common date range, tend to have similar warming rates. The strongest slowdown comes from a “family” of date ranges, which go from about 2001 to 2013 or 2014.
What about the rest of the graph. The majority of warming rates fall in the dense central region, with warming rates from about 1.4 to 2.2. The overall average is about 1.75.
Then there are the departures from the central area. A speedup in the middle of the graph, from about 1992 to 2004 (about 12 years). This speedup reached a warming rate of 3.39.
There was a weaker slowdown, from about 1987 to 1997, with a warming rate of about 0.43.
Finally, there is a small number of speedups which end in 2016 and 2017. The 4 years from 2014 to 2017, are the warmest in the date range, from 1980 to 2017. So it is no surprise that the warming rates calculated using these years, will tend to have higher warming rates. This is another speedup, which started after the recent slowdown.
In summary, notice how clearly the slowdowns and speedups stand out from the dense central region. These are NOT vague climate events, which are hard to pick out from the other climate events. These are “in your face” climate events, which no intelligent person would deny.
But make no mistake, there are plenty of unintelligent, or deceitful, people out there, who will still deny the recent slowdown. These people have their own agenda, and scientific truth is not important to them.
Bear in mind that a slowdown of 0.12, compared to the average warming rate of about 1.75, is less than 7% of the average warming rate.
Imagine driving your car at 100 km/h on the motorway, and having to slow down to less than 7 km/h for 10 years!
Many Warmists and Alarmists would claim that you hadn’t even slowed down, and that 7 km/h and 100 km/h were statistically the same value.
However, reasonable people accept that there was a recent slowdown, and that it was “special”.
Accepting that there was a temporary slowdown, does not invalidate global warming. So Warmists and Alarmists can have their cake, and eat it too. They can still believe in global warming, but accept that there was a temporary slowdown in warming rates from about 2002 to 2012.