Global temperature measurements from RSS satellite show temperatures have been flat from September 1996 to July 2014. No change for 18 years 10 months despite rising CO2.
This is a serious problem for the idea that CO2 causes global warming. If nothing else it means there is another more powerful mechanism which has been causing cooling.
One possibility is having risen for some years, temperatures are pausing before falling.
Just like slack water at high tide before sea level falls only to rise again on the next high tide.
RSS showing no change has already been reported by many websites. However this report relies just on the trend value. If we take into account the error in determining the trend we can say there has been no rise in temperature since January 1996, as the trend is 0.002 ± 0.002ºC/year. Here the error is the same size as the trend so it is not possible to say the trend is different from 0.
The HADCRUT4 dataset shows a rise of 0.007ºC/year from September 1996 to July 2014, larger the rise reported from 1880 to 2010 (about 0.0061ºC/year), which the UK Met Office claim is “statistically significant” – thought it’s entirely unclear what they mean by this.
This Met Office statement seems to have been taken by politicians and media to mean
Global Warming Is Real
The UAH satellite measurements shows a larger rise of 0.009/year from September 1996 to July 2014
On the other hand CET (Central England Temperature record – the longest running instrumental temperature record in the world) shows a fall from September 1996 to July 2014.
UAH temperatures are flat from January 2002 to July 2014, as the error is larger than the trend.
Or from February 2001 if you are happy to count from when the trend is the same size as the error in calculating the trend.
HADCRUT4 is flat from January 2001 to September 2014
or November 2000, if you are content to count from when trend is same size as error.
So depending on which dataset you pick temperatures have been
- flat for 19 years 6 months
- flat for 12 years 6 months
- flat for something in between
- or falling for 18 years 10 months
CET shows a rise of 0.02 ºC/year from September 1966 to September 2014 which would amount to a rise of 2.6 ºC over 130 years, over 3 times as much as the 0.8ºC UK Met Office got so worried about from 1880 to 2010.
The CET record runs from 1659 and the trend is 0.0026ºC/year, ie about 10 times smaller than for the period 1966 to 2014.
The CET record show recurring rises and falls from 1659 to 2014.
There have been regular maximums in temperature anomaly of about 4ºC from about 1677 to 2014. There has been effectively not increase in these maximums.
It seems any warming trend is due to the reduction in number of minimum temperature anomaly.
There are several lows of below -6ºC below about 1820 but none after.
It is known that temperatures were lower from 1650 to 1820.
Using a linear trend implies you think the temperatures (or at least average temperatures) will rise continuously in a straight line for ever.
CET record clearly shows there are cycles in the temperature record.
Sometimes temperature go up.
Sometimes temperatures go down.
This is hardly news to anyone who has realised winters are colder than summers.
Cycles look something like this (which should be familiar to anyone who lives by the sea).
Depending on which part of the cycle you fit a linear trend to, you may find it is
- rising
- flat
- falling
As CET shows there have been cycles of temperature rise and fall of temperatures for over 350 years, the simplest explanation for the pause (be it 19 years or 12) is temperatures are about to fall globally and we should expect a fall of at least 4ºC, possibly 6ºC and a worst case of 8ºC.
A fall of 4ºC would be dramatic and have a huge negative effective on agricultural yields.
A fall of 6ºC let alone 8ºC is likely to be catastrophic.
If temperature is rising and falling in cycles, as it has for at least the last 350 years then CO2 is having a negligible effect.
On the other hand if CO2 was responsible for the rise in temperatures towards the end of the 20th century what is causing the pause. Do we have to invoke some other, as yet unknown mechanism which can overpower CO2.
Just suppose CO2 was responsible for the 20th century temperature rise, how do we know the unknown mechanism which is causing the pause will ever stop and let temperatures rise again.
How do we know this unknown mechanism causing the pause will not get even stronger and cause temperatures to fall?
RSS shows a fall from November 2000
HADCRUT4 falls from June 2004, which you can check with the wonderful wood for trees
woodfortrees.org/plot/hadcrut4gl/from:1995/plot/hadcrut4gl/from:2004.42/trend
UAH shows a fall from July 2008
http://woodfortrees.org/plot/uah/plot/uah/from:2008.42/trend
As we have seen CET shows a fall from September 1996.
So it’s a FALL not a pause
The next time I hear anyone talking about the pause I think I’ll complain to Advertising Standards.
Finally it temperatures continue fall, at the very least it makes continued sea level rise less likely and we may even see sea levels fall.
Technical note
Months follow the woodfortrees scheme
Months are counted as 1/12 of a year, starting from January which is 0/12, through to December which is 11/12.
Month fractions are rounded to 2 decimal places so the sequence for January to December goes
0.00, 0.08, 0.17, 0.25, 0.33, 0.42, 0.5, 0.67, 0.75, 0.83, 0.92