Posted by Co2sceptic on Oct 16th 2012
views 13,902
A reply to Met Office in the Media: 14 October 2012, from sunshinehours.wordpress.com

“As we’ve stressed before, choosing a starting or end point on short-term scales can be very misleading. Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system. If you use a longer period from HadCRUT4 the trend looks very different. For example, 1979 to 2011 shows 0.16°C/decade (or 0.15°C/decade in the NCDC dataset, 0.16°C/decade in GISS). Looking at successive decades over this period, each decade was warmer than the previous – so the 1990s were warmer than the 1980s, and the 2000s were warmer than both.”

Ok, lets look at a non-arbitrary endpoint (the last datapoint) and go back in 5 year increments.

HADCRUT4 Last 5 years colder than previous 5 years

Mean of the anomaly of the last 5 years = .45C

Mean of the anomaly of the previous 5 years = .49C

Mean of the anomaly of the previous previous 5 years = .41C

HADCRUT3 – Last 5 years colder than previous AND colder than the previous previous 5.


Mean of the anomaly of the last 5 years = .39C

Mean of the anomaly of the previous 5 years = .45C

Mean of the anomaly of the previous previous 5 years = .41C

Warming stopped. HADCRUT3 trend is negative.

IPCC predicted .2C per decade. HADCRUT4 has been created to change the negative trend of HADCRUT3 to a positive one.

But even with the “adjustments”, the last 15 years trend in HADCRUT4 is 1/6th that predicted by the IPCC.