I was wondering if the above average
temperatures we have been enjoying
for the last few years had happened gradually over a long period of
time or more rapidly.
As previously stated the averages I have been recently giving are based
on a series of data
for 30 years in this case 61-90: 71- 00 is now also in use. The 30 year
data is used to smooth
out any unusually hot or cold years. Recent averages have been well
above both the 61-90
and the 71-00 series.
To see if there was anything significant happening in a
shorter time frame I averaged all the mean annual
temperature for five year blocks from 1916- 2010 and plotted them on a
The results would tend to suggest that we really do have something to
You can see from the period 1916- 1995 the mean
temperature tended to see saw around 7C
some five year blocks were colder, some warmer. 31-35 , 56-60 and 71-75
bringing a warmer spell
and 16-20, 61- 70 seeing cooler conditions. Over an 80 year period from
1916-1995 the mean temperature
never moved out of the band 6.7C- 7.3C. Somewhere around 1996 it
started to increase, rapidly
hitting 7.6C in the band 1996-2000 and 7.99C in the band 2000-2005.
Whatever is happening the temperature over the last fifteen years has
far exceeded the norm of the previous 80 years. Although the recent
trend is heading downwards 2011 saw an average temprature of 8.06C.
Still donít believe in global warming?