2014 was a warm year for much of Europe and the globe, and may end up being the warmest year on record globally. But, no-one experiences a global mean temperature directly, so how about more locally? Can the signal of a warming climate be seen?
The timeseries of the annual averages shows an overall increase in temperatures of around 1.5°C, and considerable fluctuations around the long-term trend (see figure). Some of these fluctuations are probably due to changes in solar activity & volcanic eruptions, but much is just due to the chaotic variations in weather experienced in the UK.
The long-term trend, especially since 1950, is at least partly due to human activity. And, for the January-December average, 2014 is the warmest on record (see figure), although note the uncertainties of about 0.10°C for an annual average. [This uncertainty is larger, around 0.3°C, before 1772.]
These rankings should not be over-interpreted – there is clearly a strong influence of random weather on UK climate in each particular year. However, the warming global average temperatures are increasing the chance of seeing warm years locally, such as 2014 in the UK and Europe.
The surface area represented by CET is tiny (≈1/22000 of the entire planet), and is in one of the most climatically variable parts of the world. Yet, the signal of a warming world is still clearly visible even at this local scale where changes in climate are actually experienced.
[02/12/14: Updated with fraction of surface area sentence.]
[03/12/14: Figure updated to include: (i) finalised November data for 2014, (ii) a better representation of pre-1772 uncertainty (0.3°C – see Comment from Mark McCarthy) and (iii) using the daily data after 1772.]
[22/12/14: Figure and text updated to include data up to 21st December]
[01/01/15: Figure and text updated to include all data from 2014]