“Global” temperature is necessarily a construct. It is “calculated” by taking raw temperature data as measured at particular locations, massaging this data according to algorithms devised by those calculating the “global temperature, applied to areas where there are no measurements by some other algorithms (oceans, poles, forests and deserts), adjusting past data and then coming up with a “global” temperature.
Raw data is never used without “adjustment”. Remarkably the adjustments invariably cool the past. Every year, data from the past is further adjusted! The trends and results presented represent more the adjustment algorithms used rather than the parameters themselves. As this example of “adjustment” of raw data from Puerto Casada to convert an actually measured cooling trend into an adjusted warming trend illustrates
Cooling the past: Puerto Casada From raw to adjusted data
Studies have already shown that, in the US, Australia, New Zealand, the Arctic and South America, in far too many cases, temperatures have been adjusted to show a stronger and clearer warming trend than is justified by the raw data.
As RealScience shows with this more dramatic example from Vestmanneyja
https://stevengoddard.files.wordpress.com/2015/01/vestmannaeyja.gif?w=640
An investigation now to be carried out by an international team is to establish a full and accurate picture of just how much of the published record has been adjusted in a way which gives the impression that temperatures have been rising faster and further than was indicated by the raw measured data.
Christopher Booker writes in the Daily Telegraph:
…. something very odd has been going on with those official surface temperature records, all of which ultimately rely on data compiled by NOAA’s GHCN. Careful analysts have come up with hundreds of examples of how the original data recorded by 3,000-odd weather stations has been “adjusted”, to exaggerate the degree to which the Earth has actually been warming. Figures from earlier decades have repeatedly been adjusted downwards and more recent data adjusted upwards, to show the Earth having warmed much more dramatically than the original data justified.
So strong is the evidence that all this calls for proper investigation ……… The Global Warming Policy Foundation (GWPF) has enlisted an international team of five distinguished scientists to carry out a full inquiry into just how far these manipulations of the data may have distorted our picture of what is really happening to global temperatures.
The panel is chaired by Terence Kealey, until recently vice-chancellor of the University of Buckingham. His team, all respected experts in their field with many peer-reviewed papers to their name, includes Dr Peter Chylek, a physicist from the National Los Alamos Laboratory; Richard McNider, an emeritus professor who founded the Atmospheric Sciences Programme at the University of Alabama; Professor Roman Mureika from Canada, an expert in identifying errors in statistical methodology; Professor Roger Pielke Sr, a noted climatologist from the University of Colorado, and Professor William van Wijngaarden, a physicist whose many papers on climatology have included studies in the use of “homogenisation” in data records.
Their inquiry’s central aim will be to establish a comprehensive view of just how far the original data has been “adjusted” by the three main surface records: those published by the Goddard Institute for Space Studies (Giss), the US National Climate Data Center and Hadcrut, that compiled by the East Anglia Climatic Research Unit (Cru), in conjunction with the UK Met Office’s Hadley Centre for Climate Prediction. All of them are run by committed believers in man-made global warming.
Since “global” temperature – by definition – is a calculated construct it is inevitable that data must be “applied” in some way to make this calculation.
But no matter what the calculation method, rewriting history is suspect. When the data of the past keeps being adjusted, and adjusted again, and always systematically downwards, and when all the adjustments invariably cool the past more than the present, then the apparent trend in global temperature has little to do with any definition of global temperature and is merely a trend of the adjustments.
The k2p blog 
