Climate Skeptic presents the argument that the warming is solely in the adjustments made by various agencies.
Here are the NASA GISS numbers for US temperature over the last century or so:
The warming trend is hard to read, with current temperatures relatively elevated vs. the last 120 years but still lower than the peaks of the 1930's.
But the trick is that these are not the directly measured results.
These numbers, and in fact all numbers you will ever see in the press, are not the raw instrument measurements - they include a number of manual adjustments made by climate scientists to correct for both time of observation as well as changing quality of the measurement site itself. These numbers include adjustments both from the NOAA, which maintains the US Historical Climate Network on which the numbers are based, and from NASA's GISS. All of these numbers are guesstimates at best.
Though the GISS is notoriously secretive about revealing much about its temperature correction and aggregation methodologies...
Needless to say, this is not good scientific practice. How can your peers check and review your theories, ideas and data if you will not show how you arrived at them? But, then, we should all know by now that climate scientists are a dishonest bunch of bastards anyway.
... but the NOAA reveals theirs here. The sum total of these adjustments are shown on the following chart in purple:
There are a couple observations we can make about these adjustments. First, we can be relatively astonished that the sign on these adjustments is positive. The positive sign implies that modern temerpature measurement points are experiencing some sort of cooling bias vs. history which must be corrected with a positive add-on. It is quite hard to believe that creeping urbanization and poor site locations, as documented for example here, really net to a cooling bias rather than a warming bias (also see Steve McIntyre's recut of the Peterson urban data here).
Essentially, what the NOAA are saying is that their measuring sites are showing a relative cooling and that therefore they are applying a normalising positive bias. In basic terms, when they take a measurement from their stations, they are adding a few tenths of a degree because they think that that station is actually measuring things below what the scientists think they should be.
The trouble is that this is very hard to justify. As surfacestations.org is in the process of showing, many stations are probably recording temperatures higher than they would have done a century ago because they are now based around heat-radiating substances such as asphalt; in the case of one station, it is situated right next to the heat exchangers of an air-conditioning system.
As such, one would expect the NOAA to be applying a negative bias to the measurements, to counteract the majority of the changes to the measurement stations (mostly caused by urban sprawl).
So, what happens when we remove any bias and simply make a graph of the raw data?
The other observation we can make is that the magnitude of these adjustments are about the same size as the warming signal we are trying to measure. Backing into the raw temperature measurements by subtracting out these adjustments, we get this raw signal:
When we back out these adjustments, we see there is basically no warming signal at all. Another way of putting this is that the entirety of the warming signal in the US is coming not from actual temeprature measurements, but from adjustments of sometimes dubious quality being made by scientists back in their offices. Even if these adjustments are justifiable, and some like the time of observation adjustment are important, the fact is that the noise in the measurement is at least as large as the signal we are trying to measure, which should substantially reduce our confidence that we really know what is going on.
In other words, the entirety of the warming that we are seeing from the US surface stations is effectively made up by the scientists.
Without their positive bias, the raw data shows no significant warming trend at all. Further, if we accept that many of the measuring stations are now in "warmer areas"—i.e. they are now near roads, or heat exchangers, or are in any other way affected by the warmer air of a city or town when twenty years ago they were not—surely any bias applied should be a negative one.
In other words, in terms of the raw data, there is no real warming. If we were to apply a sensible negative bias, the US data would actually show a cooling trend.
Now, Warren Meyer admits that he is only looking at the US figures, but this is because the US is the only place in the world with long-term stations, and thus accurate figures going back for a century or more.
ut the US is the one part of the world with the best, highest quality temperature measurement system. If signal to noise ratios are low here, then how bad are they in the rest of the world? After all, we in the US do have some rural sites with 100 year temperature measurement histories.
But, the irrefutable truth is that the entire warming trend is being applied after the raw data has been taken, by scientists who have a vested interest in showing a warming trend.
So, really, should we be ploughing the amount of energy, money, time and stress into this climate change idea that we are already? And does this data justify shovelling even more money into this bottomless pit? I rather think that the answer is, "no".
But as long as there are fat, ignorant turds like Johann Hari* writing poisonous, ill-informed, doomsday-scenario lies in national newpapers, people will continue to think that it is justified.
As I keep on saying, wake up: we are being lied to.
* I saw his 2002 Edinburgh Fringe play, Going Down. It was cliched, pretentious shit acted out by humourless stereotypes.