i voted for the 4th one:

the man made global warming movement is a political movement where there is trillions of UK pounds at stake. there is big money at stake, and they are going to see to it that all the evidence is on their side....using any and all underhanded means possible.
the michael mann graph is an example. its is a poltical graph designed to give the impression to the layman that man is causing warming, and it is taken by the IPCC as being definitive. yet there are some very suspicious facts about it:

a) he refuses to publish the source of his data. i wonder why
b) the little ice age and the medieval warm period strangely disappeared from the graph, even though they have been scientifically proven to be global in extent.
c) when random data is fed into the algorithm used to produce the michael man graph, it also produces the hockey stick shape. again, i wonder why

the truth is, we are only just coming out of the little ice age, and thats why the little ice age had to "disappear" from the graph. the mediavel warm period had to disappear because it shows that temperatures rose at a faster rate and achieved a warmer period that now without any fossil fuel burning.