1) it is indisputable that the earth warms and cools, historical data provides the proof.
2) what causes the earth to warm and cool, seemingly at random, is not known.
3) until 1998, it is assumed that the earth reached a peak in temperature. i say assume because numerous outlets have begun to raise questions about the locations and possible cherry-picking of locations (urban because temperatures tend to be higher in urban areas than rural areas), and
lower altitude locations, for the same reasons). see also this
piece about how CRU "normalized" a temperature increase at Darwin, Australia despite actual temperature data showing no such increase in temperature.
4) arctic ice levels have been increasing since
2007, likely due to the arctic decadal oscillation
reversing itself. of note is that NASA explaining that this reversal has nothing to do with "global warming" and basically just reverses itself.
this is important- IPCC models are based on a number of assumed variables (as GGW noted, though, the assumptions all are based on man-made increases in CO2 being the main driver) that are, in fact, very highly variable and not necessarily dependent on man. A recent
report cited a decrease in water vapor as a reason for the flattening of temperatures over this decade; yet, most assumptions rely on CO2 driving an increase in water vapor.....however, CO2 levels have been increasing. what could cause water vapor levels to drop then?
all of this is to say that. . . . . .climate models should not be used as facts and should not be used to push policy. the past 10 years should be evidence of that. with each passing day, it seems, new information is learned that continues to tear down, bit by bit, the IPCC report (aside from the simply false information about the himalayan glaciers, more questions are being raised about the sources of the conclusions) and the underlying foundation about CO2.
as i stated at the outset, there is historical support for climate change- the earth routinely warms and cools, sometimes on its own, sometimes as the result of other influences. we simply do not and cannot account for the staggering number of variables and stuff we don't know about the atmosphere to really be able to make 1 determination as to why temperatures go up and why they go down.