2 of 2

Water vapour also stays at lower altitudes due to precipitation, and turns into clouds which have very unpredictable effects as they absorb and/or reflect most wavelengths of light: it varies with temperature (cold surfaces radiate less heat so they don't benefit from a blanket effect) and the altitude of the cloud.

Subtle errors are repeatedly adduced with the purpose of labelling people who are alarmed by the potential for human activity to seriously alter the climate as "alarmist". Frankly I wear it with pride, and will continue to do so until my worst fears are comprehensively dispelled by some *real* science proving beyond doubt that the climate is fundamentally stable.

Some of these errors were scientifically credible in decades past, like the claim that CO2-related forcing levels off logarithmically with increasing CO2 (it would, if the atmosphere were at the same pressure and temperature for its entire depth, but it isn't) and that water vapour's greater forcing somehow swallows the CO2 forcing (it doesn't swallow much of it, as absorption lines are very narrow, in fact it reinforces it by being directly proportional to temperature over most of the earth's surface).

Commentators like the Lavoisier institute, Durkin, our honourable OLO editor and our colleague Leigh here parrot these distortions, and less-credible guff about solar forcing that ignores the dramatic departure of temperatures from measured solar activity in the last quarter-century.

Worse, they then compare the 'vested interest' of IPCC salaries and publishing credits with the 'vested interest' of investment $billions in the fossil fuel industry (which is of course the accusation leveled in the other direction by environmentalists). This is backed up by pointing at somebody's nine-year-old poorly-centred graph and saying this is discredited and represents a failure of peer review ... while of course the scientific discourse has moved on, because science itself is a dialectic, not a polemic.

Engineering perspective: This is a complex beast. If it ain't broke, don't fix it. But don't push it too hard, because if you do break it I won't be able to fix it for you.