Geoscience Reference
In-Depth Information
modelisconcerned,andmakesomethingofadog'sbreakfastoftheforecastfromthattime
on.
Alloftheaboveisbackgroundtooneofthegreatmysteriesoftheclimatechangeissue.
Virtuallyallthescientistsdirectlyinvolvedinclimatepredictionareawareoftheenormous
problems and uncertainties still associated with their product. How then is it that those of
them involved in the latest report of the Intergovernmental Panel on Climate Change (the
IPCC)canputtheirhandsontheirheartsandmaintainthereisa95percentprobabilitythat
humanemissionsofcarbondioxide(CO
2
)havecausedmostoftheglobalwarmingthathas
occurred over the last several decades?
Bear in mind that the representation of clouds in climate models (and of the water
vapourwhichisintimatelyinvolvedwithcloudformation)issuchastoamplifytheforecast
warming from increasing atmospheric CO
2
—on average over most of the models—by a
factor of about three. In other words, two-thirds of the forecast rise in temperature derives
from this particular model characteristic. Despite what the models are telling us—and
perhaps
because
itismodelsthataretellingus—noscientistclosetotheproblemandinhis
right mind, when asked the specific question, would say that he is 95 per cent sure that the
effect ofclouds is to amplify rather than to reduce the warming effect ofincreasing CO
2
.If
heisnotsurethatcloudsamplifyglobalwarming,hecannotbesurethatmostoftheglobal
warming is a result of increasing CO
2
.
Bear in mind too that no scientist close to the problem and in his right mind, when
asked the specific question, would say there is only a very small possibility (that is, less
than 5 per cent) that internal ocean behaviour could be a major cause of the warming over
the past half-century. He would be particularly careful not to make such a statement now
that there has been no significant warming over the most recent fifteen-or-so years. In the
mad scurry to find reasons for the pause, and to find reasons for an obvious failure of
the models to simulate the pause, suddenly we are hearing that perhaps the heat of global
warming is being 'hidden' in the deep ocean. In other words we are being told that some
internal oceanic fluctuation may have reduced the upward trend in global temperature. It is
thereforemorethanalittlestrangethatwearenothearingfromtheIPCC(oratanyratenot
hearing very loudly) that some natural internal fluctuation of the system may have given
rise to most of the earlier upward trend.
In the light of all this, we have at least to consider the possibility that the scientific
establishment behind the global warming issue has been drawn into the trap of seriously
overstating the climate problem—or, what is much the same thing, of seriously
understatingtheuncertaintiesassociatedwiththeclimateproblem—initsefforttopromote
thecause.Itisaparticularlynastytrapinthecontextofscience,becauseitrisksdestroying,
perhaps for centuries to come, the unique and hard-won reputation for honesty which
