Mann: “Its (sic) hard to imagine what sort of comparison wouldn’t be deceptive.”
The e-mails are below.
On Wed, 2009-10-14 at 18:06, Michael Mann wrote:
> Hi Tom,
> thanks for the comments. well, ok. but this is the full CMIP3
> ensemble, so at least the plot is sampling the range of choices
> regarding if and how indirect effects are represented, what the cloud
> radiative feedback & sensitivity is, etc. across the modeling
> community. I’m not saying that these things necessarily cancel out
> (after all, there is an interesting and perhaps somewhat disturbing
> compensation between indirect aerosol forcing and sensitivity across
> the CMIP3 models that defies the assumption of independence), but if
> showing the full spread from CMIP3 is deceptive, its hard to imagine
> what sort of comparison wouldn’t be deceptive (your point re MAGICC
> perhaps Gavin has some further comments on this (it is his plot after
> On Oct 14, 2009, at 5:57 PM, Tom Wigley wrote:
> > Mike,
> > The Figure you sent is very deceptive. As an example, historical
> > runs with PCM look as though they match observations — but the
> > match is a fluke. PCM has no indirect aerosol forcing and a low
> > climate sensitivity — compensating errors. In my (perhaps too
> > harsh)
> > view, there have been a number of dishonest presentations of model
> > results by individual authors and by IPCC. This is why I still use
> > results from MAGICC to compare with observed temperatures. At least
> > here I can assess how sensitive matches are to sensitivity and
> > forcing assumptions/uncertainties.
> > Tom.
> > +++++++++++++++++++
> > Michael Mann wrote:
> > > thanks Tom,
> > > I’ve taken the liberty of attaching a figure that Gavin put
> > > together the other day (its an update from a similar figure he
> > > prepared for an earlier RealClimate post. see:
> > > http://www.realclimate.org/index.php/archives/2009/05/moncktonsdeliberate-
manipulation/). It is indeed worth a thousand words, and drives home
Tom’s point below. We’re planning on doing a post on this shortly, but would be
nice to see the Sep. HadCRU numbers first,
> > > mike
> > > On Oct 14, 2009, at 3:01 AM, Tom Wigley wrote:
> > > > Dear all,
> > > > At the risk of overload, here are some notes of mine on the
> > > > recent
> > > > lack of warming. I look at this in two ways. The first is to
> > > > look at
> > > > the difference between the observed and expected anthropogenic
> > > > trend relative to the pdf for unforced variability. The second
> > > > is to remove ENSO, volcanoes and TSI variations from the
> > > > observed data.
> > > > Both methods show that what we are seeing is not unusual. The
> > > > second
> > > > method leaves a significant warming over the past decade.
> > > > These sums complement Kevin’s energy work.
> > > > Kevin says … “The fact is that we can’t account for the lack
> > > > of warming at the moment and it is a travesty that we can’t”. I
> > > > do not
> > > > agree with this.
> > > > Tom.
> > > > +++++++++++++++++++++++
> > > > Kevin Trenberth wrote:
> > > > > Hi all
> > > > > Well I have my own article on where the heck is global
> > > > > warming? We are asking that here in Boulder where we have
> > > > > broken records the past two days for the coldest days on
> > > > > record. We had 4 inches of snow. The high the last 2 days
> > > > > was below 30F and the normal is 69F, and it smashed the
> > > > > previous records for these days by 10F. The low was about 18F
> > > > > and also a record low, well below the previous record low.
> > > > > This is January weather (see the Rockies baseball playoff game
> > > > > was canceled on saturday and then played last night in below
> > > > > freezing weather).
> > > > > Trenberth, K. E., 2009: An imperative for climate change
> > > > > planning: tracking Earth’s global energy. /Current Opinion in
> > > > > Environmental Sustainability/, *1*, 19-27,
> > > > > doi:10.1016/j.cosust.2009.06.001. [PDF]
> > > > >
(A PDF of the published version can be obtained from the author.)
> > > > > The fact is that we can’t account for the lack of warming at
> > > > > the moment and it is a travesty that we can’t. The CERES data
> > > > > published in the August BAMS 09 supplement on 2008 shows there
> > > > > should be even more warming: but the data are surely wrong.
> > > > > Our observing system is inadequate.
> > > > > That said there is a LOT of nonsense about the PDO. People
> > > > > like CPC are tracking PDO on a monthly basis but it is highly
> > > > > correlated with ENSO. Most of what they are seeing is the
> > > > > change in ENSO not real PDO. It surely isn’t decadal. The
> > > > > PDO is already reversing with the switch to El Nino. The PDO
> > > > > index became positive in September for first time since Sept
> > > > > 2007. see