The figures reveal that from the beginning of 1997 until
August 2012 there was no discernible rise in aggregate global
This means that the ‘pause’
in global warming has now lasted for about the same time as the
previous period when temperatures rose, 1980 to 1996
The regular data collected on global
temperature is called Hadcrut 4, as it is jointly issued by the Met
Office’s Hadley Centre and Prof Jones’s Climatic Research Unit.
The new data, compiled from more than
3,000 measuring points on land and sea, was issued quietly on the
internet, without any media fanfare, and, until today, it has not been
reported. This stands
in sharp contrast to the release of the previous figures six months
ago, which went only to the end of 2010 – a very warm year. Ending
the data then means it is possible to show a slight warming trend since
1997, but 2011 and the first eight months of 2012 were much cooler, and
thus this trend is erased.
Some climate scientists, such as
Professor Phil Jones, director of the Climatic Research Unit at the
University of East Anglia, last week dismissed the significance of the
plateau, saying that 15 or 16 years is too short a period from which to
disagreed. Professor Judith Curry, who is the head of the climate
science department at America’s prestigious Georgia Tech university,
told The Mail on Sunday that it was clear that the computer models used
to predict future warming were ‘deeply flawed’. Even
Prof Jones admitted that he and his colleagues did not understand the
impact of ‘natural variability’ – factors such as long-term ocean
temperature cycles and changes in the output of the sun.
Here are three not-so trivial
questions you probably won’t find in your next pub quiz. First, how much
warmer has the world become since a) 1880 and b) the beginning of
1997? And what has this got to do with your ever-increasing energy bill?
may find the answers to the first two surprising. Since 1880, when
reliable temperature records began to be kept across most of the globe,
the world has warmed by about 0.75 degrees Celsius. From
the start of 1997 until August 2012, however, figures released last
week show the answer is zero: the trend, derived from the aggregate data
collected from more than 3,000 worldwide measuring points, has been
There has been a response from the UK Met Office (Link)
Q.1 “First, please confirm that they do indeed reveal no warming trend since 1997.”
The linear trend from August 1997 (in the middle of an exceptionally
strong El Nino) to August 2012 (coming at the tail end of a double-dip
La Nina) is about 0.03°C/decade, amounting to a temperature increase of
0.05°C over that period...
Q.2 “Second, tell me what this says about the models used by the
IPCC and others which have predicted a rise of 0.2 degrees celsius per
decade for the 21st century. I accept that there will always be periods
when a rising gradient may be interrupted. But this flat period has now
gone on for about the same time as the 1980 – 1996 warming.”
The models exhibit large variations in the rate of warming from year
to year and over a decade, owing to climate variations such as ENSO, the
Atlantic Multi-Decadal Oscillation and Pacific Decadal Oscillation.
Definitely Non Gorgon Judith Curry.
Dr Judith Curry wrote to David Rose (the author of the Daily Mail article): (link)
The data confirms the existence of a ‘pause’ in the warming. The
impact of this pause within the climate dynamic community has been to
focus increased attention on the impact of natural variability,
particularly the impact of internal multi-decadal oscillations in the
ocean. The new climate model calculations for the AR5 have focused on
trying to assess what it would take to accurately simulate these
multi-decadal ocean oscillations and how predictable they might be.
These new observations and climate modeling results will hopefully
impact the the IPCC AR5 deliberations so that we do not see the same
overly confident consensus statements that we saw in the AR4.
Meanwhile, Ex IPCC expert (and 0.0001 Nobel Laureate) John Christy has written recently:David
The recent claims that July 2012 and Jan-Jul 2012 were the hottest
ever in the conterminous US (USA48) are based on one specific way to
look at the US temperature data. NOAA, who made the announcement,
utilized the mean temperature or TMean (i.e. (TMax + TMin)/2) taken from
station records after adjustments for a variety of discontinuities were
applied. In other words, the average of the daily high and daily low
temperatures is the metric of choice for these kinds of announcements.
Unfortunately, TMean is akin to averaging apples and oranges to come up with a rather uninformative fruit.
Finally, a misinformed person has written:
It is very easy to pick one’s own start and stop dates to show that
there has been no warming, that there has been cooling or that the
warming is twice as fast.
David Whitehouse of the Global Warming Policy Foundation addresses this : (Link)
Finally, it has been said that the 16-year standstill observed in the
Hadcrut4 data since 1997 has been cherry-picked with its start and end
dates. This is not so, the period is simply the answer to the question
how far back does one have to go to see significant warming taking the
errors into account. In fact, start and end dates are irrelevant, only
its duration is important, not where it occurs in the dataset.