Salieron los Primeros resultados
Preliminares del
Berckeley surface temperature.
Para los que no están en el tema el proyecto de Berckeley pretende hacer una nueva serie de anomalías de temperatura globales
la más completa, utilizando todas las estaciones posibles en existencia unas 39,000, varias veces más que la de cualquier serie hasta el momento y pretende con esto confirmar o no lo que muchos escépticos han criticado en cuanto a que las series disponibles están sobrestimando el calentamiento actual por diferentes causas como la baja en el numero de estaciones, estaciones ubicadas en sitios inadecuados,que se han movido de lugar,estaciones afectados por isla de calor,etc....
En el equipo a cargo de este proyecto esta el conocido y
declarado
Escéptico Richard Muller y es quien lo preside.
Berkeley Earth Team
Berkeley Earth team members include:
Robert Rohde, Physicist (Lead Scientist)
Richard Muller, Professor of Physics (Chair)David Brillinger, Statistical Scientist
Judith Curry, Climatologist
Don Groom, Physicist
Robert Jacobsen, Professor of Physics
Elizabeth Muller, Project Manager
Saul Perlmutter, Professor of Physics
Arthur Rosenfeld, Professor of Physics, Former California Energy
Commissioner
Charlotte Wickham, Statistical Scientist
Jonathan Wurtele, Professor of Physics
Voy a dejar el testimonio al congreso de EEUU de sus primeros resultados preliminares,
lamentablemente no apoyan las presunciones de los escépticos.
Es un poco largo pero vale la pena..
TATEMENT TO THE COMMITTEE ON SCIENCE, SPACE AND TECHNOLOGY
OF THE UNITED STATES HOUSE OF REPRESENTATIVES
Richard A. Muller
Professor of Physics
University of California, Berkeley
Chair, Berkeley Earth Surface Temperature Project
31 March 2011Executive Summary
The Berkeley Earth Surface Temperature project was created to make the best possible
estimate of global temperature change using as complete a record of measurements as
possible and by applying novel methods for the estimation and elimination of systematic
biases. It was organized under the auspices of Novim, a non-profit public interest group.
Our approach builds on the prior work of the groups at NOAA, NASA, and in the UK
(Hadley Center – Climate Research Unit, or HadCRU).
Berkeley Earth has assembled 1.6 billion temperature measurements, and will soon make
these publicly available in a relatively easy to use format.
The difficult issues for understanding global warming are the potential biases.
These can
arise from many technical issues, including data selection, substandard temperature
station quality, urban vs rural effects, station moves, and changes in the methods and
times of measurement.
We have done an initial study of the station selection issue. Rather than pick stations
with long records (as done by the prior groups) we picked stations randomly from the
complete set. This approach eliminates station selection bias. Our results are shown in
the Figure; we see a global warming trend that is very similar to that previously reported
by the other groups.
We have also studied station quality. Many US stations have low quality rankings
according to a study led by Anthony Watts. However, we find that the warming seen in
the “poor” stations is virtually indistinguishable from that seen in the “good” stations.
We are developing statistical methods to address the other potential biases.
I suggest that Congress consider the creation of a Climate-ARPA to facilitate the study of
climate issues.
Based on the preliminary work we have done, I believe that the systematic biases that are
the cause for most concern can be adequately handled by data analysis techniques. The
world temperature data has sufficient integrity to be used to determine global temperature
trends.
Testimony of Richard A. Muller
Thank you Chairman Hall and Ranking Member Johnson for this opportunity to testify
before the Committee.
I am a Professor of Physics at UC Berkeley and Faculty Senior Scientist at the Lawrence
Berkeley Laboratory. I founded the Berkeley Earth Surface Temperature project under
the auspices of Novim, a non-profit public interest group. My testimony represents my
personal views and not those of the above organizations.
[[Italic part for written statement only, not to be read aloud]]
I’ve published papers on climate change in Science, Nature, and other refereed journals;
I am the author of a technical book on the subject.
My papers on climate change have appeared in Nature, Science, Paleoceanography, and
the Journal of Geophysical Research. I wrote a technical book on the Earth’s past
temperature changes: “Ice Ages and Astronomical Causes”, Springer 2000. I am the
author of “Physics for Future Presidents”, a popular book which describes many
misuses of data in climate. I was a cited referee on the report of the NRC on the hockey
stick controversy. For two years I wrote an online column for MIT’s Technology Review.
My major awards for scientific achievement include the Alan T. Waterman Award of the
National Science Foundation, the Texas Instruments Founders Prize, a MacArthur Prize
Fellowship, and election to the American Academy of Arts and Sciences and to the
California Academy of Sciences.
The Berkeley Earth Surface Temperature study has received a total of $623,087 in
financial support from:
The Lee and Juliet Folger Fund ($20,000)
Lawrence Berkeley National Laboratory ($188,587)
William K. Bowes, Jr. Foundation ($100,000)
Fund for Innovative Climate and Energy Research (created by Bill Gates) ($100,000)
Charles G. Koch Charitable Foundation ($150,000)
The Ann & Gordon Getty Foundation ($50,000)
We have also received funding from a number of private individuals, totaling $14,500.
For more information on Berkeley Earth, see
www.BerkeleyEarth.orgFor more information on Novim, see
www.Novim.orgI begin by talking about
Global Warming
Prior groups at NOAA, NASA, and in the UK (HadCRU) estimate about a 1.2 degree C
land temperature rise from the early 1900s to the present. This 1.2 degree rise is what we
call global warming. Their work is excellent, and the Berkeley Earth project strives to
build on it.
Human caused global warming is somewhat smaller. According to the most recent
IPCC report (2007), the human component became apparent only after 1957, and it
amounts to “most” of the 0.7 degree rise since then. Let’s assume the human-caused
warming is 0.6 degrees.
The magnitude of this temperature rise is a key scientific and public policy concern. A
0.2 degree uncertainty puts the human component between 0.4 and 0.8 degrees – a factor
of two uncertainty. Policy depends on this number. It needs to be improved.
Berkeley Earth is working to improve on the accuracy of this key number by using a
more complete set of data, and by looking at biases in a new way.
The project has already merged 1.6 billion land surface temperature measurements from
16 sources, most of them publicly available, and is putting them in a simple format to
allow easy use by scientists around the world. By using all the data and new statistical
approaches that can handle short records, and by using novel approaches to estimation
and avoidance of systematic biases, we expect to improve on the accuracy of the estimate
of the Earth’s temperature change.
I’ll now talk about potential
Bias in Data Selection
Prior groups (NOAA, NASA, HadCRU) selected for their analysis 12% to 22% of the
roughly 39,000 available stations. (The number of stations they used varied from 4,500
to a maximum of 8,500.)
They believe their station selection was unbiased. Outside groups have questioned that,
and claimed that the selection picked records with large temperature increases. Such bias
could be inadvertent, for example, a result of choosing long continuous records. (A long
record might mean a station that was once on the outskirts and is now within a city.)
To avoid such station selection bias, Berkeley Earth has developed techniques to work
with all the available stations. This requires a technique that can include short and
discontinuous records.
In an initial test, Berkeley Earth chose stations randomly from the complete set of 39,028
stations. Such a selection is free of station selection bias.
In our preliminary analysis of these stations, we found a warming trend that is shown in
the figure. It is very similar to that reported by the prior groups: a rise of about 0.7
degrees C since 1957. (Please keep in mind that the Berkeley Earth curve, in black, does
not include adjustments designed to eliminate systematic bias.)
Figure: Land average temperatures from the three major programs, compared with an
initial test of the Berkeley Earth dataset and analysis process. Approximately 2 percent
of the available sites were chosen randomly from the complete set of 39,028 sites.
TheBerkeley data are marked as preliminary because they do not include treatments for the
reduction of systematic bias.
The Berkeley Earth agreement with the prior analysis surprised us, since our preliminary
results don’t yet address many of the known biases. When they do, it is possible that the
corrections could bring our current agreement into disagreement.
Why such close agreement between our uncorrected data and their adjusted data? One
possibility is that the systematic corrections applied by the other groups are small. We
don’t yet know.
The main value of our preliminary result is that it demonstrates the Berkeley Earth ability
to use all records, including those that are short or fragmented. When we apply our
approach to the complete data collection, we will largely eliminate the station selection
bias, and significantly reduce statistical uncertainties.
Let me now address the problem of
Poor Temperature Station QualityMany temperature stations in the U.S. are located near buildings, in parking lots, or close
to heat sources.
Anthony Watts and his team has shown that most of the current stations
in the US Historical Climatology Network would be ranked “poor” by NOAA’s own
standards, with error uncertainties up to 5 degrees C.
Did such poor station quality exaggerate the estimates of global warming? We’ve
studied this issue, and our preliminary answer is no.The Berkeley Earth analysis shows that over the past 50 years the poor stations in the
U.S. network do not show greater warming than do the good stations.Thus, although poor station quality might affect absolute temperature, it does not appear
to affect trends, and for global warming estimates, the trend is what is important.Our key caveat is that our results are preliminary and have not yet been published in a
peer reviewed journal. We have begun that process of submitting a paper to the Bulletin
of the American Meteorological Society, and we are preparing several additional papers
for publication elsewhere.
NOAA has already published a similar conclusion – that station quality bias did not
affect estimates of global warming – -- based on a smaller set of stations, and Anthony
Anthony Watts and his team have a paper submitted, which is in late stage peer review,
using over 1000 stations, but it has not yet been accepted for publication and I am not at
liberty to discuss their conclusions and how they might differ.
We have looked only at
average temperature changes, and additional data needs to be studied, to look at
(for
example) changes in maximum and minimum temperatures.
In fact, in our preliminary analysis the good stations report more warming in the U.S.
than the poor stations by 0.009 ± 0.009 degrees per decade, opposite to what might be
expected, but also consistent with zero. We are currently checking these results and
performing the calculation in several different ways.
But we are consistently finding that
there is no enhancement of global warming trends due to the inclusion of the poorly
ranked US stations.Berkeley Earth hopes to complete its analysis including systematic bias avoidance in the
next few weeks.
We are now studying new approaches to reducing biases from:
1. Urban heat island effects. Some stations in cities show more rapid warming than
do stations in rural areas.
2. Time of observation bias. When the time of recording temperature is changed,
stations will typically show different mean temperatures than they did previously.
This is sometimes corrected in the processes used by existing groups. But this
cannot be done easily for remote stations or those that do not report times of
observations.
3. Station moves. If a station is relocated, this can cause a “jump” in its
temperatures. This is typically corrected in the adjustment process used by other
groups. Is the correction introducing another bias? The corrections are
sometimes done by hand, making replication difficult.
4. Change of instrumentation. When thermometer type is changed, there is often an
offset introduced, which must be corrected.
Potential Legislation
I was asked what legislation could advance our knowledge of climate change. After
some consideration, I felt that the creation of a Climate Advanced Research Project
Agency, or Climate-ARPA, could help.
Without the efforts of Anthony Watts and his team, we would have only a series of
anecdotal images of poor temperature stations, and we would not be able to evaluate the
integrity of the data.
This is a case in which scientists receiving no government funding did work crucial to
understanding climate change.
Similarly for the work done by Steve McIntyre. Their
“amateur” science is not amateur in quality; it is true science, conducted with integrity
and high standards.
Government policy needs to encourage such work. Climate-ARPA could be an
organization that provides quick funding to worthwhile projects without regard to
whether they support or challenge current understanding.
In Summary
Despite potential biases in the data, methods of analysis can be used to reduce bias effects
well enough to enable us to measure long-term Earth temperature changes. Data integrity
is adequate.
Based on our initial work at Berkeley Earth, I believe that some of the most
worrisome biases are less of a problem than I had previously thought.
3756 Respuestas
1239767 Vistas