[Vision2020] Goddard Institute for Space Studies: July 2010 Global Temp., Paper in Review "Global Surface Temperature Change"

[Ted Moffett]

Graphs are omitted from the content pasted in below, from the following GISS
release, which as far as I have been able to determine just went up on the
GISS website today.

Note that calendar year 2010, according to GISS, from January-July, is the
warmest since 1880, but that July 2010 was tied for third warmest July.  The
cooling effect of La Nina could lower the full 12 month calendar year 2010
average global temperate far enough that 2010 will not set a new calendar
year global average temperature record, though a new record high *12 month
running mean global average temperature* was already set during 2010,
according to the analysis presented in a scientific paper, from GISS
scientists, now in peer review (read here for summery:
http://data.giss.nasa.gov/gistemp/paper/gistemp2010_summary.pdf ; full paper
here: http://data.giss.nasa.gov/gistemp/paper/gistemp2010_draft0803.pdf ).
Note the effort in this scientific paper, due to the peer review critique,
discussed below, to fully quantify the urban effect in temperature analysis:

http://data.giss.nasa.gov/gistemp/2010july/

>From website above:
 GISS Surface Temperature Analysis July 2010 — What Global Warming Looks
Like

The July 2010 global map of surface temperature anomalies (Figure 1),
relative to the average July in the 1951-1980 period of climatology,
provides a useful picture of current climate. It was more than 5°C (about
10°F) warmer than climatology in the eastern European region including
Moscow. There was an area in eastern Asia that was similarly unusually hot.
The eastern part of the United States was unusually warm, although not to
the degree of the hot spots in Eurasia.

There were also substantial areas cooler than climatology, including a
region in central Asia and the southern part of South America. The emerging
La Niña is now moderately strong, as evidenced by the region cooler than
climatology along the equator in the eastern and central Pacific Ocean.

The global average July 2010 temperature was 0.55°C warmer than climatology
in the GISS analysis, which puts 2010 in practically a three way tie for
third warmest July. July 1998 was the warmest in the GISS analysis, at
0.68°C.

The 12-month running mean of global temperature (Figure 2) achieved a record
high level during the past few months. Because the current La Niña will
continue at least several months, and likely strengthen somewhat, the
12-month running mean temperature is expected to decline during the second
half of 2010.

Will calendar year 2010 be the warmest in the period of instrumental data?
Figure 3 shows that through the first seven months 2010 is warmer than prior
warm years. The difference of +0.08°C compared with 2005, the prior warmest
year, is large enough that 2010 is likely, but not certain, to be the
warmest year in the GISS record. However, because of the cooling effect of
La Niña in the remainder of the year, there is a strong possibility that the
2005 and 2010 global temperatures will be sufficiently close that they will
be practically indistinguishable.

Climate anomalies in the Northern Hemisphere summer of 2010, including the
heat in Eastern Europe and unusually heavy rainfall and floods in several
regions, have received much attention. Are these climate anomalies an
example of what we can expect global warming to look like? Maps of
temperature anomalies, such as Figure 1, are useful for helping people
understand the role of global warming in extreme events.

The location of extreme events in any particular month depends on specific
weather patterns, which are unpredictable except on short time scales. The
weather patterns next summer will be different than this year. It could be a
cooler than average summer in Moscow in 2011.

But note in Figure 1, and similar maps for other months, that the area
warmer than climatology already (with global warming of 0.55°C relative to
1951-1980) is noticeably larger than the area cooler than climatology. Also
the magnitude of warm anomalies now usually exceeds the magnitude of cool
anomalies.

What we can say is that global warming has an effect on the probability and
intensity of extreme events. This is true for precipitation as well as
temperature, because the amount of water vapor that the air carries is a
strong function of temperature. So the frequency of extremely heavy rain and
floods increases as global warming increases. But at times and places of
drought, global warming can increase the extremity of temperature and
associated events such as forest fires.

The paper describing the GISS analysis of global temperature has been
revised in response to reviewer suggestions and submitted to Reviews of
Geophysics. The biggest change in the paper is inclusion of an additional
analysis is which global temperature change is based only on stations
located in "pitch dark" regions, i.e., regions with satellite-observed
brightness below the satellite's detection limit (1 μW/m2/sr/μm). Our
standard analysis uses stations with satellite-observed brightness below 32
μW/m2/sr/μm. This more strict brightness limitation has no significant
effect on analyzed global temperature change, providing additional
confirmation that any urban effect on the GISS analysis of global
temperature change is small.

The summary section of the revised paper is available
here<http://data.giss.nasa.gov/gistemp/paper/gistemp2010_summary.pdf>and
the entire paper
here <http://data.giss.nasa.gov/gistemp/paper/gistemp2010_draft0803.pdf>.

A copy of this webpage text is also available as a PDF
document<http://data.giss.nasa.gov/gistemp/2010july/WhatGlobalWarmingLooksLike.pdf>
.
Reference

Hansen, R., R. Ruedy, M. Sato, and K. Lo, 2010: Global surface temperature
change <http://data.giss.nasa.gov/gistemp/paper/gistemp2010_draft0803.pdf>,
Rev.
Geophys., submitted. (PDF)
Contacts

Please address media inquiries regarding the GISS surface temperature
analysis to Ms. Leslie McCarthy by e-mail at Leslie.M.McCarthy at nasa.gov or
by phone at 212-678-5507.

Scientific inquiries about the analysis may be directed to Dr. James E.
Hansen <http://www.giss.nasa.gov/staff/jhansen.html>.
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Vision2020 Post: Ted Moffett
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