Transcript NASA Global SURFACE Temperature Record 1880

http://www.pbs.org/wgbh/warming/debate/singer.html
www.realclimate.org
CE 401
Climate Change Science and Engineering
evolution of climate
change since the industrial revolution
9 February 2012
http://solar-center.stanford.edu/sun-onearth/glob-warm.html
http://www.hillsdale.edu/news/imprimis/archive/iss
ue.asp?year=2007&month=08
http://www.skepticalscience.com/global-cooling-mid20th-century-advanced.htm
http://hockeyschtick.blogspot.co
m
/2010/09/is-sun-causing-globalwarming.html
where are we in the syllabus: latest version always on website

the global picture
Global CO2 distribution in ppm
380 parts / million
372 ppm
NASA Global Temperature Record 1880 - 2008
source: GISS, 2010
• last decade is the warmest decade on record
• increase in past 25 years is ~ 0.2°C/decade
• why the leveling off/cooling in the 50’s? – CO2 record
is very smooth – no big bumps and wiggles
NASA Global
source: GISS, 2010
SURFACE Temperature Record 1880 - 2008
surface temps are different than temps above the earth surface – where do satellites measure
huge discussions about “where” to measure temp – stratosphere shows a cooling
altitude dependent weighting functions for satellite temp sensitivity
temperature anomaly vs time 1960 – 2006 as obsv by satellite
stratosphere
mid troposphere
lower troposphere
actual surface
What are some of the problems with these graphs of
surface temperature vs time?
There are lots of problems with these graphs!! name some
• where is temperature data collected (geographic
distribution)
• how is temperature collected? (same method
everywhere?)
• what affects the reading of the thermometer?
(surroundings)
• consistency of measurement method over a period of
years
urban heat island effect
California weather stations
California surface weather stations
Robinson et al (2007): Surface temperature trends 1940-1996 from 107 measuring stations
in 49 CA counties. Trends combined for counties of similar population. The “X” show the
stations used by NASA GISS for their estimate of global surface temperatures.
original source: F. Singer, Hot Talk, Cold Science, 1997
how would you go about quantifying the urban heat island effect?
where are the urban areas?
where are the urban areas?
current locations of global thermometers
source, J Geophys Res.,2003
NOAA  2010 tied 2005 as the hottest year on record
look at other data sets
sea surface temperature 1850 - 2004
models
red = observations
source: IPCC 2007
what are potential problems with this graph?
sea level change 1880 - 2004
red: reconstructed sea level fields since 1870 (Church and White, 2006)
blue: coastal tide measurements since 1950 (Holgate/Woodworth 2004)
black: satellite altimetry (Leudiette et al, 2004)
source: IPCC 2007
Figure 5.1
Global ocean heat content
0-700m layer. shading = 90% confidence.
source: IPCC 2007
total column water vapor in %/decade monthly averages 1988 – 2004 over ocean
Snow cover and Arctic sea ice are decreasing (area vs time)
Spring snow
cover in millions
of square km
1920 - present
glaciers are retreating
Arctic sea ice
area decreased
by 2.7% per
decade
1979 - 2005
source: IPCC, 2007
Glaciers and frozen ground are receding
increased Glacier retreat
since the early 1990s
area of seasonally frozen
ground in NH has decreased
by 7% from 1901 to 2002
source: IPCC 2007
Palmer Drought Severity Index 1900 - 2002
source: IPCC, 2007
observations of measured change – IPCC 2007
detection of significant change is a statistical problem:
• finding a small signal in a sea of poorly understood noise
• the instrumental record is short --> rely on proxy measurements
• changes have obviously occurred over the past 100 years that are
not human related
• if an observed change in the record is judged unlikely to have occurred
due to natural processes --> implicates human factors (???)
• assignment of attribution to a human cause requires consideration
and elimination of all plausible non-human mechanisms
• can’t eliminate all plausible mechanisms
• cause and effect are usually approached with a series of controlled
experiments, but this cannot be done in this case
• experiment is not systematic - too many parameters are being changed at
one time
Global Mean Temperatures
Annual mean
Smoothed series
5-95 decadal error bars
11 of the past 12 years are the hottest on record
source: IPCC = Intergovernmental Panel on Climate Change, 2007
Hansen et al, 2001 – on class website now
% time during year when temps were below 10th percentile for cold nights or above
the 90th percentile for warm nights: black 1901-1950, blue 1951-1978, orange 1979-2003