ce 401 climate change science and engineering evolution of climate
DESCRIPTION
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-on-earth/glob-warm.html. - PowerPoint PPT PresentationTRANSCRIPT
CE 401Climate Change Science and Engineering
evolution of climatechange since the industrial revolution
9 February 2012
http://www.skepticalscience.com/global-cooling-mid-20th-century-advanced.htm
http://www.hillsdale.edu/news/imprimis/archive/issue.asp?year=2007&month=08
www.realclimate.org
http://solar-center.stanford.edu/sun-on-earth/glob-warm.html
http://hockeyschtick.blogspot.com/2010/09/is-sun-causing-global-warming.html
http://www.pbs.org/wgbh/warming/debate/singer.html
where are we in the syllabus: latest version always on website
POSTER PROJECT DUE
2/23/2012 (2 WEEKS)
TERM PAPER/ORAL PRESENTATIONTOPIC DUE2/21/2012 – LESS THAN 2 WEEKS
sample topics from other classes:• carbon sequestration from power plants• biofuel impacts on CO2 emissions• aerosols and climate change• wind energy as a renewable resource• solar voltaic cells• sustainable options and climate change
the global picture since the industrial revolution
Global COGlobal CO2 2 distribution in ppmdistribution in ppm
380 parts / million380 parts / million
372 ppm372 ppm
• 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 Temperature Record 1880 - 2008
source: GISS, 2010
NASA Global SURFACE Temperature Record 1880 - 2008
source: GISS, 2010
surface temps are different than temps above the earth surface- how good is the surface record – where do satellites measure
huge discussions about “where” to measure temp e.g. stratosphere shows cooling
altitude dependent weighting functions for satellite temp sensitivity
NOAA satellites measure temperature from space, but not at the surface
stratosphere
mid troposphere
lower troposphere
actual surface
temperature anomaly vs time 1960 – 2006 as obsv by satellite
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 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
California weather stations
how would you go about quantifying the urban heat island effect?
e.g. where are the urban areas?
satellite picture of lights at night
source, J Geophys Res.,2003
current locations of global thermometers
NOAA 2010 tied 2005 as the hottest year on record
UK Met office: 2011 11th hottest year on record; data confirms the overall warming trend since 1860.Of the 10 warmest years on record, nine occurred since 2000. Each successive decade since 1950 has been warmer than the last.
look at other data sets
sea surface temperature 1850 - 2004
source: IPCC 2007 what are potential problems with this graph?
red = observations
models
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)
sea level change 1880 - 2004
source: IPCC 2007
Figure 5.1
0-700m layer. shading = 90% confidence.
Global ocean heat content
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 km1920 - present
Arctic sea ice area decreased by 2.7% per decade
1979 - 2005
source: IPCC, 2007
glaciers are retreating
Glaciers and frozen ground are receding
area of seasonally frozen ground in NH has decreasedby 7% from 1901 to 2002
increased Glacier retreat since the early 1990s
source: IPCC 2007
Palmer Drought Severity Index 1900 - 2002
source: IPCC, 2007
% time during year when temps were below 10th percentile for cold nights or abovethe 90th percentile for warm nights: black 1901-1950, blue 1951-1978, orange 1979-2003
observations of measured change – IPCC 2007
how is climate warming detected
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 considerationand 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 meanSmoothed series5-95 decadal error bars
source: IPCC = source: IPCC = Intergovernmental Panel on Climate Change, 2007Intergovernmental Panel on Climate Change, 2007
11 of the past 12 years are the hottest on record
Hansen et al, 2001