View
219
Download
6
Tags:
Embed Size (px)
Citation preview
Brooks Range, AK
Global measurements of atmospheric gases and aerosolsAmazon Basin, 2008 -- 2009Arctic Ocean measurements, 2009 -- 2011
Steven C. Wofsyand the Science Team of theBARCA Program and the HIAPER Pole-to-Pole Observations Program
Global environmental changes—in the “natural” environment and the built environment—represent some of the most powerful forces that give rise to “extreme” or “sudden” events.
This lecture discusses changes in the chemical composition of the atmosphere – what we know about the past, and the present changes that are unfolding.
The temperature of the earth has increased by 0.8 C since 1920 http://data.giss.nasa.gov/gistemp/graphs/
The heavier temperature lines from 160,000 BP to present reflect more data points for this time period, not necessarily greater temperature variability.
Climate and Atmospheric History of the past 420,000 years from the Vostok Ice Core, Antarctica , by Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J. Delaygue G., Delmotte M. Kotlyakov V.M., Legrand M., Lipenkov V.M., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M., Nature, 3 June 1999.
Paleoclimate data from Antarctic Ice Cores
Changes in atmospheric composition: “Greenhouse gases”, CO2
Time from present 1000’s of years
CO
2 c
hang
e fr
om t
he p
rese
nt,
ppm
How are people changing the global environment?
Atmospheric methaneAt
mos
pher
ic M
etha
ne C
once
ntra
tion
(par
ts p
er b
illio
n)
500
100
0
1500
Atm
osph
eric
Met
hane
Con
cent
ratio
n
500
100
0
1500
-150,000 -100,000 -50,000 0 -4000 -3000 -2000 -1000 0 Time before present (Years) Time before present (Years)
Intergovernmental Panel on Climate Change – IPCC
Insert a news item showing that increasing numbers of the public think "Climate Change" is a hoax, or too uncertain to inform policy, etc.
Some questions about the global environment:Q1. How quickly is the earth warming, and what are the consequences ? (Not required to ask, and answer this question: perfect knowledge of how much warming might be attributed to human activities.)Q2. Is aridity (dryness; Precipitation – Evaporation) increasing in vulnerable places?Q3. What climate changes are ongoing in the Arctic; what is the response of sea level, and of “greenhouse” gases (CO2, CH4)?
Examples of recent studies of the Arctic environment
Changes in Sea Level are linked to climate through the temperature of the ocean and the stranded ice on the continents
Rate of Ice volume change:
All Greenland: -238 km3/yr
South Greenland: -164
North Greenland: -65
73.250 N
-238 km3/yr = 0.5 mm/yr sea level rise
1979
2007
The Arctic Ocean has been covered by floating ice for all human history……until
What do these changes mean for climate, forests, crops?
1. Arctic
GV launch in the rain, Anchorage, January, 2009 (HIPPO-1)
HIPPO platform: NCAR Gulfstream V "HIAPER"
41+ kft
28 kft
Flight Plan across the arctic ocean 60N to 82N, August 2011
Photos: S. Wofsy
August, 2011
UT NN GGLAT GGLON ALT m To C74520 1467 75.04469 -161.5916 653.708 -4.736278
UT NN GGLAT GGLON ALT m To C 74580 1469 75.11114 -161.5076 403.508 -3.894623
UT NN GGLAT GGLON ALT m To C74640 1473 75.17651 -161.4241 257.740 -3.14
UT NN GGLAT GGLON ALT m To C77280 1481 78.70973 -156.4544 3854.904 -25.08
Photos from 19 Aug 2011
Photos: S. Wofsy
Mist rising from very warm water 200km in the ocean
CH4 in the arctic atmosphere
GLOBAL METHANE SOURCES, Tg a-1 [IPCC, 2007]
ANIMALS80-90
LANDFILLS40-70
GAS50-70
COAL30-50RICE
30-110
TERMITES20-30
WETLANDS100-230
BIOMASSBURNING10-90
Sink: oxidation by OH (lifetime of 10 years)
CH4
HIPPO
Methane is being produced in the surface waters of the Arctic Ocean, especially where the ice pack has broken up, and we see this new emission in the atmosphere.
Slide from: E. A. Kort
Relationships between tracers with distinct sources: A tool for understanding large scale sources and sinks of GHGs.
82N 15 April 2010
CO2
78N 02 Nov. 2009
385 386 387 ppm
1880
189
0 1
900
CH
4
CH4:CO2 = .0085
Photos: by; B. C. Daube & J. V. Pittman
Summary: The Arctic
The data show:
•Dense pollution at both very high altitudes, and at low levels, in the Arctic.
•Sources of CH4 in the Arctic from from the ocean surface, significant compared to fossil fuel extraction and land surface.
•Extensive loss of floating ice in the Arctic Ocean, and melting of glacial ice on Greenland.
… and a lot more
Summary: Environmental Science and Engineering, Global Change element
What people in this field are doing:
• Making measurements in the atmosphere, in the sea, on land, and in the ecosystems of land an sea.
•Creating databases that can be accessed widely, and constructing models to simulate natural systems.
• Analyzing and modeling these observations to address questions important to science, and to society.
… and a lot more