Title: The Anthropocene
1The Anthropocene
- Quaternary Seminar
- Fall, 2005
- Bud J. Benneman
2Anthropocene
- Anthropocene The term refers to the most recent
period of the Earths history starting in the 18
th century when activities of the human race
first began to have a significant global impact
on ecosystems and climate. - The term Anthropocene was coined by Paul Crutzen.
3Anthropogenic Global Warming
- Describes an increase in the average temperatures
of the Earths atmospheric and oceans. - The terms global warming or anthropogenic global
warming are used to describe the theory that
increasing temperatures are the result of
strengthening greenhouse effect caused primarily
by human actions.
4Major Topics
- Ruddimans Hypothesis.
- Importance of Green House Gases.
- Explanations of pre-industrial Green
- House Gases (GHGs).
- Industrial Revolutions I and II.
- Major Greenhouse Gases.
- Population.
5 Major Topics
- Industrial Revolution III.
- Stream Flow Modification.
- The Nitrogen Cascade.
- Solar Radiation and Global Dimming.
- Melting of the Permafrost.
- The Colorado River
- Sea Surface Temperatures.
- Climate Modeling
- Paper Discussion (Joos et al., 2004)
6Ruddimans Hypothesis
- Humans discovered agriculture 12,000 years ago.
- Prior to religion, writing, and great cities
humans started alerting climate. - Ruddiman puts forth the hypothesis that through
the discovery of plant and animal domestication
the Anthropocene began 8,000 years ago.
7Ruddimans Anthropocene
- CO2 and CH4 are the two most talked about Green
House Gases. - CH4 Cycles may be linked to monsoon intensity
(greater wetland extent) and increases in CH4
concentrations in the Vostock Ice cores. They
measured monsoon maxima at 10, 80, 105, and 130
kyr BP, which corresponds to interglacial
periods.
8Important Concepts
- Temperature does not control CH4. what is
important is that temperature controlled the
aerial extent of wetlands, which releases
methane. - Earths orbital variations such as 23,000 orbital
precession. The tilt varies and changes, thus in
10,500 years the Earth will have a summer tilt
when it is closer to the sun resulting in a net
increase in solar radiation (northern
Hemisphere). -
9Percessional- Wobble Like a TopNorthern
Hemisphere v Southern Hemisphere Facing the Sun
Change in the direction of the Axis of rotation
relative to the Sun
Southern
Northern
25,800 Year Cycle
10Percessional- Wobble
11Obliquity Tilt Variation 2.4 Degree
Milder Winters Cooler Summers
Colder Winters Warmer Summers
40,000 Year Cycle
12Eccentricity
Current 365.4 day orbit around the Sun
Day of the CCSN Field Trip The Earth Was Here
Fall
Summer
Sun
Winter
100,000 Orbital variation eccentricity around the
Sun
Spring
This drawing is not to scale, its not even close
so dont worry man
13- These Earth orbital variations result in normal
climate change. - Humans through the introduction of agriculture
changes and Greenhouse Gases such as CO2 and
CH4 have resulted in a continuation of a warming
period. - According to Ruddiman, we have delayed a
glaciation.
14- Methane follows the insolation until the
Holocene. - CO2 also varies with the orbital cycles
- CO2 reaches a maximum at the height of the
interglacial - From Ice core evidence it is apparent that the
last 10,000 have been different than the last
100,000
15- There is a seemingly anomalous trend in which CO2
levels start to increase 8,000 years ago when
they should be decreasing.
16Hare
Tortoise
8000
177,800-6800
9,000-7,800
6,800-5700
gt10,000
Mediterranean Sea
9,000-7,800
10,000-9000
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19Solar Radiation
Natural CH4 Trend
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21Carbon Based Fuels
- Industrial revolution I and II has caused an
increase in CO2 - Industrial Revolution III India and China will
contribute additional CO2
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24Carbon Dioxide Variations
25Major Greenhouse Gases
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29Industrial Revolution III
- China and India are in the process of
industrializing. - The catalyst for this industrialization is
western investment, inexpensive labor, reduced
regulations, innovations in communication, and
transportation.
30World Population 2004
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33 Stream Flow Modification
- 75 of the worlds rivers have seen some kind of
stream flow modification. - Some rivers that had continuous flow now run dry
every year. - Other river systems, can no longer provide the
necessary energy to disperse sediment up and down
the coast. -
34Colorado Delta
Santa Clara Wetland
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36Mississippi Delta Spring Runoff
37Stream Flow Modifications
- Some river systems can no longer sweep the
fine-grained organic matter and mud out of their
estuaries systems. - Reservoir storage and impacts of river systems
varies according to climate. - This variation results in difficult modeling
concepts (Syvitski, 2002)
38 Stream Flow Modification
- Other rivers that were one dominated by suspended
load have become bedload-rivers through the
trapping efficiency of upstream reservoirs. - Amazon River has an increase in sediment load due
to deforestation and runoff. - Amazon soil erosion is a unique and a large
problem.
39Nitrogen Cascade
- More nitrogen is fixed synthetically and applied
as fertilizers than in all ecosystems combined
120Tg/Yr vs 90Tg (McNiell, 2004). - Of the 120 Tg/year (280,000kg), 100 Tg is wasted,
discharged into rivers, lakes and subsurface
reservoirs. - The result is eutrophication of surface waters.
40- Fossil fuel consumption adds another 25 Tg/
yr,(25,000 kg) which as NOX is highly reactive ,
causing photochemical ozone formation. - The disturbance of the Nitrogen cycle also leads
to the microbiological production of the
greenhouse gas NO. - Oceans, worldwide are releasing increased amounts
of NO (Galloway, 2002).
41Galloway, 2002
42Global Warming and Water Resources of Southern
Nevada
- Increased temperature without the influences of
melting ice equates to dryer conditions. - Warmer Dryer v. Cooler Wetter
431927 Compact
1944 Amendment
441927 1944 Allocations
Odd Years 1961-1970 Glen Canyon Reservoir Filling
45Gunnison River Tributary to Colorado River
46Colorado River Compact Site
471,138.47 ft Elevation as of 10-22-05
48Southern Nevada allocation 300,000 MAF/year, Use
475,000 due to return credits
49Climate Modeling
- Significant amount of variation with respect to
reconstructions of climate and future
projections. - Considerable amount of variables.
- Climate modeling is the best alternative for
future climate predictions. - In this case the past climates are the key to the
future.
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51Classon, 2002
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53Discussion of Paper
- Differences Between this paper and Ruddiman.
- In specific reference to upward revisions of land
use change. - Carbon emissions by anthropogenic land use
changes v. Oceanic Sediment interaction.
54Paper Discussion Continued
- Can the coral reef buildup scenario account for
CO2 buildup of 40 ppm? - Do climate forcing models account for CO2
Holocene increases, and how reliable are these
models?
55Hare
Tortoise
8000
567,800-6800
9,000-7,800
6,800-5700
gt10,000
Mediterranean Sea
9,000-7,800
10,000-9000
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58Carbon Dioxide Variations
59Response to Atmospheric CO2
Figure-1
60 Precipitation and Temperature Anomalies
Figure-2
61Changes in Land Availability for Plant Growth
Figure-3
62Simulated Changes in Terrestrial Carbon
Figure-4
63 Simulated CO2 v. Holocene Ice Core
Figure-5
64Figure-6 Contribution of CaCO3
65Figure-7 CO2 Increase By CaCO3 Compensation
66Figure-8 Reconstructed v Simulated
Reconstructed v Simulated Atmospheric CO2
67Figure-9 Simulated Delta Carbon 13
68Figure-10 LGM Holocene Changes
69Figure-11 Biome Types
70Figure-12 Biome Distribution
71End of Anthropogenic Climate Change
Punta Gaspareno Baja California, Sur. N22o4722
72Solar Radiation
- Widespread decline in solar radiation from
1960-1990. - This global decline in solar radiation referred
to as Global Dimming may have masked some of
the greenhouse effect and related impacts. - Since the late 1980s the Northern Hemisphere has
seen a widespread brightening.
73Global Brightening
- The Brightening seems to conenside with the
greenhouse signals in the late 1990s - Whereas, the decline in in solar energy could
have counterbalanced the increase in down-welling
of long-wave energy from the enhanced greenhouse
effect. - Now beginning to see the true effects of
greenhouse gases (Wild et al.,2005).
74- Time series of mean annual solar radiation
- AAll Sky conditions BClear Sky
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76Melting of the Permafrost
- Rising temperatures in permafrost regions may
release tons of carbon stored in permafrost
soils. - This will influence global climate change.
- Permafrost soils have an average carbon content
of 2.5 which, equates to 500 gigatons of carbon,
2.5 times that of all the rainforest combined.
77Permafrost Siberia
78Increasing Sea Surface Temperatures
- Important in the Caribbean and Gulf of Mexico.
- Increased incidence, and intensity of tropical
storm.
79Sea Surface Temperature
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81Melting of Ice
- Since industrialization glaciers have retreated.
- Sea level increase have impacted low lying costal
areas.
82Sea Level Increases
83Increased Incidence of Costal Flooding
84Higher Tidal Surges
85If Current Trends Continue
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87In the Year 2050 some Red States Become Blue
88Permafrost Regions
- This carbon is a relatively liable product of
plant roots that were incorporated from a
productive steppe vegetation during the
Pleistocene. - Upon thaw, microbes will begin converting the
carbon into CO2 under aerobic conditions, and
into methane under anaerobic conditions (Nisbet,
2002).