III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
RESERVOIRS:
Most atmospheric carbon
has been transferred to the
hydrosphere (dissolved CO2)
and lithosphere (limestone
and fossil deposits).
Dead and dissolved organic
matter are other large
reservoirs
The atmosphere and
biosphere have some, too.
reservoirs in gigatons and
exchanges in GT/year
FLUXES:
Flux between hydro and
atmo is still a major
exchange
reservoirs in gigatons and
exchanges in GT/year
FLUXES:
Photosynthesis balances
respiration
Volcanism balances by
sedimentation and
deposition
Net transfer to
atmosphere is by burning
of fossil fuels (7 GT) and
reduction of
photosynthesis by
forests from
deforestation (1 GT)
reservoirs in gigatons and
exchanges in GT/year
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
Decrease due to terrestrial plant
evolution and Carboniferous storage
- last 160,000 years (ice cores)
401
280
- Since 1000: up 43% (all since 1830 – industrial revolution)
- Since 1955: 318 to 401 (April 21, 2014) – 26%
- Ocean absorption and acidification
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
3. Consequences – Global warming
- August 2014 – warmest August on Record (since1888)
- September 2014 – warmest September on record
2. Since 1860 – increase of 0.8oC – ten hottest years all since 1991
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
3. Consequences – Global warming
4. Correlates
-Reductions in Polar Ice
(area covered)
1979
Nasa.gov
2003
Summer 2012 – Record low summer sea ice
-Reductions in Polar Ice
(thickness)
- deep sea ice depth decreased
from mean of 3.1 meters in 1958
to mean of 1.8 m in 1997
Nasa.gov
- Reductions in polar ice
- Reductions in glacial ice
B-15 is the size of Connecticutt (2000)
- Icebergs calving off Ross Shelf – April 2000
(B15 is 4,280 miles2 – about the size of CONNECTICUT….)
- Reductions in polar ice
- Reductions in glacial ice
- Reductions in polar ice
- Reductions in glacial ice
- Sea level rise
- Increases in Sea Level
-
Reductions in polar ice
Reductions in glacial ice
Sea level rise
Melting of Permafrost
14% of the world’s organic
carbon is stored in permafrost.
As the poles warm (and they
are warming faster than
anywhere else), this carbon
may be mobilized as
decomposing bacteria gear
up….
This is a type of threshold
response (not a gradual
response), and would involve
positive feedback loops…
- More big storms: March 24, 2004 –
Atlantic Cyclone off Brazil.
- More big storms: March 24, 2004 – Atlantic Cyclone off Brazil.
(earthobservatory.nasa.gov)
“The South Atlantic is generally not thought of by meteorologists as a place where tropical
cyclones can form. The water temperatures are generally too cool and the vertical wind
shear too strong. The area is so devoid of tropical storm activity that no government
agency has an official warning system for storms there, which is why this storm is
unnamed.”
- More big storms
“Natural disasters caused by extreme weather claimed seven times as many victims in
2003 as in the previous year and the trend is set to continue, says the world's biggest
reinsurance company. (They insure insurance companies.) Munich Re said global
warming would cause increasing economic damage in the future. "It is to be feared that
extreme events which can be traced to climate change will have increasingly grave
consequences in the future," the report said, adding that insurance premiums would rise
and that clear-cut indemnity limits would be needed.”
– Reuters New Service, Feb 27, 2004
1900-2010
-
Reductions in polar ice
Reductions in glacial ice
Sea level rise
Melting of Permafrost
Stronger Storms
Effects on the Biosphere
- Changes in Plant Growth:
Qualitative Effects:
Laurance et al. (March 2004, Nature):
- Pristine rainforests have changed composition in last 20 years, with
an increase in fast-growing species and a decrease in slow growing
species… probably as a result of increased CO2 availability.
-
Reductions in polar ice
Reductions in glacial ice
Sea level rise
Melting of Permafrost
Stronger Storms
Effects on the Biosphere
-Changes in Reef Communities:
“Almost 15% of the world's reefs are already beyond repair thanks to
global warming. Another 30% may be lost over the next 30 years.”
– (Nature, February 2004)
- Reefs are home to 25% of all marine species
- Reefs are nursery areas for the larvae and fry of commercially important
fish and crustacean species
- Reefs are important storm breaks for tropical coasts
-Changes in Reef Communities:
-
Reductions in polar ice
Reductions in glacial ice
Sea level rise
Melting of Permafrost
Stronger Storms
Effects on the Biosphere
- Changes in Species Diversity
15-37% of terrestrial species may go extinct in
the next 50 years, largely because of global warming. (Thomas et al.
2004)
-
Reductions in polar ice
Reductions in glacial ice
Sea level rise
Melting of Permafrost
Stronger Storms
Effects on the Biosphere
- Increases in Human Diseases:
UN Environmental Programme Report, Feb 21, 2005:
- Environmental change may be the cause of the resurgence of some
infectious diseases.
- The fatal Nipah virus, normally found in Asian fruit bats, is believed
to have crossed over to humans as the bats lost their habitats
through forest fires in Sumatra and the clearance of land for palm
plantations.
- Dengue fever, which was present in only nine countries in the
1970s, is now found in more than 100, most likely the result of
increasing urban populations.
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
3. Consequences – Global warming
4. Correlates
5. Perspectives
5. Perspectives
- Canadian Environment Minister David Anderson said that global warming posed a
greater long-term threat to humanity than terrorism because it could force hundreds of
millions from their homes and trigger an economic catastrophe. – March 2004
World bank: “global warming requires immediate action” (2003)
- commissioned an independent panel to investigate options.
- Recommendation: “The WBG [World Bank Group] should aggressively increase
investments in renewable energies by about 20 percent annually. WBG lending should
concentrate on promoting the transition to renewable energy..."
- The World Bank rejected the recommendation. 2004 energy lending dedicates 6% to
renewables, 94% percent to oil.
In FY 2013, the Bank provided nearly US$7 billion in energy lending, including US$2.7
billion in fossil fuels (39%), US$1.7 billion in clean energy (24%), and US$2.6 billion (38%)
in “other” energy projects, such as large hydropower or transmission projects.
5. Perspectives
“We need an energy bill that encourages consumption.”
-President G. W. Bush, Sept. 23, 2002, Trenton, NJ
The Pentagon Report (2004): global warming “should be elevated beyond a scientific
debate to a US national security concern.” It declares that “future wars will be fought over
the issue of survival rather than religion, ideology or national honour.” – Fortune magazine
– March 2004.
Senator James Inhofe, OK-R, who will be the Chairman of the Senate Committee on
Environment and Public Works in 2015:
Inhofe’s top ten climate (mis)-statements
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
3. Consequences – Global warming
4. Correlates
5. Perspectives
6. Methane
6. Methane
“Globally, over 60% of total CH4 emissions come
from human activities… Pound for pound, the
comparative impact of CH4 on climate change is
over 20 times greater than CO2 over a 100-year
period.” (EPA)
Livestock
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
1. OVERVIEW
2. Change in CO2
3. Consequences – Global warming
4. Correlates
5. Perspectives
6. Methane
7. IPCC – 2013-14 report
“It is extremely likely that human influence on climate caused
more than half of the observed increase in global average surface
temperature from 1951 to 2010. There is high confidence that
this has warmed the ocean, melted snow and ice, raised global
mean sea level and changed some climate extremes in the second
half of the 20th century.”
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
D. The Nitrogen Cycle
ULTIMATE RESERVOIR:
Atmosphere – N2 = 78% by
volume, 75% by weight, of dry
air.
3900 GT
FLUXES:
Atmospheric nitrogen is “fixed” by bacteria on land and in marine/aquatic systems; the
N atoms are separated and H bonds, creating Ammonium ions (NH4+).
FLUXES:
Atmospheric nitrogen is “fixed” by bacteria on land and in marine/aquatic systems; the
N atoms are separated and H bonds, creating Ammonium ions (NH4+).
Ammonium can be converted to Nitrite (NO2) and Nitrate (NO3) by nitrification; also a
process only performed by certain bacteria in terrestrial and marine environments.
FLUXES:
Both ammonium and NO3 are absorbed by bacteria and plant roots, and assimilated
into organic molecules.
A lot of the nitrogen is taken up by bacteria,
outcompeting plant roots. Perhaps this
favored plants incorporating nitrogen fixing
bacteria, to escape this competition with
soil bacteria.
FLUXES:
Both ammonium and NO3 are absorbed by bacteria and plant roots, and assimilated
into organic molecules.
When proteins/DNA are metabolized, excess nitrogen is released as waste (NH3). This
is ammonification.
FLUXES:
When proteins/DNA are metabolized, excess nitrogen is released as waste (NH3). This
is ammonification.
Again, nitrifying bacteria convert this to nitrites and nitrates.
FLUXES:
Again, nitrifying bacteria convert this to nitrites and nitrates.
Besides assimilation, NO2 can be denitrified by bacteria and released an N2. This
happens under anaerobic conditions, and starves soils of N.
Fixation is balanced by
denitrification on land.
Fixation requires energy, supplied to
Rhizobium by plant symbionts as
glucose.
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
D. The Nitrogen Cycle
Effects of Life
- Fundamental for nearly
every transformation
3900 GT
III. BIOGEOCHEMICAL CYCLES
A. Overview
B. The Water Cycle
C. The Carbon Cycle
D. The Nitrogen Cycle
Effects of Life
- Fundamental for nearly
every transformation
Effects of Humans:
- We produce nitrogen
fertilizer, and produce NOx
compounds in internal
combustion engines.
NEARLY EQUAL TO THE AMOUNT FIXED NATURALLY
3900 GT
“Fertilizing” the oceans results in a burst of production, then aerobic decomposers
explode as they decomose all this new biomass…resulting in dramatic declines in oxygen,
which is not replenished quickly by diffusion – especially at depth. This results in the
death of other aerobic organisms, and “dead zones”