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Carbon Cycle
Global Carbon Pools and Exchange Rates
0.001%
0.003%
0.001%
0.06%
99.9%
Net Ecosystem Exchange (NEE)
= Carbon absorbed or released by the entire ecosystem
(GPP – ecosystem respiration)
The rate of
carbon/energy
fixation: Gross
Primary
Productivity
(GPP)
The rate of ecosystem
respiration (RP+Rs)
Net Ecosystem
Exchange
This is the carbon
that stays in the
ecosystem.
Net Ecosystem Exchange (NEE)
= Carbon absorbed or released by the entire ecosystem
(GPP – ecosystem respiration)
The rate of
carbon/energy
fixation: Gross
Primary
Productivity
(GPP)
The rate of ecosystem
respiration (RP+Rs)
Net Ecosystem
Exchange
This is the carbon
that comes out of
the ecosystem.
Eddy Flux Towers
Measure the CO2 exchange rates between terrestrial
ecosystems and the atmosphere.
Eddies cells of turbulent air. They are created when a
wind blows over a rough surface.
Eddy Flux Towers
Rapid measurement of upward and downward wind speed,
together with the concentration of CO2 of the flux, allows the
calculation of net exchange of CO2.
-
+
Hundreds of Eddy flux towers worldwide are connected in a
network that aims to estimate the NEE of all terrestrial biomes.
FLUXNET
A global network of eddy flux tower sites (>500)
AMERIFLUXFLUX
Net Ecosystem Exchange at Freeman Ranch
Grassland site
Woodland site
Transition site
The Mauna Loa Observatory
The Mauna Loa observatory
has recorded CO2
concentrations in the
atmosphere since 1959.
CO2 levels have never been higher in the last 500,000 years.
Atmospheric carbon budget:
1 Petagram =
1015 g
or
1 Gigaton
Missing sink suspects:
Temperate forests of America
and Eurasia (reforestation)
Fire suppression in mid-latitude grasslands
(woody encroachment).
Anticipated effects of unchecked climate
change by 2100:

Melting of glaciers, polar caps and and sea ice.

Global sea level rise by as much as 6 m.

Redistribution of global climate zones, especially at high
latitudes)

More extreme weather: longer droughts, more violent storms
(flooding)

Massive population migrations and increases in civil war
activities.
The Kyoto Protocol
The first legally binding rules on greenhouse gas emissions were set
at the 1997 Climate Conference in Kyoto, Japan.
Highlights of the Kyoto Protocol:
Overall: global emissions reduction by at least 5% from 1990 levels by
2008-2012.
Countries have different responsibilities:
• “Annex I” countries must adopt policies that aim to reduce
greenhouse gas emissions relative to 1990 levels. Specific emissions
targets vary between countries.
• “Annex II” countries are required to provide financial resources to
help developing countries control emissions.
• “Non-Annex” countries have no obligations.
Emissions targets by
country
European
community,Bulgaria,
Czech Rep.,
Lithuania, Monaco,
Switzerland…
USA
Canada, Japan,
Hungary, Croatia…
New Zealand,
Russia, Ukraine
Australia
Iceland
Signing the treaty is not the same
as the treaty
“coming into force”.
The Kyoto Protocol came into
force when Russia ratified its
emissions goals. At that point,
emissions reductions added
up to 55% of the global
reductions goal.
ratified
In 2001, the United States withdrew support from the Kyoto Protocol.
The reasons:
1. Not enough sound science surrounding the climate change issue*.
2. Too great a strain on the economy.
3. Major flaw: developing nations not called to action.
* US scientists disagree.
Highlights, continued
Six greenhouse gases are regulated by the treaty:
CO2 (1 GWP)
Methane (24 GWP)
Nitrous oxide (170-190 GWP)
Hydroflourocarbons (4,000 – 10,000 GWP)
Perflourocarbons (6,000 – 10,000)
Sulphur hexaflouride (25,000 GWP) (GWP: Global Warming Potential)
States must have made demonstrable progress by 2005 and must submit
a report January 1, 2006.
Measures taken towards emissions targets are open: enhancing energy
efficiency, promoting renewable energy and sustainable agriculture,
reducing transport sector emissions, protecting greenhouse gas sinks.
Emissions trading among Annex I countries is allowed.
The Chicago Climate Exchange
Most can agree that the Kyoto Protocol does not go far
enough:
• Emissions reduction targets too moderate to stabilize CO2.
• The treaty expires in 2012.
The most important benefit from the Kyoto Protocol coming
into force is paving the way for the next stage:
• New target: stabilizing CO2 at 550 ppm. Requires an
emissions peak no later than 2025.
• Limiting the damage: live with a global warming of 1 to 3°C, &
a sea level rise of 0.3 to 0.8 m by 2100.
• Prevent more dangerous climate change.
Copenhagen Climate Summit, December 2010
Main results:

Keep increase in global
temperatures below 2°C

Reduce global emissions soon (no
binding dates)

Commitment to emissions targets
for 2020 but not 2050 by 1 Feb,
2010.

Prevention of deforestation

More financial support to
developing nations to implement
emissions targets
Reactions to Copenhagen:
“Low targets, goals dropped: Copenhagen ends in failure.”
(UK’s Guardian)
“Today we've made a meaningful and unprecedented
breakthrough here in Copenhagen. For the first time in history
all major economies have come together to accept their
responsibility to take action to confront the threat of climate
change.” (Barak Obama at the close of the conference)
Summary:
 Human agriculture and industrialization has impacted earth’s
energy balance, making the world warmer.
 Complex feedbacks between the atmosphere, land cover,
vegetation and the oceans tend to amplify small changes in
radiative forcing, and could cause non-linear dynamics in the
climate system.
 Warming of > 2°C would have catastrophic consequences for
human populations and biodiversity.
 Prevention of catastrophic consequences requires concerted
global action, which is difficult in a divided world.
 US political views are largely against mandatory emissions
targets, which slows progress towards stabilizing earth’s energy
balance.