Carbon Cycle

Global Carbon Pools and Exchange Rates

0.001%0.003%

0.06%

0.001%

99.9%

Net Ecosystem Exchange (NEE)

= Carbon absorbed or released by the entire ecosystem(GPP – ecosystem respiration)

The rate of ecosystem respiration (RP+Rs)

The rate of carbon/energy fixation: Gross

Primary Productivity

(GPP) Net Ecosystem Exchange

This is the carbon that stays in the

ecosystem.

The rate of ecosystem respiration (RP+Rs)

The rate of carbon/energy fixation: Gross

Primary Productivity

(GPP) Net Ecosystem Exchange

This is the carbon that comes out of the ecosystem.

Net Ecosystem Exchange (NEE)

= Carbon absorbed or released by the entire ecosystem(GPP – ecosystem respiration)

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.

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.

Eddy Flux Towers

- +

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 gor1 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

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

Signing the treaty is not the same as the treaty

“coming into force”.

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.