Carbon Cycle. 0.2 Gtonne/year goes into solid earth 0.2 Gt/yr goes into atmosphere from outgassing Today 2012 approximately 10 Gt/yr are put into the.

Carbon Cycle

Carbon Cycle

0.2 Gtonne/year goes into solid earth0.2 Gt/yr goes into atmosphere from outgassing

Today 2012 approximately 10 Gt/yr are put into the atomosphere from Fossil fuel emission

Thus natural fluxes from volcanoes and outgassing account for about 2% of the anthropogenic sources.

Carbon Cycle

1.6 Gt/yr from deforestation6.4 Gt/yr from fossil fuel emission (1994)

1.6/6.4=0.25=25% (deforestation accounts for 25 % of total Carbon flux into atmosphere)

Biosphere takes up (2.6 Gt /yr more ) carbon than it did in preindustrial times.

Biosphere takes up (2.6 Gt /yr more ) carbon than it did in preindustrial times.

Preindustrial RR=120 GT/yr Now it is 122.6 Gt/yr RR=Content/lifetimePreindustrial content =597 Gt Now(1994)= 763 Gt

The atmosphere contains the least amount of carbon and sediments and rocks contain the most.

The ultimate removal of carbon from the climate system is an extremely slow process. In nature this is balanced by the slow injection of carbon into the atmosphere by volcanoes and outgassing near mid ocean ridges. When humans bring carbon in the form of fossil fuels (coal, natural gas, oil) to the surface they rapidly disrupt this balance.

The annual cycle of vegetation is dominated by flucuations in the Northern hemisphere.

Carbon Reservoirs (stocks)

Carbon Cycle

Land use changes (deforestation) contribute about 20% to the total anthropogenic emissions of carbon into the atmosphere.

Short Term Carbon Cycle

Short Term Carbon Cycle

As atmospheric CO2 increases from photosynthesis or combustion, O2 decreases.

O2 is presently decreasing faster than atmospheric CO2 is increasing. This indicates the importance of the oceans in removing CO2 from the atmosphere.

13C/12C ratios in atmospheric CO2 are lower for human activity than for natural processes.

Seasonal Cycle is driven by Northern Hemisphere Vegetation

When the atmospheric carbon dioxide increases plants are growing or decaying? Circle one. When the atmospheric carbon dioxide decreases plants are growing or decaying? Circle one.

Seasonal Cycle is driven by Northern Hemisphere Vegetation

When the atmospheric carbon dioxide increases plants are growing or decaying? Circle one.

When the atmospheric carbon dioxide decreases plants are growing or decaying? Circle one.

From www.learner.org/courses/envsci/ Unit 12

Atmospheric carbon dioxide concentrations are strongly correlated with surface temperatures on most time scales.

+sunlight

Residence Time

Residence Time

Removal Rate= outflow

Source=inflow

Constant Time

Content

Time Response

Content

lifetime

Content

TimeResident

ContentRR

Residence Time

At equilibrium (steady state) inflow = outflow

Removal Rate= outflow

Source=inflow

TimeResident

Content mEquilibriuSource

timeResidence*SourceContent mEquilibriu

A lake has an annual average outflow of 5 Mgallons per year (5,000,000 gal/yr) and an annual average content of 10 Mgallons. From this information estimate the residence time for the lake.

If the annual mean inflow into the lake increased to 20 Mgallons/yr what would be the new steady state content of the lake?

A lake has an annual average outflow of 5 Mgallons per year (5,000,000 gal/yr) and an annual average content of 10 Mgallons. From this information estimate the residence time for the lake.

If the annual mean inflow into the lake increased to 20 Mgallons/yr what would be the new steady state content of the lake?

yr2Mgal/yr 5

Mgal 10TimeResident

TimeResident

105 or

TimeResident

ContentRR

timeResidence*SourceContent StateSteady =20 Mgal/yr*2 yr=40 Mgal

CFC-12 has an atmospheric lifetime of 100 yrs. In the 1980s the emission rate of CFC-12 was 22 ppt/yr.

What is the corresponding equilibrium concentration of CFC-12?

CFC-12 has an atmospheric lifetime of 100 yrs. In the 1980s the emission rate of CFC-12 was 22 ppt/yr.

What is the corresponding equilibrium concentration of CFC-12?

timeResidence*SourceContent StateSteady =22 ppt/yr*100yr=2200 ppt

Note: the highest CFC -12 concentration level reached was 540 ppt. International agreements to phase out production and use of CFC-12 ( reduce emissions) were able to keep levels down.

CFC-12 has an atmospheric lifetime of 100 yrs. In the 1980s the emission rate of CFC-12 was 22 ppt/yr.

What emission rate (source) would limit the steady state atmospheric concentration of CFC-12 to 500 ppt?

CFC-12 has an atmospheric lifetime of 100 yrs. In the 1980s the emission rate of CFC-12 was 22 ppt/yr.

What emission rate (source) would limit the steady state atmospheric concentration of CFC-12 to 500 ppt?

ppt/yr 5 yr 100

ppt 500

timeResidence

ionConcentrat StateSteady sourceEmission

or

timeResidence*SourceContent StateSteady

=22 ppt/yr*100yr=2200 ppt

This is less than 25% of the 1980s emission rate.

The solubility of water increases with decreasing temperature.

Positive climate feedback

Phytoplankton shell: Diatom (SiO2)

Phytoplankton Shell: coccolithophorid (CaCO3

Zooplankton shell: Foraminifer (CaCO3)

Zooplankton shell: Radiolarian SiO2

More Ice on continents leaves more 18O in oceans

Carbon Cycle

Total flux from land use changes 1.6 (1.6/8) =20 % of the total flux from both Fossil Fuel and land use change (1.6+6.4=8.0)

Ocean Biological Pump. Slowly taking Carbon to the seafloor for ultimate burial. Most of this carbon is recycled back to the surface a very small fraction is removed from the ocean into the deep earth.

Coastal Zone Color scanner

http://earthobservatory.nasa.gov/IOTD/view.php?id=1297

Porosity: the fraction of rock that is pore spacePermeability: the ability of a fluid to be able to flow through a rock formation.Gas, oil, and water are often trapped in porous rock with an impermeable cap. Gas on top, then oil, then water

water

pH 7.0 is neutral (not acidic not alkaline) less than 7.0 is acidic greater than 7.0 is alkaline. pH of 2.0 is highly acidic.

Long term Carbon Cycle

Draw a causal loop diagramDescribing the feedback structure at left. Is this a positive or negative feedback structure?

All loops are negative feedbacks

Weather of carbonate rock does not change atmospheric CO2 levels

Weather of silicate rock removes CO2 from the atmosphere

From www.learner.org/courses/envsci/ Unit 1

Outgassing is the release of CO2 via volcanic activity and seafloor spreading. Over the long term (millions of years) the CO2 flux from outgassing is in near balance with the removal of carbon from the subduction of carbonate sediments.

Small fragmented rocks have much more surface area compared to large rocks and hence weather more easily.

80 % of chemically weathered ions in Amazon come from the Andes.

The Andes have been uplifted in the past 20 Million years.

Most uplift in the western US region occurred 70 to 45 Myr ago

Biomass growth (Lichen) on rocks can enhance the weathering process.

http://en.wikipedia.org/wiki/File:Hubbert_peak_oil_plot.svg