Climate model results from IPCC 2007

See details in IPCC 2007 Chapter 2.

Variable Land Carbon Sink

b, CO2 emissions from fossil fuel combustion and cement production, and from LUC. c, Land CO2 sink (negative values correspond to land uptake). d, Ocean CO2 sink (negative values correspond to ocean uptake).

Le Quéré C, Raupach MR, Canadell JG, Marland G, others. Trends in the sources and sinks of carbon dioxide. Nature Geoscience. 2009;2(12):831–836.


"An increasing total airborne fraction implies that total sinks are increasing more slowly than total emissions, so that sinks are not keeping pace with emissions.

The CO2 growth rate also varies strongly at interannual (1 to 10 y) time scales, through mainly biophysical mechanisms. Fluctuations in CO2 growth rate correlate with the El-Nino-Southern-Oscillation (ENSO) climate mode (Keeling and Revelle, 1985; Keeling et al., 1995; Jones and Cox, 2005), because the terrestrial carbon balance in tropical regions is tilted from uptake to release of CO2 during dry, warm El-Ni ˜ no events (Zeng et al., 2005; Knorr et al., 2005).

Volcanic events are also significant: the CO2 growth rate decreased for several years after the eruption of Mt. Pinatubo in June 1991 (Jones et al., 2001), probably because of increased net carbon uptake by terrestrial ecosystems due to higher diffuse solar radiation (Gu et al., 2003) and cooler temperatures (Jones and Cox, 2001) caused by volcanic aerosols."
1. Raupach MR, Canadell JG, Le Quéré C. Anthropogenic and biophysical contributions to increasing atmospheric CO2 growth rate and airborne fraction. Biogeosciences. 2008;5(6):1601–1613.

Carbon Tracker


Fig. 1. A demonstration of how carbon flux indices [GSNF, growing season net flux; DSNF, dormant season net flux; AMP, amplitude (|DSNF – GSNF|); NCF, net carbon flux (GSNF + DSNF)] are calculated. Any month for which the net carbon flux is negative is included in the GSNF (open vertical bars). Any month for which the net carbon flux is positive is included in the DSNF (filled vertical bars). Mean 2000–2008 fluxes shown for boreal North America (a) southern Africa (b) and tropical Asia (c).

GURNEY KR, ECKELS WJ. Regional trends in terrestrial carbon exchange and their seasonal signatures. Tellus B.

Fig. 2. Comparison of decadal mean net carbon flux for individual land regions. Black cross symbols (X) denote the mean of 13 TransCom 3 models, open circle symbols (O) denote mean of the three S07 TransCom 3 models, individual model estimates within the S07 average are denoted by a filled square, circle and triangle. Vertical error bars represent the total 1σ flux uncertainty (quadrature sum of model spread and the root mean square of individual model posterior uncertainty) associated with the mean of the 13 TransCom 3 models. (c) 2000–2008 mean net carbon flux.

Coal-tar sealants contain PAH

source: "Pollution Prevention and Management Strategies for Polycyclic Aromatic Hydrocarbons in the New York/New Jersey Harbor" by the New York Academy of Sciences

An interesting debate has arisen over an emerging contaminant of concern, PolyAromatic Hydrocarbons, or PAHs. These compounds are produced whenever organic materials are heated in the absence of oxygen and water. This can occur whenever combustion is incomplete, such as smoky campfires, flickering candles, incense sticks, cigarettes, poorly functioning gasoline and diesel combustion engines, forest fires, and charcoal and tar production. PAHs form a large and diverse family of compounds, some of which are known to be potent genotoxic carcinogens.

Regulators are cracking down, but they don't know where to turn first, because these compounds are ubiquitous in modern, industrialized, civilization. Washington State and Washington DC have become two of the first areas in the US to begin taking action by banning coal-tar sealants. These sealants are typically applied to parking lots and driveways to make them black and pretty, and they also contain high levels of PAHs.

But are driveway sealants really the culprit? The coal-tar sealant industry points out that some shampoo bottles contain as much PAH as 100 acres of sealed parking lot. Indeed, a basic understanding of aromatic chemistry indicates that these compounds should be extremely water insoluble; they are most hazardous when they are volatilized in fires and the soot is inhaled. So the debate continues, with both industry, government, and citizen action groups trying to make sense of the science.

Ohio Agricultural Production

Ohio agricultural production has declined, so why hasn't fertilizer pollution?

A Mississippi River Wetland National Park?

http://www.osu.edu/news/newsitem3123

El Nino 1,000 Year Record

Dr. John Reiger, Historian at SENR

Weather Prediction: Accuracy and Skill

type weather text here

For a huge database of historical comparisons between the model predictions and observed weather:
http://www.emc.ncep.noaa.gov/mmb/mmbpll/zverif_ops/ or http://www.emc.ncep.noaa.gov/mmb/verif.php

For comparisons of the various model runs:
http://eyewall.met.psu.edu/ensembles/

Terrestrial Fertilization to Sequester CO2?

One of the main uncertainties in the global carbon cycle is measuring the amount of carbon bound up in ecosystems such as forests and grasslands. This Net Ecosystem Production (NEP) converts CO2 to plant material, detritus, and some animals. Most escapes back to the atmosphere as respired CO2, but some is sequestered in soil organic matter and trees.

Most ecosystems are Nitrogen limited because fertilization with nitrogen increases NEP. Interestingly, many ecosystems are already fertilized by Nitrogen deposition from drifting clouds of various nitrogen compounds emitted by urban areas, industry, and agriculture.

Nitrogen deposition increases productivity and decreases respiratory losses from decomposition (Hogberg). But how much? And how much is too much? Natural vegetation may be satiated/saturated with a low quantity of nitrogen, and any more would begin acidifying the soil, killing plants and washing away to pollute the watersheds.

Magnani et al attempt to answer some of these questions and measure the size of the "The human footprint in the carbon cycle of temperate and boreal forests" of Europe. They find that the amount of nitrogen deposited in European forests confers a huge increase in fertility; they find no sign of a decrease due to Nitrogen saturation.

However, their findings rested on a number of unpublished studies, and a flurry of correspondence questioned their main conclusions. De Shrivjer et al point out that just because NEP continues to increase with increasing Nitrogen deposition, this doesn't mean that the forest ecosystems aren't loosing nitrogen as runoff. Indeed, it makes sense that at very high applications of fertilizer an increasing fraction would be wasted. Many farmers have to contend with the problem that, beyond a certain point, a doubling of Nitrogen fertilizer may confer only an incremental increase in crop productivity, while vastly increasing the amount of Nitrogen that washes off.

de Vries present a more central problem in Magnani et al's results: according to Magnani's data correlation, for every unit of Nitrogen applied to European forests, 470 units of carbon are sequestered. Yet the only plant material with a C:N ratio that high is pure xylem wood, and it seems unlikely that all of the deposited nitrogen is being used to grow tree stems. Furthermore, de Vries et al find that Magnani et al failed to control for a range of other variables that could affect forest NEP. de Vries reanalyze that portion of Magnani's data that is publicly available and find a more plausible -- and vastly reduced -- C:N ratio of 20 to 40 (20-40 units carbon for every unit nitrogen).

It doesn't end there, though. Magnani et al respond that they agree with De Shrivjer, but refute de Vries. Magnani point out differences between wet and dry deposition, to argue that their stoichiometric ratio is really closer to 175-225. They claim that this ratio is not implausible, even though it is much higher than actual forest fertilization experiments (Nadelhoffer). They explain this difference by suggesting that up to 70% of the actual nitrogen deposited is absorbed by leaves, whereas the forest fertilization experiments applied nitrogen to the soil. (Nadelhoffer).

{[It is not clear to me what the consensus is on how much nitrogen can be absorbed by the canopy, or why wet versus dry deposition matters. }

News and Views: Hogberg P. Environmental science: Nitrogen impacts on forest carbon. Nature. 2007 June 14;447(7146):781-782.

Original Paper: Magnani F, Mencuccini M, Borghetti M, Berbigier P, Berninger F, Delzon S, Grelle A, Hari P, Jarvis PG, Kolari P, et al. The human footprint in the carbon cycle of temperate and boreal forests. Nature. 2007 June 14;447(7146):849-851.

Questions: De Schrijver A, Verheyen K, Mertens J, Staelens J, Wuyts K, Muys B. Nitrogen saturation and net ecosystem production. Nature. 2008 February 14;451(7180):E1.

More Questions: de Vries W, Solberg S, Dobbertin M, Sterba H, Laubhahn D, Reinds GJ, Nabuurs G-J, Gundersen P, Sutton MA. Ecologically implausible carbon response? Nature. 2008 February 14;451(7180):E1-E3.

Response:Magnani F, Mencuccini M, Borghetti M, Berninger F, Delzon S, Grelle A, Hari P, Jarvis PG, Kolari P, Kowalski AS, et al. Magnani et al. reply. Nature. 2008 February 14;451(7180):E3-E4.

More Information: Nadelhoffer, K. J. et al. Nitrogen deposition makes a minor contribution to carbon sequestration in temperate forests. Nature 398, 145–148 (1999)

Follow Up: SUTTON MA, SIMPSON D, LEVY PE, SMITH RI, REIS S, Van OIJEN M, De VRIES WIM. Uncertainties in the relationship between atmospheric nitrogen deposition and forest carbon sequestration. Global Change Biology. 2008 September 1;14(9):2057-2063.

EPA Pollution Standards

EPA Where You Live

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Point Source Discharge

Glossary of EPA terms

USDA NRCS Phosphorus Index