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Forest fires may produce as much CO2 as half of all fossil fuels burned

Posted By Joanne Nova On July 7, 2015 @ 3:27 pm In Global Warming | Comments Disabled

Globally, fires have been overlooked as a key player in the global CO2 cycle. Tom Quirk has dug up some studies showing that CO2 emissions from fires can be as high as half of the total emissions from human fossil fuel use.

Smoke from fires over Indonesia, and Borneo, Satellite, NASA, 1997

“In October and November 1997, the haze from fires in Indonesia spread as far the Philippines to the north, Sri Lanka to the west, and northern Australia to the south. In the Malaysian state of Sarawak on Borneo, there was a pollution index reading of 860.” | Annette Gartland

Peat deposits can be an extraordinary 20 metres thick. In 1997, a fire consumed 8,000 square kilometers of mostly peatland in Borneo. Researchers estimated 0.2 Gt of carbon were released in this one area that year, and that carbon emissions from fires across Indonesia in 1997 emitted between 0.8 and 2.5 Gt — or “13 to 40%” of the size of global human fossil fuel emissions.[1] Obviously uncertainties are large, but so are the numbers. It all makes the idea of a “carbon market” pretty meaningless: the largest players in this market can’t play and don’t pay. In carbon accounting, fires are “an act of God” (non-anthropogenic), and are considered neutral because the trees will grow back. But humans play a role in fire management and the regrowth…

Other researchers, der Werf et al 2004, looked at fires around the world during the El Nino year and estimated that 2.1 Gt of carbon was released — which explained 66% ± 24% of the extra CO2 emitted globally that year.[2] Bowman et al estimate fires produced emissions around 50% of the size of human emissions.[3] Murry Salby argues that ocean temperatures drive CO2 levels and the warmth of the El Nino in 1997 released more CO2, but here a lot of the extra CO2 released that year looks like it comes from fires.

To put all this in perspective, total human emissions of carbon in a year is about 8 to 10 Gt. Australian emissions are a mere 100 mt*. Indonesia’s are 150 mt, while China’s are 2.5 Gt and increasing by 100mt each year. China is adding emissions equivalent to the entire Australian output each year. India puts out 500 mt, increasing by 50 mt each year. Shaving a mere 5% of the Australian output which is a mere 1.16% of the total output, seems as futile as it gets. How much should we pay?

— Jo

We didn’t start the fire   (with thanks to Billy Joel)

The southern hemisphere is the innocent hemisphere in the rise in atmospheric CO2.

Map, Global fires, pyrogeography on Earth

This statement can be seen by looking at the estimates of fossil fuel emissions from the Carbon Dioxide Information Analysis Center (CDIAC), an agency of the US government.

Fossil Fuel emissions, graph, latitiude

For the year 2010 CDIAC estimates 8,900 million tonnes of carbon (Mt C) in CO2 was produced world wide. Only 406 Mt C was produced in the Southern Hemisphere below a latitude of 120S. This is only 4.7% of the total global emissions.

carbon emissions in the Southern Hemisphere, graph, longitude

These emissions are spread across three continents with Australia being the smallest continental contributor. So to put this in perspective, the annual increase of fossil fuel emissions from China is equal to Australia’s total annual emissions while the annual increase from Indian fossil fuel emissions is half of Australia’s total emissions.

Continent

Fossil fuel emissions Mt C

% of global total

South Africa

138.0

1.60%

Australia

100.4

1.16%

New Zealand

    8.7

0.10%

South America

159.0

1.84%

Total

406.1

4.71%

It is worth noting that during the 1997-98 El Nino, forest and peat fires in Borneo were estimated to contribute 240 to 280 Mt C in CO2 to the atmosphere. When extended to Indonesia as a whole, the estimate was 819 to 2,370 Mt C in CO2 from fires.

The Bowman review 2009:

Currently, all sources of fire (landscape and biomass) cause CO2 emissions equal to 50% of those stemming from fossil-fuel combustion (2 to 4 Pg C year−1 versus 7.2 Pg C year−1) (7, 40, 41).

There is an imbalance between Northern and Southern Hemispheres. The highest concentrations of atmospheric CO2 occur in the far North measured at Alert in Canada, 820N and Point Barrow on the north shore of Alaska 710N. The figure below shows the average difference of atmospheric CO2 levels at latitudes greater than that of the South Pole from 1994 to 2014.

...

The conclusion is that not only are Southern Hemisphere and, in particular, Australia very small contributors to fossil fuel emissions but also the recipients of the overflow of CO2 from the Northern Hemisphere..

So will efforts to reduce CO2 concentrations from Southern Hemisphere continents have any effect on the Northern Hemisphere? Our only part in this is a very small contribution to the southern sinks of CO2 that might displace CO2 from the North..

So if there is a problem, it is a problem of the North.

REFERENCES

[1^] Page, S et al (20o2) The amount of carbon released from peat and forest fires in Indonesia during 1997, Letters to Nature, vol 420, p 61

[2^] der Werf et al (2004) Continental-Scale Partitioning of Fire Emissions During the 1997 to 2001 El Niño/La Niña Period, Science: Vol. 303 no. 5654 pp. 73-76 DOI: 10.1126/science.1090753

[3^] Bowman et al (2009) Fire in the Earth System. Science Vol. 324 no. 5926 pp. 481-484, DOI: 10.1126/science.1163886

*Figures here are in pure carbon terms. If we talk in terms of CO2 emissions rather than pure C, the numbers are 44/12 times higher.

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