10 August, 2010
Russia is in smoke, with fires raging all over the country. Everything which can burn is burning – forests, steppes… then buildings…
As to Russia’s central region, the heart of the country’s European part, the largest contribution to the blazing, smoky disaster was probably made by peat fires – burning peat bogs dried-up naturally or drained by man.
Most of them are located in Meschiora and the surrounding lands – in Eastern Moscow Region, Ryazan, Vladimir and Ivanovo Regions.
They’re often named the most dangerous fire hazard – and, accordingly, the biggest source of smoke, for the following reasons:
- peat deposits can be very large, occasionally with very thick peat beds;
- peat ignites very easily and releases a lot of energy while burning – between 10 and 25 MJ/kg. That puts peat somewhere between firewood and black coal, but closer to firewood;
- it’s very hard to locate and extinguish seats of fire early (i.e. in time). This, in turn, is due to the following two reasons:
1) fire doesn’t always (immediately) comes to the surface, the peat bed may burn out underground;
2) understandably, a lot of peat bogs are located in hard-to-reach places where fire engines cannot go, so the only way to fight these fires is from helicopters – which is quite expensive.
Peat is widely used as a fertiliser (it greatly improves land productivity), and as fuel. In Russia – like in all other countries – peat is mostly used in agriculture, primarily in fruit and vegetable gardens and hothouses.
However, right now peat is primarily associated with the partly natural, partly man-made disaster raging throughout a major chunk of the country’s territory.
Let’s start with the basics:
- what is peat?
- how is it formed?
- is there a lot of it?
- where the biggest peat deposits are in Russia?
- why are they burning now?
First let’s see what classic dictionaries and encyclopaedias have to say.
“Peat is a combustible fossil formed through natural atrophy and incomplete disintegration of helophytes under excess humidity and limited air supply conditions. Peat is the product of the first stage of coal-forming process. Peat is used as fertiliser, fuel and raw material for chemical industry”. (Dictionary of Natural Science)
“Peat… is formed as a result of dead plants’ remains’ sedimentation to swamp beds and their subsequent incomplete decomposition due to microorganisms’ activities, under excess humidity and limited air supply conditions…
Peat is – <…>a fibrous (low degree of decomposition) or pliable amorphous (high degree of decomposition) mass of light yellow, brown or brownish-black (earthy) colour. Depending on the phytologic composition, formation conditions and physicochemical properties, three types of peat are distinguished: high-moor peat, transitional peat and valley peat… (peat classification is based on various stages of peat bogs evolution).
- combustible or organic mass;
- liquid (86-95% of the total mass in natural state);
- mineral impurities (no more than 50% in the dry matter); turn into ash after burning…”
Note that high moors are the biggest fire hazard. They are cut off from ground waters by nature itself; and “feed off” exclusively of rain water – so they’re the first to turn into “inflammable materials” depots in the time of drought.
Also, in most cases they’re located higher (in watershed dips), and account for most of the peat reserves.
At the same time droughts cause reduction of the groundwater table, so other types of bogs can dry out too.
So it’s peat’s organic component which burns – the above-mentioned decomposed plant matter. And it wouldn’t be hard to guess that only dry peat burns – dried either naturally or artificially.
The current drought intensifies evaporation and ultimately the drying-up of peat bogs, turning them into a fire hazard.
Dry peat’s density is 1.4-1.7 g/cm3 which makes it heavier than water (whose density is 1 g/cm3). However, peat’s volume porosity is 96-97%; actually, it’s these pores which are filled with water in peat’s damp state.
Accordingly, a dried peat “brick” won’t drown in water since the empty pores would keep it on the surface , and its mass (let’s say it’s a 1 cubic decimetre brick, i.e. a 10х10х10 cm cube) wouldn’t equal 1.5 kilos (as its density suggests) but only about 10% of that, i.e. only 150 g.
This high porosity allows air to easily get inside peat layers – which results in their ability to burn underground.
It’s hard to tell what is worse about a peat fire – the actual flame or what comes with it.
If we take a look at peat’s chemical composition, the “big three” elements (in terms of their mass shares) would be the following:
- Carbon (С) – more than half (sometimes up to 2/3), or 48%-65%;
- Oxygen (О) – 25%-45%;
- Hydrogen (Н) – 4,7%-7%.
Then come nitrogen (N) – 0,6%-3,8% and sulphur (S) – 1,2%-2,5%.
Note that up to 50% of peat mass is made by ash (i.e. inorganic) components released when it burns. Namely:
- oxides – SiО2, CaO, A12O3, Fe2O3, MgO, K2O, P2O5, SO3;
- microelements – Zn, Сu, Со, Мо, Мn.
Another product of incomplete peat burning is carbon monoxide (CО).
Plus, one wouldn’t be hard-pressed to figure out that peat bog fires and the inevitable rise of air temperature they cause, lead to increased evaporation and humidity, especially since most of peat bogs are located in areas rich with water – marshy, with lots of lakes and dense river networks.
All of that is spread around by wind and makes that unpleasant and unhealthy mist we see and breathe now. Burning of a higher-quality, “cleaner” fuel wouldn’t have produced so strong negative effect.
Of course actual peat layers are different in terms of their porosity and humidity, maturity and chemical composition, depth and position. Hence, the unpredictable nature of peat fires. They may move on slowly, just a few metres a day, take curious trajectories, go deep down and then suddenly burst out in the open. Walking around a possibly burning peat bog (the signs include warm soil, smoke “oozing” from the ground) involves a risk of falling down into a blazing pit.
A peat bog may burn for a very long time. If its area is measured in square kilometres and thickness in metres, it can “last” for months. And there are much bigger peat bogs than that around.
Anything at all may start a peat fire. It doesn’t necessarily have to be human factor (a match or a cigarette butt thrown down, a campfire left smouldering, a sparkle during some kind of works).
For example, a lightning will suffice. Note that in this summer’s anomalous atmosphere there are lots of thunderstorms and lightning – alas, not resulting in desperately needed rains.
A peat fire may be “provoked” by a forest fire. Burning trees, bushes and grass touch a peat layer and on top of the forest or steppe fire we get an even more dangerous peat one.
Finally, as was noted earlier, fires dry the air, the neighbouring forests and peat bogs; a peat fire in one area turns the surroundings into fire hazards as well.
Thus a drought creates a domino effect in the ecosystem.
As to the human factor, in normal weather it doesn’t have such severe consequences; but this year the situation is similar to an organism with weakened immune system. There’s no telling which bug will get it down, but it’s quite obviously at risk. So it’s the organism which must be treated, instead of putting the blame on a particular virus or microbe.
It would be interesting to find out just how big the risk zone is in this case – both in Russia and internationally. According to the International Peat Society (IPS), at the early 2000s there were about 3 million sq.km. of peat lands in the world – i.e. 4,5% of Earth’s land surface.
The three leaders are:
- Canada – 1.1 million sq.km. (10% of the country’s land area, 2.6% of the world’s peatland area);
- USA – 0.6 million sq.km. (6% of the country’s land area, 1.6% of the world’s peatland area);
- Russia and the former USSR countries – 0.6 0,6 million sq.km. (3% of the country’s land area, 1.6% of the world’s peatland area). About 80% of that is in the Russian Federation.
- Altogether, these countries account for 25% of Earth’s land surface and 90% of the world’s peatland area.
World peatland areas distribution
|Country||Totalpeatlandarea (sq.km.)||Peatland area used for agriculture (sq.km.)|
|Germany||14 ,200||12, 000|
|Total for Europe and Russia||892, 769||120 ,672|
|Canada||1, 114, 000||170, 000|
|USA||611, 000||61, 000|
|Total for North America||1, 725, 000||231, 000|
|Indonesia||200, 728||42, 000|
|Total foe Asia||237, 058||52, 895|
|Total for the World||2, 854, 827||404,567|
The above distribution looks quite logical. Peat bogs form in areas with favourable conditions – sufficiently damp climate and lots of wetlands.
Most of the current peat reserves have formed during the Holocene (the last few thousand years) in the territories freed from Valdai (in North America – Wisconsin) glaciers – as a result of lakes’ and marshes’ evolution left behind after the glacier’s retreat.
The last glacier covered practically the whole of modern Canada, the northern parts of the USA and Europe and the north-west of European Russia – which have caused formation of large lake and marsh basins (and subsequently peat layers) in these areas.
At the same time, interestingly, the “credit” for the current Moscow smog mostly belongs to Meschiora peat bogs (the eastern part of Moscow Region, Ryazan, Vladimir and Ivanovo Regions) – and these areas never were covered by Valdai glacier. Still, their geologic-geomorphological structure caused formation of lots of lake and marsh basins and subsequently to active formation of peat; development of peat bogs (and the inevitable drying out of wetlands) started there as early as 200 years ago.
World peat reserves (adjusted to 40% humidity) amount to 500 billion tonnes. The following countries have the largest reserves (1987 data):
USSR – 200 billion tonnes;
USA – 36.3 billion tonnes;
Canada – 35 billion tonnes;
Finland – 35 billion tonnes;
Sweden – 11.2 billion tonnes;
Indonesia – 78.5 billion tonnes;
China – 27.0 billion tonnes;
Zaire – 3.5 billion tonnes;
Australia – 1.0 billion tonnes;
New Zealand – 1.3 billion tonnes.
Russia accounts for 17% of the global peat and peat products production. In the Soviet period the total peat production peaked at 160-180 million tonnes.
After the breakdown of the USSR peat production in Russia dropped sharply (according to some estimates, “manifold”); currently the country is the fourth largestpeat producer in the world after Finland, Ireland and Canada.
By the way
Some of the high moors in European Russia have surface area measured in tens of thousands of hectares (hundreds of square kilometres).
Most of the peat produced and processed in Russia and other countries is used not by the energy sector but by agriculture (the ratio is approximately 20%-25% to 75%-80%, respectively). Use of peat as power plant fuel in Russia peaked in 1965 (28 million tonnes), and since then went downhill.
Globally, peat’s contribution to energy generation remains under 0.1%, but in certain countries its share is between 10% and 20% (Finland, Sweden, Ireland). Milled peat, lump peat and fuel bricks are used locally as household and communal fuel. Fuel peat is also used at small fuel-burning power plants, boiler rooms etc.