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The contribution of USSR sources to global methane emission
Chemosphere,Vol.26,Nos.1-4,pp 11I- 126, 1993 Printcd in GreatBritain
0045-6535/93$6.00+ 0.00 PergamonPressLtd.
T H E C O N T R I B U T I O N OF U S S R S O U R C E S TO G L O B A L M E T H A N E E M I S S I O N N. G. A n d r o n o v a 1,2, I. L. K a r o l 1 1 Voeikov Main Geophysical Observatory 7, Karbyshev St. St.-Petersburg, 194018, Russia 2 Department of Atmospheric Sciences University of Illinois at Urbana-Champaign 105, South Gregory Avenue Urbana, IL, 61801, USA (Received in USA 20 November 1991; accepted 4 May 1992) ABSTRACT In this study the release of methane to the atmosphere by the USSR is estimated. This paper includes estimate of the methane fluxes from USSR wetlands, fossil fuel mining and cattle, and also their possible geographical distributions. It is shown that the USSR methane sources are 11% of the global value of 540 Tg. Using a simple model of the transformation of soil organic matter, it is estimated that the maximum methane flux from USSR wetlands is 11 Tg/yr. Thus the USSR contributes less than 10-13% of the world's methane flux from wetlands. The estimates of the maximum methane fluxes from coal mining, oil mining and gas mining (including transportation and storage) are 18, 7 and 11 Tg/yr, respectively. Thus the USSR contributes up to 43% of the global fossil fuel source of methane. The upper limit of the methane flux from USSR cattle is 12 Tg which is 15% of the global cattle methane source. It is concluded that geographically there are two maximum values of methane flux from the USSR which are formed by inputs from the different methane sources. The first methane flux maximum is located in the West Siberian Plain and is formed dominantly by gas and oil mining. The second methane flux maximum is located in the Ukraine and neighboring regions, and is formed by coal mining, wetlands and cattle.
1. INTRODUCTION Methane is an i m p o r t a n t component of atmospheric photochemistry and the climate system. At the present time the atmospheric methane concentration is increasing by 1% per year (Steele et al., 1987). Therefore, investigation of the cause of the rapid increase on the methane concentration is an extremely important problem. It is known that all methane sources are located on the Earth's surface and that the main 111
112
m e t h a n e sinks are located in the atmosphere. The inventory showed by Cicerone and Oremland (1988) indicated t h a t the main methane sources are wetlands, rice paddies, fossil fuel mining and cattle. Among these sources the l a s t three can be considered as anthropogenic sources. The Soviet Union is likely an i m p o r t a n t source of m e t h a n e because it is a principal producer of gas and oil, and because of its large area of wetlands. Unfortunately, there is only a limited amount of data about the regional distributions of wetlands and coal, oil and gas production in the USSR. This p a p e r includes estimations of the m e t h a n e fluxes from USSR wetlands, fossil fuel mining and cattle, and shows their possible geographical distributions.
2. METHANE FLUX FROM USSR WETLANDS 2.1. Methane Production from Wetlands The production of methane by natural ecosystems depends on the geochemical conditions in the soil and is controlled by soil temperature and soil moisture. Wetlands have sufficient soil moisture to create the effectively oxygen-free reducing conditions necessary for methane production. Consequently, if the geochemical soil conditions are uniform, the intensity of m e t h a n e production from wetlands is d e t e r m i n e d by the geographical distribution of temperature. The process of microbial m e t h a n e production from wetlands is shown schematically in Fig.1. Annually, there is input of organic m a t t e r (OM) to the soil. According to Kobak (1988) and Andersen (1985), the intensity of this input, G, mainly depends on climatic conditions. The biologic transformation of OM produces h u m u s which consists of two components: the biologically active (labile) h u m u s and the stable component ("the stable reservoir"). According to the estimates in Zavarzin (1984); Kononova (1976) and Kobak (1988), the range of the annual generation of h u m u s equals 2 - 10% of the mass of G. It follows from the data analysis presented in Zavarzin (1984) and Kobak (1988) that the labile h u m u s constitutes about 30 - 60% of the total humus. Thus, the amount the labile h u m u s matter, g, can be related to G by g = {0.02-0.1} x {0.3-0.6} G = {0.006-0.06} G .
(1)
According to Andersen (1985) and Kobak (1988), the labile part of humus consist mainly of humic acids and is biologically processed, with methane as one of the final products. We assume t h a t all the labile h u m u s is transformed into methane and that all the methane goes to the atmosphere. This gives an estimate of the upper limit of the m e t h a n e flux from wetlands, qmax, as qmaX = gmax = 0.06 G .
(2)
113
In accordance with the presentation in Kobak (1988), we divide the Earth's surface into the five climatic zones. The border of these climatic zones we choose as it is shown in Table 1, each having an average t e m p e r a t u r e from Babanova et al. (1986), T i , and intensity of the annual input of organic m a t t e r in carbon units from Kobak (1988), G i . Table 1 shows that G i decreases with decreasing temperature, with a m a x i m u m in the tropical climatic zone and minimum in the polar zone.
Organic m a t t e r of the E a r t h
Intensity of OM input into the soil G(T) 0.02 - 0.1
Soil OM
Humus
Intensity of OM destruction of OM in the soil (0.006-0.06) k/k
0.3 - 0.6 (T)
H2S , NH~
Labile humus
1.0
Soil methane
{
I
Intensity of the methane release to the atmosphere v
.....
I i
1.0
Atmospheric methane
]
CO
Fig. 1. Model of transformation of organic m a t t e r to methane (relative units).
Following Andersen (1985), we assume t h a t the intensity of the transformation of OM into humus is defined by
114
G.
1
ki - D
'
(3)
1
where D i is storage of organic carbon i n the soil. The t h i r d column of Table 1 lists the values of D i from K o b a k (1988), t h e d i s t r i b u t i o n of which g e n e r a l l y decreases w i t h i n c r e a s i n g temperature.
The f o u r t h c o l u m n of Table 1 lists the v a l u e s of k i , the reciprocal of which
corresponds to the life time of OM i n the soil. The OM life time is e s t i m a t e d to be 1/k4, 5 = 200 300 years for the boreal a n d polar climatic zones, 1/k 3 = 70 y e a r s for the s u b b o r e a l climatic zone, a n d 1/kl, 2 = 26 - 35 years for the t e m p e r a t e a n d tropical climatic zones. Following the surface t e m p e r a t u r e d i s t r i b u t i o n , the m a x i m u m r a t e of d e s t r u c t i o n occurs i n the tropical climatic zone, t h u s kl/kma x = 1 (see the fifth column of Table 1).
T a b l e 1. E s t i m a t e of the m e t h a n e flux from different climatic zones (T is global t e m p e r a t u r e , G is a n n u a l i n p u t organic m a t t e r into soil, D is carbon storage i n soil, qmaX is the a n n u a l m e t h a n e flux from m -2 of wetlands)
Climatic
Ti a
Gi b
(Di/103) b
k i ffi Gi/D i
ki/kma x
qi max
K
g(C) m 2 year
g(C) m2
1 year
_
297
390
10.3
0.038
1.0
31.2
286
370
12.9
0.029
0.763
22.6
275
220
14.6
0.015
0.395
7.0
~7
180
31.1
0.005
0.158
2.3
258
80
23.9
0.003
0.079
0.5
Zones
Tropical
g(CH4) m 2 year
(30ON- 30os) Temperate (50o - 30ON, 30° _ 50os) Subboreal (60° _ 50ON,500 _ 60os) Boreal (600 _ 70ON) Polar (700 _ 80ON) a)
b) (Babanova et al., 1986), (Kobak,1988) F i g u r e 2a d e m o n s t r a t e s the dependence of k/kma x on t e m p e r a t u r e a n d its l i n e a r regression
is k/kmax = 0.0253 T - 6.53 .
(4)
E q u a t i o n (4) allows e s t i m a t i o n of (k/kmax )o = 0.7 for the p r e s e n t global-mean t e m p e r a t u r e , To=
115
288 K. S i m i l a r l y , Fig. 2b shows t h e d e p e n d e n c e of G on t e m p e r a t u r e a n d i t s l i n e a r r e g r e s s i o n is G = 8.32T-
2.05x10
3
,
[g(C) m - 2 y e a r -1] .
(5)
E q u a t i o n (5) allows e s t i m a t i o n of G o = 346 g(C) m -2 y e a r -1 for To= 288 K. According to K o b a k (1988), t h e a n n u a l global OM i n p u t into soil is Go= 320 g(C) m-2 y e a r -1, w h i c h is 8% less t h a n the v a l u e e s t i m a t e d here.
1
I
(a)
I
0.8
0.8
0.6
_
0.4
_
0.2
_
0.6
E
/
-~
Global m e a n - for p r e s e n t c o n d i t i o n s _
0.4
0.2
0 250
• il
260
I
I
I
270
280
290
0 300
Temperature, K
450
I
(b)
t~ cD
I
I
I
450
350
350
250
250
150
150
c?
d
Q
50 250
I
260
I
I
270 280 Temperature, K
I
290
50 300
F i g . 2. T e m p e r a t u r e d e p e n d e n c e of (a) d e s t r u c t i o n r a t e of organic m a t t e r , a n d (b) a n n u a l i n p u t of organic m a t t e r into soil.
116
We relate the intensity of the OM destruction in soil with the methane flux to the atmosphere, qi, for each of the geographical climatic zones by
'
!
q~ - km a x ~ = {0.006-0.06}~--~x Gi
(6)
The sixth column of Table 1 lists the values of qmax, given by Eq. (6) for 0.06, and shows that the intensity of the methane release to the atmosphere decreases considerably from the tropics (ql = 31.2 g(CH4) m -2 year-l) to the polar regions (q5 = 0.5 g(CH4) m -2 year-l). Experimental data of the average diurnal and seasonal variations of the methane flux to the atmosphere from wetlands vary from 10 -4 to 10-1 g(CH4)/m2/day. Use of these data together with consideration of the length of the vegetation period for each the climatic zone leads to large uncertainties. Whalen and Reeburg (1988) estimate the annual methane flux to the atmosphere from wetlands located in the boreal/subboreal climatic zones as 0.48 - 8.0 g(CH4) m -2year-1. Comparison of this value with the corresponding values from Table 2 shows good agreement. 2.2. Estimation of Methane Production from USSR Wetlands The annual methane released from wetlands, FWTL, is given by FWT L --
SWTL q ,
(7)
where SWTL is the area of wetlands and q is the methane flux from wetlands. According to Maslov (1970), the area of wetlands in the USSR is 0.91.1012 m 2, 82% of which is located in the Russia, 6% in the Baltic States, 3% in the Ukraine, and 3% in Byelorussia. According to Glebov (1973), 89% of the wetlands of the Russia, with an area 0.67' 1012 m 2, is located in the West Siberian Plain. The orography of the USSR and the high level of continentality of the USSR significantly transform the borders of the climatic zones defined in Table 2, and this makes it difficult to estimate the m e t h a n e flux from wetlands in each climatic zone. Accordingly, we will assume that the distribution of climatic zones in the USSR corresponds to the distribution of soil types presented in the Geographic Atlas of the USSR (1989), with (1) the polar and boreal climatic zones defined as the set of the arctic, tundro-gleevoi, taiga and podzol soils, (2) the subboreal climatic zone defined as the dernovo-podsol soil, and (3) the temperate climatic zone given by the other soil types. Figure 3 demonstrates the resulting distribution of climatic zones in the USSR, based on soil types. This figure shows that the largest part (about 2/3) of the West Siberian Plain is located in the polar and boreal climatic zones, a small part located in the subboreal climatic zone; the Baltic States and Byelorussia are located in the subboreal climatic zone; the largest part (about 2/3) of Ukraine is located in the temperate climatic zone, with a small part located in the subboreal climatic zone. We now consider a scenario for maximum methane flux from USSR wetlands. According
ll7
to this scenario, 2/3 of t h e W e s t S i b e r i a n w e t l a n d s is located in t h e boreal c l i m a t e zone a n d 1/3 in the s u b b o r e a l zone. T h e m e t h a n e flux from t h e w e t l a n d s of t h e Baltic S t a t e s , B y e l o r u s s i a a n d U k r a i n e w a s e s t i m a t e d b y expression: (8)
FWTL = ~ Sik ~k q~ ' ~k
w h e r e Sik is t h e k - t h a r e a in t h e i - t h climatic zone, a n d jlk is a r a t i o of t h e w e t l a n d s a r e a to total a r e a in t h e k - t h zone. In Eq. (8) the product Sik ~lk defines the a r e a of t h e w e t l a n d s , SWTL, of t h e i - t h c l i m a t i c zone. T h e a r e a s of t h e Baltic S t a t e s a n d B y e l o r u s s i a together, a n d of t h e U k r a i n e w e r e t a k e n from S t a t i s t i c Y e a r b o o k (1990), a n d a r e 0.37.1012 m 2 a n d 0.6-1012 m 2, respectively. F o r t h e E u r o p e a n p a r t of U S S R , R o m a n o v (1962) e s t i m a t e d t h a t t h e w e t l a n d s of t h e s u b b o r r e a l climatic zone occupy as m u c h as 50% of the total area, a n d t h e w e t l a n d s of the t e m p e r a t e c l i m a t i c zone occupy a s m u c h a s 15% of t h e . t o t a l a r e a .
T h u s , t h e a r e a of t h e
w e t l a n d s of t h e Baltic S t a t e s a n d B y e l o r u s s i a t o g e t h e r a r e 50
60
70
80 .
.
.
.
.
,.t
,,
•
,,~ ~m.I
50
II i
60
i
I I
70
!
~ IR m ml I F i k !
80
I
,
m~l II
90
100
110
12 0
130
P o l a r a n d boreal climate (arctic, tundro-gleevoi, taiga, podzol soil) S u b b o r e a l c l i m a t e (dernovo-podzol soil) T e m p e r a t e c l i m a t e (other soil types) R
Region b o r d e r s
F i g . 3. Correspondence of U S S R climatic belts a n d soil types. Regions: 1 - Russia, 2 - Baltic States, 3 - Byelorussia, 4 - U k r a i n e , 5 - o t h e r regions.
118
0.19.1012 m 2, a n d t h e a r e a of t h e U k r a i n i a n w e t l a n d s is 0.09-1012 m 2. A c c o r d i n g to M a s l o v (1970), t h e s e w e t l a n d s c o m p r i s e 85% o f t h e t o t a l a r e a of U S S R w e t l a n d s .
For the maximum
scenario we a s s u m e t h a t t h e o t h e r U S S R w e t l a n d s a r e located in t h e t e m p e r a t e climatic zone. The l a s t c o l u m n o f T a b l e 2 p r e s e n t s t h e m e t h a n e e m i t t e d from U S S R w e t l a n d s c a l c u l a t e d u s i n g t h e above e s t i m a t e s of t h e m e t h a n e p r o d u c t i o n for t h e d i f f e r e n t c l i m a t i c zones. F r o m T a b l e 2 i t follows t h a t t h e m a x i m u m m e t h a n e e m i t t e d from U S S R w e t l a n d s by m i c r o b i a l activity is a b o u t 10 Tg(CH4)/year. A c c o r d i n g to Glotov et al. (1985), t h e r e is a n o t h e r source of m e t h a n e from t h e S i b e r i a n w e t l a n d s in a d d i t i o n to t h a t due m i c r o b i a l activity, n a m e l y , n a t u r a l l e a k a g e from t h e E a r t h ' s i n t e r i o r in r e g i o n s of p e r m a f r o s t . F r o m t h e d a t a of Glotev et al. (1985) we e s t i m a t e t h a t t h e a n n u a l m e t h a n e flux f o r m e d b y m i g r a t i o n p r o c e s s e s t h r o u g h t h e frozen soil is 2 - 8.10 -2 g(CH4) m - 2 y e a r -1. According to F o t i e v (1978), t h e a r e a of p e r m a f r o s t in the U S S R is 11.1.106 k m 2. C o n s e q u e n t l y , t h e a d d i t i o n a l m e t h a n e e m i t t e d from w e t l a n d s due to n a t u r a l l e a k a g e is about 0.2 - 0.9 Tg(CH4)/year. T h u s , t h e m a x i m u m m e t h a n e flux f r o m U S S R w e t l a n d s d u e to m i c r o b i a l a c t i v i t y a n d n a t u r a l l e a k a g e is e s t i m a t e d a s 11 Tg(CH4)/year.
Table
2. E s t i m a t e of U S S R w e t l a n d s m e t h a n e source (Sik is the k - t h a r e a in the i-th climatic
zone, gk is a r a t i o of t h e w e t l a n d s a r e a to total a r e a in the k - t h zone, SWTL is the w e t l a n d s a r e a , qmax is t h e a n n u a l m e t h a n e flux from m -2 of w e t l a n d FWTL is t h e m e t h a n e flux) Sik a
~tkb
SWTL
qi max
FWTL
C l i m a t i c Zone & Region 106 k m 2
.%
g(CH 4)
M t ( C H 4)
m 2 year
year
0.45
2.3
1.1
106 k m 2
Boreal
2/3 W e s t S i b e r i a n P l a i n
-
-
Subboreal
1/3 W e s t S i b e r i a n P l a i n Baltic S t a t e s & B y e l o r u s s i a
-
-
0.22
7.0
1.6
0.37
50
0.19
7.0
1.4
0.6 -
15 -
0.09 0.15
22.6 22.6
2.1 3.4
Temperate
Ukraine Other wetlands
Total a)
b) (Statistical Yearbook, 1990), (Romanov, 1962)
0.86
9.6
119
3. M E T H A N E F L U X F R O M U S S R F O S S I L F U E L M I N I N G 3.1. Coal M i n i n g M e t h a n e is k n o w n to b e l o c a t e d in coal deposits, b u t such m e t h a n e is n o t u t i l i z e d in t h e U S S R (Ettinger, 1988). We e s t i m a t e t h e m e t h a n e flux from coal m i n i n g b y Fcoal = ~oal Vcoal '
(9)
w h e r e Vcoal is t h e a m o u n t of coal m i n e d a n n u a l l y a n d qcoal is t h e a m o u n t of m e t h a n e e m i t t e d p e r t e n of coal mined. According to U S S R Coal I n d u s t r y (1989) t h e coal p r o d u c t i o n of U S S R i n c r e a s e d a t a m e a n r a t e of 8% p e r y e a r from 1970 to 1988. According to Geological E n c y c l o p e d i a (1990) coal in the U S S R is m i n e d p r e d o m i n a n t l y in t h r e e regions; t h e Donetski, K u z n e t s k i , a n d K a r a g a n d i n s k i a n d E k i b a s t u z coal r e g i o n s , w h i c h t o g e t h e r c o n t r i b u t e m o r e t h a n 80% of t h e t o t a l coal p r o d u c t i o n of t h e U S S R . T h e d a t a from Geological E n c y c l o p e d i a (1990) p r e s e n t e d in the first column of Table 3.
Table 3. E s t i m a t e of U S S R coal m i n i n g m e t h a n e source (Vcoal is coal production in 1988, qcoal is gas factor for coal) Coal r e g i o n
Vcoal (1988) 106 t / y e a r
qeoal kg (CH 4)
Methane Flux Tg (CH4)/year
1.
Donetski
198.
0.7 - 23 (36")a
0.13 - 4.6 (7.1")
5. 4.
Kuznetski Karagandinski
154.
0.7 - 14a
0.10 - 2.2
and Ekibastuz
143.
8 - 11 (31")b
1.14 - 1.6 (4.4*)
3.
Pechorski
32.
2 - 20 (50")a 2 - 24 c
0.06 - 0.6 (1.6")
Other regions
82.
0 - 24
0.0 - 2.0
Total
609
1.4 - 11.0 (17.3")
a) (Zorkin, 1986); b) (Ksenofontova et al., 1960); c) (Ettinger, 1988); *) maximum possible value T h e r e a r e s e v e r a l e s t i m a t e s of t h e gas factor for coal - t h e a m o u n t of m e t h a n e e m i t t e d p e r ton of coal m i n e d , w h i c h is e q u a l to t h e a m o u n t of gas s a t u r a t e d in t h e coal - for the different coal regions of t h e U S S R .
T h e second c o l u m n of T a b l e 4 p r e s e n t s t h e s e e s t i m a t e s , a n d the
120
m a x i m u m p o s s i b l e v a l u e s of t h e g a s factor for t h e D o n e t s k i , K a r a g a n d i n s k i a n d P e c h o r s k i coal regions a r e p r e s e n t e d i n t h e p a r e n t h e s e s .
F r o m t h e s e e s t i m a t e s a n d t h e p r o d u c t i o n for
t h e U S S R coal r e g i o n s , t h e m e t h a n e flux from coal m i n i n g is e s t i m a t e d to be 1 - 12 Tg (CH4)/year , w i t h a m a x i m u m - p o s s i b l e v a l u e 18 Tg(CH4)/year. 3.2. Oil a n d G a s M i n i n g M e t h a n e is also l o c a t e d i n oil deposits, b u t a l m o s t all such m e t h a n e is utilized. However, s m a l l l o s s e s of m e t h a n e occur d u r i n g oil m i n i n g , s t o r a g e a n d t r a n s p o r t a t i o n . losses also occur d u r i n g g a s m i n i n g , s t o r a g e a n d t r a n s p o r t a t i o n .
S m a l l gas
Unfortunately, there has
not b e e n a complete i n v e n t o r y of t h e m e t h a n e losses due to g a s a n d oil m i n i n g in t h e USSR. To e s t i m a t e t h e m e t h a n e losses from oil m i n i n g we use Foi1 = a ~ T V o i 1 ,
(10)
w h e r e a is t h e g a s c o n t e n t of oil, [~ is the m e t h a n e s h a r e of this gas, T is the e v a p o r a t i o n factor for oil, a n d VoiI is t h e a m o u n t of oil m i n e d a n n u a l l y . S t a t i s t i c a l Yearbook, (1990) p r e s e n t s U S S R oil production from 1970 to 1988. According this d a t a from 1970 to 1980 oil p r o d u c t i o n monotonically i n c r e a s e d a t a m e a n r a t e of 8% p e r year. After 1980 oil p r o d u c t i o n leveled off a n d t h e m e a n r a t e of oil production from 1980 to 1988 was d r o p p e d to 0.3% p e r year, a n d i n 1988 y e a r oil p r o d u c t i o n w a s VoiI = 624 Tg.
The m a i n oil
p r o d u c i n g region of t h e U S S R is t h e W e s t S i b e r i a n region. I n 1980 t h i s region provided 53% of t h e t o t a l oil p r o d u c t i o n of t h e U S S R , a n d m o r e t h a n 67% in 1985.
We interpolated data
p r e s e n t e d b y S t a t i s t i c a l Yearbook, (1990) for t h e W e s t S i b e r i a n region given for 1980 - 1985 period on 1985 - 1988 p e r i o d w i t h a s s u m p t i o n of a m e a n r a t e i n c r e a s e of 4.8% p e r year. Thus, we o b t a i n e d Voi! (West Siberia, 1988) = 481 Tg. A c c o r d i n g to Z o r k i n (1986), t h e m e a n gas c o n t e n t of oil m i n e d in t h e U S S R is 60 m3/t (43 kg/t). The g a s c o n t e n t of oil m i n e d in t h e W e s t S i b e r i a n region is 20 - 120 m3/t (14 - 86 kg/t), w i t h a m e a n v a l u e of 70 m3/t (50 kg/t) w h i c h is m u c h l a r g e r t h a n t h e m e a n v a l u e for the USSR. The m e t h a n e contents of t h e gas a c c o m p a n y i n g t h e oil, a n d the gas dissolved in the oil a r e 70 - 90% a n d 5 - 15%, respectively. Also, a c c o r d i n g to t h e e s t i m a t e s of T o m a s h p o l s k i (1968), oil c a n e v a p o r a t e b y a s m u c h a s 14% from t h e t i m e of m i n i n g to t h e t i m e of consumption. F r o m t h e s e d a t a we t a k e t h e following v a l u e s for the p a r a m e t e r s in Eq. (10): = 43 kg/t of m i n e d oil, [~ = 0.5 (~min = 0.05, ~max = 0.95), a n d T = 0.14. F o r oil m i n e d in t h e W e s t S i b e r i a n region, a = 50 kg/t (ami n = 14 kg/t, areax = 86 kg/t). F r o m t h e e s t i m a t e s p r e s e n t e d above we e s t i m a t e t h e m e t h a n e flux f r o m oil m i n i n g in U S S R for 1988 y e a r a s 1.9 Tg(CH 4) a n d t h e n o m i n a l m e t h a n e flux from W e s t S i b e r i a as 1.7 Tg(CH 4) w i t h t h e m a x i m u m v a l u e 2.9 Tg(CH4). U s i n g t h e m a x i m u m v a l u e of t h e gas content of oil, area x = 86 kg/t, a n d t h e m a x i m u m v a l u e of t h e m e t h a n e c o n t e n t of oil, ~max = 0.95, we e s t i m a t e t h e m a x i m u m m e t h a n e losses from oil m i n i n g in 1988 as 7.2 Tg(CH4). Thus, we e s t i m a t e t h e U S S R m a x i m u m v a l u e of m e t h a n e source in 1988 d u e to oil m i n i n g as 7.2 Tg(CH4).
121
It follows from Zorkin (1986), t h a t the oil regions of the USSR are also the gas regions. For the m e t h a n e losses during gas mining we take the estimate derived by Barns and Edmonds (1990) t h a t gas losses from the time of mining to the time of consumption are 2% of the total amount of the gas mined. Statistical Yearbook, (1990) presents USSR gas production from 1970 to 1988. From this data it follows t h a t gas mining increased during the entire period at 16% per year and at 1988 USSR gas production was Vgas = 552 Tg, and we estimate the methane losses from USSR gas mining as 11 Tg(CH4). In 1980 the main region of the USSR gas mining, West Siberia, produced 29% of the total amount, and 60% in 1986. We interpolated the increase rate of West Siberia gas production of 10% per year from 1980 - 1986 period given by Statistical Yearbook, (1990) on 1986 -1988 period. Thus, we obtained Vgas (West Siberia, 1988) = 339 Tg. From this data we estimated t h a t West Siberia contributed 6.8 Tg(CH4). Summing the contributions for coal, oil and gas, the total m a x i m u m amount of methane emitted in 1988 from fossil fuel mining in the USSR was 30 Tg(CH 4) with m a x i m u m possible value 37 Tg(CH4).
4. METHANE FLUX FROM USSR CATTLE To estimate the m a x i m u m m e t h a n e flux from USSR cattle we use the upper limit of methane emission from a single animal (milk cattle) cited by Crutzen et al. (1986), 95 kg (CH 4) per year and data from Statistical Yearbook (1990) about USSR cattle 120.106 for 1988 year. Using these data we estimate that the m a x i m u m methane flux from USSR cattle in 1988 was
12Wg. 5. ESTIMATE OF GEOGRAPHICAL DISTRIBUTION OF USSR METHANE SOURCE To estimate the geographical distribution of the USSR m e t h a n e sources we divide the USSR into 5 °x 10 ° latitude-longitude grid boxes and determine the m e t h a n e source at each grid node using the following rules: (1) if a region having methane source O (Tg/year) occupies n grid nodes, then the source at each node is O/n. For example, the boreal wetlands of the West Siberian Plain occupy the area between longitudes 60°W - 90°W and latitudes 60°N - 65°N (Fig. 3) and includes 8 nodes with coordinates (65°N, 60°W), (65°N, 70°W), (65°N, 80°W), (65°N, 90°W), (60°N, 60°W), (60°N, 70°W), (60°N, 80°W) and (60°N, 90°W). Thus, for each of these nodes the methane source from boreal wetlands is one-eight of 1.1 Tg/year (Table 2); (2) if a methane source region crosses only one side of a grid box, then the source at each of the two nodes of this side is 0/2. For example, the Donetski coal region (Fig. 4) crosses the side of the grid box at longitude 40°W between 45 °- 50°N. Thus, the methane source at nodes (50°N, 40~vV) and (45°N, 40~N) is one-half of 7.1 Tg/year (Table 3); (3) if the m e t h a n e source region lies completely within a grid box, then the source at each four its node is @/4; (4) the total m e t h a n e source was obtained by summing the separate sources at the grid
122
node. 50
60
70
80
"
50
60
'
70
80
90
100
110
,
120
130
Fig. 4. USSR coal mining regions To estimate distribution of methane flux from wetlands we used data presented in Section 2 and according this data the contribution of wetlands to the total methane USSR source distribution is small. This is because the largest area of USSR wetlands is located in the permafrost region where the microbial methane production is low. To estimate distribution of methane flux from USSR cattle we used the data presented by Statistical Yearbook (1990) for separate republics. According to this data the dominate cattle methane source is located in the southwest region of the USSR. For the other regions the contribution to the total methane distribution for the USSR of this source is small. To estimate the methane distribution from USSR coal, oil and gas mining we used data presented in Section 3. Figure 4 presents the distribution of the USSR coal regions (Zorkin et al., 1986). From our estimates it follows that a considerable methane source located in the Ukrainian region. The methane distributions from the USSR oil and gas mining are most uncertain because there are not available data for all regions of the USSR. The distribution of the oil and gas regions over USSR presented on Fig. 5. To obtain the methane distribution from the USSR oil mining we used the data from Atmosphere (1991) for the hydrocarbon gas inputs to the atmosphere by the USSR regional oil industry. From these data we obtained that the contribution of the oil industry to the total methane source distribution is small. To obtain the m e t h a n e distribution from the USSR gas mining we assume that the main methane losses exist only in the gas mining region. This assumption was made because there are not data for the gas losses in the USSR. But the indirect data of Haritonovski (1990) show that the largest number of pipeline troubles (consequently, methane losses) exists in permafrost conditions where the main USSR gas region is located. We estimated that gas mining in the region 60 °-- 70°N and 50 °- 90°W is the main methane source.
123
50
60
70
80
~j]~ I ~ l ] , ~ , ~ ~ ~ : ~ ~ ~ ~!.~! ~ . ~ L',/-"~~I ~ ~ ,
J
rski 2 - Vol_go-Uralski ~x, 3-Prikaspiyiski ~ " 4 - Amudariyinski ~[~ 5 - North-Cavcazki " ~ ~ 6 - Wes~ Siberia ~_~
f ,~'.".'~t h e ~ ~ 50
60
70
80
90
1 O0
110
120
130
Fig. 5. USSR gas and oil mining regions Table 4 presents the estimated distribution of the total USSR methane source as the sum of the five sources, wetlands, cattle, and coal, oil and gas mining, estimated above. It can be seen that there are two maxima, one in the West Siberian Plain, 55 °- 65°N and 60 °- 80°W, and another in the Ukraine, 45 °- 50°N and 30 °- 40°W. We conclude that the maximum values of the methane source in the USSR are due to different methane sources. The maximum methane source in the West Siberian Plain is formed predominantly by gas mining, while the maximum methane source located in the Ukraine and surrounding territories is formed by coal mining, wetlands and cattle. T a b l e 4. Estimate of methane source distribution in the USSR
70°N 65°N 60°N 55°N 50°N 45°N 40°N 35°N
20°W
30°W
40°W
50°W
60°W
0.0 0.0 0.6 1.4 1.0 0.0 0.0 0.0
0.0 0.4 0.5 1.4 1.2 1.3 0.0 0.0
0.0 0.2 0.1 0.9 3.5 3.7 0.1 0.0
0.0 0.2 0.2 0.9 0.2 0.3 0.1 0.0
0.0 3.3 0.4 1.0 0.1 0.2 0.4 0.1
70°W
80°W
90°W
0.0 2.3 0.9 0.7 0.9 0.1 0.7 0.1
0.0 2.1 0.9 1.7 0.9 0.1 0.6 0.0
0.0 0.0 0.4 1.5 0.0 0.0 0.0 0.0
124
6. CONCLUSIONS Table 5 presents the estimate of the total methane source from the USSR. This table shows that the main methane source of the USSR is fossil fuel mining, which contributes half of the total value. Using the inventory from Cicerone and Oremland (1988) we estimated that the USSR methane sources contribute 11% of the global value. The methane source due to USSR fossil fuel mining contributes 43% of the global fossil fuel source, but the inventory in Cicerone and Oremland (1988) for the latter does not include methane losses from the oil mining. The methane source from USSR cattle contributes 9% of the global cattle methane source. The methane source due to USSR wetlands contributes 10% of the global wetlands source if the global wetlands source is equal to 115 Tg (Matthews and Fang, 1987), and 13% if the global wetlands source is 86 Tg (Andronova, 1990, 1991).
T a b l e 5. Estimate of the total USSR methane source (maximum value). Methane Source
CH 4 ( T g / y e a r )
Wetlands 11.0 Fossil fuel mining coal oil gas Cattle
Total
30.0 (34.0*) 12.0 (18.0") 8.0 11.0 12.0
52.0 (57.0*)
*) maximum possible value
Acknowledgements: The authors express their gratitude to Professor M. E. Schlesinger for editing their English and for useful discussions.
REFERENCES Andersen, D.M. (1985), Ecolo~v and Environmental Sciences: Biosvhere. Ecosvstem. and Human. Gidrometizdat, Leningrad, 160 pp. (in Russian). Andronova, N. G. (1990), The role of natural wetlands in the evolution of land sources of methane. EOS, AGU October 1990, 71, n 43, A21B-3. Andronova, N. G. (1991), The role of natural wetlands and anthropogenic sources in the geographic distribution CH4 flux to atmosphere. Met~qrolo~a and Gidrolo~a. 8, 36 - 42. Atmosvhere (handbook) (1991), Gidrometizdat, Leningrad. 600 pp. (in Russian).
125
Babanova, V. V., A. P. Kudrayvtzev and V. A. Frolkis (1986), Two-dimensional modelling the global zonal distributions of t e m p e r a t u r e and concentrations of the m i n o r gases in troposphere and stratosphere. In Radiative-Photochemical Atmospheric Models. Karol, I. L. (ed), Leningrad, Hydrometizdat, 192 pp. (in Russian). Barns, D. W., and J. A. Edmonds (1991), An Evaluation of the Relationshio Between the PrQduction and Use of Energy and Atmosoheric Methane Emission. Report under Contract No. DE-AC06-76OR-1830, 300 pp. Cicerone, R. J., and R. S. Oremland (1988), Biogeochemical aspects of atmospheric methane. G10b. Bio~eochem. Cvcles. 2. 299-327. Crutzen, P. J., I. Aselmann and W. Seiler (1986), Methane production by domestic animals, wild ruminants, other herbivorous fauna, and humans. Tellus. 38B, 271-284. Ettinger I. L. (1988), Unlimited Stores and Unoredictable Catastrophes. Nauka, Moscow, 170 pp. (in Russian). Fotiev, S. M. (1978), The Hvdrothermic Peculiarities of the USSR Permafrost Re~ion. Nauka, Moscow, 235 pp. (in Russian). Geolo~ical EncycloDedia (1990), "Geologia", Moscow. 800 pp. (in Russian). Geographical Atlas of USSR (1989) The main administration of geodesia and kartographia, Moscow, 32 pp. (in Russian). Glebov F. Z. (ed.) (1973), The Complex Estimation of Are~ of Swamp~ and of the Wetland Forests for their Melioration, Nauka, Moscow, 250 pp. (in Russian). Glotov, V. U., V. V. Ivanov and O. V. Tsherban (1985), The changes of the hvdrocarbons content of soils and mosses as the oil and gas index. Siberian AN USSR, Magadan, 16 pp. (in Russian). Haritonovski V. V. (1990), Increasing of the Pi~e Line's Durability in the CQmplicated Conditions. Nedra, Leningrad, 179 pp. (in Russian). Kobak K. I. (1988), Biotic Components of Carbon Cvcle. Gidrometizdat. Leningrad, 247 pp. (in Russian). Kononova M. M. (1976), Formation of h u m u s in soil and its destruction. Advances in Microbiolo~¢. 11, 134-151. (in Russian). Maslov B. S. (1970), The R e , m e of the Ground W a t e r of Wetland~ and it~ Regulation. "Kolos", Moscow, 301 pp. (in Russian). M a t t h e w s E. a n d I. F u n g (1987), Methane emission from n a t u r a l wetlands: Global distribution, area and environmental characteristics of sources, Glob. Bio~eochem. Cvcles. v. 1, n. 1, 61-86.
126
Romanov V. V. (1962), E v a o o r a t i o n in the Wetlands of the E u r o o e a n P a r t of USSR. Gidrometizdat. Lenin a'rad. 250 pp. (in Russian). Statistical Yearbook (1990), BSE (the third issue), Moscow. (in Russian). Steele, L. P., P. J. Fraser, R. A. Rasmussen, M. A. K. Khalil, T. J. Conway, A. J. Crawford, R. H. Gammon, K. A. Masarie and K. W. Thoning (1987), The global distribution of methane in the troposphere. J. Atm. Chem. 5, 125 -171. Tomashpolski L.M. (1968), Oil and Natural Gas in the Global Enera, v Budget (1900-2(}00}. "Nedra", Moscow, 250 pp. (in Russian). The USSR Coal Industry (short handbook} (1989), The USSR coal Ministry, Moscow, 20 pp. (in English and in Russian). Whalen S. C. and W. S. Reeburg (1988), A methane flux time series for tundra environments. Glob. Bio~eochem. Cycles, 2, n. 4, 399-409. Zavarzin G. A. (1984), Bacteria and Atmosoheric Comoosition. Nauka, Moscow, 207 pp. (in Russian). Zorkin L. M. et al. (1986), Methane in Our Life. Nauka, Moscow, 150 pp. (in Russian).
0045-6535/93$6.00+ 0.00 PergamonPressLtd.
T H E C O N T R I B U T I O N OF U S S R S O U R C E S TO G L O B A L M E T H A N E E M I S S I O N N. G. A n d r o n o v a 1,2, I. L. K a r o l 1 1 Voeikov Main Geophysical Observatory 7, Karbyshev St. St.-Petersburg, 194018, Russia 2 Department of Atmospheric Sciences University of Illinois at Urbana-Champaign 105, South Gregory Avenue Urbana, IL, 61801, USA (Received in USA 20 November 1991; accepted 4 May 1992) ABSTRACT In this study the release of methane to the atmosphere by the USSR is estimated. This paper includes estimate of the methane fluxes from USSR wetlands, fossil fuel mining and cattle, and also their possible geographical distributions. It is shown that the USSR methane sources are 11% of the global value of 540 Tg. Using a simple model of the transformation of soil organic matter, it is estimated that the maximum methane flux from USSR wetlands is 11 Tg/yr. Thus the USSR contributes less than 10-13% of the world's methane flux from wetlands. The estimates of the maximum methane fluxes from coal mining, oil mining and gas mining (including transportation and storage) are 18, 7 and 11 Tg/yr, respectively. Thus the USSR contributes up to 43% of the global fossil fuel source of methane. The upper limit of the methane flux from USSR cattle is 12 Tg which is 15% of the global cattle methane source. It is concluded that geographically there are two maximum values of methane flux from the USSR which are formed by inputs from the different methane sources. The first methane flux maximum is located in the West Siberian Plain and is formed dominantly by gas and oil mining. The second methane flux maximum is located in the Ukraine and neighboring regions, and is formed by coal mining, wetlands and cattle.
1. INTRODUCTION Methane is an i m p o r t a n t component of atmospheric photochemistry and the climate system. At the present time the atmospheric methane concentration is increasing by 1% per year (Steele et al., 1987). Therefore, investigation of the cause of the rapid increase on the methane concentration is an extremely important problem. It is known that all methane sources are located on the Earth's surface and that the main 111
112
m e t h a n e sinks are located in the atmosphere. The inventory showed by Cicerone and Oremland (1988) indicated t h a t the main methane sources are wetlands, rice paddies, fossil fuel mining and cattle. Among these sources the l a s t three can be considered as anthropogenic sources. The Soviet Union is likely an i m p o r t a n t source of m e t h a n e because it is a principal producer of gas and oil, and because of its large area of wetlands. Unfortunately, there is only a limited amount of data about the regional distributions of wetlands and coal, oil and gas production in the USSR. This p a p e r includes estimations of the m e t h a n e fluxes from USSR wetlands, fossil fuel mining and cattle, and shows their possible geographical distributions.
2. METHANE FLUX FROM USSR WETLANDS 2.1. Methane Production from Wetlands The production of methane by natural ecosystems depends on the geochemical conditions in the soil and is controlled by soil temperature and soil moisture. Wetlands have sufficient soil moisture to create the effectively oxygen-free reducing conditions necessary for methane production. Consequently, if the geochemical soil conditions are uniform, the intensity of m e t h a n e production from wetlands is d e t e r m i n e d by the geographical distribution of temperature. The process of microbial m e t h a n e production from wetlands is shown schematically in Fig.1. Annually, there is input of organic m a t t e r (OM) to the soil. According to Kobak (1988) and Andersen (1985), the intensity of this input, G, mainly depends on climatic conditions. The biologic transformation of OM produces h u m u s which consists of two components: the biologically active (labile) h u m u s and the stable component ("the stable reservoir"). According to the estimates in Zavarzin (1984); Kononova (1976) and Kobak (1988), the range of the annual generation of h u m u s equals 2 - 10% of the mass of G. It follows from the data analysis presented in Zavarzin (1984) and Kobak (1988) that the labile h u m u s constitutes about 30 - 60% of the total humus. Thus, the amount the labile h u m u s matter, g, can be related to G by g = {0.02-0.1} x {0.3-0.6} G = {0.006-0.06} G .
(1)
According to Andersen (1985) and Kobak (1988), the labile part of humus consist mainly of humic acids and is biologically processed, with methane as one of the final products. We assume t h a t all the labile h u m u s is transformed into methane and that all the methane goes to the atmosphere. This gives an estimate of the upper limit of the m e t h a n e flux from wetlands, qmax, as qmaX = gmax = 0.06 G .
(2)
113
In accordance with the presentation in Kobak (1988), we divide the Earth's surface into the five climatic zones. The border of these climatic zones we choose as it is shown in Table 1, each having an average t e m p e r a t u r e from Babanova et al. (1986), T i , and intensity of the annual input of organic m a t t e r in carbon units from Kobak (1988), G i . Table 1 shows that G i decreases with decreasing temperature, with a m a x i m u m in the tropical climatic zone and minimum in the polar zone.
Organic m a t t e r of the E a r t h
Intensity of OM input into the soil G(T) 0.02 - 0.1
Soil OM
Humus
Intensity of OM destruction of OM in the soil (0.006-0.06) k/k
0.3 - 0.6 (T)
H2S , NH~
Labile humus
1.0
Soil methane
{
I
Intensity of the methane release to the atmosphere v
.....
I i
1.0
Atmospheric methane
]
CO
Fig. 1. Model of transformation of organic m a t t e r to methane (relative units).
Following Andersen (1985), we assume t h a t the intensity of the transformation of OM into humus is defined by
114
G.
1
ki - D
'
(3)
1
where D i is storage of organic carbon i n the soil. The t h i r d column of Table 1 lists the values of D i from K o b a k (1988), t h e d i s t r i b u t i o n of which g e n e r a l l y decreases w i t h i n c r e a s i n g temperature.
The f o u r t h c o l u m n of Table 1 lists the v a l u e s of k i , the reciprocal of which
corresponds to the life time of OM i n the soil. The OM life time is e s t i m a t e d to be 1/k4, 5 = 200 300 years for the boreal a n d polar climatic zones, 1/k 3 = 70 y e a r s for the s u b b o r e a l climatic zone, a n d 1/kl, 2 = 26 - 35 years for the t e m p e r a t e a n d tropical climatic zones. Following the surface t e m p e r a t u r e d i s t r i b u t i o n , the m a x i m u m r a t e of d e s t r u c t i o n occurs i n the tropical climatic zone, t h u s kl/kma x = 1 (see the fifth column of Table 1).
T a b l e 1. E s t i m a t e of the m e t h a n e flux from different climatic zones (T is global t e m p e r a t u r e , G is a n n u a l i n p u t organic m a t t e r into soil, D is carbon storage i n soil, qmaX is the a n n u a l m e t h a n e flux from m -2 of wetlands)
Climatic
Ti a
Gi b
(Di/103) b
k i ffi Gi/D i
ki/kma x
qi max
K
g(C) m 2 year
g(C) m2
1 year
_
297
390
10.3
0.038
1.0
31.2
286
370
12.9
0.029
0.763
22.6
275
220
14.6
0.015
0.395
7.0
~7
180
31.1
0.005
0.158
2.3
258
80
23.9
0.003
0.079
0.5
Zones
Tropical
g(CH4) m 2 year
(30ON- 30os) Temperate (50o - 30ON, 30° _ 50os) Subboreal (60° _ 50ON,500 _ 60os) Boreal (600 _ 70ON) Polar (700 _ 80ON) a)
b) (Babanova et al., 1986), (Kobak,1988) F i g u r e 2a d e m o n s t r a t e s the dependence of k/kma x on t e m p e r a t u r e a n d its l i n e a r regression
is k/kmax = 0.0253 T - 6.53 .
(4)
E q u a t i o n (4) allows e s t i m a t i o n of (k/kmax )o = 0.7 for the p r e s e n t global-mean t e m p e r a t u r e , To=
115
288 K. S i m i l a r l y , Fig. 2b shows t h e d e p e n d e n c e of G on t e m p e r a t u r e a n d i t s l i n e a r r e g r e s s i o n is G = 8.32T-
2.05x10
3
,
[g(C) m - 2 y e a r -1] .
(5)
E q u a t i o n (5) allows e s t i m a t i o n of G o = 346 g(C) m -2 y e a r -1 for To= 288 K. According to K o b a k (1988), t h e a n n u a l global OM i n p u t into soil is Go= 320 g(C) m-2 y e a r -1, w h i c h is 8% less t h a n the v a l u e e s t i m a t e d here.
1
I
(a)
I
0.8
0.8
0.6
_
0.4
_
0.2
_
0.6
E
/
-~
Global m e a n - for p r e s e n t c o n d i t i o n s _
0.4
0.2
0 250
• il
260
I
I
I
270
280
290
0 300
Temperature, K
450
I
(b)
t~ cD
I
I
I
450
350
350
250
250
150
150
c?
d
Q
50 250
I
260
I
I
270 280 Temperature, K
I
290
50 300
F i g . 2. T e m p e r a t u r e d e p e n d e n c e of (a) d e s t r u c t i o n r a t e of organic m a t t e r , a n d (b) a n n u a l i n p u t of organic m a t t e r into soil.
116
We relate the intensity of the OM destruction in soil with the methane flux to the atmosphere, qi, for each of the geographical climatic zones by
'
!
q~ - km a x ~ = {0.006-0.06}~--~x Gi
(6)
The sixth column of Table 1 lists the values of qmax, given by Eq. (6) for 0.06, and shows that the intensity of the methane release to the atmosphere decreases considerably from the tropics (ql = 31.2 g(CH4) m -2 year-l) to the polar regions (q5 = 0.5 g(CH4) m -2 year-l). Experimental data of the average diurnal and seasonal variations of the methane flux to the atmosphere from wetlands vary from 10 -4 to 10-1 g(CH4)/m2/day. Use of these data together with consideration of the length of the vegetation period for each the climatic zone leads to large uncertainties. Whalen and Reeburg (1988) estimate the annual methane flux to the atmosphere from wetlands located in the boreal/subboreal climatic zones as 0.48 - 8.0 g(CH4) m -2year-1. Comparison of this value with the corresponding values from Table 2 shows good agreement. 2.2. Estimation of Methane Production from USSR Wetlands The annual methane released from wetlands, FWTL, is given by FWT L --
SWTL q ,
(7)
where SWTL is the area of wetlands and q is the methane flux from wetlands. According to Maslov (1970), the area of wetlands in the USSR is 0.91.1012 m 2, 82% of which is located in the Russia, 6% in the Baltic States, 3% in the Ukraine, and 3% in Byelorussia. According to Glebov (1973), 89% of the wetlands of the Russia, with an area 0.67' 1012 m 2, is located in the West Siberian Plain. The orography of the USSR and the high level of continentality of the USSR significantly transform the borders of the climatic zones defined in Table 2, and this makes it difficult to estimate the m e t h a n e flux from wetlands in each climatic zone. Accordingly, we will assume that the distribution of climatic zones in the USSR corresponds to the distribution of soil types presented in the Geographic Atlas of the USSR (1989), with (1) the polar and boreal climatic zones defined as the set of the arctic, tundro-gleevoi, taiga and podzol soils, (2) the subboreal climatic zone defined as the dernovo-podsol soil, and (3) the temperate climatic zone given by the other soil types. Figure 3 demonstrates the resulting distribution of climatic zones in the USSR, based on soil types. This figure shows that the largest part (about 2/3) of the West Siberian Plain is located in the polar and boreal climatic zones, a small part located in the subboreal climatic zone; the Baltic States and Byelorussia are located in the subboreal climatic zone; the largest part (about 2/3) of Ukraine is located in the temperate climatic zone, with a small part located in the subboreal climatic zone. We now consider a scenario for maximum methane flux from USSR wetlands. According
ll7
to this scenario, 2/3 of t h e W e s t S i b e r i a n w e t l a n d s is located in t h e boreal c l i m a t e zone a n d 1/3 in the s u b b o r e a l zone. T h e m e t h a n e flux from t h e w e t l a n d s of t h e Baltic S t a t e s , B y e l o r u s s i a a n d U k r a i n e w a s e s t i m a t e d b y expression: (8)
FWTL = ~ Sik ~k q~ ' ~k
w h e r e Sik is t h e k - t h a r e a in t h e i - t h climatic zone, a n d jlk is a r a t i o of t h e w e t l a n d s a r e a to total a r e a in t h e k - t h zone. In Eq. (8) the product Sik ~lk defines the a r e a of t h e w e t l a n d s , SWTL, of t h e i - t h c l i m a t i c zone. T h e a r e a s of t h e Baltic S t a t e s a n d B y e l o r u s s i a together, a n d of t h e U k r a i n e w e r e t a k e n from S t a t i s t i c Y e a r b o o k (1990), a n d a r e 0.37.1012 m 2 a n d 0.6-1012 m 2, respectively. F o r t h e E u r o p e a n p a r t of U S S R , R o m a n o v (1962) e s t i m a t e d t h a t t h e w e t l a n d s of t h e s u b b o r r e a l climatic zone occupy as m u c h as 50% of the total area, a n d t h e w e t l a n d s of the t e m p e r a t e c l i m a t i c zone occupy a s m u c h a s 15% of t h e . t o t a l a r e a .
T h u s , t h e a r e a of t h e
w e t l a n d s of t h e Baltic S t a t e s a n d B y e l o r u s s i a t o g e t h e r a r e 50
60
70
80 .
.
.
.
.
,.t
,,
•
,,~ ~m.I
50
II i
60
i
I I
70
!
~ IR m ml I F i k !
80
I
,
m~l II
90
100
110
12 0
130
P o l a r a n d boreal climate (arctic, tundro-gleevoi, taiga, podzol soil) S u b b o r e a l c l i m a t e (dernovo-podzol soil) T e m p e r a t e c l i m a t e (other soil types) R
Region b o r d e r s
F i g . 3. Correspondence of U S S R climatic belts a n d soil types. Regions: 1 - Russia, 2 - Baltic States, 3 - Byelorussia, 4 - U k r a i n e , 5 - o t h e r regions.
118
0.19.1012 m 2, a n d t h e a r e a of t h e U k r a i n i a n w e t l a n d s is 0.09-1012 m 2. A c c o r d i n g to M a s l o v (1970), t h e s e w e t l a n d s c o m p r i s e 85% o f t h e t o t a l a r e a of U S S R w e t l a n d s .
For the maximum
scenario we a s s u m e t h a t t h e o t h e r U S S R w e t l a n d s a r e located in t h e t e m p e r a t e climatic zone. The l a s t c o l u m n o f T a b l e 2 p r e s e n t s t h e m e t h a n e e m i t t e d from U S S R w e t l a n d s c a l c u l a t e d u s i n g t h e above e s t i m a t e s of t h e m e t h a n e p r o d u c t i o n for t h e d i f f e r e n t c l i m a t i c zones. F r o m T a b l e 2 i t follows t h a t t h e m a x i m u m m e t h a n e e m i t t e d from U S S R w e t l a n d s by m i c r o b i a l activity is a b o u t 10 Tg(CH4)/year. A c c o r d i n g to Glotov et al. (1985), t h e r e is a n o t h e r source of m e t h a n e from t h e S i b e r i a n w e t l a n d s in a d d i t i o n to t h a t due m i c r o b i a l activity, n a m e l y , n a t u r a l l e a k a g e from t h e E a r t h ' s i n t e r i o r in r e g i o n s of p e r m a f r o s t . F r o m t h e d a t a of Glotev et al. (1985) we e s t i m a t e t h a t t h e a n n u a l m e t h a n e flux f o r m e d b y m i g r a t i o n p r o c e s s e s t h r o u g h t h e frozen soil is 2 - 8.10 -2 g(CH4) m - 2 y e a r -1. According to F o t i e v (1978), t h e a r e a of p e r m a f r o s t in the U S S R is 11.1.106 k m 2. C o n s e q u e n t l y , t h e a d d i t i o n a l m e t h a n e e m i t t e d from w e t l a n d s due to n a t u r a l l e a k a g e is about 0.2 - 0.9 Tg(CH4)/year. T h u s , t h e m a x i m u m m e t h a n e flux f r o m U S S R w e t l a n d s d u e to m i c r o b i a l a c t i v i t y a n d n a t u r a l l e a k a g e is e s t i m a t e d a s 11 Tg(CH4)/year.
Table
2. E s t i m a t e of U S S R w e t l a n d s m e t h a n e source (Sik is the k - t h a r e a in the i-th climatic
zone, gk is a r a t i o of t h e w e t l a n d s a r e a to total a r e a in the k - t h zone, SWTL is the w e t l a n d s a r e a , qmax is t h e a n n u a l m e t h a n e flux from m -2 of w e t l a n d FWTL is t h e m e t h a n e flux) Sik a
~tkb
SWTL
qi max
FWTL
C l i m a t i c Zone & Region 106 k m 2
.%
g(CH 4)
M t ( C H 4)
m 2 year
year
0.45
2.3
1.1
106 k m 2
Boreal
2/3 W e s t S i b e r i a n P l a i n
-
-
Subboreal
1/3 W e s t S i b e r i a n P l a i n Baltic S t a t e s & B y e l o r u s s i a
-
-
0.22
7.0
1.6
0.37
50
0.19
7.0
1.4
0.6 -
15 -
0.09 0.15
22.6 22.6
2.1 3.4
Temperate
Ukraine Other wetlands
Total a)
b) (Statistical Yearbook, 1990), (Romanov, 1962)
0.86
9.6
119
3. M E T H A N E F L U X F R O M U S S R F O S S I L F U E L M I N I N G 3.1. Coal M i n i n g M e t h a n e is k n o w n to b e l o c a t e d in coal deposits, b u t such m e t h a n e is n o t u t i l i z e d in t h e U S S R (Ettinger, 1988). We e s t i m a t e t h e m e t h a n e flux from coal m i n i n g b y Fcoal = ~oal Vcoal '
(9)
w h e r e Vcoal is t h e a m o u n t of coal m i n e d a n n u a l l y a n d qcoal is t h e a m o u n t of m e t h a n e e m i t t e d p e r t e n of coal mined. According to U S S R Coal I n d u s t r y (1989) t h e coal p r o d u c t i o n of U S S R i n c r e a s e d a t a m e a n r a t e of 8% p e r y e a r from 1970 to 1988. According to Geological E n c y c l o p e d i a (1990) coal in the U S S R is m i n e d p r e d o m i n a n t l y in t h r e e regions; t h e Donetski, K u z n e t s k i , a n d K a r a g a n d i n s k i a n d E k i b a s t u z coal r e g i o n s , w h i c h t o g e t h e r c o n t r i b u t e m o r e t h a n 80% of t h e t o t a l coal p r o d u c t i o n of t h e U S S R . T h e d a t a from Geological E n c y c l o p e d i a (1990) p r e s e n t e d in the first column of Table 3.
Table 3. E s t i m a t e of U S S R coal m i n i n g m e t h a n e source (Vcoal is coal production in 1988, qcoal is gas factor for coal) Coal r e g i o n
Vcoal (1988) 106 t / y e a r
qeoal kg (CH 4)
Methane Flux Tg (CH4)/year
1.
Donetski
198.
0.7 - 23 (36")a
0.13 - 4.6 (7.1")
5. 4.
Kuznetski Karagandinski
154.
0.7 - 14a
0.10 - 2.2
and Ekibastuz
143.
8 - 11 (31")b
1.14 - 1.6 (4.4*)
3.
Pechorski
32.
2 - 20 (50")a 2 - 24 c
0.06 - 0.6 (1.6")
Other regions
82.
0 - 24
0.0 - 2.0
Total
609
1.4 - 11.0 (17.3")
a) (Zorkin, 1986); b) (Ksenofontova et al., 1960); c) (Ettinger, 1988); *) maximum possible value T h e r e a r e s e v e r a l e s t i m a t e s of t h e gas factor for coal - t h e a m o u n t of m e t h a n e e m i t t e d p e r ton of coal m i n e d , w h i c h is e q u a l to t h e a m o u n t of gas s a t u r a t e d in t h e coal - for the different coal regions of t h e U S S R .
T h e second c o l u m n of T a b l e 4 p r e s e n t s t h e s e e s t i m a t e s , a n d the
120
m a x i m u m p o s s i b l e v a l u e s of t h e g a s factor for t h e D o n e t s k i , K a r a g a n d i n s k i a n d P e c h o r s k i coal regions a r e p r e s e n t e d i n t h e p a r e n t h e s e s .
F r o m t h e s e e s t i m a t e s a n d t h e p r o d u c t i o n for
t h e U S S R coal r e g i o n s , t h e m e t h a n e flux from coal m i n i n g is e s t i m a t e d to be 1 - 12 Tg (CH4)/year , w i t h a m a x i m u m - p o s s i b l e v a l u e 18 Tg(CH4)/year. 3.2. Oil a n d G a s M i n i n g M e t h a n e is also l o c a t e d i n oil deposits, b u t a l m o s t all such m e t h a n e is utilized. However, s m a l l l o s s e s of m e t h a n e occur d u r i n g oil m i n i n g , s t o r a g e a n d t r a n s p o r t a t i o n . losses also occur d u r i n g g a s m i n i n g , s t o r a g e a n d t r a n s p o r t a t i o n .
S m a l l gas
Unfortunately, there has
not b e e n a complete i n v e n t o r y of t h e m e t h a n e losses due to g a s a n d oil m i n i n g in t h e USSR. To e s t i m a t e t h e m e t h a n e losses from oil m i n i n g we use Foi1 = a ~ T V o i 1 ,
(10)
w h e r e a is t h e g a s c o n t e n t of oil, [~ is the m e t h a n e s h a r e of this gas, T is the e v a p o r a t i o n factor for oil, a n d VoiI is t h e a m o u n t of oil m i n e d a n n u a l l y . S t a t i s t i c a l Yearbook, (1990) p r e s e n t s U S S R oil production from 1970 to 1988. According this d a t a from 1970 to 1980 oil p r o d u c t i o n monotonically i n c r e a s e d a t a m e a n r a t e of 8% p e r year. After 1980 oil p r o d u c t i o n leveled off a n d t h e m e a n r a t e of oil production from 1980 to 1988 was d r o p p e d to 0.3% p e r year, a n d i n 1988 y e a r oil p r o d u c t i o n w a s VoiI = 624 Tg.
The m a i n oil
p r o d u c i n g region of t h e U S S R is t h e W e s t S i b e r i a n region. I n 1980 t h i s region provided 53% of t h e t o t a l oil p r o d u c t i o n of t h e U S S R , a n d m o r e t h a n 67% in 1985.
We interpolated data
p r e s e n t e d b y S t a t i s t i c a l Yearbook, (1990) for t h e W e s t S i b e r i a n region given for 1980 - 1985 period on 1985 - 1988 p e r i o d w i t h a s s u m p t i o n of a m e a n r a t e i n c r e a s e of 4.8% p e r year. Thus, we o b t a i n e d Voi! (West Siberia, 1988) = 481 Tg. A c c o r d i n g to Z o r k i n (1986), t h e m e a n gas c o n t e n t of oil m i n e d in t h e U S S R is 60 m3/t (43 kg/t). The g a s c o n t e n t of oil m i n e d in t h e W e s t S i b e r i a n region is 20 - 120 m3/t (14 - 86 kg/t), w i t h a m e a n v a l u e of 70 m3/t (50 kg/t) w h i c h is m u c h l a r g e r t h a n t h e m e a n v a l u e for the USSR. The m e t h a n e contents of t h e gas a c c o m p a n y i n g t h e oil, a n d the gas dissolved in the oil a r e 70 - 90% a n d 5 - 15%, respectively. Also, a c c o r d i n g to t h e e s t i m a t e s of T o m a s h p o l s k i (1968), oil c a n e v a p o r a t e b y a s m u c h a s 14% from t h e t i m e of m i n i n g to t h e t i m e of consumption. F r o m t h e s e d a t a we t a k e t h e following v a l u e s for the p a r a m e t e r s in Eq. (10): = 43 kg/t of m i n e d oil, [~ = 0.5 (~min = 0.05, ~max = 0.95), a n d T = 0.14. F o r oil m i n e d in t h e W e s t S i b e r i a n region, a = 50 kg/t (ami n = 14 kg/t, areax = 86 kg/t). F r o m t h e e s t i m a t e s p r e s e n t e d above we e s t i m a t e t h e m e t h a n e flux f r o m oil m i n i n g in U S S R for 1988 y e a r a s 1.9 Tg(CH 4) a n d t h e n o m i n a l m e t h a n e flux from W e s t S i b e r i a as 1.7 Tg(CH 4) w i t h t h e m a x i m u m v a l u e 2.9 Tg(CH4). U s i n g t h e m a x i m u m v a l u e of t h e gas content of oil, area x = 86 kg/t, a n d t h e m a x i m u m v a l u e of t h e m e t h a n e c o n t e n t of oil, ~max = 0.95, we e s t i m a t e t h e m a x i m u m m e t h a n e losses from oil m i n i n g in 1988 as 7.2 Tg(CH4). Thus, we e s t i m a t e t h e U S S R m a x i m u m v a l u e of m e t h a n e source in 1988 d u e to oil m i n i n g as 7.2 Tg(CH4).
121
It follows from Zorkin (1986), t h a t the oil regions of the USSR are also the gas regions. For the m e t h a n e losses during gas mining we take the estimate derived by Barns and Edmonds (1990) t h a t gas losses from the time of mining to the time of consumption are 2% of the total amount of the gas mined. Statistical Yearbook, (1990) presents USSR gas production from 1970 to 1988. From this data it follows t h a t gas mining increased during the entire period at 16% per year and at 1988 USSR gas production was Vgas = 552 Tg, and we estimate the methane losses from USSR gas mining as 11 Tg(CH4). In 1980 the main region of the USSR gas mining, West Siberia, produced 29% of the total amount, and 60% in 1986. We interpolated the increase rate of West Siberia gas production of 10% per year from 1980 - 1986 period given by Statistical Yearbook, (1990) on 1986 -1988 period. Thus, we obtained Vgas (West Siberia, 1988) = 339 Tg. From this data we estimated t h a t West Siberia contributed 6.8 Tg(CH4). Summing the contributions for coal, oil and gas, the total m a x i m u m amount of methane emitted in 1988 from fossil fuel mining in the USSR was 30 Tg(CH 4) with m a x i m u m possible value 37 Tg(CH4).
4. METHANE FLUX FROM USSR CATTLE To estimate the m a x i m u m m e t h a n e flux from USSR cattle we use the upper limit of methane emission from a single animal (milk cattle) cited by Crutzen et al. (1986), 95 kg (CH 4) per year and data from Statistical Yearbook (1990) about USSR cattle 120.106 for 1988 year. Using these data we estimate that the m a x i m u m methane flux from USSR cattle in 1988 was
12Wg. 5. ESTIMATE OF GEOGRAPHICAL DISTRIBUTION OF USSR METHANE SOURCE To estimate the geographical distribution of the USSR m e t h a n e sources we divide the USSR into 5 °x 10 ° latitude-longitude grid boxes and determine the m e t h a n e source at each grid node using the following rules: (1) if a region having methane source O (Tg/year) occupies n grid nodes, then the source at each node is O/n. For example, the boreal wetlands of the West Siberian Plain occupy the area between longitudes 60°W - 90°W and latitudes 60°N - 65°N (Fig. 3) and includes 8 nodes with coordinates (65°N, 60°W), (65°N, 70°W), (65°N, 80°W), (65°N, 90°W), (60°N, 60°W), (60°N, 70°W), (60°N, 80°W) and (60°N, 90°W). Thus, for each of these nodes the methane source from boreal wetlands is one-eight of 1.1 Tg/year (Table 2); (2) if a methane source region crosses only one side of a grid box, then the source at each of the two nodes of this side is 0/2. For example, the Donetski coal region (Fig. 4) crosses the side of the grid box at longitude 40°W between 45 °- 50°N. Thus, the methane source at nodes (50°N, 40~vV) and (45°N, 40~N) is one-half of 7.1 Tg/year (Table 3); (3) if the m e t h a n e source region lies completely within a grid box, then the source at each four its node is @/4; (4) the total m e t h a n e source was obtained by summing the separate sources at the grid
122
node. 50
60
70
80
"
50
60
'
70
80
90
100
110
,
120
130
Fig. 4. USSR coal mining regions To estimate distribution of methane flux from wetlands we used data presented in Section 2 and according this data the contribution of wetlands to the total methane USSR source distribution is small. This is because the largest area of USSR wetlands is located in the permafrost region where the microbial methane production is low. To estimate distribution of methane flux from USSR cattle we used the data presented by Statistical Yearbook (1990) for separate republics. According to this data the dominate cattle methane source is located in the southwest region of the USSR. For the other regions the contribution to the total methane distribution for the USSR of this source is small. To estimate the methane distribution from USSR coal, oil and gas mining we used data presented in Section 3. Figure 4 presents the distribution of the USSR coal regions (Zorkin et al., 1986). From our estimates it follows that a considerable methane source located in the Ukrainian region. The methane distributions from the USSR oil and gas mining are most uncertain because there are not available data for all regions of the USSR. The distribution of the oil and gas regions over USSR presented on Fig. 5. To obtain the methane distribution from the USSR oil mining we used the data from Atmosphere (1991) for the hydrocarbon gas inputs to the atmosphere by the USSR regional oil industry. From these data we obtained that the contribution of the oil industry to the total methane source distribution is small. To obtain the m e t h a n e distribution from the USSR gas mining we assume that the main methane losses exist only in the gas mining region. This assumption was made because there are not data for the gas losses in the USSR. But the indirect data of Haritonovski (1990) show that the largest number of pipeline troubles (consequently, methane losses) exists in permafrost conditions where the main USSR gas region is located. We estimated that gas mining in the region 60 °-- 70°N and 50 °- 90°W is the main methane source.
123
50
60
70
80
~j]~ I ~ l ] , ~ , ~ ~ ~ : ~ ~ ~ ~!.~! ~ . ~ L',/-"~~I ~ ~ ,
J
rski 2 - Vol_go-Uralski ~x, 3-Prikaspiyiski ~ " 4 - Amudariyinski ~[~ 5 - North-Cavcazki " ~ ~ 6 - Wes~ Siberia ~_~
f ,~'.".'~t h e ~ ~ 50
60
70
80
90
1 O0
110
120
130
Fig. 5. USSR gas and oil mining regions Table 4 presents the estimated distribution of the total USSR methane source as the sum of the five sources, wetlands, cattle, and coal, oil and gas mining, estimated above. It can be seen that there are two maxima, one in the West Siberian Plain, 55 °- 65°N and 60 °- 80°W, and another in the Ukraine, 45 °- 50°N and 30 °- 40°W. We conclude that the maximum values of the methane source in the USSR are due to different methane sources. The maximum methane source in the West Siberian Plain is formed predominantly by gas mining, while the maximum methane source located in the Ukraine and surrounding territories is formed by coal mining, wetlands and cattle. T a b l e 4. Estimate of methane source distribution in the USSR
70°N 65°N 60°N 55°N 50°N 45°N 40°N 35°N
20°W
30°W
40°W
50°W
60°W
0.0 0.0 0.6 1.4 1.0 0.0 0.0 0.0
0.0 0.4 0.5 1.4 1.2 1.3 0.0 0.0
0.0 0.2 0.1 0.9 3.5 3.7 0.1 0.0
0.0 0.2 0.2 0.9 0.2 0.3 0.1 0.0
0.0 3.3 0.4 1.0 0.1 0.2 0.4 0.1
70°W
80°W
90°W
0.0 2.3 0.9 0.7 0.9 0.1 0.7 0.1
0.0 2.1 0.9 1.7 0.9 0.1 0.6 0.0
0.0 0.0 0.4 1.5 0.0 0.0 0.0 0.0
124
6. CONCLUSIONS Table 5 presents the estimate of the total methane source from the USSR. This table shows that the main methane source of the USSR is fossil fuel mining, which contributes half of the total value. Using the inventory from Cicerone and Oremland (1988) we estimated that the USSR methane sources contribute 11% of the global value. The methane source due to USSR fossil fuel mining contributes 43% of the global fossil fuel source, but the inventory in Cicerone and Oremland (1988) for the latter does not include methane losses from the oil mining. The methane source from USSR cattle contributes 9% of the global cattle methane source. The methane source due to USSR wetlands contributes 10% of the global wetlands source if the global wetlands source is equal to 115 Tg (Matthews and Fang, 1987), and 13% if the global wetlands source is 86 Tg (Andronova, 1990, 1991).
T a b l e 5. Estimate of the total USSR methane source (maximum value). Methane Source
CH 4 ( T g / y e a r )
Wetlands 11.0 Fossil fuel mining coal oil gas Cattle
Total
30.0 (34.0*) 12.0 (18.0") 8.0 11.0 12.0
52.0 (57.0*)
*) maximum possible value
Acknowledgements: The authors express their gratitude to Professor M. E. Schlesinger for editing their English and for useful discussions.
REFERENCES Andersen, D.M. (1985), Ecolo~v and Environmental Sciences: Biosvhere. Ecosvstem. and Human. Gidrometizdat, Leningrad, 160 pp. (in Russian). Andronova, N. G. (1990), The role of natural wetlands in the evolution of land sources of methane. EOS, AGU October 1990, 71, n 43, A21B-3. Andronova, N. G. (1991), The role of natural wetlands and anthropogenic sources in the geographic distribution CH4 flux to atmosphere. Met~qrolo~a and Gidrolo~a. 8, 36 - 42. Atmosvhere (handbook) (1991), Gidrometizdat, Leningrad. 600 pp. (in Russian).
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Babanova, V. V., A. P. Kudrayvtzev and V. A. Frolkis (1986), Two-dimensional modelling the global zonal distributions of t e m p e r a t u r e and concentrations of the m i n o r gases in troposphere and stratosphere. In Radiative-Photochemical Atmospheric Models. Karol, I. L. (ed), Leningrad, Hydrometizdat, 192 pp. (in Russian). Barns, D. W., and J. A. Edmonds (1991), An Evaluation of the Relationshio Between the PrQduction and Use of Energy and Atmosoheric Methane Emission. Report under Contract No. DE-AC06-76OR-1830, 300 pp. Cicerone, R. J., and R. S. Oremland (1988), Biogeochemical aspects of atmospheric methane. G10b. Bio~eochem. Cvcles. 2. 299-327. Crutzen, P. J., I. Aselmann and W. Seiler (1986), Methane production by domestic animals, wild ruminants, other herbivorous fauna, and humans. Tellus. 38B, 271-284. Ettinger I. L. (1988), Unlimited Stores and Unoredictable Catastrophes. Nauka, Moscow, 170 pp. (in Russian). Fotiev, S. M. (1978), The Hvdrothermic Peculiarities of the USSR Permafrost Re~ion. Nauka, Moscow, 235 pp. (in Russian). Geolo~ical EncycloDedia (1990), "Geologia", Moscow. 800 pp. (in Russian). Geographical Atlas of USSR (1989) The main administration of geodesia and kartographia, Moscow, 32 pp. (in Russian). Glebov F. Z. (ed.) (1973), The Complex Estimation of Are~ of Swamp~ and of the Wetland Forests for their Melioration, Nauka, Moscow, 250 pp. (in Russian). Glotov, V. U., V. V. Ivanov and O. V. Tsherban (1985), The changes of the hvdrocarbons content of soils and mosses as the oil and gas index. Siberian AN USSR, Magadan, 16 pp. (in Russian). Haritonovski V. V. (1990), Increasing of the Pi~e Line's Durability in the CQmplicated Conditions. Nedra, Leningrad, 179 pp. (in Russian). Kobak K. I. (1988), Biotic Components of Carbon Cvcle. Gidrometizdat. Leningrad, 247 pp. (in Russian). Kononova M. M. (1976), Formation of h u m u s in soil and its destruction. Advances in Microbiolo~¢. 11, 134-151. (in Russian). Maslov B. S. (1970), The R e , m e of the Ground W a t e r of Wetland~ and it~ Regulation. "Kolos", Moscow, 301 pp. (in Russian). M a t t h e w s E. a n d I. F u n g (1987), Methane emission from n a t u r a l wetlands: Global distribution, area and environmental characteristics of sources, Glob. Bio~eochem. Cvcles. v. 1, n. 1, 61-86.
126
Romanov V. V. (1962), E v a o o r a t i o n in the Wetlands of the E u r o o e a n P a r t of USSR. Gidrometizdat. Lenin a'rad. 250 pp. (in Russian). Statistical Yearbook (1990), BSE (the third issue), Moscow. (in Russian). Steele, L. P., P. J. Fraser, R. A. Rasmussen, M. A. K. Khalil, T. J. Conway, A. J. Crawford, R. H. Gammon, K. A. Masarie and K. W. Thoning (1987), The global distribution of methane in the troposphere. J. Atm. Chem. 5, 125 -171. Tomashpolski L.M. (1968), Oil and Natural Gas in the Global Enera, v Budget (1900-2(}00}. "Nedra", Moscow, 250 pp. (in Russian). The USSR Coal Industry (short handbook} (1989), The USSR coal Ministry, Moscow, 20 pp. (in English and in Russian). Whalen S. C. and W. S. Reeburg (1988), A methane flux time series for tundra environments. Glob. Bio~eochem. Cycles, 2, n. 4, 399-409. Zavarzin G. A. (1984), Bacteria and Atmosoheric Comoosition. Nauka, Moscow, 207 pp. (in Russian). Zorkin L. M. et al. (1986), Methane in Our Life. Nauka, Moscow, 150 pp. (in Russian).