consequences of feasible future agricultural land-use change on soil organic carbon stocks and...
TRANSCRIPT
Consequences of feasible future agricultural land-usechange on soil organic carbon stocks and greenhouse gasemissions in Great Britain
P. Smith1 , A. Bhogal
2 , P. Edg ington3 , H. Black
4 , A. L i lly4 , D. Barraclough
5 , F. Worrall6 ,
J . H i ll ier1 & G. Merr ington
7
1Institute of Biological & Environmental Sciences, School of Biological Sciences, University of Aberdeen, 23 St Machar Drive,
Room G45, Aberdeen AB24 3UU, Scotland, UK, 2ADAS Ltd, Gleadthorpe Research Centre, Meden Vale, Mansfield, Notts NG20
9PF, UK, 3ADAS Ltd, Wolverhampton Research Centre, Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UK, 4Macaulay
Institute, Craigiebuckler, Aberdeen AB15 8QH, UK, 5Environment Agency, Rio House, Waterside Drive, Aztec West,
Almondsbury, Bristol BS32 4UD, UK, 6Department of Earth Sciences, Durham University, Science Labs, Durham DH1 3LE, and7WCA Environment Ltd, Brunel House, Volunteer Way, Faringdon Oxfordshire SN7 7YR, UK
Abstract
The aim of this study was to assess the consequences of feasible land-use change in Great Britain on
GHG emissions mainly through the gain or loss of soil organic carbon. We use estimates of per-area
changes in soil organic carbon (SOC) stocks and in greenhouse gas (GHG) emissions, coupled with
Great Britain (GB) county-level scenarios of land-use change based on historical land-use patterns or
feasible futures to estimate the impact of potential land-use change between agricultural land-uses. We
consider transitions between cropland, temporary grassland (<5 yr under grass), permanent grass
(>5 yr under grass) and forest. We show that reversion to historical land-use patterns as present in
1930 could result in GHG emission reductions of up to ca. 11 Mt CO2-eq. ⁄ yr (relative to a 2004
baseline), because of an increased permanent grassland area. By contrast, cultivation of 20% of the
current (2004) permanent grassland area for crop production could result in GHG emission increases
of up to ca. 14 Mt CO2-eq. ⁄ yr. We conclude that whilst change between agricultural land-uses
(transitions between permanent and temporary grassland and cropland) in GB is likely to be a limited
option for GHG mitigation, external factors such as agricultural product commodity markets could
influence future land-use. Such agricultural land-use change in GB could have significant impacts on
Land-use, Land-Use Change and Forestry (LULUCF) emissions, with relatively small changes in land-
use (e.g. 5% plough out of grassland to cropland, or reversion of cropland to the grassland cover in
Nitrate Vulnerable Zones of 1998) having an impact on GHG emissions of a similar order of
magnitude as the current United Kingdom LULUCF sink. In terms of total UK GHG emissions,
however, even the most extreme feasible land-use change scenarios account for ca. 2% of current
national GHG emissions.
Keywords: soil organic carbon, land-use change, Great Britain, agriculture, mineral soils
Introduction
Globally soils contain around 1500 Pg (Pg = 1015 g =
1000 Mt) carbon (C) in the top metre, roughly twice the
amount of carbon in the atmosphere as CO2 and about three
times the amount in global vegetation (Smith, 2004; IPCC
WGI, 2007). In Great Britain (GB: England, Wales and
Scotland; UK = GB plus Northern Ireland), soils contain
4266 Mt C (Bradley et al., 2005; Dawson & Smith, 2007) to
1 m. Soils under croplands are estimated to contain
701 Mt C, under semi-natural lands 1929 Mt C, under
pasture land 1189 Mt C and under forest 380 Mt C (Bradley
et al., 2005). Bradley et al. (2005) do not provide estimates
for permanent and temporary grasslands separately, but the
carbon content of permanent grasslands (>5 yr under grass)Correspondence: P. Smith. E-mail: [email protected]
Received May 2010; accepted after revision May 2010
Soil Use and Management, December 2010, 26, 381–398 doi: 10.1111/j.1475-2743.2010.00283.x
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science 381
SoilUseandManagement
is greater than that of temporary grasslands (<5 yr under
grass), which in turn is greater than that of croplands
(Table 1).
Land-use change is known to lead to changes in soil
carbon content (Smith et al., 1997, 2000a; Guo & Gifford,
2002), with tillage generally reducing the SOC stock
(Johnston, 1973; Guo & Gifford, 2002). Similarly, when
croplands are converted to grasslands or forest, SOC stocks
tend to increase (Johnston, 1973; Jenkinson, 1990; Guo &
Gifford, 2002; Johnston et al., 2009).
Globally, land-use change and land management change in
the agricultural sector have significant greenhouse gas (GHG)
mitigation potential. Smith et al. (2007, 2008) estimate the
yearly global mitigation potential in agriculture to be 4200,
2600 and 1600 Mt CO2-eq. ⁄ yr at 100, 50 and 20 USD ⁄ t CO2-
eq, respectively. The mitigation potential is cost competitive
with the potential estimated for other sectors such as forestry,
energy, transport, industry (Barker et al., 2007), showing that
agriculture has a significant role to play in addressing climate
change. The value of greenhouse gases that could be
mitigated each year in global agriculture is equivalent to
420 000, 130 000 and 32 000 Million USD ⁄ yr for C prices of
100, 50 and 20 USD ⁄ t CO2-eq., respectively (Smith & Olesen,
2010). Almost 90% of the global total agricultural mitigation
potential arises either from soil carbon sequestration in
mineral soils, or through carbon emission reduction in
cultivated carbon-rich soils such as peats.
There have been some previous estimates of the carbon
sequestration potential in UK croplands (Smith et al., 2000b),
with limited attempts to include other greenhouse gases
(Smith et al., 2000c). The aim of this paper is to assess for
UK the consequences of feasible land-use change on GHG
emissions, mainly through the gain or loss of soil organic
carbon. We consider transitions between cropland, temporary
grassland (<5 yr under grass), permanent grass (>5 yr
under grass) and forestry. We use county-level land-use data
and soil types, estimated GHG flux change factors, and
scenarios of land-use change based on historical (1930) and
recent (1998) land-use patterns and a range of feasible ‘worst
case’ scenarios to estimate the likely annual and 20 yr
change in GHG fluxes for each county and country of Great
Britain.
Materials & methods
The approach in this paper is similar to that used by Smith
et al. (1997, 1998, 2000a,b) and Freibauer et al. (2004) to
estimate changes in SOC because of land-management ⁄ land-use change. The approach uses estimates of SOC change on a
per-area basis under land-use and management change
derived from previous long term experiments, and scenarios
of land-use change to estimate total change in SOC for a
whole area, in this case Great Britain. In the following
sections, we (a) outline the per-area SOC change factors and
also the few cases where nitrous oxide flux changes are
estimated and give sources for their derivation, (b) provide
details of the land-use change scenarios and how they were
derived, and (c) describe the calculation method.
Per-area mitigation potentials
Table 2 shows the per-area mitigation potentials for land-use
change used in this analysis. The factors used were derived
from mineral soils, and in the absence of adequate data for
organo-mineral soils, are assumed also to apply to organo-
mineral soils. Organic soils are treated differently as
explained at the end of this section. For mineral soils, there
were insufficient data for estimating changes in baseline
methane emission ⁄oxidation under land-use change, but for
three land-use changes, there was sufficient information to
estimate changes in baseline nitrous oxide after land-use
changes.
The SOC ⁄nitrous oxide flux change was estimated in the
following ways. For permanent grass to cropland, the SOC
figures were derived from the Rothamsted Highfield and
Fosters, and the Woburn ley-arable field trials (Johnston,
1973). At the Highfield and Fosters sites, reseeded grass (i.e.
cropland converted to permanent pasture) was shown to be
2.9–3.5% greater in SOC stock each year (annualised) than
crop fields. We assume that conversion causes loss of 2.9–
3.5% of SOC per year. Using a mean cropland SOC stock of
84 t C ⁄ha to 30 cm depth (Smith et al., 2000b), this is
equivalent to a decrease in SOC of 2.4–2.9 t C ⁄ha ⁄ yr = 8.4–
10.6 t CO2-eq. ⁄ yr. The mean is taken as the middle of this
range. For the reverse transition, cropland to permanent
grassland, the global figures for conversion of temperate-
moist cropland to permanent grassland set-aside from Smith
et al. (2008) were used. This also has a nitrous oxide
component (see Smith et al., 2008 for full details).
For permanent grass to temporary grass (in a ley-arable
rotation), figures were derived from the Rothamsted
Highfield and Fosters, and the Woburn ley-arable field trials
(Johnston, 1973). In the Highfield and Fosters trials, reseeded
Table 1 Topsoil (0–15 cm) carbon stocks for cropland, temporary
and permanent grassland in Britain
Land-use
England and
Walesa Scotlandb
% C t C ⁄ hac % C t C ⁄ hac
Cropland 3.13 61.0 3.54 69.0
Temporary grassland 3.84 74.9 4.95 96.5
Permanent grassland 5.05 98.5 7.24 141.2
aNational Soil Inventory data 1983 (McGrath & Loveland, 1992).bLilly et al. (2010) (Macaulay Institute). cAssumes ‘standard’ bulk
density of 1.3 g ⁄ cm3 and soil depth of 15 cm (i.e. 1950 t ⁄ ha topsoil).
382 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
grass was shown to be 2.4–2.7% lower in SOC stock each
year (annualised) when converted from permanent grass to
ley-arable rotation, so conversion is assumed to cause a loss
of 2.4–2.7% of SOC per year. A mean cropland SOC stock
of 84 t C ⁄ha to 30 cm depth (Smith et al., 2000b) is
equivalent to a decrease in SOC of 2.0–2.3 t C ⁄ha ⁄ yr = 7.4–
8.3 t CO2-eq. ⁄ yr. A mean of 7.85 t CO2-eq. ⁄ha ⁄ yr is used.
For the reverse transition, temporary grassland to permanent
grassland, in the absence of better data, the same values are
used for the increase in SOC (with different sign).
For permanent grass to forestry (which features only as a
small component of the reversion to 1998 NVZ grassland
areas scenario – see below), the 10–20% SOC loss estimates
from Guo & Gifford (2002) were used, which is scaled to UK
soils at 8.4–16.8 t C ⁄ha over 20 yr. The 20 yr transition
period is assumed (IPCC, 1997, 2006 – see also below in
section ‘methods of calculation’) giving a loss over 20 yr (as
per IPCC, 2006) of 0.42–0.84 t C ⁄ha ⁄ yr = 1.5–3.0 t CO2-
eq. ⁄ha ⁄ yr. A mean of 2.25 t CO2-eq. ⁄ha ⁄ yr is used. For the
reverse transition, forestry to permanent grass, the ca. 10%
increase figure of Guo & Gifford (2002) is used. Using the
same conversion, this gives a gain estimate of 1.54 t CO2-
eq. ⁄ha ⁄ yr, with the same figure used for mean, minimum and
maximum in the absence of better data.
For cropland to temporary grass, reseeded permanent
grassland soils were shown to have a 2.9–3.5% higher SOC
stock each year (annualised) than cropland in the
Rothamsted Highfield and Fosters, and Woburn ley-arable
trials. At the same sites, ley-arable rotations were shown to
have a 0.3–0.8% higher SOC stock each year (annualised)
than croplands, hence ley-arable grass is up to 10 times less
effective than permanent grass in sequestering carbon. For
this reason the temperate-moist ‘cropland to permanent
grass’ figures from Smith et al. (2008) (including a nitrous
oxide component) were divided by 10. For the reverse
transition, temporary grass to cropland, the temporary
grassland increases of 0.2–0.87% SOC per year (annualised)
relative to cropland in Rothamsted Highfield and Fosters,
and Woburn ley-arable trials (Johnston, 1973), were used.
Temporary grassland to cropland conversion was therefore
assumed to cause a loss of 0.2–0.9% of SOC per year. Using
a mean cropland SOC stock of 84 t C ⁄ha to 30 cm depth
(Smith et al., 2000b) gives an equivalent decrease in SOC
of 0.17–0.67 t C ⁄ha ⁄ yr = 0.62–2.46 t CO2-eq. ⁄ yr. We have
used a mean of 1.54 t CO2-eq. ⁄ha ⁄ yr.For cropland to forest conversion, the previous value used
by Smith et al. (2000a), based on Rothamsted cropland to
natural woodland reversion experiments was adopted. The
value of 1.59 t CO2-eq. ⁄ha ⁄ yr was used for mean, minimum
and maximum in the absence of better data. For the reverse
transition, forest to cropland, the Guo & Gifford (2002)
figures of 30–50% loss on converting forest to cropland were
used which scales to 25.2–42 t C ⁄ha over 20 yr for UK soils.
If the change is assumed to occur over 20 yr (as per IPCC,
1997, 2006), this is 1.26–2.1 t C ⁄ha ⁄ yr = 4.62–7.70 t CO2-
eq. ⁄ha ⁄ yr. A mean of 6.16 t CO2-eq. ⁄ha ⁄ yr was used.For temporary grassland to forestry, there are no reliable
data, so the same value was used as for cropland to forestry.
Similarly, for forestry to temporary grassland, the same value
as for forestry to cropland was used (see above).
For organic soils, cultivation and drainage (assumed
to occur for land-use transitions: semi-natural
vegetation ⁄ permanent grassland to cropland or temporary
grassland) were assumed to follow the pattern used by Smith
et al. (2008) and result in a large carbon loss, a small decrease
in methane emissions and a slight decrease in nitrous oxide
emissions (Table 3). Reversion of croplands or temporary
grassland to semi-natural vegetation or permanent grassland on
Table 2 Estimates of change in SOC stocks and nitrous oxide emissions resulting from land-use change on mineral and organo-mineral soils. All
estimates expressed in t CO2-eq. ⁄ ha ⁄ yr as per Smith et al. (2008). For derivation of estimates, see text
Land-use Change
CO2 (t CO2 ⁄ ha ⁄ yr) N2O (t CO2-eq. ⁄ ha ⁄ yr) All GHG (t CO2-eq. ⁄ ha ⁄ yr)
Mean
estimate Low High
Mean
estimate Low High
Mean
estimate Low High
Permanent grass to cropland )9.50 )8.40 )10.60 0.00 0.00 0.00 )9.50 )8.40 )10.60Permanent grass to temporary grass )7.85 )7.40 )8.30 0.00 0.00 0.00 )7.85 )7.40 )8.30Permanent grass to forestry )2.25 )1.50 )3.00 0.00 0.00 0.00 )2.25 )1.50 )3.00Cropland to permanent grass 3.04 1.17 4.91 2.30 0.00 4.60 5.34 1.17 9.51
Cropland to temporary grass 0.30 0.12 0.49 0.23 0.00 0.46 0.53 0.12 0.95
Cropland to forestry 1.59 1.59 1.59 0.00 0.00 0.00 1.59 1.59 1.59
Temporary grass to permanent grass 7.85 7.40 8.30 0.00 0.00 0.00 7.85 7.40 8.30
Temporary grass to cropland )1.54 )0.62 )2.46 0.00 0.00 0.00 )1.54 )0.62 )2.46Temporary grass to forestry 1.59 1.59 1.59 0.00 0.00 0.00 1.59 1.59 1.59
Forestry to permanent grassland 1.54 1.54 1.54 0.00 0.00 0.00 1.54 1.54 1.54
Forestry to cropland )6.16 )4.62 )7.70 0.00 0.00 0.00 )6.16 )4.62 )7.70Forestry to temporary grass )6.16 )4.62 )7.70 0.00 0.00 0.00 )6.16 )4.62 )7.70
Land-use change and GB soil carbon stocks 383
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
organic soils was assumed to result in equivalent effects of
the opposite sign (Table 3; Smith et al., 2008).
Land-use change scenarios
The baseline year was taken as 2004 for land-use
comparisons. The considered land-use change scenarios
are for managed agricultural land in lowland Britain
(all managed lowland agricultural land excluding rough
grazing):
• Historical Best Case – Historical ‘best case’ – interwar
period (i.e. 1930): maximum area of grassland (and
associated soil C storage).
• Recent Best Case – Potential improvement scenario –
cropland reversion to permanent grassland in groundwater
protection zones (as classified for England and Wales in
1998).
• Worst case 5% – plough out of 5% of permanent
grassland to cropland, applied evenly to all GB counties.
• Worst case 10% – plough out of 10% permanent
grassland to cropland, applied evenly to all GB counties.
• Worst case 20% – plough out of 20% permanent
grassland to cropland, applied evenly to all GB counties.
Worst case scenarios of >20% plough out of grassland
were not examined as cropland distribution is limited by such
factors as climate, soil type and aspect, so much of the UK is
not suitable for crop production. Agricultural census statistics
back to 1890 were used to determine the area of the following
land-uses (at a county level, using current-2004 county
boundaries) in lowland GB for 1930 (Historical Best Case),
and for the Baseline in 2004 (Anon, 1968, Defra, 2005,
Comber et al., 2008):
Permanent grassland (>5 yr).
Temporary grassland (<5 yr).
Cropland (sometimes referred to as ‘tillage land’).
Additionally, the current area of forest was determined for
the Baseline scenario, using the National inventory of
Woodland and Trees (NIWT, Forestry Commission).
The Recent Best Case scenario was developed relative to
the 2004 baseline, but with all cropland within groundwater
protection zones reverted to permanent grassland. In this
case, the 1998 Nitrate Vulnerable Zones (NVZs) were
considered (SI, 1998), which were largely within England
(327 666 ha) and a small area in Wales (338 ha).
Total areas by county and for each country (England,
Wales, Scotland) for the baseline year and each scenario are
given in Table 4.
Each area was divided according to broad soil type based
on the amount of soil organic carbon present (mineral <5%
SOC; organo-mineral 5–12% SOC; organic >12% SOC)
using National Soils Inventory data for England and Wales
(McGrath & Loveland, 1992) and Scotland (Lilly et al.,
2010).
Proportions of each land-use on each soil type in each
county in the baseline year (proportions assumed to remain
the same across scenarios) are shown in Table 5.
Method of calculation
The area under each land-use for each county (Table 4) was
divided among the soil types in each county using the
proportions shown in Table 5. Area change for each land-use
within each county was calculated under each scenario by
subtracting the baseline year area from the scenario areas.
The change in area was then multiplied by the per-area
mitigation potentials for each transition given in Table 2 (for
mineral and organo-mineral soils) and Table 3 (for organic
soils).
For some scenarios, such as the Worst case 5%, 10% and
20% scenarios, the allocation of land-use transitions from
area change was trivial, with all cropland area decreases
arising from ploughing out of permanent grass. For other
scenarios, where an increase in the area in one land-use (e.g.
cropland) was accompanied by a loss in area of two or more
other land-uses (e.g. permanent grass and temporary grass),
the transitions were allocated in proportion to the area
Table 3 Estimates of change in SOC stocks and methane and nitrous oxide emissions resulting from land-use change on organic soils. All
estimates expressed in t CO2-eq. ⁄ ha ⁄ yr as per Smith et al. (2008). For derivation of estimates, see text
Land-use Change
CO2 (t CO2 ⁄ ha ⁄ yr) CH4 (t CO2-eq. ⁄ ha ⁄ yr) N2O (t CO2-eq. ⁄ ha ⁄ yr)All GHG
(t CO2-eq. ⁄ ha ⁄ yr)
Mean
estimate Low High
Mean
estimate Low High
Mean
estimate Low High
Mean
estimate Low High
Semi-natural vegetation ⁄ permanent
grassland to cropland or temporary
grassland
)36.67 )3.67 )69.67 3.32 0.05 15.30 )0.16 )0.05 )0.28 )33.51 )3.67 )54.65
Cropland or temporary grassland to
semi-natural vegetation ⁄ permanent
grassland
36.67 3.67 69.67 )3.32 )0.05 )15.30 0.16 0.05 0.28 33.51 3.67 54.65
384 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
4Areasunder
each
land-use
ineach
county
inthebaselineyearandunder
differentscenarios
UK
County
Baseline(2004)
HistoricalBestCase
(1930)
RecentBestCase
(1998)
WorstCase
5%
WorstCase
10%
Worstcase
20%
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Aberdeen
4419
2019
2014
1796
4006
4290
763
–4419
2019
2014
1796
4519
2019
1913
1796
4620
2019
1812
1796
4821
2019
1611
1796
Aberdeenshire
201509
55191
56900
98807
135582
142609
26284
–201509
55191
56900
98807
204354
55191
54055
98807
207199
55191
51210
98807
212889
55191
45520
98807
Anglesey
2560
5154
40040
2425
8316
11185
37663
–2560
5154
40040
2425
4562
5154
38038
2425
6564
5154
36036
2425
10568
5154
32032
2425
Angus
72089
9788
12371
20998
50041
33456
12845
–72089
9788
12371
20998
72708
9788
11752
20998
73326
9788
11134
20998
74563
9788
9897
20998
ArgyllandBute
499
7873
38768
206005
10220
11014
26977
–499
7873
38768
206005
2437
7873
36829
206005
4376
7873
34891
206005
8252
7873
31014
206005
Barnsley
6796
2067
6461
2482
4899
1024
13677
–6796
2067
6461
2482
7119
2067
6138
2482
7443
2067
5815
2482
8089
2067
5169
2482
Bath
andNorth
East
Somerset
7758
2966
12056
2176
3754
1159
22015
–7758
2966
12056
2176
8361
2966
11454
2176
8964
2966
10851
2176
10170
2966
9645
2176
Bedfordshire
68341
2169
10744
6996
43740
6590
47773
–55139
2169
23945
6996
68878
2169
10206
6996
69415
2169
9669
6996
70490
2169
8595
6996
Birmingham
1110
13
630
794
4441
1200
15798
–966
13
774
794
1142
13
599
794
1173
13
567
794
1236
13
504
794
Blackburn
with
Derwen
17
377
4708
983
1689
658
5761
–17
377
4708
983
252
377
4473
983
488
377
4237
983
958
377
3767
983
Blackpool
130
99
234
21
428
167
1459
–130
99
234
21
142
99
222
21
153
99
210
21
177
99
187
21
Blanaeu
Gwent
16
135
1622
1136
615
276
5697
–16
135
1622
1136
98
135
1541
1136
179
135
1460
1136
341
135
1298
1136
Bolton
346
394
2672
692
1707
665
5821
–346
394
2672
692
480
394
2538
692
613
394
2405
692
880
394
2137
692
Borders
103708
25957
72026
84045
51381
60240
77953
–103708
25957
72026
84045
107310
25957
68425
84045
110911
25957
64824
84045
118114
25957
57621
84045
Bournem
outh
152
20
336
196
920
298
1585
–152
20
336
196
169
20
319
196
186
20
303
196
219
20
269
196
BracknellForest
1246
230
1093
3480
2653
575
4442
–1246
230
1093
3480
1301
230
1038
3480
1355
230
983
3480
1465
230
874
3480
Bradford
29
1292
13289
1590
5478
1144
15291
–29
1292
13289
1590
694
1292
12624
1590
1358
1292
11960
1590
2687
1292
10631
1590
Bridgend
739
753
7580
3531
1140
874
8624
–739
753
7580
3531
1118
753
7201
3531
1497
753
6822
3531
2255
753
6064
3531
Brightonand
Hove
1400
186
1489
305
1165
288
3518
–1400
186
1489
305
1474
186
1415
305
1549
186
1341
305
1698
186
1192
305
Bristol
124
252
687
451
1466
679
6253
–124
252
687
451
159
252
652
451
193
252
618
451
262
252
549
451
Buckinghamshire
48636
8382
41427
15882
24406
5698
91620
–31974
8382
58089
15882
50708
8382
39355
15882
52779
8382
37284
15882
56922
8382
33141
15882
Bury
75
441
2963
452
1224
477
4175
–75
441
2963
452
223
441
2815
452
371
441
2666
452
667
441
2370
452
Caerphilly
324
895
8985
4525
1430
828
12219
–324
895
8985
4525
773
895
8536
4525
1222
895
8087
4525
2121
895
7188
4525
Calderdale
232
995
10199
1955
5366
1185
15200
–232
995
10199
1955
742
995
9689
1955
1252
995
9179
1955
2272
995
8159
1955
Cambridgeshire
218979
2996
20250
5825
106307
18964
56635
–215383
2996
23846
5825
219991
2996
19237
5825
221004
2996
18225
5825
223029
2996
16200
5825
Cardiff
318
400
2380
1160
653
472
5087
–318
400
2380
1160
437
400
2261
1160
556
400
2142
1160
794
400
1904
1160
Carm
arthenshire
3771
12545
139497
32944
15341
7295
143226
–3771
12545
139497
32944
10746
12545
132523
32944
17721
12545
125548
32944
31671
12545
111598
32944
Ceredigion
4039
10746
96436
26496
21275
13757
63670
–4039
10746
96436
26496
8861
10746
91614
26496
13683
10746
86792
26496
23327
10746
77149
26496
Cheshire
36960
28603
77945
9306
32214
20969
105316
–36563
28603
78342
9306
40857
28603
74048
9306
44755
28603
70150
9306
52549
28603
62356
9306
Clackmannanshire
2713
952
2640
1947
1941
1133
3382
–2713
952
2640
1947
2845
952
2508
1947
2977
952
2376
1947
3241
952
2112
1947
Conwy
1533
5176
54393
13338
8839
9487
42265
–1533
5176
54393
13338
4253
5176
51674
13338
6973
5176
48954
13338
12412
5176
43515
13338
Cornwall
65366
42592
144013
27474
61507
74866
123159
–65366
42592
144013
27474
72567
42592
136813
27474
79768
42592
129612
27474
94169
42592
115211
27474
Coventry
798
163
988
301
1408
480
6051
–798
163
988
301
847
163
939
301
896
163
889
301
995
163
790
301
Cumbria
34675
43862
251397
61975
54482
46975
251317
–34675
43862
251397
61975
47245
43862
238827
61975
59815
43862
226257
61975
84955
43862
201117
61975
Darlington
8964
1397
3831
467
3020
1304
7764
–8964
1397
3831
467
9156
1397
3639
467
9347
1397
3448
467
9730
1397
3065
467
Denbighshire
3843
5121
43136
11744
6486
6058
33309
–3660
5121
43319
11744
6000
5121
40979
11744
8157
5121
38823
11744
12471
5121
34509
11744
Derby
644
191
1049
87
746
226
4515
–644
191
1049
87
696
191
997
87
748
191
945
87
853
191
840
87
Derbyshire
37796
13919
94098
16637
24795
7912
146409
–37796
13919
94098
16637
42501
13919
89393
16637
47205
13919
84688
16637
56615
13919
75278
16637
Devon
94913
62766
290204
65704
101203
70122
275257
–94262
62766
290854
65704
109423
62766
275694
65704
123933
62766
261183
65704
152954
62766
232163
65704
Land-use change and GB soil carbon stocks 385
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
4(continued)
UK
County
Baseline(2004)
HistoricalBestCase
(1930)
RecentBestCase
(1998)
WorstCase
5%
WorstCase
10%
Worstcase
20%
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Doncaster
District
27413
1504
4950
3433
8816
1863
23701
–23550
1504
8813
3433
27660
1504
4703
3433
27908
1504
4455
3433
28403
1504
3960
3433
Dorset
74095
26819
73950
27387
36008
14751
116783
–74070
26819
73974
27387
77792
26819
70253
27387
81490
26819
66555
27387
88885
26819
59160
27387
Dudley
582
65
355
310
1595
444
5520
–582
65
355
310
600
65
337
310
618
65
320
310
653
65
284
310
Dumfriesand
Galloway
38008
40723
156147
175270
48729
71808
101313
–38008
40723
156147
175270
45816
40723
148339
175270
53623
40723
140532
175270
69238
40723
124917
175270
Dundee
1050
113
128
255
1518
964
483
–1050
113
128
255
1057
113
122
255
1063
113
115
255
1076
113
103
255
Durham
36968
8136
64499
15078
34357
14069
86176
–36968
8136
64499
15078
40193
8136
61274
15078
43418
8136
58049
15078
49868
8136
51599
15078
East
Ayrshire
7591
5452
32426
25708
9563
12863
31392
–7591
5452
32426
25708
9213
5452
30805
25708
10834
5452
29184
25708
14077
5452
25941
25708
East
Dunbartonshire
579
666
3000
2100
1444
1227
3411
–579
666
3000
2100
729
666
2850
2100
879
666
2700
2100
1179
666
2400
2100
East
Lothian
33541
2961
7070
5389
22348
11242
11838
–33541
2961
7070
5389
33894
2961
6716
5389
34248
2961
6363
5389
34955
2961
5656
5389
East
Renfrew
shire
464
727
5295
1846
1680
1525
5476
–464
727
5295
1846
728
727
5030
1846
993
727
4766
1846
1523
727
4236
1846
East
Ridingof
Yorkshire
170845
6232
20744
5857
104161
25296
74480
–158190
6232
33398
5857
171882
6232
19706
5857
172919
6232
18669
5857
174993
6232
16595
5857
East
Sussex
32293
9817
51542
29116
24238
5934
72641
–32293
9817
51542
29116
34871
9817
48965
29116
37448
9817
46388
29116
42602
9817
41234
29116
Edinburgh
6329
478
2737
1553
5281
3283
5514
–6329
478
2737
1553
6465
478
2600
1553
6602
478
2463
1553
6876
478
2190
1553
Essex
198182
6637
27031
15645
120072
24563
105213
–156160
6637
69052
15645
199533
6637
25679
15645
200885
6637
24328
15645
203588
6637
21625
15645
Falkirk
6688
1580
6534
3407
3116
2184
6607
–6688
1580
6534
3407
7014
1580
6207
3407
7341
1580
5881
3407
7994
1580
5227
3407
Fife
62766
7654
18174
14742
40684
22764
33136
–62766
7654
18174
14742
63675
7654
17265
14742
64584
7654
16356
14742
66401
7654
14539
14742
Flintshire
2986
2951
18789
3270
3994
4302
26726
–2860
2951
18915
3270
3926
2951
17850
3270
4865
2951
16910
3270
6744
2951
15031
3270
Gateshead
2355
282
1521
1732
2117
922
5471
–2355
282
1521
1732
2431
282
1445
1732
2507
282
1369
1732
2659
282
1217
1732
Glasgow
95
254
1299
1078
1672
1776
4227
–95
254
1299
1078
160
254
1234
1078
225
254
1169
1078
355
254
1040
1078
Gloucestershire
91413
18959
74109
29486
39023
19824
142396
–89091
18959
76430
29486
95118
18959
70403
29486
98824
18959
66698
29486
106234
18959
59287
29486
GreaterLondon
5719
802
4342
6417
26789
4142
43047
–5719
802
4342
6417
5936
802
4125
6417
6153
802
3908
6417
6587
802
3474
6417
Gwynedd
2905
8306
101508
35564
10158
14099
65671
–2905
8306
101508
35564
7981
8306
96433
35564
13056
8306
91358
35564
23207
8306
81207
35564
Halton
1681
329
521
240
1112
615
3694
–1681
329
521
240
1707
329
495
240
1733
329
469
240
1785
329
417
240
Hampshire
123553
13916
48591
66161
80599
24470
113115
–123553
13916
48591
66161
125982
13916
46162
66161
128412
13916
43732
66161
133271
13916
38873
66161
Hartlepool
3234
440
846
338
1403
610
3619
–3234
440
846
338
3276
440
804
338
3319
440
762
338
3403
440
677
338
Herefordshire
76936
17932
73576
20550
38385
11975
127615
–76862
17932
73649
20550
80615
17932
69897
20550
84293
17932
66218
20550
91651
17932
58861
20550
Hertfordshire
71909
3610
16580
13070
51692
14057
55275
–68750
3610
19739
13070
72738
3610
15751
13070
73567
3610
14922
13070
75225
3610
13264
13070
Highland
40223
31490
83233
390018
67026
59212
57483
–40223
31490
83233
390018
44385
31490
79071
390018
48546
31490
74909
390018
56869
31490
66586
390018
Inverclyde
98
459
2632
1682
1570
1425
5117
–98
459
2632
1682
230
459
2500
1682
361
459
2369
1682
624
459
2106
1682
Isle
ofWight
10603
2796
9405
4308
8095
2457
11172
–10603
2796
9405
4308
11073
2796
8935
4308
11543
2796
8464
4308
12484
2796
7524
4308
Kent
135563
12747
59211
37290
85065
8700
137063
–134657
12747
60118
37290
138524
12747
56251
37290
141484
12747
53290
37290
147405
12747
47369
37290
KingstonuponHull
691
63
91
30
3203
780
2144
–691
63
91
30
696
63
87
30
701
63
82
30
710
63
73
30
Kirklees
2317
2499
11046
2440
6113
1277
17064
–2317
2499
11046
2440
2869
2499
10494
2440
3421
2499
9942
2440
4526
2499
8837
2440
Knowsley
1758
145
706
674
1075
419
3668
–1758
145
706
674
1794
145
671
674
1829
145
635
674
1900
145
565
674
Lancashire
30329
18610
118421
13006
36340
13117
120381
–30329
18610
118421
13006
36250
18610
112500
13006
42171
18610
106579
13006
54013
18610
94737
13006
Leeds
12998
1793
8683
3738
8258
1725
23053
–12998
1793
8683
3738
13432
1793
8249
3738
13866
1793
7815
3738
14734
1793
6946
3738
Leicester
805
58
411
32
831
262
5093
–805
58
411
32
826
58
390
32
846
58
370
32
887
58
329
32
Leicestershire
90158
11322
55136
7454
23986
7542
145860
–88883
11322
56412
7454
92915
11322
52380
7454
95672
11322
49623
7454
101186
11322
44109
7454
Lincolnshire
440193
11055
43945
18108
167219
13845
111730
–386988
11055
97150
18108
442390
11055
41747
18108
444587
11055
39550
18108
448982
11055
35156
18108
Liverpool
308
0283
293
1383
539
4717
–308
0283
293
322
0269
293
336
0255
293
365
0227
293
Luton
596
56
94
113
1611
238
1745
–596
56
94
113
600
56
89
113
605
56
84
113
614
56
75
113
386 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
4(continued)
UK
County
Baseline(2004)
HistoricalBestCase
(1930)
RecentBestCase
(1998)
WorstCase
5%
WorstCase
10%
Worstcase
20%
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Manchester
110
43
647
310
1519
704
5118
–110
43
647
310
143
43
614
310
175
43
582
310
240
43
517
310
Medway
4787
216
2324
1012
4657
474
7486
–4787
216
2324
1012
4903
216
2208
1012
5019
216
2092
1012
5251
216
1859
1012
MerthyrTydfil
994
3163
1484
496
392
3724
–9
94
3163
1484
167
94
3005
1484
326
94
2847
1484
642
94
2531
1484
Middlesbrough
911
34
665
141
942
289
2088
–911
34
665
141
944
34
631
141
977
34
598
141
1044
34
532
141
Midlothian
10448
2005
5326
3196
6856
4345
6943
–10448
2005
5326
3196
10714
2005
5060
3196
10980
2005
4794
3196
11513
2005
4261
3196
MiltonKeynes
12265
532
5027
1437
4798
1106
18212
–424
532
16868
1437
12516
532
4775
1437
12767
532
4524
1437
13270
532
4021
1437
Monmouthshire
9985
6100
39396
12034
5243
2204
49378
–9956
6100
39425
12034
11955
6100
37427
12034
13925
6100
35457
12034
17865
6100
31517
12034
Moray
27266
14303
18713
63826
38464
36943
7633
–27266
14303
18713
63826
28202
14303
17777
63826
29138
14303
16841
63826
31009
14303
14970
63826
Neath
Port
Talbot
209
838
11539
16658
2007
1539
15185
–209
838
11539
16658
786
838
10962
16658
1363
838
10385
16658
2516
838
9231
16658
New
castle
uponTyne
1732
131
1116
406
747
588
4494
–1732
131
1116
406
1788
131
1060
406
1844
131
1004
406
1955
131
893
406
New
port
1966
665
5497
1523
1120
461
10557
–1966
665
5497
1523
2240
665
5222
1523
2515
665
4947
1523
3065
665
4397
1523
Norfolk
330760
8663
49319
45147
244030
52107
112456
–295710
8663
84369
45147
333226
8663
46853
45147
335692
8663
44387
45147
340623
8663
39455
45147
NorthAyrshire
1426
2469
15613
12921
6050
7766
15324
–1426
2469
15613
12921
2207
2469
14833
12921
2987
2469
14052
12921
4549
2469
12491
12921
NorthEast
Lincolnshire
11044
403
797
372
5420
446
3616
–10137
403
1704
372
11083
403
757
372
11123
403
718
372
11203
403
638
372
NorthLanarkshire
3336
1996
8053
7245
4362
4716
9826
–3336
1996
8053
7245
3739
1996
7650
7245
4142
1996
7248
7245
4947
1996
6442
7245
NorthLincolnshire
56104
867
3572
3208
23457
1992
16680
–48191
867
11485
3208
56283
867
3393
3208
56461
867
3215
3208
56818
867
2858
3208
NorthSomerset
3571
2859
13273
3339
3973
1224
23398
–3571
2859
13273
3339
4235
2859
12609
3339
4899
2859
11946
3339
6226
2859
10618
3339
NorthTyneside
1498
126
490
168
529
417
3194
–1498
126
490
168
1522
126
465
168
1547
126
441
168
1596
126
392
168
NorthYorkshire
242521
36350
209952
59671
151713
40583
314938
–238176
36350
214297
59671
253019
36350
199454
59671
263516
36350
188957
59671
284512
36350
167962
59671
Northamptonshire
120891
7113
48029
12674
39565
9126
138998
–99315
7113
69605
12674
123292
7113
45628
12674
125693
7113
43226
12674
130496
7113
38423
12674
Northumberland
96571
18943
130952
81388
32381
25598
195290
–96571
18943
130952
81388
103118
18943
124404
81388
109666
18943
117857
81388
122761
18943
104762
81388
Nottingham
380
0489
165
2208
562
3069
–380
0489
165
404
0465
165
429
0440
165
478
0392
165
Nottinghamshire
110125
6211
21806
16854
61569
15672
85819
–87843
6211
44089
16854
111216
6211
20716
16854
112306
6211
19625
16854
114487
6211
17445
16854
Oldham
8263
3005
230
1936
554
5916
–8
263
3005
230
158
263
2855
230
308
263
2704
230
608
263
2404
230
Orkney
Islands
6215
11851
37399
105
19302
17752
6762
–6215
11851
37399
105
8085
11851
35529
105
9955
11851
33659
105
13695
11851
29919
105
Oxfordshire
125194
9979
46916
17597
65262
18816
121178
–119573
9979
52537
17597
127540
9979
44570
17597
129885
9979
42225
17597
134577
9979
37533
17597
Pem
brokeshire
17462
15759
82757
13846
19598
14767
83656
–17462
15759
82757
13846
21599
15759
78619
13846
25737
15759
74481
13846
34013
15759
66205
13846
Perth
andKinross
65904
16577
38196
85559
40780
33082
40704
–65904
16577
38196
85559
67813
16577
36286
85559
69723
16577
34376
85559
73543
16577
30557
85559
Peterborough
22164
122
2084
1362
8116
1628
14842
–22164
122
2084
1362
22268
122
1979
1362
22373
122
1875
1362
22581
122
1667
1362
Plymouth
850
61
523
604
1234
856
3352
–850
61
523
604
876
61
497
604
902
61
471
604
954
61
419
604
Poole
417
185
490
748
913
379
3014
–417
185
490
748
442
185
466
748
466
185
441
748
516
185
392
748
Powys
11945
22673
278010
69390
30650
26147
188885
–11945
22673
278010
69390
25845
22673
264110
69390
39746
22673
250209
69390
67547
22673
222408
69390
Reading
112
2554
140
997
239
1725
–112
2554
140
139
2526
140
167
2499
140
222
2443
140
RedcarandCleveland
4925
639
2853
2672
4280
1314
9483
–4925
639
2853
2672
5068
639
2710
2672
5211
639
2567
2672
5496
639
2282
2672
Renfrew
shire
352
1029
6441
2274
2536
2302
8266
–352
1029
6441
2274
674
1029
6119
2274
996
1029
5797
2274
1641
1029
5153
2274
Rhondda,Cynon,Taff
188
924
12434
9981
1898
1478
14309
–188
924
12434
9981
810
924
11813
9981
1432
924
11191
9981
2675
924
9947
9981
Rochdale
35
402
3854
373
1924
749
6561
–35
402
3854
373
228
402
3662
373
421
402
3469
373
806
402
3084
373
Rotherham
11409
711
2824
1971
4294
900
11993
–11409
711
2824
1971
11550
711
2683
1971
11691
711
2542
1971
11974
711
2259
1971
Rutland
22923
700
6630
1980
9494
2174
24110
–21651
700
7902
1980
23254
700
6299
1980
23586
700
5967
1980
24249
700
5304
1980
Salford
1474
79
457
453
1215
476
4141
–1474
79
457
453
1497
79
434
453
1520
79
411
453
1566
79
365
453
Sandwell
61
16
315
216
1245
411
4805
–61
16
315
216
77
16
300
216
93
16
284
216
124
16
252
216
Sefton
2636
262
875
547
1812
706
6181
–2636
262
875
547
2679
262
831
547
2723
262
788
547
2811
262
700
547
Land-use change and GB soil carbon stocks 387
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
4(continued)
UK
County
Baseline(2004)
HistoricalBestCase
(1930)
RecentBestCase
(1998)
WorstCase
5%
WorstCase
10%
Worstcase
20%
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Sheffield
1559
1090
4943
3773
5178
1137
16358
–1559
1090
4943
3773
1806
1090
4696
3773
2053
1090
4449
3773
2548
1090
3955
3773
Shropshire
101415
32552
113624
24468
48383
20657
190750
–96114
32552
118925
24468
107096
32552
107943
24468
112777
32552
102262
24468
124140
32552
90900
24468
Slough
91
26
254
48
493
111
1848
–82
26
263
48
103
26
242
48
116
26
229
48
141
26
203
48
Solihull
3653
639
3085
643
2566
874
11017
–3653
639
3085
643
3808
639
2931
643
3962
639
2777
643
4270
639
2468
643
Somerset
63912
33988
149143
23976
36801
11500
214970
–63554
33988
149501
23976
71369
33988
141686
23976
78826
33988
134229
23976
93741
33988
119315
23976
South
Ayrshire
6415
6509
34682
35486
9194
12366
30179
–6415
6509
34682
35486
8149
6509
32948
35486
9883
6509
31214
35486
13351
6509
27746
35486
South
Gloucestershire
10659
3305
17392
2185
7258
3757
26718
–10659
3305
17392
2185
11529
3305
16522
2185
12398
3305
15653
2185
14137
3305
13914
2185
South
Lanarkshire
16120
9907
37995
30633
17373
19756
38582
–16120
9907
37995
30633
18019
9907
36095
30633
19919
9907
34196
30633
23719
9907
30396
30633
South
Tyneside
1023
57
541
36
946
411
2439
–1023
57
541
36
1050
57
514
36
1077
57
487
36
1131
57
433
36
SouthendonSea
44
35
311
51
1433
293
1256
–44
35
311
51
59
35
295
51
75
35
280
51
106
35
249
51
StHelens
4423
398
673
574
1663
648
5671
–4423
398
673
574
4456
398
639
574
4490
398
606
574
4557
398
538
574
Staffordshire
58679
20609
94074
18549
33961
13150
146392
–50846
20609
101907
18549
63382
20609
89370
18549
68086
20609
84666
18549
77493
20609
75259
18549
Stirling
6860
4394
20357
48456
17543
13552
26793
–6860
4394
20357
48456
7878
4394
19339
48456
8896
4394
18321
48456
10932
4394
16286
48456
Stockport
103
359
2113
687
1787
1063
6300
–103
359
2113
687
209
359
2007
687
314
359
1902
687
526
359
1690
687
Stockton
6815
853
2658
852
3203
1290
7969
–6815
853
2658
852
6947
853
2525
852
7080
853
2392
852
7346
853
2127
852
StokeonTrent
160
438
1102
102
1205
467
5188
–160
438
1102
102
215
438
1047
102
271
438
992
102
381
438
881
102
Suffolk
237508
6366
28932
28184
102388
16996
54259
–207022
6366
59418
28184
238954
6366
27486
28184
240401
6366
26039
28184
243294
6366
23146
28184
Sunderland
3132
170
831
548
2062
897
5318
–3132
170
831
548
3174
170
789
548
3215
170
748
548
3298
170
665
548
Surrey
18462
5842
26896
37440
16504
3752
46440
–18462
5842
26896
37440
19806
5842
25551
37440
21151
5842
24207
37440
23841
5842
21517
37440
Swansea
1646
1637
12475
3465
1710
1312
12940
–1646
1637
12475
3465
2270
1637
11852
3465
2894
1637
11228
3465
4141
1637
9980
3465
Swindon
8068
1111
4658
631
3730
1234
11070
–7879
1111
4847
631
8301
1111
4425
631
8533
1111
4192
631
8999
1111
3726
631
Tameside
51
137
1553
455
1445
797
4790
-51
137
1553
455
128
137
1476
455
206
137
1398
455
361
137
1243
455
Telford
andWrekin
12883
1451
4053
1982
4408
1882
17385
–9768
1451
7168
1982
13086
1451
3851
1982
13288
1451
3648
1982
13694
1451
3243
1982
Thurrock
5556
239
1586
311
5636
1153
4939
–5556
239
1586
311
5636
239
1507
311
5715
239
1427
311
5874
239
1269
311
Torbay
460
289
1365
427
942
653
2558
–460
289
1365
427
528
289
1296
427
596
289
1228
427
733
289
1092
427
Torfaen
144
218
3420
1581
749
303
7089
–144
218
3420
1581
315
218
3249
1581
486
218
3078
1581
828
218
2736
1581
Trafford
1250
507
813
168
1533
891
5068
–1250
507
813
168
1291
507
773
168
1332
507
732
168
1413
507
651
168
Vale
ofGlamorgan
4974
1808
13698
2152
1504
1153
11379
–4974
1808
13698
2152
5659
1808
13013
2152
6344
1808
12328
2152
7714
1808
10958
2152
Wakefield
13079
751
2387
1344
5058
1056
14119
–13079
751
2387
1344
13198
751
2267
1344
13318
751
2148
1344
13556
751
1909
1344
Walsall
1128
172
987
379
1357
526
5839
–856
172
1260
379
1178
172
938
379
1227
172
888
379
1326
172
790
379
Warrington
4886
962
1759
632
2444
1224
8190
–4886
962
1759
632
4974
962
1671
632
5062
962
1583
632
5238
962
1407
632
Warw
ickshire
87728
10115
44434
8455
28474
9825
121571
–76193
10115
55969
8455
89950
10115
42212
8455
92172
10115
39990
8455
96615
10115
35547
8455
WestBerkshire
30594
2765
9913
9681
16979
3713
28560
–28373
2765
12134
9681
31090
2765
9417
9681
31585
2765
8922
9681
32577
2765
7930
9681
WestDunbartonshire
244
331
2796
2964
1210
1107
2935
–244
331
2796
2964
383
331
2657
2964
523
331
2517
2964
803
331
2237
2964
WestLothian
8786
2586
7754
6793
9865
5813
11130
–8786
2586
7754
6793
9174
2586
7366
6793
9561
2586
6978
6793
10337
2586
6203
6793
WestSussex
54444
8744
41025
37997
27981
6913
84421
–54444
8744
41025
37997
56495
8744
38974
37997
58546
8744
36923
37997
62649
8744
32820
37997
Western
Isles
01331
13273
3454
7480
5914
6121
–0
1331
13273
3454
664
1331
12610
3454
1327
1331
11946
3454
2655
1331
10619
3454
Wigan
2508
912
2669
847
2293
893
7820
–2508
912
2669
847
2642
912
2535
847
2775
912
2402
847
3042
912
2135
847
Wiltshire
124176
20345
77546
26617
52529
17397
156789
–124117
20345
77605
26617
128054
20345
73668
26617
131931
20345
69791
26617
139685
20345
62037
26617
WindsorandMaidenhead
4149
386
2541
2748
4588
999
8449
–4106
386
2583
2748
4276
386
2414
2748
4403
386
2287
2748
4657
386
2033
2748
Wirral
1680
798
1572
617
2418
1575
7903
–1680
798
1572
617
1759
798
1494
617
1838
798
1415
617
1995
798
1258
617
Wokingham
3744
843
2368
1981
4324
939
7241
–3414
843
2699
1981
3863
843
2250
1981
3981
843
2132
1981
4218
843
1895
1981
388 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
change in each category losing land area, for example, if
cropland increased by 100 ha, temporary grass decreased by
40 ha and permanent grass decreased by 60 ha, the land-use
transitions were assumed to be 40 ha of temporary grass to
cropland, and 60 ha of permanent grass to cropland. If there
were anomalies in the area change data (e.g. because of the
data not including all land-uses, or because of small
allocation areas arising from projecting 1930 data onto
current county boundaries), the most conservative estimate of
area change was made, for example if cropland area increased
by 130 ha, but the only other land-use changes were a
decrease in temporary grass of 40 ha and of permanent grass
by 60 ha, the land-use transitions were assumed to be 40 ha
of temporary grass to cropland and 60 ha of permanent grass
to cropland because the remaining 30 ha increase in cropland
could not be allocated.
The resulting calculations give projected changes in SOC
for each soil type under each land-use transition for each
county in GB under each land-use change scenario. The
estimates are for yearly change in GHG emissions. All
estimates are expressed in carbon dioxide equivalents (t CO2-
eq. ⁄ha ⁄ yr) based on the global warming potentials (GWPs) in
the IPCC Third Assessment Report (TAR: IPCC WGI, 2001)
for nitrous oxide and methane of 296 and 23, respectively.
These GWPs were updated in the Fourth Assessment Report
(AR4: IPCC WGI, 2007), but the convention adopted by
parties to the United Nations Framework Convention on
Climate Change (UNFCCC) uses the GWPs from the TAR
for national GHG accounting. The yearly mitigation
potentials have also been aggregated over 20 yr to show the
total change, using the simplification employed in national
greenhouse gas inventories that soil carbon changes occur
over a 20 yr period after which a new equilibrium is achieved
(IPCC, 1997, 2006). In all cases, a GHG benefit ⁄SOC
increase is shown as a positive number and a GHG emission
increase ⁄SOC loss is shown as a negative number.
Results
Impacts of land-use change on GHG emissions ⁄SOC
storage
The Historical Best Case scenario shows a GHG benefit ⁄SOC
increase in England, (mean: 298 Mt CO2-eq. over 20 yr) but
SOC losses ⁄ increased GHG emissions in Scotland (mean:
)47 Mt CO2-eq. over 20 yr) and Wales (mean: )9 Mt CO2-
eq. over 20 yr; Figure 1a) relative to the 2004 baseline. This
largely arises from increased grassland, especially permanent
grass, in most of England, but more cropland at the expense
of grassland in Scotland and Wales. The effect in Wales is
slight, but in Scotland the most notable loss of grassland area
and thereby SOC loss occurs on the west coast, in particular
in Argyll & Bute, Dumfries & Galloway, Highland, and the
Western Isles, but also in Orkney. The total change for eachTable
4(continued)
UK
County
Baseline(2004)
HistoricalBestCase
(1930)
RecentBestCase
(1998)
WorstCase
5%
WorstCase
10%
Worstcase
20%
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Arable
Tem
p
Grass
Perm
Grass
Woodland
Wolverhampton
71
113
121
89
907
352
3906
–71
113
121
89
77
113
115
89
83
113
109
89
95
113
97
89
Worcestershire
58906
10951
47407
11168
36532
6794
98854
–57952
10951
48361
11168
61276
10951
45037
11168
63647
10951
42667
11168
68388
10951
37926
11168
Wrexham
C.B.
4171
3881
22932
3774
5129
4713
25668
–4171
3881
22932
3774
5318
3881
21785
3774
6465
3881
20639
3774
8758
3881
18345
3774
York
12084
877
3702
1025
7459
1876
9853
–12084
877
3702
1025
12269
877
3517
1025
12454
877
3332
1025
12825
877
2961
1025
Totalareas
England
4403542
6581043022222
1053389
2559661
7958485297620
–4075875
6581043349888
1053389
4554653
6581042871111
1053389
4705764
6581042720000
1053389
5007986
6581042417777
1053389
Scotland
735740
269625
749992
1339557
638817
608430
625397
–735740
269625
749992
1339557
773240
269625
712493
1339557
810739
269625
674993
1339557
885738
269625
599994
1339557
Wales
75734
106777
999689
272022
148351
123103
866926
–75396
1067771000028
272022
125719
106777
949705
272022
175703
106777
899720
272022
275672
106777
799752
272022
GB
521501610345064771904
2664968
334682815273816789943
–488701110345065099908
2664968
545361110345064533308
2664968
569220610345064294713
2664968
616939710345063817523
2664968
Land-use change and GB soil carbon stocks 389
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
5Proportion
ofeach
land-use
typein
each
county
oneach
soiltype.
See
textfordefinitionofsoiltypes
UK
County
Proportionarable
Proportiontemporary
grass
Proportionpermanentgrass
Proportionforest
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Aberdeen
0.04
0.03
0.93
0.03
0.02
0.94
0.04
0.03
0.93
0.01
0.02
0.96
Aberdeenshire
0.28
0.28
0.44
0.23
0.30
0.47
0.20
0.32
0.48
0.09
0.68
0.23
Anglesey
0.21
0.00
0.79
0.14
0.00
0.86
0.16
0.00
0.83
0.50
0.00
0.50
Angus
0.31
0.03
0.67
0.31
0.13
0.56
0.27
0.19
0.54
0.14
0.45
0.41
ArgyllandBute
0.00
0.99
0.01
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
Barnsley
0.86
0.04
0.10
0.56
0.23
0.21
0.50
0.30
0.20
0.59
0.18
0.23
Bath
andNorth
East
Somerset
0.16
0.00
0.83
0.23
0.00
0.76
0.32
0.00
0.68
0.23
0.00
0.77
Bedfordshire
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
0.99
0.00
0.01
Birmingham
0.99
0.00
0.01
0.98
0.00
0.02
0.98
0.00
0.02
0.94
0.02
0.05
Blackburn
withDerwen
0.00
0.00
1.00
0.01
0.01
0.98
0.01
0.01
0.98
0.00
0.00
1.00
Blackpool
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
Blanaeu
Gwent
0.00
0.71
0.29
0.00
0.73
0.27
0.00
0.72
0.28
0.00
0.68
0.32
Bolton
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
Borders
0.51
0.05
0.44
0.28
0.09
0.63
0.25
0.16
0.59
0.20
0.41
0.39
Bournem
outh
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.08
0.00
0.92
BracknellForest
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Bradford
0.01
0.42
0.57
0.01
0.52
0.47
0.01
0.54
0.44
0.02
0.44
0.54
Bridgend
0.77
0.01
0.22
0.42
0.09
0.49
0.25
0.15
0.60
0.15
0.20
0.66
BrightonandHove
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
Bristol
0.69
0.00
0.31
0.68
0.00
0.32
0.68
0.00
0.32
0.72
0.00
0.28
Buckinghamshire
0.80
0.00
0.20
0.74
0.00
0.26
0.72
0.00
0.28
0.93
0.00
0.07
Bury
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
Caerphilly
0.18
0.00
0.82
0.20
0.02
0.78
0.13
0.05
0.81
0.15
0.01
0.85
Calderdale
0.00
0.36
0.64
0.00
0.74
0.26
0.00
0.73
0.27
0.00
0.70
0.30
Cambridgeshire
0.36
0.01
0.63
0.41
0.00
0.59
0.45
0.01
0.55
0.42
0.00
0.57
Cardiff
0.15
0.03
0.82
0.15
0.01
0.84
0.15
0.01
0.84
0.04
0.00
0.96
Carm
arthenshire
0.44
0.02
0.54
0.31
0.12
0.57
0.26
0.12
0.62
0.14
0.13
0.73
Ceredigion
0.46
0.16
0.38
0.21
0.32
0.47
0.16
0.35
0.48
0.07
0.68
0.25
Cheshire
0.93
0.00
0.07
0.88
0.02
0.09
0.79
0.09
0.13
0.74
0.10
0.16
Clackmannanshire
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
Conwy
0.39
0.39
0.22
0.17
0.58
0.25
0.15
0.61
0.24
0.08
0.78
0.13
Cornwall
0.71
0.00
0.29
0.62
0.01
0.37
0.55
0.02
0.43
0.63
0.02
0.35
Coventry
0.97
0.00
0.03
0.97
0.00
0.03
0.94
0.00
0.06
1.00
0.00
0.00
Cumbria
0.44
0.11
0.45
0.32
0.22
0.46
0.20
0.37
0.43
0.11
0.60
0.30
Darlington
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Denbighshire
0.59
0.09
0.32
0.28
0.28
0.44
0.25
0.32
0.43
0.12
0.54
0.34
Derby
0.26
0.00
0.74
0.16
0.00
0.84
0.16
0.00
0.84
0.07
0.00
0.93
Derbyshire
0.61
0.01
0.38
0.48
0.11
0.41
0.40
0.17
0.43
0.34
0.18
0.48
390 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
5(continued)
UK
County
Proportionarable
Proportiontemporary
grass
Proportionpermanentgrass
Proportionforest
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Devon
0.79
0.01
0.20
0.72
0.04
0.24
0.65
0.08
0.27
0.60
0.11
0.29
Doncaster
District
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Dorset
0.93
0.00
0.07
0.89
0.00
0.11
0.87
0.00
0.13
0.86
0.00
0.14
Dudley
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
DumfriesandGalloway
0.00
0.62
0.38
0.00
0.64
0.36
0.00
0.67
0.33
0.00
0.87
0.13
Dundee
0.69
0.00
0.31
0.75
0.00
0.25
0.73
0.00
0.27
0.80
0.00
0.20
Durham
0.41
0.02
0.57
0.31
0.17
0.53
0.18
0.37
0.44
0.20
0.33
0.47
East
Ayrshire
0.00
0.51
0.49
0.00
0.65
0.35
0.00
0.72
0.28
0.00
0.85
0.15
East
Dunbartonshire
0.00
0.50
0.50
0.00
0.75
0.25
0.00
0.76
0.24
0.00
0.83
0.17
East
Lothian
0.01
0.00
0.99
0.01
0.00
0.99
0.02
0.00
0.98
0.01
0.00
0.99
East
Renfrew
shire
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
East
RidingofYorkshire
0.97
0.00
0.02
0.98
0.00
0.02
0.98
0.00
0.02
0.98
0.00
0.02
East
Sussex
0.70
0.00
0.30
0.73
0.00
0.27
0.79
0.00
0.21
0.91
0.00
0.09
Edinburgh
0.94
0.00
0.06
0.77
0.00
0.23
0.81
0.00
0.19
0.94
0.00
0.06
Essex
0.91
0.00
0.09
0.98
0.00
0.02
0.96
0.00
0.04
0.94
0.00
0.06
Falkirk
0.00
0.01
0.99
0.01
0.01
0.98
0.00
0.01
0.98
0.00
0.07
0.93
Fife
0.24
0.00
0.76
0.29
0.00
0.71
0.31
0.00
0.69
0.22
0.00
0.78
Flintshire
0.60
0.00
0.40
0.57
0.00
0.43
0.50
0.00
0.50
0.45
0.01
0.55
Gateshead
0.28
0.00
0.72
0.39
0.00
0.61
0.41
0.00
0.59
0.39
0.00
0.61
Glasgow
0.00
0.96
0.04
0.00
0.88
0.12
0.00
0.90
0.10
0.00
0.93
0.07
Gloucestershire
0.85
0.00
0.15
0.88
0.00
0.12
0.89
0.00
0.11
0.81
0.00
0.19
GreaterLondon
0.83
0.00
0.17
0.86
0.00
0.14
0.89
0.00
0.11
0.81
0.00
0.19
Gwynedd
0.34
0.46
0.20
0.23
0.59
0.18
0.13
0.76
0.11
0.03
0.89
0.08
Halton
0.24
0.00
0.76
0.46
0.00
0.54
0.44
0.00
0.56
0.57
0.00
0.43
Hampshire
0.51
0.00
0.49
0.58
0.00
0.41
0.58
0.00
0.41
0.51
0.00
0.48
Hartlepool
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Herefordshire
0.97
0.00
0.03
0.97
0.00
0.03
0.92
0.00
0.08
0.91
0.00
0.09
Hertfordshire
0.99
0.00
0.01
0.99
0.00
0.01
1.00
0.00
0.00
0.99
0.00
0.01
Highland
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
Inverclyde
0.00
0.51
0.49
0.00
0.80
0.20
0.00
0.80
0.20
0.00
0.95
0.05
Isle
ofWight
0.97
0.01
0.03
0.96
0.00
0.04
0.95
0.01
0.05
0.97
0.01
0.02
Kent
0.84
0.00
0.16
0.82
0.00
0.18
0.83
0.00
0.17
0.81
0.00
0.19
KingstonuponHull
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Kirklees
0.13
0.01
0.86
0.10
0.19
0.71
0.05
0.32
0.63
0.11
0.26
0.63
Knowsley
0.03
0.01
0.95
0.02
0.01
0.97
0.02
0.02
0.97
0.00
0.05
0.95
Lancashire
0.06
0.17
0.76
0.14
0.11
0.75
0.13
0.17
0.70
0.09
0.29
0.62
Leeds
0.80
0.00
0.20
0.51
0.00
0.49
0.52
0.00
0.48
0.66
0.00
0.34
Leicester
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Leicestershire
0.91
0.00
0.09
0.87
0.00
0.13
0.89
0.00
0.11
0.95
0.00
0.04
Land-use change and GB soil carbon stocks 391
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
5(continued)
UK
County
Proportionarable
Proportiontemporary
grass
Proportionpermanentgrass
Proportionforest
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Lincolnshire
0.89
0.00
0.11
0.88
0.01
0.11
0.89
0.00
0.11
0.87
0.00
0.13
Liverpool
0.05
0.00
0.95
0.00
0.00
0.00
0.01
0.00
0.99
0.05
0.00
0.95
Luton
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Manchester
0.49
0.00
0.51
0.82
0.00
0.18
0.50
0.00
0.50
0.23
0.01
0.75
Medway
0.91
0.00
0.09
1.00
0.00
0.00
0.92
0.00
0.08
0.64
0.00
0.36
MerthyrTydfil
0.00
0.59
0.40
0.01
0.38
0.62
0.01
0.39
0.61
0.01
0.41
0.58
Middlesbrough
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Midlothian
0.13
0.00
0.87
0.14
0.00
0.86
0.14
0.00
0.86
0.12
0.00
0.88
MiltonKeynes
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Monmouthshire
0.84
0.00
0.16
0.76
0.00
0.24
0.78
0.00
0.22
0.81
0.00
0.19
Moray
0.15
0.59
0.26
0.12
0.69
0.19
0.10
0.73
0.17
0.08
0.80
0.12
Neath
Port
Talbot
0.32
0.04
0.64
0.21
0.09
0.69
0.17
0.21
0.62
0.08
0.11
0.81
New
castle
uponTyne
0.06
0.00
0.94
0.10
0.00
0.90
0.06
0.00
0.94
0.06
0.00
0.94
New
port
0.50
0.00
0.50
0.63
0.00
0.37
0.63
0.00
0.37
0.60
0.00
0.40
Norfolk
0.84
0.05
0.12
0.77
0.07
0.16
0.86
0.03
0.11
0.84
0.02
0.14
NorthAyrshire
0.00
0.63
0.37
0.00
0.58
0.42
0.00
0.59
0.41
0.00
0.90
0.10
NorthEast
Lincolnshire
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
NorthLanarkshire
0.00
0.15
0.85
0.00
0.26
0.74
0.00
0.27
0.73
0.00
0.30
0.70
NorthLincolnshire
0.96
0.00
0.04
0.98
0.00
0.01
0.99
0.00
0.01
0.99
0.00
0.01
NorthSomerset
0.75
0.00
0.25
0.87
0.00
0.13
0.84
0.00
0.16
0.80
0.00
0.20
NorthTyneside
0.00
0.04
0.96
0.00
0.02
0.98
0.00
0.02
0.98
0.00
0.14
0.86
NorthYorkshire
0.83
0.01
0.16
0.52
0.19
0.29
0.30
0.40
0.30
0.30
0.24
0.46
Northamptonshire
0.89
0.00
0.11
0.82
0.00
0.17
0.84
0.00
0.15
0.96
0.00
0.04
Northumberland
0.52
0.03
0.46
0.44
0.15
0.41
0.34
0.30
0.35
0.18
0.64
0.18
Nottingham
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Nottinghamshire
0.86
0.00
0.14
0.90
0.00
0.10
0.92
0.00
0.08
0.63
0.01
0.36
Oldham
0.00
0.85
0.15
0.00
0.77
0.23
0.00
0.82
0.18
0.00
0.83
0.17
Orkney
Islands
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
Oxfordshire
0.96
0.00
0.04
0.96
0.00
0.04
0.95
0.00
0.05
0.95
0.00
0.05
Pem
brokeshire
0.90
0.00
0.10
0.83
0.00
0.17
0.78
0.00
0.22
0.77
0.01
0.23
Perth
andKinross
0.60
0.03
0.37
0.41
0.17
0.42
0.29
0.28
0.44
0.16
0.59
0.26
Peterborough
0.31
0.00
0.68
0.66
0.00
0.34
0.56
0.00
0.44
0.73
0.00
0.27
Plymouth
0.04
0.00
0.96
0.05
0.00
0.95
0.05
0.00
0.95
0.14
0.00
0.86
Poole
0.64
0.00
0.36
0.61
0.00
0.39
0.57
0.00
0.43
0.57
0.00
0.43
Powys
0.60
0.07
0.33
0.31
0.22
0.47
0.24
0.28
0.49
0.15
0.50
0.35
Reading
0.99
0.00
0.01
1.00
0.00
0.00
0.98
0.00
0.02
1.00
0.00
0.00
RedcarandCleveland
0.32
0.00
0.68
0.17
0.02
0.81
0.25
0.03
0.72
0.27
0.00
0.73
Renfrew
shire
0.00
0.82
0.18
0.00
0.94
0.06
0.00
0.95
0.05
0.00
0.93
0.07
Rhondda,Cynon,Taff
0.09
0.24
0.67
0.02
0.37
0.61
0.02
0.42
0.56
0.01
0.67
0.32
392 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
Table
5(continued)
UK
County
Proportionarable
Proportiontemporary
grass
Proportionpermanentgrass
Proportionforest
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Rochdale
0.02
0.10
0.88
0.03
0.24
0.73
0.03
0.24
0.73
0.04
0.09
0.88
Rotherham
0.86
0.00
0.14
0.83
0.00
0.17
0.79
0.00
0.21
0.85
0.00
0.15
Rutland
0.99
0.00
0.01
0.99
0.00
0.01
0.99
0.00
0.01
1.00
0.00
0.00
Salford
0.01
0.04
0.96
0.01
0.02
0.97
0.01
0.02
0.96
0.00
0.00
1.00
Sandwell
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
0.96
0.00
0.04
Sefton
0.03
0.04
0.93
0.02
0.05
0.93
0.04
0.08
0.88
0.05
0.03
0.92
Sheffield
0.15
0.40
0.45
0.08
0.69
0.23
0.07
0.65
0.28
0.08
0.63
0.29
Shropshire
0.88
0.00
0.12
0.78
0.00
0.22
0.78
0.00
0.22
0.85
0.00
0.15
Slough
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Solihull
0.99
0.01
0.00
0.99
0.01
0.00
0.98
0.01
0.01
0.99
0.00
0.01
Somerset
0.41
0.01
0.58
0.38
0.02
0.60
0.31
0.07
0.62
0.49
0.04
0.48
South
Ayrshire
0.00
0.44
0.56
0.00
0.44
0.56
0.00
0.59
0.41
0.00
0.90
0.10
South
Gloucestershire
0.14
0.00
0.86
0.20
0.00
0.80
0.29
0.00
0.71
0.21
0.00
0.79
South
Lanarkshire
0.00
0.46
0.54
0.00
0.51
0.49
0.00
0.57
0.43
0.00
0.75
0.25
South
Tyneside
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
SouthendonSea
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
StHelens
0.03
0.01
0.96
0.03
0.00
0.96
0.03
0.01
0.96
0.01
0.02
0.97
Staffordshire
0.71
0.01
0.29
0.54
0.06
0.40
0.41
0.08
0.51
0.46
0.07
0.47
Stirling
0.00
0.05
0.95
0.00
0.13
0.87
0.00
0.19
0.81
0.00
0.72
0.28
Stockport
0.03
0.03
0.93
0.05
0.05
0.90
0.06
0.04
0.90
0.02
0.10
0.87
Stockton
0.98
0.00
0.02
0.98
0.00
0.02
0.98
0.00
0.02
0.98
0.00
0.02
StokeonTrent
0.67
0.00
0.33
0.80
0.00
0.20
0.77
0.00
0.23
0.80
0.00
0.20
Suffolk
0.92
0.00
0.08
0.93
0.01
0.06
0.93
0.00
0.06
0.96
0.00
0.03
Sunderland
0.02
0.00
0.98
0.00
0.00
1.00
0.01
0.00
0.99
0.00
0.00
1.00
Surrey
0.99
0.00
0.01
1.00
0.00
0.00
0.99
0.00
0.01
1.00
0.00
0.00
Swansea
0.03
0.01
0.96
0.02
0.03
0.95
0.02
0.04
0.94
0.02
0.02
0.96
Swindon
0.39
0.00
0.61
0.22
0.00
0.78
0.24
0.00
0.76
0.16
0.00
0.84
Tameside
0.01
0.75
0.24
0.01
0.75
0.24
0.01
0.75
0.24
0.00
0.69
0.31
Telford
andWrekin
0.89
0.00
0.11
0.91
0.00
0.09
0.91
0.00
0.09
0.86
0.00
0.14
Thurrock
0.71
0.00
0.29
0.69
0.00
0.31
0.69
0.00
0.31
0.47
0.00
0.53
Torbay
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Torfaen
0.01
0.09
0.89
0.01
0.18
0.81
0.02
0.15
0.84
0.01
0.15
0.84
Trafford
0.04
0.00
0.96
0.15
0.00
0.85
0.17
0.00
0.83
0.12
0.00
0.88
Vale
ofGlamorgan
0.53
0.00
0.47
0.52
0.00
0.48
0.47
0.00
0.53
0.21
0.00
0.79
Wakefield
0.90
0.00
0.10
0.73
0.00
0.27
0.84
0.00
0.16
0.95
0.00
0.05
Walsall
0.98
0.00
0.02
0.97
0.00
0.03
0.97
0.00
0.03
0.93
0.00
0.07
Warrington
0.03
0.01
0.96
0.02
0.00
0.98
0.02
0.01
0.97
0.00
0.01
0.99
Warw
ickshire
0.79
0.00
0.21
0.80
0.00
0.19
0.77
0.00
0.23
0.89
0.00
0.11
WestBerkshire
0.84
0.00
0.16
0.88
0.00
0.12
0.84
0.00
0.16
0.84
0.00
0.16
Land-use change and GB soil carbon stocks 393
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
county under the Historical Best Case scenario is shown in
Figure 2a.
The Recent Best Case scenario (based on cropland
reversion to permanent grass as per 1998 land-use under
NVZ legislation) affects only England, with no land-use
change in Scotland and only very small area changes (338 ha;
SOC change mean: 0.07 Mt CO2-eq. over 20 yr) in Wales
(Figure 1b). Even for England, the change in GHG emission
reduction ⁄SOC increase is an order of magnitude lower than
for the Historical Best Case scenario (mean: 37 Mt CO2-
eq. over 20 yr). The total change for each county under the
Recent Best Case scenario is shown in Figure 2b.
The Worst Case grassland plough out to cropland
scenarios are all applied evenly to all counties in GB, so the
effect is proportional to the grassland area in each county. A
change of 5% permanent grassland to cropland in GB under
the Worst Case 5% scenario would result in increased GHG
emissions ⁄decreased SOC stocks, giving a net impact of
)70 Mt CO2-eq. over 20 yr, comprised of )37, )18 and
)16 Mt CO2-eq. over 20 yr for England, Scotland and Wales,
respectively (Figure 1c). Equivalent figures for the Worst
Case 10% and Worst Case 20% are as follows: Worst Case
10% = )75, )35 and )32 Mt CO2-eq. over 20 yr for
England, Scotland and Wales, respectively, and Worst Case
20% = )150, )70, )64 Mt CO2-eq. over 20 yr for England,
Scotland and Wales, respectively (Figure 1d,e for Worst Case
10% and Worst Case 20%, respectively). The total changes
for each county under the Worst Case 5%, 10% and 20%
scenarios are shown in Figure 2c,d,e, respectively.
The difference between the broad soil types (mineral and
organo-mineral vs. organic) in each country largely reflects
the proportion of organic to mineral soils in each country,
with mineral soils dominating in England, large contributions
from organic soils in Scotland, and significant contributions
from organic soils in Wales. For example, in the Historical
Best Case scenario, only 2% of the increase in SOC occurs on
organic soils whereas in Scotland, a small gain on mineral
soils (0.1 Mt CO2-eq. ⁄ yr) is offset by large losses
(>3 Mt CO2-eq. ⁄ yr) on organic soils, whilst in Wales,
though the total SOC losses are small, 79% occurs on
organic soils.
Discussion
Land-use change within the agricultural sector may not be a
feasible large-scale option for climate mitigation with land-
use primarily being determined by agricultural market
conditions. Indeed, much of the potential global mitigation
within this sector will be by changing management on land
that remains in agricultural use (Smith et al., 2007, 2008). We
are therefore not proposing large-scale land-use change as a
mitigation option, but instead have examined the
consequences in terms of GHGs should land-use change
occur through other pressures.Table
5(continued)
UK
County
Proportionarable
Proportiontemporary
grass
Proportionpermanentgrass
Proportionforest
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
Mineral
Organic
Organo-m
ineral
WestDunbartonshire
0.00
0.64
0.36
0.00
0.93
0.07
0.00
0.94
0.06
0.00
0.93
0.07
WestLothian
0.24
0.00
0.76
0.08
0.00
0.92
0.07
0.00
0.93
0.07
0.00
0.93
WestSussex
0.90
0.00
0.10
0.84
0.00
0.16
0.86
0.00
0.14
0.95
0.00
0.05
Western
Isles
0.00
0.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
Wigan
0.03
0.00
0.97
0.01
0.00
0.99
0.01
0.00
0.99
0.00
0.00
1.00
Wiltshire
0.47
0.00
0.53
0.45
0.00
0.55
0.38
0.00
0.62
0.60
0.00
0.39
WindsorandMaidenhead
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
0.98
0.00
0.02
Wirral
1.00
0.00
0.00
0.99
0.00
0.01
0.99
0.00
0.01
0.98
0.00
0.02
Wokingham
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Wolverhampton
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
Worcestershire
1.00
0.00
0.00
0.99
0.00
0.01
0.99
0.00
0.01
1.00
0.00
0.00
Wrexham
C.B.
0.87
0.01
0.13
0.72
0.11
0.18
0.58
0.19
0.23
0.40
0.22
0.38
York
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
1.00
0.00
0.00
394 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
The Historical Best Case scenario presents land-use as it
has been in the past (1930), but agricultural land-use is not
considered likely to return to conditions similar to these in
the near future. We included this scenario as it presents a real
case of land-use for GB to show what SOC stocks ⁄GHG
emissions would have been under such circumstances.
However, the historical best case for GB as a whole is clearly
not a ‘best case’ for Scotland in terms of GHG
emissions ⁄SOC storage with SOC storage higher in the
baseline. A best case scenario from a soil C perspective for
Scotland and Wales would see less cropland and more
grassland as seen in England in this scenario. The Recent Best
Case scenario is probably closer to what could feasibly be
achieved in the near term, but it only has a significant impact
–10
0
10
20
30
40
50
60
70
England Scotland Wales
Country
–120
–100
–80
–60
–40
–20
00England Scotland Wales
Country
Cha
nge
in G
HG
(M
t CO
2-eq
.)C
hang
e in
GH
G (
Mt C
O2-
eq.)
–150
–100
–50
0
50
100
150
200
250
300
350
England
Scotland
Wales
Country
Cha
nge
in G
HG
(kt
CO
2-eq
.)
–60
–50
–40
–30
–20
–10
England Scotland Wales
Country
Cha
nge
in G
HG
(M
t CO
2-eq
.)
(b)(a)
(d)(c)
–250
–200
–150
–100
–50
0England Scotland Wales
Country
Cha
nge
in G
HG
(M
t CO
2-eq
.)
(e)
Figure 1 The total change in GHG emissions (Mt CO2-eq. ⁄ ha over 20 yr) for England, Scotland and Wales under each land-use change
scenario. Different scales are used to show the differences between countries and scenarios. (a) Historical Best Case scenario, (b) Recent Best
Case scenario, (c) Worst Case 5% scenario, (d) Worst Case 10% scenario and (e) Worst Case 20% scenario. Soil C gains are shown in white,
losses in black. The bars represent the range of estimates and boxes would represent the equivalent of 1 SE about the mean estimate, if the
range were a true 95% CI about the mean. For some mitigation measures (e.g. those based on Smith et al., 2008), the range does represent the
statistical 95% CI, for others (where the range is derived from limited data) it does not, so the bars and boxes should be taken as indicative of
range and confidence about the mean, but are not robust 95% CIs and SEs.
Land-use change and GB soil carbon stocks 395
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
in England, with no significant impact in Wales or Scotland.
Even for England, the impact is an order of magnitude lower
than that of the historical best case scenario. Conversion of
cropland to grassland is not a feasible mitigation option if a)
there is no market incentive to convert (i.e. demand for
livestock products derived from the grassland), or b)
cropland increases elsewhere to meet the demand for
cropland products. In such a circumstance, GHG emissions
are simply displaced with no net GHG benefit (see Berry
et al., 2008; Carlton et al., 2009, 2010). In any case, increased
livestock emissions from the new grassland if used to raise
more livestock would increase, thus negating at least some if
not all of the GHG benefit.
The Worst Case scenarios, with 5, 10 and 20% plough out
of permanent grassland, represent potential futures should
cropland products (largely cereals in the UK) increase in
N
N N
N
N
–20 –10 0 2010
–20 –10 0 2010 –20 –10 0 2010 –20 –10 0 2010
–20 –10 0 2010
(a) (b)
(d) (e)(c)
Figure 2 The total change in GHG emissions (Mt CO2-eq. ⁄ ha over 20 yr – estimates using the mean mitigation factor shown) for each county
under each land-use change scenario. (a) Historical Best Case scenario, (b) Recent Best Case scenario, (c) Worst Case 5% scenario, (d) Worst
Case 10% scenario and (e) Worst Case 20% scenario.
396 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
market value to favour more crop production. High cereal
commodity prices in recent years have seen cropland areas
increase, and with demand for food growing with increasing
population, and competition for land potentially increasing in
the future (Smith et al., 2010), an increase in cropland area at
the expense of grasslands is a possibility leading to a trade-off
with grazed livestock production.
The Historical Best Case scenario delivers a GB emission
reduction of ca. 243 Mt CO2-eq. over 20 yr, or an annual
GHG emission reduction of ca. 12 Mt CO2-eq. ⁄ yr relative to
the 2004 baseline. The Worst Case 20% grassland plough out
scenario increases GB emissions by a similar magnitude
()283 Mt CO2-eq. over 20 yr; )14 Mt CO2-eq. ⁄ yr). In the
context of overall UK GHG emissions (635 Mt CO2-eq. ⁄ yrin 2007; Committee on Climate Change, 2010), the yearly
reductions ⁄ increases examined here are small accounting for
ca. 2% of yearly annual GHG emissions even for the most
extreme scenario (Worst Case 20%). However, in the context
of current UK Land-use, Land-Use Change and Forestry
(LULUCF) emissions, the changes in GHG emissions
examined here are considerable. UK LULUCF emissions in
1990 (source) were ca. 3 Mt CO2-eq. ⁄ yr and around
)2 Mt CO2-eq. ⁄ yr in 2005 (sink; Dyson, 2009). The Recent
Best Case scenario would deliver further emission reductions
of around half of the 2005 LULUCF sink (i.e. )1.4 Mt CO2-
eq. ⁄ yr) whereas even limited grassland plough out (5% Worst
Case scenario: 3.5 Mt CO2-eq. ⁄ yr) would reverse the 2005
sink and leave a LULUCF source approaching 1990 levels.
Conclusions
Land-use change between agricultural land-uses (transitions
between permanent and temporary grassland and cropland)
in GB is likely to be a limited option for GHG mitigation as
land-use is largely determined by market factors for
agricultural products and the climatic ⁄ edaphic suitability of
the land. However, external factors such as agricultural
product commodity markets could influence future land-use.
The impacts of such agricultural land-use change in GB could
have significant impacts on LULUCF emissions, with
relatively small changes in land-use (e.g. 5% plough out of
grassland to cropland, or reversion of cropland to the
grassland cover in NVZs of 1998) having an impact on GHG
emissions of a similar order of magnitude as the current UK
LULUCF sink. However, in terms of total UK GHG
emissions even the most extreme feasible land-use change
scenarios account for ca. 2% of current emissions.
Acknowledgements
Funding for this study came from Defra under project
SP0567 ‘Assembling UK-wide data on soil carbon (and
greenhouse gas fluxes) in the context of land management’.
PS is a Royal Society-Wolfson Research Merit Award holder.
References
Anon. 1968. A century of agricultural statistics; Great Britain, 1866-
1966. Ministry of Agriculture, Fisheries and Food, London.
Barker, T., Bashmakov, I., Bernstein, L., Bogner, J., Bosch, P.,
Dave, R., Davidson, O., Fisher, B., Grubb, M., Gupta, S.,
Halsnaes, K., Heij, B., Kahn Ribeiro, S., Kobayashi, S., Levine,
M., Martino, D., Masera Cerutti, O., Metz, B., Meyer, L.,
Nabuurs, G.-J., Najam, A., Nakicenovic, N., Rogner, H.-H., Roy,
J., Sathaye, J., Schock, R., Shukla, P., Sims, R., Smith, P., Swart,
R., Tirpak, D., Urge-Vorsatz, D. & Zhou, D. 2007. Summary for
Policy Makers. In: Climate change 2007: mitigation. Contribution
of Working group III to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change (eds B. Metz, O.R.
Davidson, P.R. Bosch, R. Dave & L.A. Meyer), p. 35. Cambridge
University Press, Cambridge, United Kingdom and New York,
NY, USA.
Berry, P.M., Kindred, D.R. & Paveley, N.D. 2008. Quantifying the
effects of fungicides and disease resistance on greenhouse gas
emissions associated with wheat production. Plant Pathology, 57,
1000–1008.
Bradley, R.I., Milne, R., Bell, J., Lilly, A., Jordan, C. & Higgins, A.
2005. A soil carbon and land-use database for the United
Kingdom. Soil Use and Management, 21, 363–369.
Carlton, R., Berry, P. & Smith, P. 2009. Investigating the interplay
between UK crop yields, soil organic carbon stocks and
greenhouse gas emissions. Aspects of Applied Biology, 95, 60–64.
Carlton, R., Berry, P. & Smith, P. 2010. Impact of crop yield
reduction on GHG emissions from compensatory cultivation of
pasture and forested land. International Journal of Agricultural
Sustainability, 8, 164–175.
Comber, A., Procter, C. & Anthony, S. 2008. The creation of a
national agricultural land-use dataset: combining pycnophylactic
interpolation with dasymetric mapping techniques. Transactions in
GIS, 12, 775–791.
Committee on Climate Change 2010. UK and regions. Available at:
http://www.theccc.org.uk/topics/uk-and-regions accessed 3 ⁄ 2 ⁄ 2010.Dawson, J.J.C. & Smith, P. 2007. Carbon losses from soil and its
consequences for land management. Science of the Total
Environment, 382, 165–190.
Defra 2005. MAGPIE: updating and re-developing structure,
databases and models for wider application. Final Report of
Defra Project NT2503. Available at: http://randd.defra.gov.uk/
Document.aspx?Document=NT2503_3457_FRP.doc accessed
18 ⁄ 5 ⁄ 2010.Dyson, K.E. (ed.) 2009. Inventory and projections of UK emissions
by sources and removals by sinks due to land-use, land-use change
and forestry. Annual Report, July 2009. DEFRA Contract
GA01088. Available at: http://www.edinburgh.ceh.ac.uk/ukcarbon/
reports.htm#2009 (accessed June 2010).
Freibauer, A., Rounsevell, M., Smith, P. & Verhagen, A. 2004.
Carbon sequestration in the agricultural soils of Europe.
Geoderma, 122, 1–23.
Guo, L.B. & Gifford, R.M. 2002. Soil carbon stocks and land-use
change: a meta analysis. Global Change Biology, 8, 345–360.
IPCC 1997. IPCC 1996 revised good practice guidelines for
greenhouse gas inventories. Intergovernmental Panel on Climate
Change (IPCC), Institute for Global Environmental Strategies,
Tokyo, Japan.
Land-use change and GB soil carbon stocks 397
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398
IPCC 2006. IPCC 2006 revised good practice guidelines for
greenhouse gas inventories. Intergovernmental Panel on Climate
Change (IPCC), Institute for Global Environmental Strategies,
Tokyo, Japan.
IPCC WGI 2001. Climate change: the scientific basis. Cambridge
University Press, Cambridge, UK.
IPCC WGI 2007. Climate change 2007: the physical science basis.
Cambridge University Press, Cambridge, UK.
Jenkinson, D.S. 1990. The turnover of organic carbon and nitrogen
in soil. Philosophical Transactions of the Royal Society, London B,
329, 361–368.
Johnston, A.E. 1973. The effects of ley and arable cropping systems
on the amounts of soil organic matter in the Rothamsted and
Woburn Ley-Arable Experiments. Rothamsted Report for 1972,
Part 2, 131–159.
Johnston, A.E., Poulton, P.R. & Coleman, K. 2009. Soil organic
matter: its importance in sustainable agriculture and carbon
dioxide fluxes. Advances in Agronomy, 101, 1–57.
Lilly, A., Bell, J.S., Hudson, G., Nolan, A.J. & Towers, W. 2010.
National Soil Inventory of Scotland 1 (NSIS_1): site location,
sampling and profile description protocols. (1978-1988). Technical
Bulletin, Macaulay Institute (in press).
McGrath, S.P. & Loveland, P.J. 1992. The soil geochemical atlas of
England and Wales. Blackie Academic and Professional, Glasgow.
SI 1998. The Action Programme for Nitrate Vulnerable Zones
(England and Wales) Regulations, 1998. SI 1998 ⁄ 1202. The
Stationary Office, London, ISBN 011 079114 2.
Smith, P. 2004. Soils as carbon sinks – the global context. Soil Use
and Management, 20, 212–218.
Smith, P. & Olesen, J.E. 2010. Synergies between mitigation of, and
adaptation to, climate change in agriculture. Journal of
Agricultural Science, doi:10.1017/S0021859610000341.
Smith, P., Powlson, D.S., Glendining, M.J. & Smith, J.U. 1997.
Potential for carbon sequestration in European soils: preliminary
estimates for five scenarios using results from long-term
experiments. Global Change Biology, 3, 67–79.
Smith, P., Powlson, D.S., Glendining, M.J. & Smith, J.U. 1998.
Preliminary estimates of the potential for carbon mitigation in
European soils through no-till farming. Global Change Biology, 4,
679–685.
Smith, P., Powlson, D.S., Smith, J.U., Falloon, P.D. & Coleman, K.
2000a. Meeting Europe’s climate change commitments:
quantitative estimates of the potential for carbon mitigation by
agriculture. Global Change Biology, 6, 525–539.
Smith, P., Milne, R., Powlson, D.S., Smith, J.U., Falloon, P.D. &
Coleman, K. 2000b. Revised estimates of the carbon mitigation
potential of UK agricultural land. Soil Use and Management, 16,
293–295.
Smith, P., Goulding, K.W., Smith, K.A., Powlson, D.S., Smith,
J.U., Falloon, P.D. & Coleman, K. 2000c. Including trace gas
fluxes in estimates of the carbon mitigation potential of UK
agricultural land. Soil Use and Management, 16, 251–259.
Smith, P., Martino, D., Cai, Z., Gwary, D., Janzen, H.H., Kumar,
P., McCarl, B., Ogle, S., O’Mara, F., Rice, C., Scholes, R.J.,
Sirotenko, O., Howden, M., McAllister, T., Pan, G.,
Romanenkov, V., Rose, S., Schneider, U. & Towprayoon, S. 2007.
Agriculture. In: Chapter 8 of Climate change 2007: mitigation.
Contribution of Working group III to the Fourth Assessment Report
of the Intergovernmental Panel on Climate Change (eds B. Metz,
O.R. Davidson, P.R. Bosch, R. Dave & L.A. Meyer), pp. 497–
540. Cambridge University Press, Cambridge, United Kingdom
and New York, NY, USA.
Smith, P., Martino, D., Cai, Z., Gwary, D., Janzen, H.H., Pushpam,
K., McCarl, B., Ogle, S., O’Mara, S., Rice, C., Scholes, B.,
Sirotenko, O., Howden, M., McAllister, T., Pan, G.,
Romanenkov, V., Schneider, U., Towprayoon, S., Wattenbach,
M. & Smith, J. 2008. Greenhouse gas mitigation in agriculture.
Philosophical Transactions of the Royal Society, B., 363, 789–813.
Smith, P., Gregory, P., van Vuuren, D., Obersteiner, M.,
Rounsevell, M., Woods, J., Havlik, P., Stehfest, E. & Bellarby, J.
2010. Competition for land. Philosophical Transactions of the
Royal Society, B., 365, 2941–2957.
398 P. Smith et al.
ª 2010 The Authors. Journal compilation ª 2010 British Society of Soil Science, Soil Use and Management, 26, 381–398