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LETTER
Local and social ace s o plane a y bounda ies: igh o nu ien s
Helena Kahiluo o
1
, Miia Kuisma
2
, Anna Kuokkanen
3
, Mi ja Mikkilä
3
and Lassi Linnanen
3
1
Na u al Resou ces Ins i u e Finland (Luke), Jokiniemenkuja 1, FI-01370 Van aa, Finland
2
Na u al Resou ces Ins i u e Finland (Luke), Lönn o inka u 5, FI-50100 Mikkeli, Finland
3
Lappeen an a Uni e si y o Technology, PO Box 20, FI-53851 Lappeen an a, Finland
E-mail: helena.kahiluo o@luke.fi
Keywo ds: global equi y, locali y, his o y, bo om-up assessmen , ipping poin , social plane a y bounda y, ea h sys em go e nance
Supplemen a y ma e ial o his a icle is a ailable online
Abs ac
An h opogenic nu ien flows exceed he plane a y bounda ies. The bounda ies and he cu en
excesses a y spa ially. Such a ia ions ha e bo h an ecological and a social ace . We explo ed he
spa ial a ia ion using a bo om-up app oach. The local c i ical bounda ies we e de e mined h ough
he cu en o accumula ed flow o he p eceding fi e yea s be o e he plane a y bounda y c i e ia
we e me . Finland and E hiopia se ed as cases wi h con as ing ecology and weal h. The a ia ion in
excess depends on his o ical global inequi ies in he access o nu ien s. Globally, he accumula ed use
pe capi a is 2300 kg eac i e ni ogen (N
)and 200 kg phospho us (P). Fo Finland, he accumula ed
use pe capi a is 3400 kg N
and 690 kg P, whe eas o E hiopia, i is 26 kg N
and 12 kg P. The c i ical N
bounda y in Finland is cu en ly exceeded by 40 kg cap
−1
a
−1
and he accumula ed excess is
65 kg cap
−1
a
−1
, while he global cu en excess is 24 kg cap
−1
a
−1
and he e is space in E hiopia o
inc ease e en he accumula ed flow. The c i ical P bounda y is exceeded in Finland and (al hough less
so)in E hiopia, bu o con a y easons: (1) he excessi e pas inflow o he ag i ood sys em in Finland
and (2) he excessi e ou flow om he ag i ood sys em igge ed by defici s in inflow and was e
managemen in E hiopia. The c i ical bounda ies se by Finnish ma ine sys ems a e lowe and hose
se by eshwa e s a e highe han he plane a y bounda ies downscaled pe capi a. The shi o
dominance o in e nal loading in wa e cou ses ep esen s a ipping poin . We conclude ha ood
secu i y wi hin he sa e bounda ies equi es global edis ibu ion o nu ien s in esidues, soils and
sedimen s and o igh s o use nu ien s. Bo om-up assessmen s e eal local dynamics ha shed new
ligh on he ele an bounda y c i e ia and on es ima es and emedies.
1. In oduc ion
Resea ch sugges s ha an h opogenic nu ien flows
ha e ansg essed he uppe ole able limi s o he
Ea h sys em (Rocks öm e al 2009, Ca pen e and
Benne 2011, S e en e al 2015a). Beyond such
‘plane a y bounda ies’unp edic able changes ha a e
di ficul o e e se a e p obable. The sa e bounda ies
a y acco ding o he cha ac e is ics o local ecosys-
ems. The excess in nu ien flows a ies acco ding o
local c i ical bounda ies and, in addi ion, acco ding o
local socio-economic ea u es ha a ec nu ien use.
De e mining such spa ial a ia ions wi h hei ecologi-
cal and social ace s can ad ance he unde s anding o
he dynamics unde pinning he plane a y bounda ies
and hei ansg ession, as well as o equi y issues
(S e en e al 2015b)when alloca ing he necessa y
educ ion in he flows and ailo ing he emedies o
e u n o he sa e space.
Plane a y bounda ies can be ansg essed by bo -
om-up o cing h ough cumula i e change o by eme -
gen op-down o cing h ough a sys emic change
(Tu ne e al 1990,Ba noskye al 2012).Rega ding
nu ien s, bo h o hese wo modes o o cing occu .
Ni ogen-con aining (N)g eenhouse gas emissions and
N con ibu ion o acidifica ion ep esen global o cing,
while N and phospho us (P)flows o coas al and esh-
wa e sys ems cons i u e local o cing. In addi ion, he
human dimension o ansg essing he bounda ies
h ough he excess use o nu ien s a ies a ound he
OPEN ACCESS
RECEIVED
4 No embe 2014
REVISED
8 Augus 2015
ACCEPTED FOR PUBLICATION
10 Augus 2015
PUBLISHED
16 Oc obe 2015
Con en om his wo k
may be used unde he
e ms o he C ea i e
Commons A ibu ion 3.0
licence.
Any u he dis ibu ion o
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au ho (s)and he i le o
he wo k, jou nal ci a ion
and DOI.
© 2015 IOP Publishing L d
globe, mainly acco ding o a o dabili y, illus a ing he
spa ial inequi y. I espec i eo he oleo global o cing,
plane a y bounda ies a e ansg essed by local ac ions
and he gaps (i.e., he excess use o nu ien s),mus be
b idged locally. In ligh o he in e egional linkages
o spa ial equi y, global ac ions may also be equi ed.
Humani y’s ood supply depends on N and P, he
wo elemen s mos limi ing o ag icul u e. In addi ion,
74% o he con e sion o a mosphe ic N
2
o eac i e N
(N
)and 80% o P flows o wa e sys ems se e ag i ood
sys ems (Kahiluo o e al 2014a). The global spa ial a ia-
ion in c op yield is p ima ily nu ien and wa e -limi ed
(Muelle e al 2012).The a ia ioninnu ien use ela-
i e o c op up ake is ma ked: 32% o he N su plus and
40% o he P su plus occu on 10% o he global field
a ea (Foley e al 2011). The his o ical weal h- ela ed a -
ia ion in nu ien use is eflec ed in he cu en local
ese es in field soils, wa e sys ems and esidues. These
ese es essen ially influence cu en c op yields and he
equi emen o e ilize applica ion o main ain ag i-
cul u al p oduc i i y. The u bulence in global ood p i-
ces in ecen yea s has agg a a ed ood insecu i y mos
hea ily in he coun ies elying on ood impo s and
especially among he u al poo (Comp on e al 2010,
FAO 2011,Headey2011), emphasizing he impo ance
o esou ce dis ibu ion o ood p oduc ion.
P io assessmen s o plane a y bounda ies exclu-
ded he dimension o spa ial and empo al social-eco-
logical a ia ion. In his s udy, we quan i y he spa ial
a ia ion o c i ical nu ien bounda ies and he dis-
ance om he bounda y, i.e., excess in nu ien flows
o capaci y o inc ease hose flows, aking in o accoun
he his o ical nu ien accumula ion. Then we assess
he a ia ion in he p opo ions o ag i ood sys ems
o he eac i e nu ien flows. We downscale he pla-
ne a y nu ien bounda ies h ough e en pe capi a
dis ibu ion and compa e hem o he locally de e -
mined c i ical nu ien bounda ies o Finland wi h a
agile ecology, and o he socio-ecologically con as -
ing E hiopia. We posed he ollowing ques ions:
1. How can plane a y nu ien bounda ies be made
spa ially explici a he na ional scale?
2. How much do c i ical nu ien bounda ies, excesses
and p opo ions o ag i ood sys ems a y in space?
3. A e he ecological o socio-economic and cu en
o his o ical spa ial a ia ions mo e decisi e o he
excess?
2. Me hods
4
2.1. S eps in he assessmen
The plane a y nu ien bounda ies p oposed by
Rocks öm e al (2009), he P bounda y o eshwa e
sys ems p oposed by Ca pen e and Benne (2011),
and he N bounda y eassessed by de V ies e al
(2013), e ised by S e en e al (2015a,b)and
complemen ed by Kahiluo o e al (2014a)we e
applied in he socio-ecologically con as ing local
cases o Finland and E hiopia. Fi s , he p oposed
plane a y nu ien bounda ies we e downscaled
h ough an equal dis ibu ion wi hin he global
popula ion ( able 1). The ea e , he sa e bounda ies
we e locally de e mined o Finland o compa ison,
based on he cha ac e is ics o he local ma ine (N,
P)and eshwa e (P)ecosys ems (see sec ion 2.2).
Rega ding E hiopia, he downscaled plane a y
bounda ies we e used due o lack o his o ical
ecological da a. To indica e he socio-economic
spa ial a ia ion, he cu en and accumula ed
(1900–2010)use o N and P, and P flow o wa e
sys ems, we e es ima ed globally and o Finland and
E hiopia (see sec ion 2.3). The excess was de e mined
as he di e ence be ween he cu en o he accumu-
la ed flows and he c i ical bounda y. Finally, he
p opo ion o he ag i ood sys ems o he local
eac i e nu ien flows was assessed. Fo he s eps in
he assessmen , see also able 1.
2.2. Plane a y nu ien bounda ies: owa ds a
bo om-up app oach
P e iously, he plane a y N bounda y including bo h
he clima ic and wa e sys em isks, was se a
20 M N
a
−1
(de V ies e al 2013, S e en e al 2015a,
b). Fo P in oceans, he p oposed bounda y c i e ion
was o a oid an ex ensi e anoxia in he nea -bo om
laye s o he nex 1000 yea s (Rocks öm e al 2009).
Fo P in eshwa e s, 24 mg P m
−3
o wa e , which
ep esen s he meso-eu ophic in e ace, i.e., a ypical
a ge o limi he eu ophica ion o lakes and ese -
oi s, and o P flow om e es ial ecosys ems o
eshwa e sys ems, 1.2 M a
−1
(Ca pen e and Ben-
ne 2011)was p oposed. In his s udy, he p oposed
plane a y bounda ies we e downscaled o he local
case h ough an equal dis ibu ion wi hin he global
popula ion o 7.0 billion in 2010 (UN 2011).
When a emp ing a bo om-up app oach by
locally de e mining a c i ical N bounda y, he local
con e sion o he a mosphe ic N
2
o N
in Finland was
es ima ed. This a emp is in line wi h he s a emen o
S e en e al (2015a):‘The plane a y bounda y (PB) a-
mewo k is no designed o be ‘downscaled’o ‘dis-
agg ega ed’ o smalle le els, such as na ions o local
communi ies.’In he assessmen o he cu en N
con e sion, syn he ic e ilize use in ag icul u e and
o es y (153 k a
−1
)(G ön oos and Nikande 2002,
MMM 2008, Me la 2012, Tike 2013), o he use o
Habe -Bosch N (36 k a
−1
)(Galloway e al 2004, 2003,
2008), cul i a ion-induced biological N
2
fixa ion (C-
BNF, 9 k a
−1
)(An ikainen e al 2005, Sipiläinen e al
2012)and ossil ene gy use (42 k a
−1
)(S a is ics Fin-
land, 2013, 2014a,b; Minis y o Employmen and he
4
Re e ences ci ed in his sec ion a ailable in supplemen a y
ma e ial.
2
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al
Economy 2012)we e aken in o accoun (see Kahi-
luo o e al 2014a). The mean alues o 2006–2010
we e used o all da a unless o he wise s a ed. Rega d-
ing he accumula ed local N
con e sion o Finland,
he global bounda y downscaled o he Finnish popu-
la ion (16 k a
−1
)was adop ed as ou p oposed c i ical
N bounda y. The N
use accumula ed a e he accu-
mula ed bounda y was ansg essed es ima ed (N
con e sion o he global bounda y downscaled,
1900–2010, 16 000 k ). When assessing he necessa y
annual educ ion o he accumula ed excess, i was
assumed ha he excess would be educed du ing as
many yea s as i needed o e ol e.
The ecology o he Bal ic Sea was hypo hesized o
se an addi ional bounda y o ha by he N
con e -
sion because ‘i has been deba ed whe he N o P is he
mos limi ing nu ien in he Bal ic Sea’(HELCOM
2009). Reduc ions in bo h P and N a e equi ed, and
he p ima y p oduc ion o he sp ing pe iod is N lim-
i ed in he open basins, excep o in he Bo hnian Bay
and Bo hnian Sea. The decade o he apid expansion
o hypoxia in he Bal ic Sea was iden ified (Sa chuk
Table 1. Spa ial a ia ion in nu ien flows, c i ical nu ien bounda ies and excess globally and locally (Finland and E hiopia). Nu ien s:
ni ogen (N)(N
2
con e sion o eac i e N (N
)) and phospho us (P)flow o wa e sys ems.
Flow Bounda y Excess
kg cap
−1
kg cap
−1
a
−1
kg cap
−1
kg cap
−1
a
−1
kg cap
−1
kg cap
−1
a
−1
Global
N
Downscaled
a
27 2.9 24
P
Downscaled
Oceansa
1.5 1.6 -0.1
Downscaled
F eshwa e sb
1.3–4.6 0.2 1.1–4.4
Finland
N
Cu en
Con e sionc
43 2.9 40
Cu en
Bal ic Sead
43 8.4 34
Cu en
Lakese
No limi ing
Accumula ed
Con e sion
1900–2010
3,400 68
g
No known 2.9
g
>3400 65
g
P
Cu en
Bal ic Seah
0.7 0.2 0.5
Cu en
Lakesi
0.7 0.7 0.01
Accumula ed
Bal ic Sea
1900–2010
j
44 1.3
g
0.2 0.004
g
44 1.3
g
Accumula ed
Lakes
1900–2010
k
39 1.5
g
4.9 0.1
g
34 1.4
g
E hiopia
N
Cu en
Con e sionc
1.7 2.9 -1.2
Accumula ed
Con e sion
1900–2010
l
26 2.8
g
51 2.9
g
–25 -0.1
g
P
Cu en
F eshwa e sm
0.2 0.2 0.1
Accumula ed
F eshwa e s
1900-2010
l
5.5 0.6
g
3.1 0.2
g
2.4 0.4
g
a
The plane a y bounda ies o N (de V ies e al 2013, S e en e al 2015a,b)and o P Rocks öm e al (2009)equally di ided o he global
popula ion in 2010; o he cu en flow es ima e see Kahiluo o e al (2014a).
b
The plane a y bounda y es ima e o Ca pen e and Benne (2011)equally di ided o he global popula ion in 2010; o he cu en flow
es ima e see Kahiluo o e al (2014a).
c
The downscaled plane a y bounda y see
a
. The local cu en a e age flow 2006–2010.
d
The local bounda y based on he ca ying capaci y o he Bal ic Sea and on he local a e age flow 1926–1930. The local cu en flow see
c
.
e
P limi ing ac o o eu ophica ion.
The bounda y o accumula ed use: he global downscaled bounda y; he local flow exceeded ha al eady be o e 1900. The flow
accumula ed 1900–2010.
g
Assuming ha he excess will be deple ed du ing as many yea s as i needed o e ol e.
h
The local bounda y based on he ca ying capaci y o he Bal ic Sea, equally di ided o he popula ion o he Bal ic Sea d ainage in 2010,
and on he local a e age flow o wa e sys ems 1926–1930. The local cu en a e age flow o wa e sys ems 2006–2010.
i
The local bounda y based on he ca ying capaci y o local lakes and on he local a e age flow o wa e sys ems 1956–1960. The local cu en
flow see
h
.
j
The bounda y o accumula ed use: he flow o wa e sys ems accumula ed (since 1900)when exceeding he local bounda y (in he end o
1930s). The flow accumula ed 1940–2010.
k
The bounda y o accumula ed use: he flow o wa e sys ems accumula ed (since 1900)when exceeding he local bounda y (1960). The
flow accumula ed 1961–2010.
l
The bounda y o accumula ed use: he global downscaled bounda y.The flow accumula ed 1993–2010.
m
The downscaled plane a y bounda y see
b
. The local cu en a e age flow o wa e sys ems 2006–2010.
3
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al
e al 2008; Ca s ensen e al 2014), indica ing he ans-
g ession o he ca ying capaci y. The mean con e -
sion o N
2
o N
pe capi a in Finland o he p eceding
fi e-yea pe iod (1926–1930, 47 k a
−1
)was es ima ed
as he c i ical N bounda y se by he Bal ic Sea. Addi-
ionally, he c i ical N bounda y was assessed in ana-
logy wi h he assessmen o he c i ical P bounda y,
i.e., based on he mean N flow in he Bal ic Sea ca ch-
men du ing ha pe iod (331 k a
−1
)(HELCOM 2011,
Gus a sson e al 2012, Bal ic S e n, 2013). The excess
was es ima ed as he di e ence be ween ou p oposed
c i ical bounda y and he cu en flow in Finland
(73 k a
−1
)(Biodi e si y/SYKE, 2014).
Rega ding a c i ical P bounda y o he Bal ic Sea,
he same bounda y c i e ion o ex ensi e hypoxia as
o N was used. P is he limi ing ac o o oxic sum-
me blooms o cyanobac e ia in he Bal ic Sea bo h
cu en ly and, o an e en g ea e ex en , p e iously
(Vah e a e al 2007, Sa chuk e al 2008, Conley 2012).
Cyanobac e ia con ibu e ‘ emendous quan i ies’o
N o he ecosys em, making i especially impo an o
educe P loads. The P flows in he Bal ic Sea ca chmen
we e es ima ed o he p eceding fi e yea s’pe iod o
he apid expansion o hypoxia (1926–1930, 18 k a
−1
)
(HELCOM 2011, Gus a sson e al 2012, Bal ic S e n,
2013) o define a c i ical P bounda y o he Bal ic Sea.
The excess was es ima ed based on he cu en P flow
in Finland (4,1 k a
−1
)(Biodi e si y/SYKE, 2014). The
expanding hypoxia has he e been empo ally ela ed o
Pflows and no o soil P s ocks o e ilize inpu s, as
S e en e al (2015a)sugges o local/ egional scales
because P flows a e di ec ly ela ed o he isk o eu o-
phica ion and a e compa able wi h N bounda y and
ac oss spa ial (e.g., globe . Finland . E hiopia)and
empo al (1960s . cu en )scales; by con as , he
ela i e significance o he soil nu ien s ocks and e -
ilize inpu a ies among hose scales (see Ca pen e
and Benne 2011, S e en e al 2015a). The Finnish P
flow o 1900–1954 was based on he ag icul u al flow
in e pola ed elying on he e ilize P use in
1900–1954 and on he a io o P flow and e ilize P
use in 1956–1960. The e ilize P use in 1900–1910
was assumed o be equal o ha es ima ed o 1910
(An ikainen e al 2008). Fo he accumula ed P flow,
ou p oposed local c i ical bounda y o he Bal ic Sea
was de e mined based on he accumula ed annual P
flow o 1900–1939 (0.02 k a
–1
), i.e., un il he local P
bounda y was ansg essed. The P flow accumula ed
a e he accumula ed bounda y was ansg essed was
es ima ed (1940–2010, 250 k )
Rega ding he Finnish lakes, o de e mine a c i ical
P bounda y, he same bounda y c i e ion o ex ensi e
hypoxia was used as o he Bal ic Sea and N
(Rocks öm e al 2009). Eu ophica ion o Finnish
lakes has since he 1960s been conside ed la gely
P-limi ed. While he h esholds be ween he mul i-
s abili y s ages o shallow lakes a e mul iple (Sche e
and an Nes 2007), he uppe ole able limi o P
flows was de e mined based on he c i e ion o
expanding hypoxia (Rocks öm e al 2009)and/o
ab up eu ophica ion and hen empo ally ela ed o
he P flow in o he eshwa e sys em. The decade o
apid eu ophica ion and expansion o hypoxia was
iden ified based on (1)biological changes in he sedi-
men s o obse ed lakes (Räsänen e al 1992, Me -
iläinen and Hamina 1993, Kauppila e al 2002,
Kauppila and Valpola 2003, Kauppila 2005, Heikkinen
and Väisänen 2007, Koi unen 2008, Kihlman and
Kauppila 2010, Kauppila unpublished)and (2) he
de elopmen o he concen a ion o o al o bioa ail-
able P (Mi ikka and Ekholm 2003, Räike e al 2003,
Ekholm and Mi ikka 2006). The mean P flow o a p e-
ceding fi e yea pe iod (1956–1960, 4.0 k a
−1
), o igi-
na ing om sca e ed sou ces (ag icul u e 1.1 k a
−1
,
u al dwellings 0.5 k a
−1
, o es y 0.03 k a
−1
)and
poin sou ces (indus y 0.6 k a
−1
, municipali ies
1.8 k a
−1
, and fish a ming, u a ming and pea p o-
duc ion 0.0 k a
−1
)was hen es ima ed (Biodi e si y/
SYKE 2014). The P flow om ag icul u e in
1955–2010 was es ima ed elying on he ag icul u al
soil P s a us in 1955–2000 (Män ylah i 2002)and
2005–2009 (Uusi alo e al 2014)and on he es ima es
o he flow a ailable o 1995–2010 (Biodi e si y/
SYKE 2014). The P load om field soils o he wa e -
cou ses linea ly depends on soil ex ac able P (Ekholm
e al 1999), and mo e han 90% o he ag icul u al load
o igina es in field soils (Rekolainen e al 1995). The
es ima es o P flow om popula ion cen es o
1971–2010 and om sca e ed dwellings o
1995–2010 (Biodi e si y/SYKE 2014)we e ex a-
pola ed o 1955–1970 and 1955–1994, espec i ely,
based on he deg ee o u baniza ion (S a is ics Finland
1997). The es ima es o P flow om indus y o
1972–2010 and om o es y o 1995–2010 (Biodi-
e si y/SYKE 2014)we e ex apola ed o 1955–1971
and 1955–1994, espec i ely, based on he g ow h a e
o he o es indus y (Kahiluo o 1986). The P flow
om o he poin sou ces was assumed ze o be o e he
fi s o ficial es ima ion in 1976 (0.025 k a
−1
; Biodi-
e si y/SYKE 2014). Fo he accumula ed P flow, a
local c i ical bounda y was de e mined based on he
accumula ed annual P flow o 1900–1960 o he
eshwa e s (0.4 k a
–1
), i.e., un il he local P bounda y
was ansg essed. The P flow accumula ed a e he
accumula ed bounda y was ansg essed was es i-
ma ed (1961–2010, 220 k ).
Fo E hiopia, he plane a y N bounda y (de V ies
e al 2013, S e en e al 2015a,b)and he plane a y P
bounda y o eshwa e s (Ca pen e and Ben-
ne 2011)we e ansla ed o he pe capi a alloca ion
by di iding he global bounda y wi h he cu en
wo ld popula ion (2.9 kg N
, and 0.2 kg P cap
−1
a
−1
).
The cu en N
con e sion in E hiopia (133 k a
−1
)
was es ima ed, including he syn he ic e ilize use
(91 k a
−1
)(FAO 2013), o he use o Habe -Bosch N
(0.2 k a
−1
)(Galloway e al 2003, 2004, 2008), he
C-BNF (37 k a
−1
)and he ossil ene gy use
(4.7 k a
−1
). The C-BNF in E hiopia was assessed
4
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al

assuming he global a io o C-BNF and he syn he ic
e ilize use. The con e sion o N
2
o N
in ossil
ene gy use in E hiopia (Wo ld Bank 2014c)was asses-
sed assuming he a io o N
c ea ion pe ossil ene gy
use in Finland. The cu en P flow o wa e sys ems in
E hiopia (21 k a
−1
)was assessed based on he sca ce
a ailable da a on he P flow om ag icul u e
(17 k a
−1
)(Haileslassie e al 2005, 2007)and om
sewage o u ban households (3.4 k a
−1
)(Nyenje e al
2010, Wo ld Bank 2014a). Fo E hiopia, he mino
accumula ed N
con e sion (1800 k )was es ima ed
o 1993–2010. The accumula ed P flow in E hiopia
(460 k )was es ima ed conside ing he empo al
(1993–2010)de elopmen o he a able land a ea
(FAO 2015)and u ban popula ion (Wo ld Bank
2014a). Conclusions ega ding he p ecise es ima es
wa an cau ion.
2.3. Spa ial a ia ion in nu ien use: he socio-
economic ace
In e ms o he G oss Domes ic P oduc (GDP,
pu chasing powe pa i y)in in e na ional dolla s (In
$)pe capi a, Finland is anked 24 h (36 000 In $)and
E hiopia 172nd (1 240 In $)among he 182 coun ies
epo ed (Wo ld Bank, 2014b). The accumula ed N
and P use o 1900–2010 globally and o Finland and
o 1993–2010 o E hiopia we e es ima ed (including
he cu en use, see sec ion 2.2).
Da a sou ces o hese es ima es included he con-
e sion o N
2
o N
in he Habe -Bosch p ocess o
syn he ic N e ilize s, o he N chemicals (Galloway
e al, 2003, 2004, 2008), C-BNF (Vi ousek e al 1997,
Galloway e al 2003, 2008, An ikainen e al 2008, Sipi-
läinen e al 2012)and he ossil ene gy use (N emis-
sions)(S a is ics Finland 2013, 2014a, b, Galloway e al
2003, 2004, 2008, An ikainen 2007, Vi ousek e al
1997, Minis y o T ade and Indus y 1977, Wo ld
Bank 2014c). Global syn he ic e ilize use was egis-
e ed a 5–10 yea in e als o he pe iod 1900–1960
(Smil 2004, Smil 2000)and annually o he pe iod
1961–2010 (FAO 2013). Syn he ic e ilize use in Fin-
land in 1910–1950 (An ikainen e al 2008), 1961–1993
(FAO 2013)and 1994–2010 (FAO 2013, Tike 2013,
Me la 2012, MMM 2008, G ön oos and Nikande
2002)was conside ed. The es ima e o he e ilize
nu ien use in E hiopia elied on he da a ha ep e-
sen he pe iod 1993–2010 (FAO 2013).
Rega ding P use, he es ima es o syn he ic P e i-
lize use we e complemen ed by es ima es on he use
o syn he ic P eed (Smil 2000; Pou iainen 2002, Lin-
de holm e al 2012)and de e gen s (O and Rechbe -
ge 2012, Smil 2000).
The p opo ion o N
con e sion in he local ag i-
ood sys em consis ed o he syn he ic e ilize use,
C-BNF and ossil ene gy use. The es ima e o ossil
ene gy use in he Finnish ag i ood sys em was based
on he GDP sha e o ag icul u e (2.8%)and oodp o-
cessing indus y (7.1%)(Vii aha ju e al 2014),in
E hiopia based on he GDP sha e o ag icul u e
(47%)(Wo ld Bank 2015). The con ibu ion o he
Finnish ag i ood sys em o he P flow o wa e sys-
ems was es ima ed elying on he flows om ag i-
cul u e, fish a ming, municipali ies, sca e ed
dwellings and indus ies apa om he pulp and
pape indus ies (Biodi e si y/SYKE, 2014).The
po ion o he ag i ood sys em om P flows om
municipali ies, sca e ed dwellings and indus ies
was es ima ed based on he de e mined (see abo e)
p opo ion o syn he ic P use in he ag i ood sys-
em (89%).
Figu e 1. Spa ial a ia ion in access o nu ien s. Accumula ed ni ogen (N
)and phospho us (P)use (kg cap
−1
)and he cu en
a e age (2006–2010) ood supply (kcal cap
−1
d
−1
)(FAO 2014)globally and in Finland and E hiopia.
5
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al
3. Resul s
3.1. Plane a y nu ien bounda ies: owa ds a
bo om-up app oach
The ecology o he Bal ic Sea did no se an N bounda y
based on he a oidance o a la ge-scale ocean hypoxic
e en addi ional o ha based on he con e sion o N
2
o N
( able 1). I only he N flow o he Bal ic Sea was
conside ed (excluding con e sion o a mosphe ic N
2
),
aflow o 13 kg, bounda y o 3.7 kg and excess o
9.4 kg N cap
−1
a
−1
was es ima ed. Consequen ly, he
downscaled PB o N is also he p oposed c i ical N
bounda y o Finland. Rega ding P, applying he
global bounda y c i e ion o en imes he p e-
indus ial flow would allow a u he inc ease in P flow
o he sea ( able 1). Howe e , he P flow pe capi a
ole a ed by he local ma ine ecology is below he
global a e age. Expanded hypoxia has been eco ded
since he 1930s in he Bal ic Sea, and he cu en
Finnish flow o he sea clea ly exceeds ou p oposed
c i ical bounda y. Fo he local lake sys em, he uppe
ole able P bounda y was es ima ed o be ansg essed
in he mid-1960s. In con as wi h he global s a e, he
local P flow o lakes has cu en ly e u ned o wi hin
he sa e bounda ies, bu he accumula ed flows exceed
he co esponding sa e bounda y by 15 old.
3.2. Spa ial a ia ion in nu ien use: he socio-
economic ace
The highe excess in he local N
flow in Finland
compa ed wi h he global flow, ela i e o he sa e
bounda y, is due o he di e ence in nu ien use,
while he bounda y pe capi a is equal ( able 1).In
2010, he nu ien use in Finland was 41 kg N
wi h
2.9 kg P, wi h he N
use being one- hi d highe han
bu he P use sligh ly lowe han he global a e age pe
capi a. The nu ien use in E hiopia in 2010 was
2.1 kg N
and 1.0 kg P capi a
−1
. Fe ilize use ep e-
sen s 64% o he o al N
use and 74% o he o al P use
o Finland and 69% and 21% o E hiopia, espec-
i ely. The excess cumula ed ac oss he las cen u y
e eals he en i e global spa ial dispa i y. The cumu-
la ed (1900–2010)N
and P uses pe capi a a e
2300 kg N
and 200 kg P globally, 3400 kg N
and
690 kg P o Finland, and 26 kg N
and 12 kg P o
E hiopia (figu e 1). While he pe capi a use o P in
Finland has exceeded he global a e age since he
beginning o he cen u y, peaking in 1973, he local use
o N
has only exceeded he global a e age since he
beginning o he 1950s, peaking in 1974. I he global
his o ical nu ien equi y pe capi a we e induced, and
he excess in he nu ien use we e educed a he same
pace as i accumula ed in Finland (1900–2010 o N
and 1961–2010 o P), no u he N
con e sion o
i gin P flow o wa e sys ems would be possible
globally o in Finland, con a y o E hiopia ( able 1).
The Finnish ag i ood sys em was esponsible o 69%
o he local N
con e sion and o 81% o he local P
flow o wa e sys ems, while he co esponding
p opo ions o he E hiopian ag i ood sys em we e
98% o N
con e sion and 83% o P flow o wa e
sys ems.
4. Discussion
4.1. Plane a y nu ien bounda ies: owa ds a
bo om-up app oach
Nu ien flows ac as d i e s o o he human-induced
shi s in he Ea h sys em, making i di ficul o assess
he c i ical h esholds. The ‘fi s guess’on he quan i-
a i e plane a y N bounda y by Rocks öm e al (2009)
has been e ised by de V ies e al (2013), Kahiluo o
e al (2014a)and S e en e al (2015a). The global N
use al eady had exceeded he bounda y e ised by
S e en e al 2015a (20 M a
−1
)in 1909 and he Finnish
use had al eady exceeded he downscaled plane a y N
bounda y 16 k a
−1
be o e he beginning o he 20 h
cen u y (31 k a
−1
in 1900). In E hiopia, howe e , e en
he accumula ed N
use may be inc eased wi hin he
p oposed bounda y. N
con e sion a he han eu o-
phica ion as he bounda y c i e ion was suppo ed by
he local si ua ion in Finland whe e N
is no a limi ing
ac o o eu ophica ion ei he in he local eshwa e
o in he ma ine sys em (Sa chuk e al 2008). In e nal
P loading and consequen N emo al igge ed by he
la ges anoxic seafloo in he wo ld (Ca s ensen
e al 2014)p omo es N-fixing cyanobac e ia (Vah e a
e al 2007), main aining he P limi a ion. The bu e ing
capaci y p o ided by he o iginally oligo ophic,
shallow lakes wi h a egula ice co e (Sche e and an
Nes 2007)which ep esen 10% o he spa sely
popula ed Finnish a ea, ole a es g ea e pe capi a P
flows han he global a e age.
The pas shi o dominance o in e nal loading
bo h in he local ma ine sys em and in ag icul u al
lakes has made eu ophica ion p ac ically i e e sible
(Ekholm e al 1997, Räike e al 2003, Ekholm and
Mi ikka 2006, Vah e a e al 2007, Sa chuk e al 2008,
A o ii a e al 2014). This si ua ion is eflec ed in he
c i ical bounda ies o P flow o he local lake sys em
de e mined he e: while he cu en flow al eady is
wi hin he bounda ies, he accumula ed flow by a
exceeds hem. A shi o dominance o in e nal loading
ep esen s a po en ial ipping poin in he wo ld’s
eshwa e sys ems and es ua ies, agg a a ed by cli-
ma e change (Meie e al 2012). This obse a ion
se es one goal o bo om-up assessmen s o plane a y
bounda ies also e e ed o by S e en e al (2015b):
‘We emphasize ha ou subglobal-le el ocus is based
on he necessi y o conside his le el o unde s and
he unc ioning o he Ea h Sys em as a whole.’
4.2. Spa ial a ia ion in nu ien use: he socio-
economic ace
The his o ical access o nu ien s— he c i ical
esou ce o ood p oduc ion—illus a es he social
6
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al
ace o plane a y nu ien bounda ies. Es ima es show
ha 80% o he wo ld’s expo s o he i gin,
economically exploi able P ese es o igina ed in 2011
in No h A ica (de Ridde e al 2013)whe e li le
e ilize P is used because o a o dabili y issues. The
excess in nu ien use is high in weal hy indus ialized
coun ies such as Finland; howe e , he di e ences
be ween he weal hies and poo es na ions a e declin-
ing, and he e o e, he inequi y is mos eflec ed in he
accumula ed ese es. In Finland he o iginally low
field soil P con en inc eased by a ac o o 2.2 om
1960 o 1995 (Män ylah i 2002)wi h li le change
he ea e (Aakkula and Leppänen 2014). In many o
he poo es egions o he wo ld such as in sub-
Saha an A ica, he use ne e eally began and small P
ese es and low o ganic ma e con en wi h N and P
s ocks occu in a able soils (Johns on 1986, San-
chez 2002)deg aded by exploi a ion. Whe eas he
i gin P ese es we e a eason o wa s in he pas
(Bu ne 2005), he ecyclable ese es a e a mo e
impo an asse o ealloca e as he wo ld e u ns o
he c i ical bounda ies.
When conside ing he accumula ed use, he e is
no longe any space wi hin he c i ical bounda ies
globally and in he weal hy No h o exploi i gin
nu ien s. E en in he Sou h, such as in E hiopia,
whe e he cu en annual con e sion a e o N
can be
nea ly doubled, he e is only a li le space o inc ease
he accumula ed annual con e sion a e o N
. The
‘ze o ole ance’ o N
con e sion poses a highe chal-
lenge due o he una oidable gaseous losses han o
he P flow. The N
losses can be educed, e.g., by epla-
cing ossil ene gy wi h he anae obic diges ion o ag i-
ood esidues o wi h o he enewable esou ces no
compe ing o , o emi ing, nu ien s such as sola and
wind powe . The nu ien esidues and ese es a e
mos e ficien ly used whe e he need o a esponse o
ood secu i y is highes and he local nu ien flow is
leas abo e he ole able limi , as in E hiopia.
4.3. Limi s o he local ood supply
The pe spec i e o he plane a y bounda ies empha-
sizes he o e all ecological ole o ag i ood sys ems
ela i e o he dominan Finnish iew o da e, which
was based only on he ag icul u al nu ien flows o
wa e s. The local sha e o he nu ien flows ha occu
wi hin he ag i ood sys em (see sec ion 3.2)is a hi d
highe han he local sha e o he nu ien load o
wa e s ha o igina e in ag icul u e ( o N 47%, P 57%)
(SYKE 2014). This di e ence is due fi s o he en i e
‘ag i ood sys em’and no only p ima y p oduc ion
(‘ag icul u e’)and, second, o gaseous emissions, no
only leaching o wa e sys ems, being included in he
plane a y nu ien bounda y pe spec i e. P and N use,
was e and emissions in a ious pa s o he ag i ood
sys em such as in consump ion, ading, ood and eed
p ocessing and fish a ming, in addi ion o ag icul u e,
a e included. The N
con e sion also co e s gaseous
emissions om e ilize s and manu e and om
ene gy use in e ilize manu ac u e, anspo a ion,
p ocessing and ading, as well as loading o wa e
sys ems. Only h ough such shi s in pe spec i es he
majo o e all ole o ood o e u ning o he ‘sa e
space o humani y’e en in pu ely ecological e ms
(Ga ne 2011)becomes e iden , and he selec ion o
means o e u n o he bounda ies while simul a-
neously enhancing ood secu i y becomes b oade .
Inno a ions a e necessa y o ulfil his ask, and he
po en ial ood secu i y wi hin he c i ical bounda ies is
no ye known.
The la ge sha e o he nu ien s flowing h ough
ag i ood sys ems emphasizes he need o ans o ma-
ions in hose sys ems o educe he nu ien excess
and secu e he local access o ood globally. In sub-
Saha an A ica such as in E hiopia, he icious cycle o
nu ien deple ion and insu ficien eplenishmen o
N, P, po assium, sulphu and ca bon d i es he u he
decline o soil o ganic ma e (Ki kby e al 2013, Kahi-
luo o e al 2014b)and hus nu ien losses h ough
e osion (Haileslassie e al 2005)and ca bon and N
emissions, as well as leads o low p oduc i i y, limi ed
nu ien flows in he ag i ood sys ems and ood inse-
cu i y. Consequen ly, he c i ical P bounda y appea s
o be exceeded in Finland and E hiopia o he ollow-
ing con a y easons: (1)excessi e pas inflow o he
ag i ood sys em in Finland, and (2)excessi e ou flow
om he ag i ood sys em igge ed by defici s in he
inflow and in sewage managemen in E hiopia, con-
ibu ed o by imp ope managemen in bo h cases.
While imp ope managemen in Finland implies ine -
ficien ecycling o nu ien s due o manu e con-
cen a ion, low u iliza ion o o he ag i ood esidues
and excessi e e ilize use (Kahiluo o e al 2011),i
implies o e exploi a ion o ag icul u al land in E hio-
pia wi h insu ficien nu ien inpu s and low ecycling
o esidues ha se e as odde and u he as ene gy
sou ce (Rimhanen and Kahiluo o 2014).
Equi y in he access o nu ien s is necessa y o
inc ease he global e ficiency in nu ien use o ood.
The added alue o nu ien use o c op yield and
comba ing hunge may be many imes g ea e and he
loads o wa e s smalle in a eas wi h a low his o ical
access o nu ien esou ces. Equi y in he access o
nu ien s is also a s ep owa ds access o ood despi e
global p ice ola ili y, conflic s, and poo local in a-
s uc u e and go e nance. The his o ical spa ial a ia-
ion in wel a e limi s he p esen ag icul u al
p oduc ion and consump ion wi hin he sa e bound-
a ies mo e han he local ecosys em o he cu en spa-
ial inequi y. The pas inequi y in access o esou ces
mani es s in he nu ien ese es a ailable in soil and
sedimen s and, mo e impo an ly, in he inequi y in
nu i ion e iden in he social and human capaci ies
oday. The unde -nu i ion o child en leads o he
i e e sibly diminished physical de elopmen o he
body and b ains (s un ing), educing he cogni i e
7
En i on. Res. Le . 10 (2015)104013 H Kahiluo o e al
capaci ies; s un ed women being mo e likely o gi e
bi h o s un ed child en (UNICEF 2014).
4.4. B idging he gap
The cu en and p ojec ed u u e ailu e in e e sing
he local nu ien cycles h ough educing P flow only
(Ekholm and Mi ikka 2006, Ja is e al 2013, Aakkula
and Leppänen 2014, Hayga h e al 2014)shows ha
o a ansi ion o a low-nu ien socie y, majo
echnological, social and ins i u ional inno a ions a e
s ill o come. This is highligh ed by he scena io ha i
nu ien inpu s a e educed o he le el ha exis ed
mo e han 100 yea s ago, he Bal ic Sea would no be
eco e ed e en a e 130 yea s (Sa chuk and
Wul 2009). Recycling he ese es in soils (Sa a i
e al 2012), in wa e biomass (Kahiluo o e al 2011)and
in ag icul u al lake and ma ine sedimen s may help o
es o e he ecology o wa e sys ems and he p oduc-
i i y o he deg aded soils in he global Sou h, i i is
based on a fi m ecological unde s anding. To mee he
shown equi emen o educe nu ien use in he
global No h, many means in a ious pa s o he
ag i ood sys ems, such as die a y shi s and was e
p e en ion, a e equi ed in addi ion o ecycling
(Kahiluo o e al 2014a). Fo example, he exchange o
nu ien quo a (NEFCO 2008)o a combina ion o
axes (Goulde and Schein 2013)and subsidies,
spa ially di e en ia ed in he global scale, may igge ,
finance, and complemen he ading o nu ien
ese es and he igh s o use nu ien s.
The plane is a social-ecological sys em. The majo
complemen o he PB amewo k equi ed o se e as
a sus ainabili y a ge is he social dimension o global
equi y, igh ly coupled wi h he bounda ies o he key
biophysical p ocesses (Rocks öm e al 2009; S e en
and S a o d Smi h 2013, S e en e al 2015a,b). The
ipping poin o he pi o al social bounda y, equi y in
he access o nu ien s and hus o ood, equi es bo -
om-up conside a ions a lowe hie a chical le els
han he plane a y scale. This c i ical bounda y has
been epea edly ansg essed in he pas and is cu -
en ly locally ansg essed, highligh ing he impe a i e
o he local social-ecological con ex when assessing
and comba ing hese ansg essions.
5. Conclusions
The unequal pas dis ibu ion o nu ien flows
hinde s cu en equal access o nu ien s and ood.
The ealloca ion o he ecyclable ese es is a p e-
condi ion o achie ing ood secu i y. Spa ial a ia ion
in c i ical nu ien bounda ies and, pa icula ly, in pas
nu ien use highligh s he necessi y o moni o ing he
cumula i e ansg ession o he bounda ies and o a
wo ld-wide financing amewo k o enable he edis-
ibu ion o nu ien s. Bo om-up assessmen s e eal
local sys em dynamics ha u he elucida e he
ele an bounda y c i e ia, es ima es and emedies.
Spa ial equi y in nu ien flows implies a c i ical ac o
o global equi y and human igh s, namely, he igh
o ood.
Acknowledgmen s
The wo k was pa o he T ansi ion Towa ds Sus ain-
able Nu ien Economy (NUTS)p ojec o he G een
G ow h P og am o Tekes— he Finnish Funding
Agency o Technology and Inno a ion. We app eci-
a e he use ul discussions wi h Tommi Kauppila and
Pe i Ekholm on he ecological his o y o he Finnish
eshwa e sys ems.
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