than Newtonian equations, and in this form it
is widely used today. It may be used for the
assessment of likely policy impacts by project-
ing changes to origin and destination totals,
introducing different travel mode and pricing,
and making the model dynamic. The gravity
model approach has come under heavy criti-
cism because of its mimicking of equations
and models from physics, rather than being
rooted in social science, but much recent
work has shown how the various assumptions
of the models (such asdistance decay) may
be derived from concepts ofaccessibility,
utility theoryandintervening opportun-
ity. The physical analogy is just that, an
analogy and no more. lwh
Suggested reading
Fotheringham and O’Kelly (1989); Sen and
Smith (1995); Senior (1979).
green belt A designated area of land sur-
rounding a built-up area, into which urban
expansion is strictly limited by planning pol-
icies. Initially proposed as part of thegarden
citymovement, delimitation of green belts
around all major urban areas was part of
the innovatory procedures made mandatory
under the UK’s 1947 Town and Country
Planning Act, both to contain urbansprawl
and to protect high-quality agricultural land
plus that used for recreational and other
amenity purposes. The proportion of the
land surface designated as green belts has
been substantially increased since, despite
opposition from interest groups – such as
development companies that want to build
there in response to growing pressure for new
housing, which governments instead wish
to focus on ‘brownfield’ (i.e. redevelopment)
sites within existing urban areas. The policy’s
success has stimulated urban development
beyond the green belts, leading to increased
commuting costs for many workers and
casting doubt on the overall economic and
environmental justification for the continued
constraints (cf. counter-urbanization).
Comparable policies have been instituted in
many other countries. rj
Suggested reading
Elson (1986).
Green Line The most common use of the
term denotes the Armistice line separating
Israel and the Palestinian territories of the
West Bank and the Gaza Strip. The term
is occasionally used elsewhere, as in thede
factopartition lines in Beirut (Lebanon) and
Nicosia (Cyprus). The Israeli line was demar-
cated in 1949 following the 1948–9 war
between Israel and several Arab states over
the 1947 UN partition plan for Mandatory
Palestine. The Green Line separated Israel
from Palestinian territories captured by
Jordan and Egypt. In 1967, Israel conquered
the West Bank and the Gaza Strip. There have
been repeated attempts to ‘erase’ the Green
Line, although it has remained to date the
de factoborder demarcating the limit of inter-
nationally recognized Israeli sovereignty.
Themilitary occupationof the Palestinian
territories continues, however, and Israel has
also built a so-called ‘separation barrier’ or
wall beyond the Green Line and extending
deep into the Occupied Territories. oySuggested reading
Biger (2004); Newman (1995).Green Revolution A term coined in the late
1960s to refer to the so-called miracle seeds –
the high-yielding varieties (HYVs), and espe-
cially wheat and rice – that held out the
prospect for spectacular increases in cereal
production in thethird world. Associated
with 1970 Nobel Prize winner and crop gen-
eticist Norman Borlaug, the term ‘Green
Revolution’ continues to have wide currency
30 years after it was minted. Nonetheless, it
remains somewhat controversial and indeed
there is often little consensus on what the
Green Revolution actually denotes. The adjec-
tive ‘Green’ implies, at least in our epoch, a
sensitivity tosustainability(but ironically the
ecological costs of the HYVs have been a pur-
ported major failing) and implicitly is opposed
to ‘Red’ in a way which technical achieve-
ments – a technical fix – could banish not
simply hunger but political unrest. In order
to understand the origins and genesis of the
‘heroic age’ (Jirstrom, 1996, p. 15) of the
Green Revolution between 1963 and 1970,
the miracle seeds must be located on the earl-
ier landscape of thecold war, which em-
braces Americanimperialismin Vietnam, a
Malthusian view of food shortages in the
post-1945 period, and the recognition that
the Green Revolution was wrapped up with
US foreign policy and the perceived threat
posed by poor peasants inclined towards
socialism(cf.malthusian model).
The meaning of ‘Green Revolution’ remains
a contested issue. The heart of the revolution-
ary thrust was quite simple: seeds plus nitro-
gen plus water would produce increased yieldsGregory / The Dictionary of Human Geography 9781405132879_4_G Final Proof page 317 2.4.2009 6:30pmGREEN REVOLUTION