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Water
e�ciency
Sustainable
management
Harvested
area
Water
demand
Forest
land
Organic
fertilizer
Chemical
fertilizer
Oil
price
GDP
Water
stress
Agriculture
labour
Agriculture
capital
Soil
quality
Fertilizer
use
R&D
Population
in the longer term (after 2015). In accordance with the
forestry production growth in green scenarios, forestry
employment will reach 30 million people in 2050, which
is 20 per cent above BAU. As a result of the enhanced
reforestation and avoided deforestation efforts, total
forestland is projected to reach 4.5 billion hectares over
the 40-year period, outperforming the BAU case by 21
per cent. This will allow 502 Gt of carbon to remain in
Natural crop
yield per ha
Pre harvest
losses
E�ective crop
yield per ha
Agriculture
production
Figure 16: Causal loop diagram (CLD) representing the main factors influencing crop yield in the agriculture
sector of the model (blue boxes). Orange boxes represent the green investment options analysed
Modelling
The effective crop yield is defined as the difference between natural yield and losses due to plant diseases. The
natural crop yield instead is influenced by capital and labour, as well as by R&D (e.g. seed improvements), soil
quality, the use of fertilisers and water availability. Soil quality is further influenced by the use of fertilisers and by
forestland.
forest ecosystems in 2050, which is 71Gt above BAU
and 21Gt higher than the current level. Furthermore, a
greater extent of forested land improves soil quality
and often increases water availability, two factors
that impact agriculture production positively (Pretty
et al. 2006). In the short term, however, the efforts of
reforestation (2.5 and 3 times that of BAU) and avoided
deforestation (60 per cent and 46 per cent above BAU)
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