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4.2 Desertification
impacts
Desertification leads to a series of socio-economic and
eco-environmental issues (Bangladesh and IUCN, 2005), including lowered
land productivity (Tao, 2014), reduction of soil carbon storage (Anjum
et al., 2010), texture destruction (Zhang and Huisingh, 2018) and
economic loss (Cheng et al., 2018). Studies have primarily foci on the
influence of desertification on economic development, land productivity
and regional climate condition.
In the BRI region, economic cost for desertification is large
particularly when taking account of the expense for
rehabilitation/desertification mitigation. In the MENA region, the
annual average income loss by desertification reached at $1.98 billion.
The estimated costs for rehabilitation reached $8 billion per year,
which means it costs about $160 billion anti-desertification measures
in the region (without considering inflation and other economic factors)
for two decades (from 1970s to 1990s) (Mamdouh, 1999). Al-Saidi and
AI-Juaiali (2013) found that the cost of combating desertification is
around $10.3 billion (USD) to $20.5 billion (USD) in Iraq. This huge
cost affects the present and future economic developments and slows down
further development. Soil degradation costs around 12% of the country’s
overall agronomic outputs or account for 2.5% of the “Gross
National Product ” (GNP) in Syria (Haktanir et al., 2004). In China,
Cheng et al. (2018) found that desertification costs at the range of
0.6% - 1.1% in the GDP through refining previous estimations. Overall,
the economic cost due to desertification is lacking of consideration and
assessment in the BRI countries. Even in countries experienced for
desertification research (e.g. China), the economic cost of
desertification has not been fully evaluated (Cheng et al., 2018).
Desertification also leads to loss of productive lands. For example in
Iraq, desertification has many negative impacts and particularly leads
to the degradation of productive land-use areas (Haktanir et al., 2004).
Looking up north in C Asia, land degradation has decreased productivity
by 30% to 40% that occurs in the highland areas of Kyrgyzstan, and
decreased by 40% to 60% in Tajikistan (Gringof and Mersha, 2006).
Kazakhstan’s arable land has lost up to 20% to 30% of its humus (the
top soil with soil organic matter and essential for vegetation), and
approximately 30% of the pastureland vegetation
(6.5×105 km2) has been degraded,
which largely affected the agricultural developments (Gringof and
Mersha, 2006).
Desertification may affect the regional environment. The GCM modelling
work conducted by Xue (1996) suggested that the desertification expanded
in grasslands of Inner Mongolia and Mongolia largely affected the
simulated climate through altering the water balance and surface energy
balance. Wang et al. (2020) also found that desertification reversion
would alter soil greenhouse gas emission in the eastern Hobg desert,
China. More prominently, further land-use changes and landscape
deterioration (i.e. deforestation, de-vegetation etc.) caused by rapid
developments on infrastructures (e.g. building roads, transport
networks, urbanisations, etc.) will exert more adverse impacts of
desertification to semi-arid and arid areas and countries that are
currently involved in the BRI program. For example, the effects of BRI
developments may further exacerbate the dust/sand storms in the dryness
and half dryness areas of C Asia and thus enhance the cumulative effects
of desertification on local eco-environment and socio-economy (Indoitu
et al., 2012).
4.3 Impacting factors and their relative
importance
Desertification results from numerous natural and anthropogenic
(human-induced) factors (EI Shaer, 2015, Feng et al., 2015, Park et al.,
2018); and their interactions (Zhang et al., 2020b). Our review provided
the specific drivers of desertification that have previously been
investigated for 23 countries that recently joined the BRI program
(Table 3).