Introduction and Background–Challenges and Limitations of GM Plants for Animal Nutrition - Animal Nutrition with Transgenic Plants - page 6

adaptation to climate change will result in
adequate or lower plant yields (Whitford et
al ., 2010). h e UN (2010) expects an
increase of greenhouse gas emissions from
about 48 (2010) to about 66 Gt in 2030 and
estimates a rise in global average tem-
peratures of more than 5°C by the end of
the century. Extreme weather situations
such as thunderstorms, heavy rains,
hailstorms, tornadoes, long dry periods or
droughts, etc., as consequences of expected
climate change, may have a dramatic
inl uence on feed production and the
feeding of food-producing animals. To
achieve a 450 ppm CO 2 equivalent in the
air, carbon dioxide emissions would need to
be reduced from 48 Gt per year to 35 Gt in
2030. Plants undergo adaptive change to
acclimatize to new environments. Drought-
resistant, high water-use ei cient, heat-
tolerant and disease-resistant plants will be
the important objectives of plant breeding
under climate change. h erefore, techniques
that are able to enhance the speed,
l exibility and ei ciency of plant breeding
are required for the so-called 'second green
revolution'.
In addition, insect-protected and
herbicide-tolerant plants may also reduce
the use of pesticides, with consequences for
lower CO 2 emissions (lower carbon foot-
prints) and a general reduction of global
pesticide use (Phipps and Park, 2002). Life-
cycle assessments to compare the environ-
mental impact of isogenic and genetically
modii ed herbicide-tolerant and/or insect-
resistant plants are a great challenge for
scientists working in the i eld (Persley, 2003;
Bennett et al ., 2004).
Land and water are considered to be the
greatest challenges on the supply side of
food production. In 2030, Dobbs et al .
(2011) estimate a 30% higher water need
(an additional 1850 km 3 ) and between 140
and 175 million hectares (Mha) (about 10%
of the present area) deforestation. Further-
more, the genetic pool available in plants,
animals and microorganisms could also
contribute to optimizing plants and animals
for a more ei cient conversion of limited
resources into feed and food (see Table 1.4).
Future strategies have to acknowledge the

multifunctionality of agriculture and take
into account the complexity of agricultural
systems within dif erent socio-economic
situations. Farmers are not just producers;
they are also managers of ecosystems.
h erefore, dif erent opinions and experi-
ences on the impact of genetically modii ed
(GM) plants on smallholder farmers in
various regions should be expected (Kathage
and Qaim, 2012; Kleemann, 2012).
Discussions on the potential of plant
breeding by 'green biotechnology' are old
(Persley, 1990; Hodges, 1999, 2000; Qaim,
2000; Borlaug, 2003; Avery, 2004) and they
are not free from criticism (Altieri, 1998)
and conl icts starting with the i rst steps of
breeding and cultivating GM crops (Perlas,
1994; Altieri and Rosset, 1999). Never-
theless, there has been a dramatic increase
in the cultivation of GM crops, starting with
1.7 Mha in 1996. In 2012, about 170 Mha of
GM plants were cultivated worldwide (about
11% of total arable land; James, 2013). Most
of these GM plants are tolerant of herbicides
and/or resistant to insects (Fig. 1.2). Such
plants do not contain higher amounts of
desirable and undesirable substances and
can be considered as substantially equivalent
to their isogenic counterparts (OECD, 1993;
see Chapters 4 and 6).
Currently, the interests of individuals or
of some companies dominate, and these are
not always in agreement with public
interests, as discussed above (SCAR, 2008;
Godfray et al ., 2010; Foley et al ., 2011). More
fundamental and applied research should be
conducted by independent, publicly spon-
sored research institutions (h e Royal
Society, 2009; Pardue, 2010) and the results
should be made available to all those who are
interested in such plants. Public-private
partnerships should be formed with the
mission to reach set goals in the coming
decades (Arber, 2010).

1.3 Food-producing Animals as Part
of the Food Chain

High portions of the yield of the most
important GM plants (soybean, maize,
cotton, rapeseed; see Fig. 1.2) are fed to