Abstract: This paper reviews the evidence on the socio-economic impacts of GM crops
and analyzes whether there are patterns across space and time. To this end, we investigate
the effect of GM crops on farm-level costs and benefits using global data from more than
one decade of field trials and surveys. More specifically, we analyze the effects of
GM-crops on crop yields, seed costs, pesticide costs, and management and labor costs and
finally gross margins. Based on collected data from studies on Bt cotton and Bt maize,
statistical analyses are conducted to estimate the effect of GM crop adoption on these
parameters. Our results show that, compared to conventional crops, GM crops can lead to
yield increases and can lead to reductions in the costs of pesticide application, whereas
seed costs are usually substantially higher. Thus, the results presented here do support the
contention that the adoption of GM crops leads on average to a higher economic
performance, which is also underlined by the high adoption rates for GM crops in a
number of countries. However, the kind and magnitude of benefits from GM crops are very
heterogeneous between countries and regions, particularly due to differences in pest
pressure and pest management practices. Countries with poor pest management practices
benefited most from a reduction in yield losses, whereas other countries benefited from cost reductions.
However, our study also reveals limitations for meta-analyses on farm-level costs and benefits
of GM crops. In particular, published data are skewed towards some countries and the
employed individual studies rely on different assumptions, purposes and methodologies
(e.g., surveys and field trials). Furthermore, a summary of several (often) short-term individual
studies may not necessarily capture long-term effects of GM crop adoption...

Quelle: Sustainability 2011, 3, 743-762; doi:10.3390/su3050743

_______________

Anm. d. Red.: