Archive for March, 2014

Interfacing GAMS and R

GAMS is perhaps THE programming language for developing and running optimization models. R is an excellent and efficient tool for analysing data, including producing attractive graphs.

A tool for combining the two is provided with GDXRRW. GDXRRW acts as an interface between GAMS and R and offers facilities for the transfer of data between GDX and R and a function to call GAMS from within R.

A presentation by Dirkse et al. gives an introduction to the use of GDXRRW.




Graph of the year 2013: Proportion of calories delivered as food

Although already well into 2014, here is my personal “Graph of the Year 2013”: The proportion of produced calories that are delivered to the food system.


Source: Cassidy et al., Environm. Res. Lett. 8 (2013) 034015

The figure is one output of a study carried out by Emily Cassidy and colleagues of the University of Minnesota that was published in the journal Environmental Research Letters.

The researchers approach the challenge to provide sufficient amounts of food amidst global population growth, increased biofuel production and changing dietary preferences from a different angle than is widely done. Instead of estimating the increases in farm prodution necessary to satisfy the rising needs for agricultural products they analyze the current allocation of the world’s crop production to different uses.

According to the study, only 55% of global calorie production is directly used for human consumption. The remaining 45% serve either as animal feed or other uses such as industrial purposes and biofuels. In consequence, 41% of all calories produced are lost from the global food system. While the crops grown on one hectare could satisfy the caloric needs of 10 people, currently only 6 people are fed.

The graph gives a global overview of the fraction of the calories delivered to the food system per calories produced.  It shows that the losses from the food system are highest where livestock production, industrial uses and biofuels production are of a high importance. These are mainly the most affluent regions (e.g. North America, Europe), but also the regions in which agriculture is oriented at the production of animal feed for the global market (e.g. Eastern South America).

The arguably most important conclusion from the analysis is that if the crop calories used for feed and other uses were shifted to direct human consumption, up to around 4 billion more people could be fed. Or, perhaps easier to achieve, already small changes in the allocation of crops to animal feed and biofuels could significantly increase global food availability.