Andrew started off by telling us some of the environmental implications of farming worldwide. Today, existing agriculture covers more than half of ‘useable’ land (i.e., excluding unproductive deserts, etc.), and it has doubled nitrogen fixation rates from a pre-industrial baseline. Globally, agriculture is responsible for between 19 and 35% of all greenhouse gas emissions, and it has caused approximately 40% increase in observed sea-level rise (1961-2003). Not surprisingly, agriculture already occupies the regions of highest biodiversity globally, and is subsequently the greatest source of threat to species.
This means that for the regions and species studied, most species will decline as food production must inevitably increase to feed our growing human population, land sparing will support more species than land sharing, and high-yield farming is the best approach to maintain species with small ranges and narrow ecological niches.
Andrew thankfully also talked about the demand-side issues of food production, including the necessity of moving more people to a vegetarian-based diet, as well as methods for reducing food waste; however, how we grow and produce our food (supply side) is possibly more important than modifying our demand per se, even though all approaches are required to ensure that we can feed the world without costing the Earth.
Thank you, Andrew, for an enlightening, if scary, seminar.