The relationship between the global food system and climate change is bidirectional. Firstly, diverse international organisations (FAO, 2003a; IPCC, 2007) affirm that the four dimensions of food security, that is, the availability of foodstuffs (production and trade), the stability of the food supply, access to food, and its utilization, will probably be affected by climate change.
The Fourth IPCC Assessment Report (2007) predicts an increase in potential food production on a global scale, which could increase as a consequence of the increase in the average local temperature (between 1 and 3 °C), but above this interval a decrease in this production is expected, together with the existence of more heat waves and the reduction of precipitation. Changes in the patterns of extreme weather events, such as the increase in the frequency and intensity of droughts and floods, will also affect stability and access to food supplies. In addition, food insecurity and loss of livelihoods will be exacerbated by the loss of arable land and fish farms, due to flooding and coastal erosion in lowlands (FAO, 2003b).
On the other hand, the food sector is a significant source of greenhouse gas emissions. The various stages of the food supply chain (production, processing, storage, transport, sale and consumption) represent between 15 and 30 percent of global greenhouse gas emissions (Garnett, 2008). More specifically, the production of synthetic fertilizers represents 38%; livestock, 31%, rice cultivation, 11%, and manure management, 7% (Stern, 2005a). In the Catalan domain, according to the Catalan Office for Climate Change, in 2015, livestock and agriculture represented 11% of emissions. Finally, the food waste generated throughout the food supply chain is another source of emissions which must also be taken into account. In Catalonia alone it corresponds to 35 kilos per person per year (ARC, 2012).
The food system is therefore a key element in the development of society, which is why it is a significant element when it comes to studying the effects that climate change can have in the city, and what strategies must be adopted to adapt and improve our resilience.