Oxfam America has published a briefing paper
http://www.oxfamamerica.org/files/Extreme-Weather-Extreme-Prices.pdf
modeling the impact of climate change on food prices.
It's already happening, of course. Drought in middle America this summer means higher corn and wheat prices, among other things. But that doesn't just mean that your loaf of bread or corn flakes will cost more. Most corn goes to feed lots or ethanol production or corn derivatives used in highly processed foods. So prices go up at McDonald's and the meat counter, at the pump, and on any foods containing high fructose corn syrup or corn starch or dextrose or any number of unpronounceables. And prices go up for countries which buy our surpluses.
The long form of the report is here, at the international Oxfam site.
http://www.oxfam.org/en/grow/reports
I haven't read these reports yet, just skimmed, but I'm planning on doing it soon, when I'm not gleaning, or contacting gleaners, or processing my own produce, or editing documents for our Sonoma County Community Garden Network, or wondering when I am going to find the time this weekend to seek some donations for the brand new Interfaith Sustainable Food Collaborative. I'm still committed to keeping up with the global issues, no matter how busy I get with the actions here. The context of every local food system is global.