Case 1: when you fail to define your basic terms correctly.
Laurie A. Garrett, a senior fellow at the Council on Foreign Relations, tried to write an interesting piece about climate change and food security recently.  Her case is compelling, though she draws far too heavily on a few high profile examples of possible climate impacts on food supply without providing appropriate caveats about the difference between climate change (a trend over time) and climate variability (which can be one-off events, or the byproduct of a larger trend).  This is somewhat standard fare in the popular media, as such caveats really don’t make for good reading.
What got my attention was Garrett’s complete failure to properly define food security.  She argues “The overwrought phrase “food security” connotes literally obtaining sufficient calories and nutrients to stay alive.”  Well, maybe in 1980.  Since then, a tremendous amount of work (to which I have made a very small contribution) has expanded this definition dramatically – food security is about access and entitlement to food and other livelihoods resources – in other words, food security is more than enough calories on hand – you also have to have rights of access to those calories, or you are out of luck.
Why is this a problem in her article?  Well, Garrett is trying to draw a link between climate change a food prices . . . which are presumed to hit the global poor the hardest.  However, rising prices are only a part of the food security story.  If we don’t know people’s rights of entitlement to the calories they need, then it becomes hard to say if we have enough or not enough food available.
For example, let’s assume that a Ghanaian husband and wife have three children – one girl and two boys.  The household needs, at a basal level around 6000 calories a day to meet basic needs.  We can go to their farm, and measure the food they eat, and get a caloric figure.  Perhaps that figure comes back at 6500 calories per day.  This is not enough to say that this household, and all its members are food secure.  Does the wife and her girl child, have the same rights to food as the husband and boys, or must the females wait for the men to eat their fill, before eating whatever remains?  If the females do not have the same rights of access, it may be that the husband and boys are more than food secure, while the wife and her girls are not.
Certainly, it is useful to know where there simply isn’t any food around – but even this is tricky.  Most people forget that Ethiopia was actually increasing its agricultural exports across its famous mid-1980s famines.  It’s just that the food was sold overseas for foreign currency, which was then used to pay off their national debt . . . as the Ethiopian population starved.
This article addresses but one part of the global food security equation – not enough to make sweeping claims of what is to come.