When is a drought not a drought? When the lack of water is due to a permanent change of climate rather than a temporary or seasonal absence of rain.
That is the question posed – and then answered – by Carlos Gay, an atmospheric physicist and head of the Climate Change program at Mexico City's Universidad Nacional Autonoma de Mexico, Latin America's largest university.
He has reached his conclusion after noting not just the length and severity of the drought currently gripping much of northern Mexico, but also the other changing climate patterns around the world, across Latin America, and, in particular, Mexico.
"You can't reach any conclusions from looking at a single event," he tells me. "But when you look at the patterns, then the picture is very clear. Northern Mexico's climate has already changed."
Although northern Mexico has historically been semi-arid, the current drought has gone on for an unprecedented length of time. It has also been preceded by other severe droughts.
Gay's message is that farmers waiting for the rains to resume their pre-global warming levels are likely to be waiting in vain.
After several days roaming the agricultural heartland of Chihuahua, photographing desiccated cattle carcasses, surveying dried-out lakebeds, and interviewing desperate farmers, it is hard to disagree.
Although famous for its desert, Chihuahua is Mexico's largest state and contains several distinct geographic zones. It is also home to extensive forests as well as many farms and beef ranches.
It has been that way since the conquering Spaniards first arrived here in the 16th century. But, if Gay is right, today's generation of farmers and ranchers could be among the last.
Locals are not giving up though. I saw one local farmers' association debating the merits of "Solid Rain," a Mexican product that some claim can help retain more than 90 percent of the moisture in the soil after irrigation or precipitation.
Looking like white sugar, the biodegradable, non-toxic grains swell to hundreds of times their original volume when wet, absorbing the water and stopping it from evaporating under the region's harsh sun.
Possibly, with new technology like this, and greatly improved water efficiency, agriculture in Chihuahua will remain viable in the future. The region's ranchers and farmers are staking their livelihoods on it.
