While the grow-your-own ethos has gained popularity in the United States in recent years, for many people around the globe, having a garden is not a matter of choice. In many places it’s still your backyard, not the grocery store, that provides the bulk of your food. Globally, 70 percent of the food supply comes from smallholder farms — and if climate change continues unabated, those subsistence growers may be the ones most dramatically affected.

A new study published Wednesday in the journal PLOS One looked at how a changing climate will reshape the growing calendar come 2100. Under “business as usual” climate change projections, the researchers determined that the number of “suitable growing days” will drop by 11 percent, on average, around the world — and far more in certain regions. The tropics allow for a year-round growing season, but climate change impacts on temperature, drought, and solar radiation could cut 200 days from the farming calendar.

So, Why Should You Care?

According to the report, the world’s poor — nearly a third of the global population — is “highly vulnerable to changes in the supply of plant-related goods and services.” Just as low-lying island and coastal communities are on the front lines of sea-level rise, the world’s poor farmers will be hit hardest by the projected upending of the farming calendar. This will change not only the availability of food but also access to fiber, fuel, jobs, and revenue, the authors note.

There are some winners, according to the study — parts of Russia, China, and Canada in particular will gain growing days thanks to rising temperatures.

Last year, a study published in the journal Nature attempted to create the growing conditions that future farmers might be forced to cope with. Researchers grew staple crops in test plots where additional carbon dioxide was pumped in to mimic a greenhouse-gas-infused atmosphere of the future. The study environment allowed researchers to see how yield and nutrition might behave if there were 500 parts per million of carbon dioxide in the air instead of the current 400 parts per million. While yields increased, levels of zinc and iron in the grains and legumes declined. There are already 2 billion people who suffer from zinc and iron deficiencies, which contribute to 63 million deaths annually, according to the Harvard School of Public Health.

With hot, dry weather already coming to bear in California and other parts of the West, both farmers and consumers are starting to get a taste of what climate change might mean for the food we eat. But if the findings of studies such as these are borne out, the “End of Avocados” could be only the beginning.