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Globalization is bringing little change in what we're eating — or growing

“[T]he tropics produce more species and evolutionary lineages than the temperate zone.”

Shortly after last Thursday’s piece on U.S. agriculture exports went up, word came from the University of Minnesota regarding a fresh analysis of how surprisingly little change globalization is making in what people eat, and grow, around the world.

“Walk through the produce aisle in a grocery store nearly anywhere in North America and you are likely to find fruits and vegetables imported from abroad,” the announcement begins.

But despite such variety, a closer look at the general patterns of what farmers have been growing, and people eating, since 1992 finds far less change than economics would predict — especially if one focuses, as this work did, on the gaps in wealth, consumption and food production that divide the world’s temperate zones from its tropics.

This is another trade-based analysis, focused on measurements of the effects of “comparative advantage”:  the simple-sounding and sensible notion that “countries open to trade will be able to consume more — in terms of volume and diversity — if they concentrate production on commodities that they can most cost-effectively produce, while importing goods that are expensive to produce, relative to other countries.”

In other words, the ability to buy and sell food freely in a global marketplace ought to narrow the range of agriculture products flowing out of a country, and broaden the range of goods flowing in. But compared to such sectors as manufacturing, finance and technology, the changes have been small.

“The diversity of the food we eat hasn’t changed as much as we expected it would with globalization,” said Jeannine Cavender-Bares of the university’s Department of Ecology, Evolution and Behavior and also its Institute on Environment (IonE), a leader of the research team.

“We still tend to eat based on the biodiversity around us even though we could eat anything.”

A boundary of wealth and diversity

What makes this somewhat more remarkable is the significant gap between the temperate latitudes and the tropics, says Erik Nelson, formerly a graduate student at the U who now teaches at Bowdoin College, and lead author of the team’s paper published last week in the journal PLOS ONE.

They are separated not only by relative wealth but also by what Nelson’s paper calls “one of the most striking biological patterns on Earth” — “the latitudinal gradient in biodiversity, where the tropics produce more species and evolutionary lineages than the temperate zone.”

But to the extent producers in the temperate zones work to expand their output, bringing to bear the technological and economic advantages of their greater wealth, the efforts tend to be “largely determined by local evolutionary legacies of plant diversification.”

That is, they may develop many new varieties of apples or wine grapes but seldom take up an entirely new fruit from far away. A bit more lyrically:

Because tropical countries harbor a greater diversity of lineages across the tree of life than temperate countries, tropical countries produce and consume a greater diversity of plant products than do temperate countries. 

In contrast, the richer and more economically advanced temperate countries have the capacity to produce and consume more plant species than the generally poorer tropical countries, yet this collection of plant species is drawn from fewer branches on the tree of life.

Agricultural trade between the tropics and the temperate zones is hardly a new thing, the paper acknowledges, but it has certainly accelerated in the paper’s post-Cold War study period of 1992-2010:

Only since the mid-1600s, when ships started to regularly transport food, seeds, and botanical knowledge between continents, were societies able to loosen the very tight relationship between their environment and the plants they produced (e.g., the transfer of potato production from Peru to Ireland) and consumed (e.g., the import of pineapples to Europe from Suriname). For example, between 1760 and the 1850s the value of tropical food imported to Great Britain increased by 384%.

More recently, the green revolution in agricultural production, lower tariffs on imports, and more cost-effective trading technology have made it much easier for modern societies to consume a diversity of plants far beyond their pre-modern plant diversity [footnotes omitted].

The paper’s measures of these comparative diversities, and of the changes in production and consumption patterns over time, are difficult to describe in ordinary language, and are conveyed in this paper via some of the longest and most complex formulas I’ve ever seen in print.

(At times I was reminded of the late Sen. Gaylord Nelson’s gleeful quip, possibly borrowed from Walter Heller, that the economist’s heavy burden is to get things to work out in theory the way they do in real life.)

Climate and food security

But in tracing the general origins and potential implications of the patterns that researchers  found, the paper is quite concise.  Key excerpts:

Why have countries not increasingly specialized in plant production despite the theoretical financial incentive to do so? Potential explanations include the persistence of domestic agricultural subsidies that distort production decisions, cultural preferences for diverse local food production, and that diverse food production protects rural households in developing countries from food price shocks.

The cultural tradition met by locally produced food would seem to go against specialization and export-oriented crops. Although cultural traditions evolve over time, the  time scales are longer than the score of years considered in our analysis. Therefore, farmers around the world may still devote substantial effort to satisfying local cultural demands and not the few crops that they have a comparative advantage in.

[S]maller farmers in the developing world may be reluctant to switch to export-oriented crop production due to thin and volatile food markets in their home region; often it is less risky to grow your own food than to rely on spotty markets to consistently provide affordable food.

As for the future, the paper finds advantages and disadvantages in the slow pace of change so far:

On the one hand, less specialized production patterns within countries and regions will make global crop production more redundant and resilient to climatic and social perturbations.

On the other hand, global crop production will have to become much more efficient (higher yields per unit area of crop land) to make the transition to a hotter and more crowded world as smooth as possible. Each country specializing in the crops that are best suited for their agri-climate conditions would increase global efficiency in plant production.

* * *

The full paper, “Commercial Plant Production and Consumption Still Follow the Latitudinal Gradient in Species Diversity Despite Economic Globalization,” can be read here without charge. Take care not to trip over those formulas.

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