Interactive map predicts climate-driven farm decline by end of century

A team at the Institute for Economic Analysis (IAE), a center under Spain’s National Research Council (CSIC), has developed a tool that can predict, with a resolution of 9.3 by 9.3 kilometers, how the planet will gradually lose its capacity to produce food as climate change advances.

Its name is CADI, the English acronym for Climate-Induced Agricultural Decline Index, and its function is easy to explain, though not to calculate: it compares how much a plot of land could yield under different climatic conditions, while keeping the crops already being grown in 2020 fixed. This isolates the pure effect of climate, without mixing it with human decisions about what to plant or how to adapt.

How the model works

The platform (CADI (source in Spanish)), coordinated by Laura Mayoral and Hannes Mueller, who are also affiliated with the Barcelona School of Economics, has been developed in cooperation with the Center for Economic Policy Research, the UK Foreign Office and an initiative focused on conflicts arising from economic crises.

The starting point is two data sources: historical agricultural yields from the FAO and climate records from the European Copernicus program. Using these, the team reconstructs what changed between 1981–2000 and 2001–2020, and from there projects, under the different scenarios used by the IPCC, how that same variable will evolve through to the end of the century.

The premise, crucial for interpreting the results, is that no adaptation measures are introduced: the aim is to see what would happen if everything stayed the same except the climate.

Winners and losers, including within Spain

The data already observed, not projected, show that one in six of the world’s croplands has lost more than 10% of its potential productivity over the last two decades compared with the previous two.

The distribution of those losses is highly uneven: the tropics bear the brunt of the damage, while some high-latitude areas gain ground, even though they start from such low levels of production that these percentage increases hardly translate into additional actual calories.

In Europe, the familiar north–south pattern is repeated: Scandinavia, Scotland and the Alps improve their agricultural potential, while the south of the continent loses it.

Spain is no exception to that rule, but it is not uniform inside its own borders.

As Mueller explains, the Cantabrian coast, Galicia and the Pyrenees gain productivity, while much of the interior and the centre-east of the peninsula sees declines, with pockets of particularly severe losses. In a sense, it is the same imbalance seen at the planetary scale, reproduced within the country’s borders.

What it means for the next generation

At present, 15% of the world’s population already lives in areas where agricultural potential has fallen by at least 5%. If warming follows a medium-high trajectory, with around an additional 2.1°C between now and mid-century, that figure could soar to almost half of the planet’s inhabitants between 2041 and 2060.

The model also points to the problem becoming highly concentrated: barely 5% of tropical land already accounts for 35% of all recorded losses, and only about a quarter of countries are expected to bear 85–90% of global damage by mid-century.

The researchers stress a nuance that is often overlooked: even where productivity rises, tensions appear. These gains force land, water and investment to be shifted towards new areas within the same country, which can generate frictions between regions that until now did not compete for those resources.

On top of this comes a deeper injustice highlighted by the study: the countries that have emitted the least greenhouse gases throughout history are among the most exposed to these losses, and that gap is set to widen.

For its authors, CADI’s value lies not only in its diagnosis but in its practical use:

• It makes it possible to identify in advance which areas will need support to adapt
• New crops
• Technology
• Relocating production
• Channelling resources before falling yields translate into lower rural incomes, greater food insecurity or population movements forced by a lack of alternatives.

You can visit the project here (source in Spanish) and explore the two types of projections made, in 20-year steps from 2020 to 2100, on how agricultural production will evolve by region and how the climate will change.