Interactive map predicts agricultural decline from climate change by end of century
A CSIC team in Barcelona has developed CADI, a platform that uses a 10-kilometre grid to estimate how much farmland will lose productivity to climate by 2100; in Spain, inland areas fare worse than the Cantabrian coast.
A team from the Institute for Economic Analysis (IAE), a centre attached to the CSIC, has launched a tool capable of predicting, with a precision of 9.3 by 9.3 kilometres, how the planet will gradually lose its capacity to produce food as climate change advances.
It is called CADI, the English acronym for Climate-induced Agricultural Decline Index, and its function is easy to explain, though not to compute: it compares how much a plot of land could yield under different climatic conditions, keeping fixed the crops that were already being grown in 2020. That way it isolates the pure effect of the climate, without mixing it with human decisions on what to plant or how to adapt.
How the model works
The platform (CADI (source in Spanish)), coordinated by Laura Mayoral and Hannes Mueller, both also affiliated to the Barcelona School of Economics, has drawn on the collaboration of the Centre 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 programme. Using them, 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
Observed data, not projections, show that one in six croplands worldwide has lost more than 10% of its potential productivity in 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, although they start from such low levels of production that that percentage increase barely translates into more 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 sees it decline.
Spain is no exception to that rule, but it is not homogeneous internally.
As Mueller explains, the Cantabrian coast, Galicia and the Pyrenees gain in productivity, whereas much of the interior and the central-eastern part of the peninsula loses ground, with pockets of particularly severe losses. In a sense it is the same imbalance seen on a planetary scale, but reproduced within the country's borders.
What it means for the next generation
Right now, 15% of the world's population already live in areas where agricultural potential has fallen by at least 5%. If warming follows a medium-high trajectory, about an additional 2.1°C between now and mid-century, that figure could soar to almost half the planet's inhabitants between 2041 and 2060.
The model also points to a pronounced concentration of the problem: barely 5% of tropical lands already account for 35% of all recorded losses, and just a quarter of countries are expected to shoulder 85–90% of global damage by mid-century.
The researchers stress a nuance that is often overlooked: even where productivity rises, tensions emerge. The gains force land, water and investment to be shifted towards new areas within the same country, which can create frictions between regions that until now were not competing for those resources.
On top of that comes a deeper injustice highlighted by the study: the countries that have emitted the least greenhouse gases over 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 the diagnosis but in its practical usefulness:
- It makes it possible to identify in advance which areas will need support to adapt
- New crops
- Technology
- Relocating production
- Targeting 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 see the two types of projections produced in 20-year steps from 2020 to 2100, showing how agricultural output evolves by region and how the climate changes.
