NASA maps 22 years of Brazil's vanishing groundwater under the world's soy and coffee belts

A NASA-led team has reconstructed monthly groundwater changes across Brazil from 2002 to 2023 and found severe, persistent losses over about 1.97 million square kilometers, roughly 23% of the country's land area, spanning parts of the Sao Francisco, Parana, Southeast Atlantic and East Atlantic basins ^[17][14]. The work was published on June 3 in Science Advances, and it matters to procurement teams rather than to climatologists, because those basins hold the fields that produce most of the world's soybeans, sugarcane, oranges and coffee, plus a large share of its cotton and corn ^[16][4].

Groundwater supplies 55% of Brazil's water, and the study argues that many of its stores have shrunk enough over 25 years to face irreversible damage ^[1][2]. The drivers listed are drought, higher evaporation under a warming climate, and pumping for human use ^[3]. Some of the most critical aquifers went years without any recharge at all ^[18].

The method is worth understanding before the number is used in a model. Brazil holds the largest renewable freshwater reserves of any country, largely because of the Amazon Basin, but its monitoring network is thin next to the thousands of wells the United States and India operate ^[11][12]. The researchers trained AI models on records from 398 monitoring wells, satellite gravity measurements, and geology and land-cover data, then reconstructed groundwater at about 10-kilometer resolution ^[13][14]. Taking the paper's own figures, 1.97 million square kilometers at 23% implies a national area near 8.57 million square kilometers, or about one monitoring well per 21,500 square kilometers ^[2][3]. That is roughly 215 model grid cells per observed well ^[4]. The reconstruction is a defensible inference, not a measurement.

The authors are also careful about blame. The study did not attribute changes to specific pressures, though first author Augusto Getirana of NASA Goddard's Hydrological Sciences Laboratory said climate shifts clearly played a major role, with several of the sharpest declines following prolonged droughts and the 2015-2016 El Nino ^[21][10][22]. Patchy monitoring makes the agricultural, industrial and household shares hard to separate, but losses overlapped substantially with intense irrigation, urban and industrial demand, mining, land conversion and high well density ^[23][24]. Getirana's formulation: "climate creates the underlying water deficit, while extraction and land-use changes are probably amplifying its magnitude and duration in heavily used regions" ^[25]. Javier Tomasella of Brazil's National Institute for Space Research, who was not involved, told Live Science that climate change is the main cause and that droughts are lasting longer and intensifying across most of the country, particularly the central region and the Northeast ^[26][27].

The trade signal is not imminent. Getirana said declines probably will not reduce total agricultural output over the next 10 to 20 years, and that "the concern is what happens if these trends persist for several decades" ^[7][8]. He added that Brazil is one of the world's major breadbaskets, so its water security has consequences beyond its borders ^[9]. The second-order risk is electricity: experts told Live Science that depleted aquifers could collapse the river systems feeding Brazil's hydropower, pushing the country toward coal or biomass ^[6]. That would raise the energy cost of processing and crushing inside the same regions losing the water.

Watch whether the depleted basins post a recharge year, whether Brazil expands its well network so the next reconstruction rests on measurement, and whether the country's hydro output holds through the next El Nino. Also note that the study found no single national trend, with the Amazon and parts of southern Brazil flat or slightly wetter ^[20][19]. Sourcing shifts within Brazil are the cheap hedge, and they run out before the aquifers do.