Warmer climate accelerates global phosphorus loss

A Chinese study reported an increase in atmospheric phosphorus flux in a global annual average temperature range of 20°C to 23°C. With potential consequences for agriculture

by Matteo Cavallito

 

At higher temperatures, the soil tends to release greater amounts of phosphorus, a study published in the journal Science Advances has found. The investigation was carried out by collecting information on a global scale. That means this phenomenon, which had already been recognised before based on the hypothesis of an existing link between climate and dispersion rates, is now also confirmed by empirical data.

During their investigation, researchers from the Institute of Geology and Geophysics of the Chinese Academy of Sciences in Beijing compiled a geochemical dataset of global surface soils. Temperature, the authors explain, proved to be the crucial factor.

Heat contributes to phosphorus release

The release of phosphorus through weathering “is a vital process that regulates the global cycling of numerous key elements and shapes the size of the Earth’s biosphere,” the study explains. ‘“It has long been postulated that global climate should theoretically play a prominent role in governing P weathering rates. Yet, there is currently a lack of direct evidence for this relationship based on empirical data at the global scale.”

The scientists, says a statement, focused their study on the top 30 centimetres of soil by collecting measurements of temperature and phosphorus content.

Their hypothesis is that che “this amplification of nutrient supply with warming is a critical component of Earth’s natural thermostat, and that this relationship likely caused expanded oceanic anoxia (the loss of oxygen in the oceans, ed.) during past climate warming events.”

The impact on agriculture

By calculating the relationship between global annual mean temperature and atmospheric phosphorus flux, the researchers identified “a rapid increase in phosphorus weathering flux within the global mean annual temperature range of 20 °C to 23 °C.” The consequences, they explain, are especially felt in the agricultural sector, considering the decisive role phosphorus plays in soil productivity.

“The potential acceleration of phosphorus loss from soils under ongoing anthropogenic driven climate warming may pose threats to agricultural production globally,” the study explains.

 

These effects are especially evident in tropical and subtropical areas, where “soils are typically highly weathered, resulting in widespread phosphorus limitatio and corresponding requirements for fertilizer use.” To ensure adequate agricultural production in this context, therefore, it may be necessary to increase the use of chemical fertilizers. But that also means, off course, many problems in terms of environmental sustainability and availability.

Numerous factors influence the loss of the element

The research makes a new contribution to the existing literature on the phosphorus cycle and the effects of climate and other factors. In January 2023, a study by a team of researchers from Australia, Spain, Canada, the US, France and China published in the journal Nature Geoscience has found that rising levels of CO2 in the atmosphere lead to a reduction in phosphorus in rice fields. Thus threatening the security of food supplies in the future.

Also crucial is the deterioration of soil health. In 2020, a research by the University of Basel revealed that more than 50 per cent of the global phosphorus loss of the element in agriculture is attributable to soil degradation. Erosion, in particular, leaches the element from farmland to wetlands, streams and bodies of water. Thus damaging the ecosystem.