Cultures are increasingly devouring the planet – CVBJ

08/01/2022 at 13:02 CET

Ramon diaz

The advance of agriculture is unstoppable. Farmland is taking over much of the planet. Over the past two decades, cultures have devoured more than a million square kilometers of the Earth’s surface – twice the size of Spain.. Scientists have already uttered a cry: the extension of the agricultural surface, replacing in many cases forests and savannas, poses a great challenge for the protection of the climate and biodiversity.

A new world map compiled from satellite data shows that agricultural land has increased dramatically so far in this century. The study, which has just been published in ‘Science’ and ‘Nature Food’, shows how Earth becomes one gigantic, unified global farm, with rich countries increasingly “outsourcing” agricultural production to the poorest regions.

Half of the new fields replaced forests and other natural ecosystems (natural vegetation and tree cover) that stored large amounts of carbon, which threatens efforts to conserve the Earth’s increasingly precarious biodiversity and prevent a catastrophic climate change. “The inexorable advance of the human footprint is simply brutal,” says study author Matt Hansen, a geographer at the University of Maryland (UMD).

Rice field in Asia | Pixabay

Hansen and his colleagues mapped farmland using data from a United States Geological Survey and NASA program, taking advantage of images taken by various satellites designed to constantly monitor the planet’s surface.

The global agricultural land footprint increased by 9% over the study period, which runs from 2000 to 2019, mainly due to agricultural expansion in Africa and South America. The increase in the area occupied by new agricultural fields is several times greater than the estimate of 2.6% made by the Food and Agriculture Organization of the United Nations (FAO).

Despite all this, the global area of ​​cultivated land per capita has decreased by 10% due to population growth. This circumstance may be an indicator of food insecurity in poor countries that depend on subsistence agriculture, scientists say.

More population, more cultures

The situation is extremely complex and difficult to resolve. On the one hand, growth of the world population and rise in the standard of living “inevitably” the expansion and intensification of agricultural land use around the world “To meet the growing demands for food, biofuels and other basic products.”

But on the other hand, This expansion and intensification of agriculture threatens the functioning of ecosystems and leads “to the extinction of species. through habitat loss and fragmentation & rdquor ;, warn the authors of the study, who are convinced that the results of their research will help move closer to the United Nations Sustainable Development Goals (SDGs) for 2030, to improve the modeling of crop yields, to move towards sustainable food production and to reduce the environmental impact of agricultural expansion.

“The SDGs require a balance between increasing agricultural production and maintaining ecosystem services. Implementing the SDGs to improve food security, protect terrestrial and freshwater ecosystems, and mitigate climate change requires national policies and international cooperation based on consistent, independent and timely data on the extent and productivity of agriculture, ‘say scientists.

Wheat field | Pixabay

From the data collected in the study, it is extracted that the great lowland regions of the world have become homogeneous agricultural landscapes, including the Great Plains in North America, the Pampas in South America, the Pontic Steppe in Europe, North China and the Manchurian Plains in East Asia, the Indo-Gangetic Plain in South Asia, parts of the Sahel region in Africa and south-eastern Australia.

South America and Africa, in particular

The expansion of cropland in South America – largely due to a booming soybean industry supplying ranchers, especially in China – has occurred synchronously in Brazil, Argentina, Paraguay, Bolivia. and in Uruguay. . The continent’s agricultural land has increased by almost 50% during the study period.

A similar pattern of simultaneous expansion of cultivated land has been observed in the countries of the Sahel and Central Africa. Most of the new agricultural land has been created in Africa to feed a rapidly growing population. 40% of Africa’s farmland has emerged in the past two decades, and the rate is accelerating. But crop yields on this continent are the lowest in the world.

In Southwest and Southeast Asia, the gain of agricultural land has been seen mainly in arid areas, while tree plantations, orchards, aquaculture and urban areas have replaced former agricultural land. in China and other countries. Lower Mekong.

The grain, forage and hay producing lands of the northern Great Plains of North America have different dynamics in Canada, where land has been abandoned or converted to permanent pasture, and in the United States. United, where management has intensified from the ground up.

During this time, irrigated agricultural land in Saudi Arabia has shrunk due to depletion of groundwater resources and the implementation of public policies to discourage the production of water-intensive crops.

The investigation also revealed the Abandonment of agricultural land following radioactive contamination following the 2011 nuclear disaster at the Fukushima Daiichi nuclear power plant in Japan.

“The cross-border distribution of large cultivated areas and the synchronous dynamics of cultivated land illustrate the importance of International cooperation to ensure global progress towards the SDGs, ‘say the researchers.

The conversion of forests and savannas into agricultural fields causes the emission into the atmosphere of huge amounts of carbon stored in vegetation and soil, accelerating climate change. This circumstance generates about an eighth of the total carbon emissions caused by humans, according to the researchers.

Benchmark study: https://www.nature.com/articles/s43016-021-00429-z


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