Wednesday, September 28

Farmland has gained more than a million square kilometers in the last two decades and that worries scientists

Much of the future of the planet and the future of climate change it is played in your fridge. Let’s understand each other: yours, mine, that of the neighbor on the fifth floor and that of your office colleague. In a world with a rising population volume, the lands dedicated to agricultural exploitation, keys to filling the shelves of supermarkets, increase until they occupy a good pinch of the globe we call home. And that has a considerable impact on the environment.

It is not easy to appreciate it on a global scale. From the outset, the usual thing among governments and organizations that are dedicated to the control of cultivated areas is that their maps are limited to local or regional environments. Science just published a study which does provide an overall picture and its conclusion is surprising: over the last two decades -between 2003 and 2019, the study period-, the fields of corn, wheat, rice and other crops have gained more than a million square kilometers, an area equivalent to twice the surface of Spain.

Growth measured in CO2

To develop their farmland map, Matt Hansen, a geographer at the University of Maryland (UMD), and his colleagues drew on data from the Landsat program of the US Geological Survey (USGS) and NASA, which provide a detailed picture of the agricultural area on a global scale. In order to train and validate the algorithms they used to develop their map, the researchers visited farms and used satellite photos available on Google.

With the data on the table, experts have found that between 2000 and 2019, global farmland footprint increased 9% and the new extension reaches approximately the double of the surface of Spain. “We estimate that in 2019 the area of ​​farmland was 1,244 Mha (million hectares) […] Between 2003 and 2019, the area of ​​cropland increased by 9% and net primary production by 25%, mainly due to agricultural expansion in Africa and South America ”, details the report Posted by Hansen and the rest of his colleagues in Nature.

“The inexorable march of the human footprint is simply brutal,” reflects Hansen in statements collected by Science. In their report, the researchers highlight the increase noted in South America and Africa and point to key factors such as the increase in the population in the Asian Giant or the boom of soybean cultivation. In Africa, for example, about forty percent of farmland they appeared throughout the last two decades.

The Great Plains of North America and certain regions spread across the Asian continent also recorded an increase in land dedicated to agricultural production, which compensates for the decline in other parts of the globe, such as that found in territory that belonged to the USSR. The study leaves other interesting ideas. For example, despite the rise in crops, the increase in world population itself meant that between 2003 and 2019 the area of ​​cropland per capita decreased by 10%. Thanks to the intensive exploitations, the production grew.

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That agricultural operations replace forests, savannas or advance even on the basis of converting rainforests into arable land worries scientists. The reason: natural ecosystems that “take” store large amounts of carbon in the soil and trees. When transformed into fields, this CO2 is often lost to the atmosphere.

Half of the new farmland area (49%) replaced natural vegetation and tree cover, indicating a conflict with the sustainability goal of protecting terrestrial ecosystems, “they warn in your magazine article Nature.

The researchers themselves they recognize the magazine Science that there are dry ecosystems in South America that “will disappear completely soon.” “If the world wants to solve climate change, from a purely selfish point of view, you need to help Africa solve its land use challenge, and that includes much higher yield growth and food security, ”concludes Tim Searchinger of the World Resources Institute.

The oceans are our great allies for

For now, researchers already have a valuable tool at their fingertips: a global “photograph” that helps map farmland growth. “The implementation of the Sustainable Development Goals to improve food security, protect terrestrial and freshwater ecosystems and mitigate climate change requires national policies and international cooperation that are based on consistent, independent and timely data on extension and productivity. of agriculture ”, collects the article published in Nature Food.

Images | Miguel Angel Masegosa Martínez (Flickr)

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