One of the most evident effects of climate change is being the transfer of all kinds of plant and animal species to increasingly northern latitudes and increasingly higher altitudes. With agriculture it is also happening. Now, a group of researchers has estimated the future viability of 12 of the main crops in geographic areas where today the cold prevents them from bearing fruit. Among them are from rice and palm to wheat and peanuts, through cassava, sugar cane or cotton.
The work, published in the scientific journal PLoS ONE part of the thermal range supported by these products and projects it in two of the most probable climate scenarios, one in which emissions are reduced according to the Paris agreements and the other extreme, in which nothing is done to mitigate them. Whatever the future, by the end of the century most of these crops will be able to be planted further north and higher than today.
Half of the land gained is in Russia and Canada, with more than 400 million hectares each
“Areas not suitable for agriculture today will probably be in the next 50 to 100 years”, says in a note the professor of Geomatics at the University of Guelph (Canada) Krishna Bahadur. In the most likely scenario, based on the combination of various climate models, warming would make an additional 1.5 billion hectares viable for at least one crop. Those that will be able to expand the most will be wheat, potatoes and corn.
Half of the land gained is within the borders of Russia and Canada, with more than 400 million hectares each country. A good part of the Rocky Mountains, a mountain range that crosses North America from top to bottom, the southern portion of the Andes, and large tracts of Central Asia would also be arable. Due to changes in humidity patterns, wide swaths adjacent to the African and Australian deserts would be gained for agriculture, but here there is greater uncertainty. Although the total area is smaller, in relative terms it stands out that the north of the Nordic countries and the Alps could support at least two of the main crops.
Just because so many new lands – new agricultural frontiers the study authors call them – become fertile does not mean they end up being cultivated. According to the Food and Agriculture Organization of the United Nations (FAO), on the planet there are about 4,400 million hectares suitable for agriculture, although only 1,500 million actually cultivated. Even so, the authors of the study dedicate the second part of their work to determining the risks, the consequences, that would have the cultivation of so many hectares.
“The development of agriculture in large areas of the northern borders would release alarming amounts of carbon from the soils,” says ecologist Lee Hannah, head of climate change at the organization Conservation International and co-author of the study. Based on previous research, the authors of this work estimate that between 25% and 40% of all carbon trapped in the land that has never been broken could be released into the atmosphere in the first five years after plowing. According to his calculations, up to 177 billion tons of carbon could escape in that short space of time. That equates to total COtwo that the US would emit in 119 years at the rate it does today.
The release of so much gas could have an amplifying effect: North of the new agricultural frontiers is a large swath of permanently frozen land, the permafrost. Its thawing is one of the greatest fears of scientists, due to the large amount of methane it contains and this is a greenhouse gas 25 times more powerful than COtwo. “The land conversion could generate additional regional warming that would accelerate the melting of frozen peat soils, further accelerating climate change,” warns Hannah.
The clearing of the new lands could release millions of tons of COtwo
There are two other collateral damages from the expansion of agriculture to the north. On the one hand, around 1.2 billion people depend on the water that flows through these areas. The introduction of crops, with their fertilizers and pesticides, would pose risks to water quality. Even more important is the impact on biodiversity. At least 1,361 of the calls key biodiversity areas they would be affected if all the new lands were cultivated.
“Many of these areas were protected because there was no agricultural interest in them,” recalls the researcher at the University of Vigo Juan Antonio Añel, who has reviewed the scientific article. Añel recalls what happened decades ago with the Amazon region and how regional processes, such as the advancement of livestock and agriculture, had and still have a global impact. Now, he stresses, “two countries dominate a large part of the affected area and their policies can condition the global carbon balance.”