Do we only have 60 harvests left? - Our World in Data
https://ourworldindata.org/soil-lifespans
Let’s focus on the ‘conventionally managed’ soils, shown in blue. These data are relevant for understanding many of the world’s farming practices. We will look at conservation techniques later.
Many of these soils are thinning; some very quickly. 16% have a lifespan of less than 100 years if they continue to erode at their current rates. This is not a local problem: there are examples of soils with lifespans shorter than a century on all continents, including the United States, Australia, Spain, Italy, Brazil and China. The longevity of these soils is concerning and we should be acting quickly to preserve them.
But the “60 harvests” claim is quite clearly false. More than 90% of conventionally managed soils had a ‘lifespan’ greater than 60 years. The median was 491 years for thinning soils. Half had a lifespan greater than 1,000 years, and 18% exceeded 10,000 years. There were also some soils that were not eroding at all. Where soil formation rates exceeded erosion rates, soils thickened.In fact, some were thickening – soil was forming quicker than it was eroding. In the bottom-right of the chart we see the rates of soil gain. 7% of conventionally managed soils were thickening.
If we were to keep our land completely bare – by removing any vegetation and preventing any natural regrowth through pesticides – our soils could erode more quickly. One-third (34%) of bare soils had lifespans less than 100 years.
There is no single figure for how many harvests the world has left because there is so much variation in the types, quality, and management of our soils. It’s just implausible that they would all be degrading at exactly the same rate. As these results show: some soils are eroding quickly while others are thickening
