From my experience in Africa, I do view exhaustion of soils as a big immediate threath to food security, perhaps more so than climate change. People have moved from slash-and-burn to sedentary agriculture without input from minerals, still burning crop left-overs, and yields are going down.

Thanks Dr. Molleman for sharing your views. I feel the deleterious impact of soil degradation on food security could be more severe in Africa than anywhere in the world. And as you rightly envisioned, it could be a bigger threat than the climate change. really a serious but under-rated concern!

Climate change and soil degradation is very much linked, not entirely sure you can disassociate the two in future scenarios, considering drier more arid conditions in hotter climates will no doubt exacerbate the problem of soil degradation, and increased flooding in more temperate/humid regions will also degrade available soil.

The bottom line is that we have very little high quality, comprehensive, quantitative information about soils that is longitudinal. Thus we can find places where the soils are degraded now, but we cannot connect these very easily and over large areas to human activity. Thus it is easy to discuss soil degradation at the small scale, but at the larger scale (regional, continental) it is nearly impossible to say what the trajectory of soil quality or the role of soil biomass or nutrients in maintaining food security. When you are discussing threats to global food security, the impact of climate and climate variability is much easier to quantify and study. Until this changes through new ways of diagnosing the role of soil in food production over large scales, the role of soil in food security and food production will likely to continue to be obscure.