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“Worldwide, about 95 percent of our food comes directly or indirectly from soils”
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Does increasing soil erosion pose a threat to our food supply?
Worldwide, about 95 percent of our food comes directly from soils – namely, from the top 40- to 50-centimetre layer. Between 80 and 90 per cent of all life on Earth depends on this layer of soil. That said, it doesn’t take long for soils to be washed away, eroded, salinized, or chemically or biologically degraded. It can result from a single event or from years of degradation. But rebuilding just one centimetre of healthy soil takes anywhere from 100 to 300 years, depending on the climatic zone. So, when soils are washed away or degraded, it obviously has a major impact on agriculture and our food chains. But it also affects biodiversity and the climate. This is because soils can store a lot of carbon, which they can then also release back – thereby further fuelling global warming. In addition, soils are important stores of water. They can prevent flooding and make the water they absorb available to plants during dry periods.
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“If we carry on like this, 40–60 years from now we won’t be able to feed the global population”
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Staying on the topic of soil fertility: It’s possible to apply fertilizer, of course.
Indeed, you can compensate for a lot with fertilizers in the short term. But this doesn’t work forever – especially if it’s artificial fertilizer – and it doesn’t stop the degradation of soils. Additionally, it has negative consequences for biodiversity and water quality. Statistics show that fertilizer use per hectare continues to rise at the global level, despite recent declines in individual countries like Switzerland or Germany. If we take into account biodiversity loss, some studies suggest we only have 80 to 120 more harvests remaining based on current intensive land use and widespread monocultures. This means that if we carry on like this, 40 to 60 years from now we won’t be able to produce nearly enough to feed the global population.
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“Land degradation impacts us everywhere – even in Switzerland”
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In October, the UN Convention to Combat Desertification (UNCCD) announced: “If current trends persist, we will need to restore 1.5 billion hectares of degraded land by 2030”. How do you see it?
Things really don’t look good and the trend is definitely still going in the wrong direction. The global extent of land degradation is estimated at 20 to 40 per cent of the total land area, directly affecting almost half of the world’s population and spanning the world’s croplands, drylands, wetlands, forests, and grasslands. This was also highlighted by the UNCCD’s Global Land Outlook.
The UNCCD is the only international agreement focusing globally on land conservation. Unfortunately, it still receives far less attention than the other two Rio conventions on climate and biodiversity. I think this might be because of the somewhat unlucky choice of the word “desertification”. In our agroclimatic zones, many people assume it doesn’t concern them, as the nearest desert is far away. But the UNCCD is actually about degradation of land, which includes soil, water, and vegetation; or rather about preventing or reversing it. That impacts us everywhere – even in Switzerland.
How strongly does it affect Switzerland?
Depending on the data source, almost 10 percent of Switzerland’s total land area is degraded and around 20 percent of arable land is considered at risk of erosion. In addition, droughts and flooding – two major drivers of land degradation – are increasing here, too. We have to react.
How?
The UNCCD emphasizes the following responses, in this order: prevent land degradation, reduce erosion, and restore soils. Because the effort required to reverse something is much greater than that of preventing harm in the first place, at our latitudes when using land we need to focus on making sure that erosion doesn’t even begin to develop.
What does that mean in concrete terms?
For example, we need to ask ourselves: Are we going to continue to cultivate our crops intensively on “bare” land, or are we going to increase our land cover so that the soils don’t dry out? Are we going to use more and more fertilizer, endangering our biodiversity and drinking water, or will we switch to more sustainable cultivation methods? Are we going to irrigate our fields until our rivers run dry or will we begin to grow crops that require less water? We still have the choice and the scope to change our land management and to adapt to climate change.
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“Interest in taking measures has increased in some regions”
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You recently participated in an international meeting that assessed the progress of different countries in implementing the UNCCD Convention…
It’s called the Committee for the Review of the Implementation of the Convention (CRIC). It meets every year to discuss countries’ reports of where they stand and what they have achieved. This year, we saw that not all countries that had set targets for land degradation had issued reports for the most recent period. And there were major differences in reporting quality between the countries that did report.
Does this mean that little or nothing is being done?
No, things are happening, even if it’s not enough. At least in some regions, there is growing interest in monitoring land degradation at the national level and in taking measures to prevent, slow, or reverse it. At the CRIC in Samarkand in November, we talked for the first time not only about methods and indicators, but also about results. There is now a UNCCD data dashboard (see box) that illustrates what countries reported and shows the global status of degradation. This transparency makes the Convention more accessible and enables us to look for ways of improving global communication and emphasizing the severity of the situation.