Sunday, November 13, 2016

Phosphorus Peak: a Blessing in Disguise?


Since the beginning of the Industrialisation, humans have been putting the earth system under an ever-growing amount of pressure in terms of resources depletion and environmental degradation. Such pressure resulting from anthropogenic activities is believed to have caused an unexpected shift into a new geological era: the Anthropocene.

These recent changes in global environmental systems are worrying and lead us to question:

How long we can continue with business-as-usual before our wellbeing is compromised by our choices?

The answer is suggested by William Steffen who recently explored the limits to which we can push the planet before it changes irreversibly. 

He identified that a planetary boundary for phosphorus discharge into our oceans is 10 times its pre-industrial levels. Globally, 14.2 Tg/year of phosphorus are washed off from cropland into freshwater ecosystems and eventually our oceans - a rate that effectively surpasses the 11 Tg/year suggested by scientists as the safe limit.

Our agriculture currently highly depends on phosphorus to maximize and support crop yields so demanding a reduction in fertilizers usage could lead to a threat to food security. Despite the positive implications of reducing the wash-off of pollutants, it is difficult to imagine that markets and governments will put at risk human well-being to safe guard the environment.

In fact, the world population is bound to increase by 75% reaching 10 billion by the end of the century. Not only we will have to produce more food but an increasing amount of the world population is demanding for more meat. Experts believe this demand will lead to a doubling in the production of grains as well as soybeans- due to their high protein content- for livestock feed.


The issue 

Phosphorus is a non-renewable resource and studies found that if its consumption was to continue at the current rate it will run out before the end of the century. The peak in demand is thought to be in 2030 – what is known as the Phosphorus Peak. On top of the issue of quantity of phosphorus available, the rising demand is being matched by ever decreasing quality of the substance as well as increasing prices.




While reading about the negative effect of phosphorus and the dangers associated with our dependency on it for food production, I began to question:


Is this peak a blessing in disguise or a terrifying prospect? 


As the peak approaches with associated rise in prices, more and more studies have shifted their attention towards finding a more economically sustainable way to feed the world population without sacrificing the environment.  

Interestingly, the answer may lie in the investigation of the distribution of phosphorus across different landscapes and its heterogeneity across different scales. Although the exact date of the Phosphorus Peak is still widely debated, concerns remain as there is still no likely substitute to this chemical:

if we are to continue producing food for the growing world population we have to start managing the allocation of existing phosphorus in a more effective manner.

For instance, in some regions freshwater ecosystems are suffering from an excess in phosphorus inputs leading to a rise in nutrients and increasing eutrophication. On the other hand, at a global scale we are experiencing a shortage of this resource because areas that currently export phosphorus, such as West Saharan countries, are now under excessive pressure.





Looking at the map produced by MacDonald and Bennet it becomes evident that there is an imbalance in the way fertilizers are being used. For instance, Ukraine is known as the bread basket of the Russian empire despite suffering from very serious phosphorus deficit. On the other hand, Brazil is flashed as an hotspot where fertilizers are being over-used.


I strongly believe that taking spatial variability in the distribution of phosphorus would allow for a global approach to agriculture that could prevent a further rise in freshwater pollution. 

The Phosphorus Peak is a terrifying prospects but it is essentially forcing markets and global entities to develop a more sustainable approach to agriculture which would not have been considered otherwise. 

Do you agree this could be nature's blessing in disguise?

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