school energy&environment

Human weight on nature

In order to visualize the weight that our species has on the global ecosystem, consider that the entire area of the Earth, is about 51 billion hectares. The surface area above sea level, accounts for little more than 14 billion hectares, which, according to the calculations made by FAO (Food and Agriculture Organization), are in turn subdivided as follows:

• 2 billion hectares of cultivated and built-up areas;
• 3,4 billion hectares of permanent meadows and grasslands;
• 3,8 billion hectares of forests and wooded land;
• 5 billion hectares of frozen land, tundra, deserts and humid environments.

Therefore it is evident that for the production of food, in order to exploit and extract the resources, and in order to dispose of human waste, it is necessary to make use of the surface that is still available. This is a compulsory step, because the surface of the planet is suited, and its productive capacity is great, but it is not infinite. It has been calculated that humanity, at the present population pressure has about 2.3 hectares of bioproductive territory per head ( the average amount of earth that is available to obtain food), and the calculation includes the fraction of dry land for agriculture and breeding livestock, and also the fraction of ocean surface that is necessary for fishing. It has been noted however that the estimated 2.3 hectares only bear in mind the requirements of our species, neglecting the needs of all the others. Taking into consideration also these requirements, and taking the projections of the United Nations, according to which in 2050 the human population will reach a total of nine to ten billion people, to be correct, it has been noted that the bioproductive territory per head is destined to fall below one hectare. The question at this point is: will this surface per head be sufficient to guarantee the survival of mankind without further jeopardizing biodiversity of the planet?