Intuitively, you would probably think that energy would be the dominant way that humanity is impacting the planet. We've just seen how massive energy use translates into rising carbon dioxide and climate change. And energy, of course, is everywhere. It is in our transport systems, our power supplies, our industrial processes, our home use. But I would say that the agriculture sector has an even larger impact on the physical planet and the various earth systems than energy. Energy is causing climate change. Agricultural use and agricultural patterns not only have a huge impact on climate but have a huge impact on every aspect of the Earth's systems and the planetary boundaries.
We know that the food production contributes massively to greenhouse gas emissions, therefore to climate change. The nitrogen and phosphorous cycles, where we get the pollution from the runoff of nitrogen and phosphorus-based fertilizers. The fresh water use, which is about 70% used in the agricultural sector. The change of land use overwhelmingly a reflection of agriculture. The loss of biodiversity coming from the way that farmlands and pasture lands and tree crop plantations absolutely threaten habitats of other species unleash, agriculture is done in an agro-ecologically friendly manner.
Chemical pollution with the heavy application of chemicals such as herbicides and pesticides used in agriculture. There's a tremendous amount of chemical impact from the farm system. So it is quite arguable that farming dominates the all of the human activities in terms of the anthropogenic effects. That is the various human-caused impacts on the planet. Now this is in a way ironic because it takes us right back to the beginning of the modern economic era and to the very beginning of economic studies just like Adam Smith does and just like Adam Smith's wisdom is still useful today, so too is that of another great thinker Thomas Robert Malthus who wrote famous text in 1798 called Principles of Population.
Malthus was afraid. He was afraid of planetary boundaries, but for a slightly different reason. Malthus said that the human population has a tendency to rise at a geometric rate. And so if left on its own with the basic needs met the human population would continue to expand rapidly. He was right in that when he wrote the Principles of Population in 1798.
The total population may have been 800 million, maybe 900 million. Roughly one tenth of the level that it is today. So Malthus was right that human population tends to increase markedly, at a geometric rate he said. Now, he feared that the ability to grow food would only increase at an arithmetic rate. That is adding a certain number of tons of feed grain or food grain per year to the world's capacity to grow food. And Malthus said, look, any geometric growth will always overtake any arithmetic growth. So the growth of the human population is always going to overtake the ability to grow food, he said. And at some point there will be so many people that hunger will ensue. And when hunger ensues there will be various kinds of devastating feedbacks whether it's war, whether it's famine, whether it's disease or other scourges that will push population back down. But will mean that humanity won't break free of the physical constraint on the ability to grow food.
Now Malthus did not anticipate the scientific advances of the Green Revolution, for example. He didn't anticipate modern seed breeding of course even Mendel who invented the modern science of genetics would come basically about three quarters of a century after Malthus. Malthus also didn't anticipate the breakthroughs in the science of soil nutrients and the use of chemical fertilizers to replenish soil nutrients and to boost food yields. Nor did he anticipate at least the potential for the human potential to stabilize by means of modern contraception, family planning, and choices that households make. So Malthus, couldn't see the full dynamic ahead, but he worried that the human population would outstrip the carrying capacity of the planet itself.
For a long time, economists and others laughed at Malthus. They said, you've got it all wrong. You see modern science allows us to grow enough food for a geometric rise of the population. We know how to add fertilizer; we know how to have high yield seed varieties.
Malthus was a pretty clever guy and his warning rings true today. While it is the case that increases of food production technology in agronomy and food processing, storage, transport and the like has made it possible to feed about 8 billion people though not all of them by any means fed well or nutritiously. It is also the case that the food production system is so destructive of the environment that Malthus is still there, waving his finger saying not so fast. You haven't proven that you can grow this amount of food sustainably. What's going to happen when the water runs out? What's going to happen when the nitrogen and phosphorus loadings become so large and so forth.
Sustainable development necessitates a renovation, and in some instances, a revolution, in our food-growing technological systems. It also calls for wiser dietary choices, favoring foods that don't threaten the natural environment. This includes avoiding endangered fish species and land mammals, some of which are still consumed as delicacies, leading to illegal hunting and poaching, and threatening their survival.
Therefore, changing farming systems and human dietary behavior is essential. We need to demonstrate the feasibility of sustainably growing food for a properly nourished global population, while respecting planetary boundaries. Currently, we are far from achieving this goal. 'Agriculture's Role in Eco-Development: The Case for Future Food Systems' represents another step in the right direction.