Earth is becoming increasingly crowded. Global population stands at just over 7 billion and is rising by 78 million people per year. Now, if that number does not sound like a lot to you, think about it this way--we are adding close to the population of Germany every year to our crowded planet! Currently 134 million children are born every year, that is 367 thousand per day, and there are approximately 56 million deaths per year. At this rate, the population is predicted to reach 8 billion by 2027 and about 9 billion by 2046. Its mind-boggling to think that global population when many of you were born stood at just over 5 billion! The graph below shows the massive increase in global population as well as these scary projections. It demonstrates how global population increase has been driven by surging populations of Africa, and especially Asia.
The video below portrays the recent growth in population as well as the outlook.
In 1798, Thomas Malthus wrote An Essay on the Principle of Population. In this work, he predicted that populations of nations would be restricted by the availability of food because nations would not be able to control birth rate. The essay has been intensely debated by evolutionary biologists, economists and many others for the last two centuries. Repeated famines around the globe generally support Malthus' hypothesis.
Regardless, we find ourselves in a position today where the world is currently not able to feed all of its inhabitants. Currently, more than one billion people are estimated to lack sufficient food, and more than twice that number do not receive adequate nutrition. This situation will likely become a lot more dire in the future. In fact, predictions for population increase diverge significantly in the later parts of the century because some models assume mass mortality due to widespread famine. To make matters worse, climate change is predicted to cause major problems to crop yields, especially in parts of the world where the population is growing the fastest. These shortages will likely lead to mass migration of huge numbers of people, possibly entire nations.
Agriculture is an essential part of every society. Forty percent of the Earth’s surface is managed for cropland and pasture. That is more than for any other activity including forestry, which comprises 30% of Earth's area. In underdeveloped countries, approximately 70% of the population live in rural areas where agriculture is the major activity. There are many diverse sources of food, and populations around the world have very different diets and demands. In addition to crop and livestock, fish is a stable diet in many countries. Projections for climate change differ significantly for these various food sources, thus we will discuss them separately. For crop farming, in particular, the impact of climate change is very different for agro-businesses run by multinational corporations in the developed nations than for family-operated farms in the developing world.
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Climate change will have very different impacts on different continents, and socio-economic factors will govern the abilities of nations to respond. Even though the south-central and southwestern US are likely to face extreme drought in the coming decades, inhabitants and businesses should by large be able to adapt. It will be a starkly different situation in Southern Africa, India and Southeast Asia, Mexico, northeast Brazil, southern Africa and West Africa, where climate change will be coupled with a general lack of coping mechanisms. In all of these regions, the impact of climate change, and the inability of societies to fully cope with it will potentially result in security issues including soaring food prices and military conflicts.
Food shortages will not be a new problem in many places. Mass migrations driven by food supply have been an important part of human evolution and a tragic part of the history of many nations, especially those in Africa. As we saw in Module 2, famine caused by drought is thought to have caused the collapse of the Mayan civilization in Central America around 850 AD. More recently in China, famine in the late part of the 19th century caused the death of some 60 million people. Famine is possible even in the developed world. The Irish potato famine between 1845 and 1852 caused by a potato disease called potato blight led to approximately 1 million deaths, between 20 and 25% of the population of that country. This problem does not appear to be improving with time. In the 20th century 70 million people are thought to have died during famines: 30 million alone in China between 1958 and 1961, and 7-10 million in India in 1943.
Nowhere is the history of famine more devastating than in Africa. Famines on the African continent, like elsewhere, have often resulted from a combination of drought and political conflicts, oppressive military regimes, and war. Most recently the conflict in the Darfur region of Sudan erupted over water in 2003. One side of the conflict, consisting of migratory farmers, has displaced large numbers of sedentary farmers to parts of the country without sufficient food and water. Mass mortality has largely been caused by disease. Estimates of the number of dead are uncertain but are between 180,000 and 460,000. This number is much less than the number of mortalities in the Biafran conflict of Nigeria between 1967 and 1970 when nearly a million people died from conflict and starvation. Today more than a third of Africans suffer from hunger.
The following video portrays the tragic history of famines.