By Robert A. Vella

The United Nations is projecting the human population of Earth to reach 11.2 billion by the year 2100 (see: U.N.: expect 11.2 billion population by the end of the century). Today, it is 7.3 billion people. These figures represent an increase of 53.4% over a span of 85 years, nearly two-thirds of a percent average increase per year. According to the World Health Organization, Japan has the highest overall life expectancy of all nations at 84 years as well as the highest for females at 87 years. In contrast, the U.S. is ranked 34th with an overall life expectancy of 79 years (see: List of countries by life expectancy). That means many millions of people born this year in 2015 should live to see the turn of the 22nd century.

Or, perhaps not. Many scientists have placed the upper limit of Earth’s population at 10 billion, and that assumes a fairly radical shift towards a vegetarian diet since there is insufficient arable land and fresh water to produce meat for that many people (see: How Many People Can Earth Support?). Furthermore, the productivity increases in food production we’ve been accustomed to – particularly since the advent of modern agricultural techniques – has not only peaked and begun to slow down, but is also likely to be severely reduced by climate change going forward (see: This terrifying chart shows we’re not growing enough food to feed the world).

Considering the current pace of replacing traditional fossil fuels with clean energy (estimated at 19% of global energy consumption in 2013, see: World energy consumption/Renewable energy), it is apparent that climate change cannot be mitigated quickly enough to prevent major impacts to agriculture and food production. Crop irrigation will become problematic as fresh water supplies are exceeded in vital regions. Farm lands will be inundated by rising seas and deteriorated by extreme weather events. Ocean acidification, already of grave concern, will decrease fish stocks and other marine species which much of the world’s people depend on for food. How this will affect human population growth is a question few authorities seem eager to address – at least not publicly. In my research, it was difficult to find any reputable studies on the subject; though, one stood out.

From PNAS (Proceedings of the National Academy of Sciences) – Global climate change, war, and population decline in human history:

Although scientists have warned of possible social perils resulting from climate change, the impacts of long-term climate change on social unrest and population collapse have not been quantitatively investigated. In this study, high-resolution paleo-climatic data have been used to explore at a macroscale the effects of climate change on the outbreak of war and population decline in the preindustrial era. We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change.


The hypothesis we propose posits that long-term climate change has significant direct effects on land-carrying capacity (as measured by agricultural production). Fluctuation of the carrying capacity in turn affects the food supply per capita. A shortage of food resources in populated areas increases the likelihood of armed conflicts, famines, and epidemics, events that thus reduce population size.

Apocalyptic images in murals at Denver International Airport

Apocalyptic images in murals at Denver International Airport


Depopulation, in other words, appears inevitable now – the extent of which cannot be quantifiably forecast due to great variability in the determining factors. What can be generally predicted at this point in time is a steady worsening in the living conditions of most people on this planet punctuated by episodic disasters. After decades of improvement in nutrition, health, education, and the other things which human societies have strived for, we’re about to witness a very unpleasant and monumental reversal.

Such a gloomy picture must not be drawn lightly, nor should it be considered or dismissed with undue emotion. Assessing the probability of an imminent dystopian future for humankind must be made logically and dispassionately. Science has been warning us for decades; yet, we have continually resisted its pleas. With only minor alteration, people are going about their usual ways as if little-to-no threat was present. Modern civilization appears rudderless, impelled by terrific forces both unseen and unfettered. From psychological and sociological perspectives, this headlong march towards the ecological cliff is truly astounding.

However, it is consistent with the nature of life on Earth. Mass extinctions, and lesser extinctions, have occurred time after time. This one, coined by journalist and author Elizabeth Kolbert as “The Sixth Extinction,” is different only in that it is anthropogenic (i.e. manmade). We like to see ourselves as cognitively and evolutionarily superior to other species. We claim to possess the unique capacity for “free will” and adaptive abilities that transcend non-human biological constraints. We are sentient, and we have technology. What we lack is the wisdom to act collectively when necessary, and it is undeniably necessary now.

A common opinion asserts that “we’re all in this boat together,” meaning that catastrophic climate change will befall us all. In a larger sense, this is true. But, the effects won’t be applied equally. Poor, underprivileged people are the most vulnerable and it is they who will suffer first. Next in line are the vast middle classes of the developed and developing world. The wealthy elite will last the longest, and they are taking the steps necessary now to ensure their survival.

What human societies will end up looking like in the year 2100 is open to wide speculation; although, it is extremely doubtful that 11.2 billion of us will be around to see it.

6 thoughts on “U.N. projects 11.2 billion people by 2100 – why we will never get there

  1. Robert,
    In agreement with one of your elder blogger friends (sorry, unable to remember his name) that your best posts are those which are original as opposed to reposts. One of these days, and believe me I’m pulling for you and every blogger, you are going to break out and kick some serious ass. Simply looking about the world and the conditions people around the Earth are enduring, can we agree some serious “ass-kicking” (truth revelation) is necessary. Humanity is capable of so much better than this. Thanks for this too rare, original thought post.


    • Thank you kindly, Jerry, and you’re welcome. I’m not sure if there’s much breaking-out and ass-kicking left in this tired old body of mine, but I do appreciate the sentiment! 🙂


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