The real threat would  not be due to  increase in  population of human beings. However, their uncontrollable activities would definitely pose a major threat.

Angel:

Rapidly evolving human population would not be a problem posed by "Biomass", but emerging Science and Technology, mainly evolving due to energy consumption demands. The real threat would come from emerging Nuclear programs as non-renewable energy resources dwindle, and the political pressures opt for more nuclear reactors without serious concerns of radiation hazards and nuclear waste disposal.

Best

Syed

No, because even now the world, overall, is relatively sparsely populated. I agree with Subur that uncontrollable activities are the major threat :)

Except for the word "biomass" (if the weight of each person would become reduced by half, the danger to the world - especially, but not only, to biodiversity and healthy environment - would not be less!), the answer is evident: yes! Closer examination of the sources of virtualy all problems that plague the humanity (to say nothing of other living organisms...), from wars and terrorism through poverty and hunger to HIV, neuroses and many other diseases, immediately show that their rootes are just in the horrifying demographic explosion: we are 7.5 billion while even 1 billion would be too much - and (quite expectably) there are e.g. more permanently starving people in the world now than there were all people altogether living 100 years ago! If the general welfare of the living people is to be improved (I doubt if it is still possible, but perhaps...), first of all the population increase must be as quickly as possible stopped and then reversed: unless this is done, all other efforts remain no more than superficial "cosmetics"!

I think you are creating a extreme scenario propagated by doomsday prophets. There is some adverse impact, but it is being exaggerated.

I agree that the matter is complex. To argue with Malthus is unfortunate as he was surely not write that population increases geometrically and food production just linear. History of increase in agricultural productivity has proven him wrong. By the 1960s India e.g. was a huge importer of food, today the country exports considerable amount of food despite the fact that at home there are still many who go hungry every day. Globally enough food is produced for everybody and (coming to the word 'human biomass' in a very literal sense: malnutrition in the form of obesity is a huge problem, evn in many countries of the so-called developing world.

By this I do not want to say that everything is fine, but starting with Malthus and his assumptions won’t help too much. Esther Boserup, e.g. suggested that big populations have advantages, increase human creativity and –what I consider more important- challenges are only tackled once they started to exist. As long as everybody has enough food then there is obviously no reason to increase productivity in agriculture as nobody would be there to consume the food that is there in surplus (I accept that this thinking Is not complex enough, but I just wish to highlight that people start searching for solutions to real problems once they are identified…..).

The question is not about food security, but the examples are relevant as many have argued with Malthus and for him food security was the major challenge in the 19th century of industrializing Europe. Also the question about ‘human biomass’ suggests that population growth / density plays a role. Yes and No. I feel that an important aspect is the distribution of resources, but then still the question would remain that –even if resources are more equally distributed- the overall impact on the planets environment and resources would be the same. So it seems that a reduction of resource use is unavoidable. Can this mean that one should not allow the countries which have big numbers of very poor people reach standards of consumption people in the developed industrialized countries enjoy? No, it cannot. If the standards in the developed countries cannot set examples for all then these standards are too high and have to e reduced. I am certain that there is much scope to achieve this without reducing the quality of life. To reduce waste and unnecessary usage of resources, which in the meanwhile has become really huge, could be a start.

Loss of biodiversity still is a different challenge. Biodiversity is lost as human spread and utilize space for their activities and these spaces are no more available for other species. Not sure, how this can be stopped or mitigated. Not sure, if we lost much when the dinosaurs disappeared.

Coming back to Boserup: a huge advantage is that the challenges are highlighted and that people are working on them, especially the challenges that can be tackled through technology. Unfortunately it is little accepted outside the academic world that the distribution of resources are crucial as well; here the world has to become more just and with it some issues that have also environmental and resource implications can be tackled more easily. All this sound confusing, but it sound like this because the challenges are far to complex to reduce it to population growth and ‘human biomass’  

'a huge advantage is that the challenges are highlighted and that people are working on them' - no, Eberhard, the true challenges are "highlighted" almost only (and even so much too rarely and much too timidly) by those who cannot effectively do anything, while those who could (politicians, journalists) either avoid any mention of the real problems, or only "pay lip service" to them not doing effectively anything. The best example is just the very fundamental problem, catastrophic overpopulation of the Earth: most (especially, but not only, European) governments and media lament over - and try by any means to stop - just that trend which could potentially offer the sole flicker of hope: recent (anyway too late, too slight, too local) reversal of demographic explosion!

Humans are sensible beings, the existence of which until now is due to the animal instincts that are genetically enshrined in them. This is the great curse of mankind. It is impossible to ignore the rules that are encoded in our genes. Some of them, such as the instinct for self-preservation, the instinct to search for food, the instinct for breeding, and others will always prevail. It is precisely because we are intelligent beings that these laws аre distorted and degenerate to a great extent and result in a state of overproduction and over-consumption and, at the same time, a large part of the population on earth to starve?

These instincts, as well as the instinct to fight for leadership in nature, are usually suppressed only by force. We are witnesses to what causes the bioinvasion of a particular species and what destructive consequences it has. For example, the overpopulation of locusts or, for example, the innocent rabbits in Australia that turn the regions that live in a desert, or even what happens in overpopulation of such harmless animals as ladybirds, for example. What about overpopulation and the subsequent bio-invasion of the uncontrolled migrations of people on earth (what is happening in Europe and governed by force / politics from countries such as America and Japan, for example)?

I would like we to comment on some of these aspects, for example, but without using apocalyptic forecasts, but to make reflections on the subject, what is the real assessment and the perspective?

Let's leave the conspiracy theories for another topic.

Dear Aleš Kralj,

Thank you for your opinion.

However, the instinct for self-preservation has not helped any of the еxtinct species. Believe me, they are very much.

I do not worry because I deeply believe in the power of the laws of nature in every aspect.

If we are inappropriate modifications and we do not adapt, we will just disappear like many other species, and that hardly matters for others except for ourselves.

I just want to know the opinion of other people who are interested in this problem.

Kenneth, hitherto we seemed to agree, but now either I drastically misunderstand you or your formulation is glaringly misleading! 150 species extinct within 100 years? - maybe there are only 150 such of which we know 1) that they existed (i.e. they had alredy been discovered and formally named), and 2) that not a single individual does exist any more. We know of the existence of but a small fraction - according to realistic estimations between 10 and 30% - of really (still...) existing species (as you yourself mention, "New species are being found every year", but they are not "newly evolved" but only hitherto unknown!), and we can concretely know the extinction (i.e. be sure that of this particular, previously known to us, species not a single individual is living) of only very little fraction, usually large and showy mammals or birds, of endangered organisms: overwhelming majority of insects, snails, worms, fungi &c. has gone, is going, and will go extinct beyond our notice (mostly before we will discover and name them!). Realistic estimations show that several (perhaps several tens) of species disappear forever every day, and anyway it is evident that desctruction of habitats, transformation of steppe or savanna into crop land or of tropical (or any other) forest into coffee or rubber plantation must have resulted in extinction of organisms inhabiting the original biotope ("man follows forest and is followed by desert"...) - even if our knowledge is not sufficient to list a single name of concretely involved species! Any taxonomist can list a long series of species which were common 50 years ago, rare 20 years ago, and in the last deade have not been found at all - naturally it cannot be said for sure that all of them are already extinct, but it is a "statistical certainty" that many of them are or will in nearest future be! "Biodiversity crisis" is mostly disregarded (except for occasional "lip service"...) as well by general public as by "decision makers", but is very real and perhaps the most immediate consequence of human overopopulation!

Dear Kenneth M Towe,

I can agree with you that "For every area of the world that paleontologists have studied and for which people have reached for the first time in the last fifty thousand years, human arrival roughly coincided with the mass prehistoric extinction".

But in this case, I am not focusing on the fact that there are millions of still undetected species, especially those from the microbiological group. The emphasis is on mammals, birds and fish that are subject to indiscriminate and barbaric destruction, such as monkeys, especially gorillas, tigers, rhinoceroses, dolphins, whales and many others that we kill not only to eat.

How about the fact that in some countries that we think are civilized - in Asia, America and Europe, singing birds are part of gastronomic specialties? How many larks or hummingbirds will a man eat?

We can also comment on another absurd fact, for example - to protect the population of several dozens of Bulgaria bears are given more money for a bear than for several pensioners! Or that we think of an achievement that we release a single pair of Bulgarian rock eagles?

Or is the fact that the contraband with eggs of wild birds for gastronomic delicacies are in apogee? Is this reflected correctly in the reports of the International Institute for Species Exploration?

I apologize, but I think some people are just exercising in statistical equilibrium in order to justify their salaries.

Sorry, Kenneth, I understand you less and less! Once you write that "For every area of the world that paleontologists have studied and that humans first reached within the last fifty thousand years, human arrival approximately coincided with massive prehistoric extinctions", and then "a few species have been "terminated" but by a few individuals, not by the rest of us" - how does the former fit the latter??? Do you think that only prehistoric men and Polynesians exterminated the fauna - modern "civilized" people do not? Most species (even of large mammals, birds or reptiles) go extinct primarily not because "few individuals" kill the last survivors, but because "exploding" human population destroyed their habitats toe such a degreee that only few last survivors remained (to be  killed by "few individuals" few years before they would anyway die out "by themselves"). Yes, some species - like the passenger pigeon or dodo mentioned by you) has indeed been actively "overkilled", but these are rather exceptions than rule even among birds and mammals, to say nothing of unshowy invertebraes...

As to your disdainful question "passenger pigeon and the Dodo are long gone. What has been the deleterious effect?" it is very sad that a cultural civilized person can think this way! What could be more deleterious than extinction of entire species of a living organism? would you think the same if the species in question is Homo sapiens??? By the way, it is practically sure that extinction of one species must have "deleterious effects" on others because of multitude of interspecific coadaptations (predator-prey, commensalism, parasitism, &c. are only those most evident, but innumerable others are still poorly understood - the effects of extinction of dodo on the approaching extinction of tambalacoque tree (Sideroxylon grandiflorum - "the seeds of the tree had to pass through the digestive tract of the bird to overcome persistent seed dormancy. In 1681 the huge, flightless bird was extinct, and by 1973 only thirteen very old trees were left because the species had not reproduced for 300 years") or of disappearance of passenger pigeon on a great variety of animals and plants are good examples - but e.g. Catling [Catling P.M. 2001. Extinction and the importance of history and dependence in conservation. Biodiv. 2, 3: 2-13] provides many more.

Yes, human population increase eventually can upset the balance of the ecosystem, unless regulated, 

Very important question, really we are now facing the so called "Overpopulation" on the Earth !!

Regards, Emad

Kenneth, I think you start (or do already long since?) some sophistical game in this discussion. According to your logic, I should believe that nobody died in Hiroshima in 1945 or in Syria 2016-2017 because I do not know specifically of the death of any single person known to me by name! But if I know that an atom bomb has destroyed all the town, I do not need to know any person there to know that many have died - and similarly, having known that enormous forest areas are being cut every year, I do not need to know by name the species having previously living there to know that they have been extermineted there, and many of those narrowly distributed among them got extinct at all! To restrict our consideration to only "the actual data on known extinctions" is perhaps an effective "ostrich policy" for politicians &c., but has nothing to do with realistic evaluation. What is the chance of get "actual data" on the extinction of a species if we do not know even of its very existence? zero! - and we still do not know of the existence of the majority of species! And what is the chance in case of species difficult to observe and generally poorly known? almost zero! - and this is the situation with overwhwelming majority (rather more than 90%, perhaps more than 99%) of "known" (already named) species. To know the massive destroyal of their habitats and nevertheless say that none of them has suffered or is just suffering extinction because we cannot list the exterminated species by name is nothing but cynical attempt to disregard the unpleasant truth...

Human society really needs to study this dilemma. How will the growing needs of human beings be met without a clash of existing civilizations that will generate much human misery and conflict?

Many sources refer to catastrophic information such as the following:

* The human population stands at 6.5 billion and is projected to rise to more than 9 billion by 2050.

* China is the most populous country with more than 1.3 billion people. India is second with more than 1.1 billion.

* By about 2030 India is expected to exceed China with nearly 1.5 billion people.

* About one in every three people alive today is under the age of 20, which means that the population will continue to grow as more children reach sexual maturity.

* Britain's population of 60 million is forecast to grow by 7 million over the next 25 years and by at least 10 million over the next 60 years, mainly through immigration.

* By the time you have finished reading this column, an estimated 100 babies have been born in the world.

We shouldn’t rule out the Boserupian Theory to population and environmental change which states that humanity would always find a way and was quoted in saying "The power of ingenuity would always outmatch that of demand".

However, we are clearly on the losing side to preserve area for wild animals and its pretty shocking that wild mammal’s population falling down exponentially.

The number of wild animals living on Earth is set to fall by two-thirds by 2020, according to a new report, part of a mass extinction that is destroying the natural world upon which humanity depends (Theguardian, Thursday 27 October 2016).

https://www.theguardian.com/environment/2016/oct/27/world-on-track-to-lose-two-thirds-of-wild-animals-by-2020-major-report-warns

"Nobody died in Japan or in Syria because of "climate change" - and nobody claims anything like this! I only argued, that we cannot deny the fact of mass deaths (nor mass extinction) only because we do not know the exact identities of those who died (or gone extinct)! By the way, I wonder if you would be able to name all those 2000 species of birds allegedly exterminated by Polynesians, and nevertheless you accept and quoe this estimation - in this case no need for "actual data on known extinctions"???

Alemayehu: "The power of ingenuity would always outmatch that of demand" - Do you really think that the "power of ingenuity" will infinitely expand the Earth surface to make place for infinitely growing human population???

"the last paragraph is what it is all about, extinctions, real or imagined... or not" - sorry, Kenneth, I do not understand what do you mean, what do you wish to say? Which "last paragraph"? What does it mean "extinctions, real or imagined... or not"???

This will really be a great future problem. Let's see how nature responds to this over burdon. In fact total population of India+China itself is more than 1/3 of world population but with limited resources.

Its a very huge question, but given that the earth is a limited space and people are increasingly occupying that space so we certainly are headed for this problem. There have been some good arguments on this thread however. In my opinion, increasing human population sizes are definitely going to push us to rethink what we currently accept as standard and normal. For instance, water based sewage!, while many countries in the world experience a lack of sufficient water or potable water, the problem is often not that there isn't sufficient water, but that so much of it is polluted. This is commonly a huge problem with very poor communities where their suffering and life quality is exponentially affected by poor sanitation, overflowing sewage etc. That in turn leads to an increasing degradation of their surrounding environment.

Surely , it will be an over-riding threat because of the competing pressure on available resources..

Yea, because the way and manner human beings are advancing in technology is alarming with pollution from different ecosystems.

Kenneth, are you referring to some extreme events limiting the exponential growth of human population or the global growth rate of human population vis-a-via time scale..??