Are 7+ billion people too much for the Earth to sustain?

Occasionally when I get into the right mood, I read some science blogs, over the years, Lubos Motl's blog (a czech string theoretical physicist) has been my favorite. His science is pretty mainstream, and mostly perfect, and is undoubtedly a brilliant man. He also wrote numerous answers on the physics stack exchange website, through where I discovered him.

Guy is diametrically opposite to political correctness, is an anti feminist, "anti humanist" (according to rational wiki, whatever that means) and denies climate change , is hilarious sometimes in his diatribes/ when ranting. Insults people who disagree with him in the comments. Deletes comments. Almost got a troll-like quality to his blog, Lol.

Well, its clear he hasn't changed much throughout his adulthood, his "forced resignation" from Harvard (where he was a professor for a few years) is a testament of that.

I can't help but feel it's a huge waste of potential for someone like him to be not working, and instead rant about all sorts of things in his blog here.

While I agree with him on most things - including his denial of climate change and some of his other supposedly "toxic" views that the mainstream academia denounces, I can still understand the hate towards him. He indeed is obnoxious and almost childlike on occasions, it looks especially silly when it's something unrelated to his subject and he obviously doesn't know what he's talking about but still has to continue on the path he began on, because can't admit mistake, fragile ego problems, that sort of thing, you know. Reminds me of the classic Mark Twain quote

“It's easier to fool people than to convince them that they have been fooled.”

Let me show you an example...

I was reading this recent post of his.

He does a good job of tearing apart Hawking's unwarranted apocalyptic concerns, who most likely is shilling for the leftist environmentalists, if not, then he too suffers from some mental blocks that prevent him from using his intelligence outside of physics and math.

Take a look at the comments there, the replies to user 'theDOC's comment. Basically there's a "discussion" going on about how increasing population density growth rates can hurt that area's standards of living.

Motl gets completely triggered, his reply:

"the point that the Malthusians - and probably you - are missing is that the standard of living isn't something that is planned in the comments on the Internet, and not even by the governments - at least in civilized countries different than China. "

Haha, so the guy who raised some concerns over increasing population is now compared to Thomas Robert Malthus - this is basically the equivalent of an SJW calling any random person "Hitler".

He continues,

"People have as many children as they find right to optimize their overall utility function. The standards of living in Somalia - and their expectations or required ones - are low and not terribly important which is why people find it OK to have sex, many children, and see some of their children dying. Whether you say that it's "wrong" for these people to behave in this way is absolutely irrelevant. They do behave in this way because when all relevant factors are taken into account, they ultimately want to behave in this way in average."

The commenter initially said "I do think it's overall bad for any region to have population explosion"

To which Motl replies

" It's an illogical statement - the opposite of a tautology. The explosion is happening because it's how the system optimizes its well-being calculated in its own way. So your sentence is guaranteed to be wrong. The correct statement of this kind would be "If I were a dictator in charge of a whole country or region, I would make their population grow slowly or decrease". But the "detail" you're fucking overlooking is that you are not a dictator of any region or continent so your fucking Malthusian opinion is irrelevant and has nothing to do with the objective facts and the actual quantities that matter. It's pure ideology and the experimental facts unambiguously prove that the statements you are making are wrong."

Uses "fucking" twice, you can see he's losing his shit here. While it's clear there's no simple, linear relationship between the two things, (humans DO get increasingly more efficient as a species with population growth), the statement is in no way wrong- or right because it isn't something that can be meaningfully categorized as either within the context of propositional logic. Simple to see, just consider a threshold point for population growth in a region- beyond which if it grows, people may suffer, and if still under our hypothetical figure, it maybe good for the economy.
Motl views population growth as a "system that optimizes its well being calculated in its own way", for a man who probably considers 99.9% of the population imbeciles- compared to him, he is placing massive amounts of faith on people who have no friggin idea about any of this, they just want to fuck- and in one of the comments , as the commenter rightly pointed out - "....places where condoms are viewed as Haram and sexual urges are still present" . LOL.

He continues ,

"Moreover, your comment would be very unwise even if you were a dictator of a region. In recent 50+ years or so, the world population doubled. That was exactly because the people were amazingly prosperous, productivity grew etc. So the actual relationship is that the better a region is doing, the higher the population growth generally is in that period or the immediately subsequent one.
It's really true even in Somalia. Somalia's living standards are getting better at a higher rate than in the periods in the past when the population growth was much lower than today. The correct comparison is that the life in Somalia (still) sucks relatively to the West. But the source of the difference has nothing whatsoever to do with the recent higher population growth in Somalia - the latter is a symptom, not the cause, of a relatively good, not bad, life.
The same comments apply when some nations have a lower population growth than "recommended by some anointed men", e.g. a negative one. It's not a problem, either. It may ultimately be changed by some policies, too. Czechia has a positive growth rate only because of some inflow mainly from Ukraine and similar places. But no one considers it a top problem. If we would, it would be easy to make the growth rate much higher. But in average, people just don't have it a priority to keep the rate safely positive which is why it's not safely positive. Someone's claim that the growth rate A or B is "wrong for the nation, region, country" is pure prejudice by the speaker, and if he thinks that this prejudice is important, he is only showing that he would love to dictate the world. But there is no rational substance in any of that."

We’ve Consumed More Than the Earth Can Produce This Year (2015) . The self-regulation mechanisms with increasing population work only as long as the earth can provide. And while 7 billion is definitely not a maximum for Earth, its capacity isn't infinite either. It simply cannot support 14 billion people, if say, everyone decides that these are prosperous times and decides to have 4-5 children per family, we'll get there in about 3-4 generations, which isn't much. Livescience here tells us the upper limit is about 10 billion . Motl would probably claim these studies are "crackpottery" . You can't fix stupid, more so if it shows up in brilliant individuals, because they are blinded by their "authority" .

Then the commenter meekly retracts his points and admits he was talking rubbish because he was shown some stats that poverty has declined - for which there are numerous other factors which are not at all taken into consideration in this discourse, for example, advancements in technology (especially agriculture) which are new to most of these third world lands, hence the sudden decline. Expecting this trend to be linear is stupid.

Motl is happy, "upvotes" that particular comment. He has successfully converted his minion!

Discussion continues for a few more comments of Motl calling the guy stupid in various creative ways while the guy admits to his shortcomings and fully agrees to everything Motl has to say. Sigh

Off topic

One more disagreements (out of the very few) of mine with him is about the reliability of IQs as a measure of potential for academic success.

To quote Grigory Perelman's teacher -

"There are a lot of students of high ability who speak before thinking. Grisha was different. He thought deeply. His answers were always correct. He always checked very, very carefully. He was not fast. Speed means nothing. Math doesn't depend on speed. It is about depth. "

My philosophy is practically the same. Hence my skepticism of IQ tests, which cannot measure a student's depth of understanding and are ultimately time-based tests. One cannot simply quantify something as complicated as intellectual prowess in an hour long test.

Motl here listed average IQs for different fields.

Ok, as everyone expects, physicists, mathematicians and computer scientists are high on the list. So you might think there's the correlation!
I may be wrong here, but here's my guess - these tests give a sense of self-assurance to the egoist snowflakes who take them, pushing them to think only they are fit to be in these fields (these tests are taken before college, I assume) , similarly, those who score low probably see themselves as unfit, which can explain the IQ distributions across fields.
Keep in mind that the standard IQ tests became the "standard" only in the 1960s or 70s, so if someone makes some statements like

"Einstein had 160 IQ"

"Bohr had 150 IQ"

"Tesla had 180 IQ"

You know it is complete bullshit, because these (standardized) tests weren't around when they were young. They 'retroactively' measure historical figures' IQs based on their accomplishments - then justify the idea of IQ by arguing that these high IQ people were so accomplished, I mean, would anyone take these tests seriously if they estimated Einstein's or Newton's IQ to be 100? The estimates had to be high, to "prove" the test's authenticity.
Arguments of this nature cannot be used to show a "correlation". No one knows what they'd actually score on a real IQ test.
My views align almost exactly with Terry Tao's (this is one of my favorite articles. Recommended for anyone, if you have the time, please do read) on this matter. Academic success is almost always a result of hard work, grinding through the literature, collaborating with your peers and a reasonable amount of intelligence.