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Most recently settled area habitable without modern technology

Most recently settled area habitable without modern technology

Among islands or archipelagos with a size, climate, and ecology suitable to sustain a healthy population of stone age technology humans, which one was settled most recently?

Among "large" landmasses this is apparently New Zealand (no evidence before 1200 CE), but many islands and archipelagos were settled later. For example, those were empty when first encountered by Europeans:


Source: Radical Cartography

Many of those could have sustained a stone age technology population of humans if they had reached it and stayed. They need to have an accommodating climate, ecology, and be large enough to sustain a genetically healthy population. Thus it excludes islands like Rockall or Laysan, but would include the Galápagos islands (7,880 km²). For this question, let's discard boundary cases such as Pitcairn (47 km²) which are probably too small, and count the earliest certain date for islands/archipelago's settled multiple times.

Were any such islands first settled in the 19th or even 20th century?


I'm going to start by pointing out that people with stone age technology have been successfully inhabiting a very inhospitable climate (the Arctic) for thousands of years before the Age of Exploration.

Archaeologists are certain that the predecessors of today's Inuit originated in the area of the Bering Strait, which separates Asia and North America. The first Inuit group, known as Paleo-Eskimos, crossed the Strait in 3000 BCE presumably on winter ice, which was long after earlier migrations by the ancestors to the North American Indians. Archaeological finds have revealed that the Paleo-Eskimos moved to the northern Canadian Arctic in 2300 BCE, apparently because of a change in climate. From there they gradually followed the herds of game across the Arctic to Greenland, and dispersed into more distinct nomadic tribes.

Given that, I'd say an "accommodating climate" is not a prerequisite for habitation, as the Inuit managed to inhabit what is arguably the 2nd least habitable climate on the planet (to say nothing of other Native American tribes and Arab nomads that inhabited "uninhabitable" deserts, or the Tibetans and Incas that established settlements at inhospitable elevations within the Himalayas or Andes). Wikipedia has a nice series of maps of pre-contact Inuit territory and settlement activities in the Canadian Arctic which leaves a number of rather large islands as unsettled.

Probably the most hospitable of these is Banks Island, which is home to enough wildlife to presumably support a small population of Arctic hunters, like the traditional Inuit. Its first permanent settlement was in 1929, when Sachs Harbour was founded. Since the Inuit managed to settle most of the rest of the Canadian Arctic Archipelago, they probably could have survived on Banks Island and the other nearby islands that have sizable wildlife populations.

Moving beyond the Canadian Arctic Archipelago, the Prince Edward Islands seem to be a survivable candidate as well. European seal hunters visited the islands because of their large seal populations, and a shipwrecked crew established a short-lived village in 1908 while awaiting rescue. A permanent research station was established in 1948.

Similarly, the Crozet Islands are another group of tundra islands that could probably sustain a small population of hunters in the Inuit style, being home to large populations of seabirds, penguins and seals. They're also notably temperate, as far as tundra islands are concerned. A permanent research station as set up on the islands in 1963.

The Kerguelen Islands are another interesting possibility. Along with the usual tundra wildlife (seals, penguins and other sea birds), the islands are home to an indigenous, edible cabbage species that is reportedly a good source of vitamin C, so there's the potential for some level of agriculture. The French made the first attempt at a settlement on the islands in 1877, with an attempt to set up a coal mining operation that quickly failed, and the next attempt at a permanent station on the islands was establishment of a research station in 1950.

Last, and probably least for the tundra islands, would be Macquarie Island. It has the usual wildlife for a tundra island, and served as a base for an Antarctic expedition between 1911 and 1914. A permanent research station was setup in 1948.

If you're dead-set on avoiding tundra islands, you don't have a lot of options, with the more habitable temperate or tropical islands being settled rather early.

The Bonin Islands are a collection of about 30 sub-tropical islands, 1000 kilometers south of Japan that were first settled in 1830. Their current population is around 2,500, so they're capable of supporting a reasonable population, many are forested, and have flora and fauna that would make them relatively easy to colonize with minimal technology, had technologically primitive people been able to get there, somehow.

The Tristan da Cunha islands are another possibility, being first settled in 1810, and having plenty of wildlife for hunting.

Another possibility is Île Amsterdam, but at 55 square km, it's probably too small. It does (or did) have the advantage of being forested, making it more habitable than most islands of its size or isolation, as well as having a healthy seal population, so it probably could have supported a low-technology population in the low hundreds. It was first settled (briefly) in 1871.

Ascension Island would be an outside possibility, being reported as largely barren at the time of discovery. It was used mostly as a stopping off point for ships to collect fresh meat from bird and turtles on the island, and has notable ground water springs to supply fresh water. It was first inhabited as a British garrison in 1815. Flora and fauna was eventually brought in, but presumably any stone age people who ended up there wouldn't be equipped to bring vegetation to the island.

Beyond that, there's not really anything that wasn't settled by 1800.


Remains Of Legendary St. Mary’s Fort Finally Found in Maryland

Archaeologists associated with the preservation organization Historic St. Mary’s City have just announced a major discovery, which they recently unearthed at one of the most heavily explored sites in North America. At the location where Maryland’s first colonial capital (St. Mary’s City) was founded in 1634, the archaeologists have excavated what was for them the equivalent of the Holy Grail: the remains of the original St. Mary’s Fort , the secure structure erected by the first group of European settlers to reach the western side of Chesapeake Bay. Excavations have been ongoing at the St. Mary’s City site, which is now a registered historic area, for several decades. In the past 30 years approximately 200 excavations have taken place in the surrounding region, but no trace of the legendary lost St. Mary’s Fort had ever been found.


Pupil size surprisingly linked to differences in intelligence

So much for rest in peace.

  • Australian scientists found that bodies kept moving for 17 months after being pronounced dead.
  • Researchers used photography capture technology in 30-minute intervals every day to capture the movement.
  • This study could help better identify time of death.

We're learning more new things about death everyday. Much has been said and theorized about the great divide between life and the Great Beyond. While everyone and every culture has their own philosophies and unique ideas on the subject, we're beginning to learn a lot of new scientific facts about the deceased corporeal form.

An Australian scientist has found that human bodies move for more than a year after being pronounced dead. These findings could have implications for fields as diverse as pathology to criminology.

Dead bodies keep moving

Researcher Alyson Wilson studied and photographed the movements of corpses over a 17 month timeframe. She recently told Agence France Presse about the shocking details of her discovery.

Reportedly, she and her team focused a camera for 17 months at the Australian Facility for Taphonomic Experimental Research (AFTER), taking images of a corpse every 30 minutes during the day. For the entire 17 month duration, the corpse continually moved.

"What we found was that the arms were significantly moving, so that arms that started off down beside the body ended up out to the side of the body," Wilson said.

The researchers mostly expected some kind of movement during the very early stages of decomposition, but Wilson further explained that their continual movement completely surprised the team:

"We think the movements relate to the process of decomposition, as the body mummifies and the ligaments dry out."

During one of the studies, arms that had been next to the body eventually ended up akimbo on their side.

The team's subject was one of the bodies stored at the "body farm," which sits on the outskirts of Sydney. (Wilson took a flight every month to check in on the cadaver.)

Her findings were recently published in the journal, Forensic Science International: Synergy.

Implications of the study

The researchers believe that understanding these after death movements and decomposition rate could help better estimate the time of death. Police for example could benefit from this as they'd be able to give a timeframe to missing persons and link that up with an unidentified corpse. According to the team:

"Understanding decomposition rates for a human donor in the Australian environment is important for police, forensic anthropologists, and pathologists for the estimation of PMI to assist with the identification of unknown victims, as well as the investigation of criminal activity."

While scientists haven't found any evidence of necromancy. . . the discovery remains a curious new understanding about what happens with the body after we die.


How Is Modern Technology Affecting Human Development?

In the last few decades, technology has progressed at a staggering rate. Smartphones, the internet, cloud computing, and hundreds of other inventions are changing every facet of our lives. Communication, business, government, travel, fundraising, and even agriculture have been affected. But how about our brains? Is all this new technology changing us on the inside? Many think so, including psychology professionals.

As Psychology Today says, &ldquoThere is &hellip little doubt that all of the new technologies, led by the Internet and digital technology, are shaping the way we think in ways obvious and subtle, deliberate and unintentional, and advantageous and detrimental.&rdquo* While research into this field is still in its infancy and there are no scientifically agreed-upon conclusions, there are several areas where modern digital technology is certainly affecting the way we interact with the world and the way our children&rsquos brains develop. These areas include:

Attention

Evidence suggests that reliance on the internet and mobile technology is shortening our attention spans. One recent study found that our average attention span has decreased by 4 seconds, down from 12 to 8, which is shorter than that of a goldfish.&dagger One possible reason for this decrease is the significant increase in options for distraction. When we all have computers in our pockets that allow us to play games, listen to music, and connect with friends whenever we want, why should we tolerate boredom? Of course, this shortened attention span likely comes with consequences. How many times do we miss important conversations or moments happening around us because we&rsquore mesmerized by our electronic devices?

Decision-Making

You need to buy a new car. What&rsquos the first thing you do? If you&rsquore like millions of others, you go online to do research. In fact, no matter what kind of a decision you need to make&mdashwhether you&rsquore trying to figure out where to have dinner or the best way to start a new career&mdashyou can turn to the internet for advice. This means that we, as a species, no longer have to rely so much on gut instinct but can instead gather facts and knowledge in an effort to make informed decisions.

Relationship Building

By 2020, 2.9 billion people are expected to be on social media.&Dagger Couple that with person-to-person messages sent with both traditional SMS texting and messaging apps and we&rsquore radically changing the way we can build and maintain relationships. But is this a good or bad thing? If we&rsquore at dinner with friends and are simultaneously texting a family member in California and Tweeting with acquaintances about an event in Japan, are we fully engaged in any of those relationships? Then again, doesn&rsquot being able to stay connected with friends and family around the world keep relationships alive that might otherwise wither? Nearly 70% of Americans think the internet is good for our relationships,§ but it remains to be seen if children who are growing up with smartphones develop the kinds of interpersonal and relationship-building skills they need to form deep and meaningful relationships, or if our species will become isolated from&mdashand uncomfortable with&mdashclose, personal contact.

Memory

The internet gives us access to a huge amount of information plus, our personal computers can store every shopping list and stray thought we have, letting us access the information when we need it later. A new study finds that this &ldquopervasive access to information has not only changed what we remember it has changed how we remember.&rdquo** Our reliance on the internet has decreased our ability to easily retain facts. However, we appear to be improving our ability to remember where and how to locate information. For instance, we are now more likely to remember what folder we stored information in than we are to remember the information itself. Likewise, when faced with a question of fact, we are more likely to remember search terms that have helped us uncover answers to similar questions than we are to remember the fact itself.**

How Can You Learn More About Technology&rsquos Impact on Psychological Development?

If you&rsquore fascinated by how technology may be changing our brains, you should consider earning an online degree in psychology, specifically an MS in Developmental Psychology. Numerous online universities offer psychology degrees, making it convenient for you to earn your degree while continuing to work in your current job.

An online graduate degree in psychology can be particularly useful if you want to take your career in psychology to the next level. MS in Developmental Psychology career options are quite numerous, as you can use the degree in public, private, and nonprofit settings. You can also use your master&rsquos in psychology as a springboard toward earning a doctoral degree in developmental psychology.

When you earn an online MS in Developmental Psychology, you can expand your knowledge and your career options. It&rsquos a great way to help yourself get ahead.

Walden University is an accredited institution offering online degree programs in a convenient, flexible format that fits your busy life.v

&daggerK. McSpadden, You Now Have a Shorter Attention Span Than a Goldfish, Time Health, on the internet at http://time.com/3858309/attention-spans-goldfish.

&DaggerStatista, Statistics and Facts About Social Media Usage, on the internet at www.statista.com/topics/1164/social-networks.

**J. Milfred, Is Google Ruining Your Memory? The Science of Memory in the Digital Age, Yale Scientific, on the internet at www.yalescientific.org/2013/05/is-google-ruining-your-memory-the-science-of-memory-in-the-digital-age.

Walden University is accredited by The Higher Learning Commission, www.hlcommission.org.

Whether looking for information on programs, admissions, or financial aid, we're here to help.

Fill out the form and we will contact you to provide information about furthering your education.


A Desert Oasis Hints at a Long History of Resilience and Exploration

Saudi Arabia

The oasis of Jubbah stands out like a smudged green footprint in the sea of dunes that is Saudi Arabia’s Nefud Desert. It’s fitting that the image was taken by a modern explorer, an astronaut aboard the International Space Station: The site is a testament to changing climate patterns, and to human resilience and exploration.

Thousands of years ago, when the region was considerably less arid, the basin was a lake, offering fresh water to wildlife, livestock, and humans alike. Even in times of drought, the lake remained, sustaining pastoral communities. Rock art and evidence of hearths dotting its ancient shoreline suggest long-term human occupation beginning about 10,000 years ago. Our presence in the area may be considerably older, however.

The Nefud Desert is a region that archaeologists and paleoanthropologists refer to as Green Arabia: For key periods during the story of human evolution and dispersal, climate patterns shifted and this now sun-baked desertscape transformed into an area of grasslands, rivers, and lakes. Researchers have found numerous sites with stone tools around Jubbah, suggesting Homo sapiens may have first left Africa via this green corridor. In 2018, a partial human finger bone, found nearby and dated to at least 85,000 years old, confirms that at least one population of early humans passed through.

Rock art found at Jebel um Sanman, on the west side of Jubbah, includes the earliest depiction of dogs on the Arabian Peninsula. Richard Mortel/Flickr

The paleolake at Jubbah, and the oasis there today, exist courtesy of a quirk of local geography. Due west of the site, the massive sandstone formation known as Jebel um Sanman, or Jabel umm Sinman, rises sharply up to 1,300 feet from the desert floor. The mountain had been the protector of first the lake and now guards the oasis settlement. Powerful westerly winds rushing across the flat desert hit the dark rock and break around it like water cleaved by a ship’s bow, leaving the basin unscathed. Jebel um Sanman itself is home to some of the most important early rock art on the Arabian Peninsula, and is recognized by UNESCO. Some of the petroglyphs are of humans hunting with dogs, and represent the earliest known depictions of our canine companions in the region.


Neanderthal Woman's Genome Reveals Unknown Human Lineage

The existence of a mysterious ancient human lineage and the genetic changes that separate modern humans from their closest extinct relatives are among the many secrets now revealed in the first high-quality genome sequence from a Neanderthal woman, researchers say.

The Neanderthal woman whose toe bone was sequenced also reveals inbreeding may have been common among her recent ancestors, as her parents were closely related, possibly half-siblings or another near relation.

Although modern humans are the world's only surviving human lineage, others also once lived on Earth. These included Neanderthals, the closest extinct relatives of modern humans, and the relatively newfound Denisovans, whose genetic footprint apparently extended from Siberia to the Pacific islands of Oceania. Both Neanderthals and Denisovans descended from a group that diverged from the ancestors of all modern humans. [See Photos of Neanderthal Bone & Denisovan Fossils]

The first signs of Denisovans came from a finger bone and a molar tooth discovered in Denisova Cave in southern Siberia in 2008. To learn more about Denisovans, scientists examined a woman's toe bone, which was unearthed in the cave in 2010 and showed physical features resembling those of both Neanderthals and modern humans. The fossil is thought to be about 50,000 years old, and slightly older than previously analyzed Denisovan fossils.

Human interbreeding

The scientists focused mostly on the fossil's nuclear DNA, the genetic material from the chromosomes in the nucleus of the cell that a person receives from both their mother and father. They also examined the genome of this fossil's mitochondria &mdash the powerhouses of the cell, which possess their own DNA and get passed down solely from the mother.

The investigators completely sequenced the fossil's nuclear DNA, with each position (or nucleotide) sequenced an average of 50 times. This makes the sequence's quality at least as high as that of genomes sequenced from present-day people.

The genetic analysis revealed the toe bone belonged to a Neanderthal. When compared with other Neanderthal mitochondrial DNA samples, this newfound fossil's closest known relatives are Neanderthals found in Mezmaiskaya Cave in the Caucasus Mountains about 2,100 miles (3,380 kilometers) away.

These findings helped the scientists refine the human family tree, further confirming that different human lineages interbred. They estimated about 1.5 to 2.1 percent of DNA of people outside Africa are Neanderthal in origin, while about 0.2 percent of DNA of mainland Asians and Native Americans is Denisovan in origin.

"Admixture seems to be common among human groups," said study lead author Kay Prüfer, a computational geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

Intriguingly, the scientists discovered that apparently Denisovans interbred with an unknown human lineage, getting as much as 2.7 to 5.8 percent of their genomes from it. This mystery relative apparently split from the ancestors of all modern humans, Neanderthals and Denisovans between 900,000 years and 4 million years ago, before these latter groups started diverging from each other.

This enigmatic lineage could even potentially be Homo erectus, the earliest undisputed predecessor of modern humans. There are no signs this unknown group interbred with modern humans or Neanderthals, Prüferadded. [The 10 Biggest Mysteries of the First Humans]

"Some unknown archaic DNA might have caught a ride through time by living on in Denisovans until we dug the individual up and sequenced it," Prüfertold LiveScience. "It opens up the prospect to study the sequence of an archaic (human lineage) that might be out of reach for DNA sequencing."

Interbreeding took place between Neanderthals and Denisovans as well. These new findings suggest at least 0.5 percent of the Denisovan genome came from Neanderthals. However, nothing of the Denisovan genome has been detected in Neanderthals so far.

In addition, "the age of the Neanderthals and Denisovans we sequenced also doesn't allow us to say whether any gene flow from modern humans to Neanderthals or Denisovans happened," Prüfer said. The Neanderthals and Denisovans that researchers have sequenced the DNA of to date "probably lived at a time when no modern humans were around," he explained.

Modern humans' distinguishing features

It remains uncertain when modern humans, Neanderthals and Denisovans diverged from one another. The researchers currently estimate modern humans split from the common ancestors of all Neanderthals and Denisovans between 550,000 and 765,000 years ago, and Neanderthals and Denisovans diverged from each other between 381,000 and 473,000 years ago.

Genetic analysis revealed the parents of the woman whose toe bone they analyzed were closely related &mdash possibly half-siblings, or an uncle and niece, or an aunt and nephew, or a grandfather and granddaughter, or a grandmother and grandson. Inbreeding among close relatives was apparently common among the woman's recent ancestors. It remains uncertain as to whether inbreeding was some kind of cultural practice among these Neanderthals or whether it was unavoidable due to how few Neanderthals apparently lived in this area, Prüfer said.

By comparing modern human, Neanderthal and Denisovan genomes, the researchers identified more than 31,000 genetic changes that distinguish modern humans from Neanderthals and Denisovans. These changes may be linked with the survival and success of modern humans &mdash a number have to do with brain development.

"If one speculates that we modern humans carry some genetic changes that enabled us to develop technology to the degree we did and settle in nearly all habitable areas on the planet, then these must be among those changes," Prüfer said. "It is hard to say what exactly these changes do, if anything, and it will take the next few years to find out whether hidden among all these changes are some that helped us modern humans to develop sophisticated technology and settle all over the planet."

Prüfer and his colleagues detailed their findings in the Dec. 19 issue of the journal Nature.


Abstract

The movement and dispersal of human populations during the Pleistocene is a complex question, and one that has been addressed extensively in the literature. During Pleistocene glacial periods, landscapes and coastlines altered dramatically, with old routes closing and new routes opening. One of the best understood of these glacial periods, the Last Glacial Maximum (between 22 and 18 ka), is of particular interest with regards to the colonization of the New World. Despite decades of study, archaeologists still do not fully understand the timing and tempo of that process. This study contributes to this discussion by presenting an estimation of habitable land area in the New World at the LGM when sea level was 120 m lower than present day using a previously published method for mapping ancient coastlines and calculating land areas in Google Earth. Areas defined as uninhabitable include those areas covered by ice sheets, glaciers, and ice fields, and areas of extreme aridity. Combined habitable land areas of North and South America are estimated as 34,149,094.81 km 2 . Added to data from the previous study, a new estimate of global habitable land area at the LGM is calculated to be 111,108,807.21 km 2 . Data on paleocoastlines are then used to predict locations where archaeological traces of early human dispersals may potentially be found.


Modern Human Introgression

Having made the connection between Denisovans and Neanderthal physiology it is also likely that Denisovans had at least some traits in common with anatomically modern humans ( Homo sapiens ). When a previously misplaced fragment of the finger bone found in the Denisova Cave in 2008 was reunited with the second, more famous, fragment used by the Max Planck Institute to sequence the Denisovan genome, it was realized that the finger did not resemble that of a Neanderthal as had been widely expected. Although the finger bones of archaic humans such as Neanderthals and Homo erectus are extremely thick and quite stubby, the Denisovan finger bone is a lot slimmer, like that of an anatomically modern human.

This connection between anatomically modern humans and Denisovans is perhaps far deeper than anyone has so far suspected for, as the current writer has speculated elsewhere, there is a strong likelihood that the ancestors of the Siberian Denisovans, after leaving Africa, encountered pre-dispersal modern humans already occupying the Levant. Evidence for the existence of these early modern humans has come from the discovery at the Qesem Cave in Israel of eight teeth belonging to members of the Acheulo-Yabrudian Cultural Complex (AYCC), which thrived in the Levant corridor circa 420,000-250,000 years ago. These were found to be almost identical to those of anatomically modern humans.

Having interbred with these early modern humans, the Siberian Denisovans would then have continued their migration eastwards, entering Central Asia, Siberia, and finally, Mongolia and China. If correct, they would have been carrying physiological traits picked up from early modern humans living in the Levant. This is something that the Sunda Denisovans would seem to have missed out on since they most likely took a different route out of Africa, crossing the Arabian peninsula before entering southern Asia, southeastern Asia, and, finally, Island Southeast Asia.

The possibility that the Siberian Denisovans were carrying at least some early modern human genes might also help explain why the Siberian Denisovan genome is slightly different to that of the Sunda Denisovans, and why they would appear to have displayed advanced human behavior before their final disappearance around 45,000 years ago.

And so this brings us to an impression of the Siberian Densovan that appears as follows…

The face of a Siberian Denisovan by artist George Hernandez working in concert with writer-researcher Debbie Cartwright and the present author. Genetic information, Denisovan and Neanderthal fossils, and unique traits in anatomically modern humans were used to reconstruct this likeness. (Picture credit: © Hernandez/Cartwright/Collins)


Interview Highlights

On how he became interested in exploring the impacts of climate change

"I'm a journalist who's interested in the near future, and I'm also a lifelong New Yorker, which meant that I spent most of my life &mdash I was concerned about climate change. I knew it was an important issue. But I was deluded in the sense that I felt I lived in an urban fortress outside of nature in the modern world, and that while there were people elsewhere on the planet who were going to be really in harm's way from some of these impacts, that I wasn't going to be one of them and probably most of the people I loved weren't going to be among them. And as a result, I thought, 'This is an important issue, but it's not an all-encompassing, all-governing issue.' The deeper I got into the research just as a journalist, the more I realized, it's everywhere. And every aspect of life &mdash even those that we take so eternally for granted as permanent features of the world &mdash are subject to the forces of nature. So when I walk down the street, on a concrete street, look up at steel buildings, I'm still living in nature. Especially if you're on the coast, you're vulnerable from sea level. But really that's just the start.

"Absolutely everything needs to be transformed and will be transformed either by the force of climate change, or by the force that we put into avoiding climate change."

David Wallace-Wells

"We could have twice as much war as we have today because there's a relationship between temperature and conflict. Our agricultural yields could be only half as bountiful, and we'd be using that half as much food to feed 50% more people. There are public health issues, there's a relationship between temperature and mental illness. There's an effect on cognitive performance. Really everywhere you look &mdash wildfires, extreme weather, hurricanes, droughts, heatwaves &mdash every aspect of life as we know it on this planet is changing already. The planet is already hotter than it's ever been in all of human history, and it will surely change more, which means that everything we know about human life and human civilization grew up under conditions that no longer preside, and we're living in a different enough environment &mdash it may even be better to think already that we're living on a different planet &mdash and given where we're headed, things are going to change even faster, even more dramatically in the decades ahead."

On how rapidly climate change impacts have intensified just in the last 30 years, despite climate change awareness also intensifying

"It's really amazing to think, I'm 36 years old, which means my life contains this whole story. I have memories that are more than 30 years old. I remember driving and flying more than 30 years ago, and since I formed those memories, we've done more damage to the climate than in all of the centuries, all of the millennia before in human history. That's a really dispiriting fact to know in terms of how powerful knowledge is, because this is the same period of time since the U.N. established its [Intergovernmental Panel on Climate Change] body, and really advertised to all of the leaders of the world that this was a pressing, dramatic problem. But those 30 years have brought us from a stable climate to the brink of catastrophe, which is where we are now. We have about that much time again to avert some of these worst scenarios &mdash 30 years ahead of us &mdash and that means really, again, it's not just the story of the first half of that story that's going to take place in my lifetime. It's the second half, too.

"This is a drama of a scale that really we only used to understand or recognize in mythology or theology. The main driver of the future climate of the planet is what we do, and all of us are protagonists in that story and we'll determine what kind of future not just our children live in, but our grandchildren and our great-grandchildren. That is how consequential the decades ahead of us will be."

On climate change's effects on the human body

"Temperature affects cognitive performance. It affects emotional well-being and mood. It affects the rates of autism and ADHD in developing children. The number of days that a baby spends in the womb over 90 degrees can be seen on its lifetime earnings. That's how dramatic the effect of temperature on child development is.

"The most, to me, horrifying story in the book isn't about humans at all. It's about the saiga antelope, which is this dwarf antelope that lived in Siberia, and a few years ago &mdash I think it was in 2015 &mdash the entire species got wiped out because a bacteria that had lived inside their guts for millions of years was rewired by a summer that was especially hot and humid, and what had been a quite happy cohabitant of that saiga digestive tract became an enemy of the animal and killed the entire species.

"Humans are complicated. Biology is as well. We have millions and perhaps billions of bacteria living inside us and viruses living inside us. And while it's probably the case that the overwhelming majority of those won't be affected by temperature rises of just 2 or 3 or 4 degrees, the chance that one of them or several of them is transformed in that way is quite serious. And that doesn't mean that humans are going to be made extinct. But there's a relationship between schizophrenia and viruses that you've been exposed to. There's a relationship between mood disorders. There's a relationship with obesity. So many aspects of the way that we think of our relationship to the world are determined in part by these other creatures that are living inside us and every single one of them is subject to the transformations that will be brought about by climate change."

"If we get to some of these truly terrifying outcomes, it will be because of the choices we make from here on out."

David Wallace-Wells

On what needs to happen to avert a worst-case scenario

"Most scientists would say we need to zero out on carbon globally by about 2050 in order to have a chance of stabilizing the planet below this threshold of a catastrophe. I think it's unlikely that we'd do that. But that's not a reason for slowing down now.

"I think it's really important to understand that this is not a binary system, it's not a matter of whether we pass that threshold or not. It's not a matter of whether we reach a hellish climate scenario or not. Every tick upward of temperature produces more suffering, more pain, and every tick that we can avoid will make the world a better place in the future. So while I think it's unrealistic that we entirely zero out on carbon by 2050, I think we should marshal as many resources as we possibly can to achieve that goal. . The story of climate change is so big that we can't solve it through small actions. We need a big policy response."

On humanity having to adjust to the new living conditions climate change could create, regardless of what kind of action is taken

"I think that we will be on a different planet no matter what path we choose. Which is to say, even if we take quite dramatic action and really transform our trajectory on climate change &mdash which is possible, everything is within our control, everything is up to us. It's not outside of our power. But even if we do that, we will be left with a world that is dramatically shaped by climate change, because it will mean huge new plantations of solar panel plants. It will mean plantations of carbon-capture technology which suck carbon out of the atmosphere. It will mean an entirely new infrastructure. It will mean new kinds of airplanes, new kinds of public transportation. It will mean a new approach to diet and agriculture.

"Absolutely everything needs to be transformed and will be transformed either by the force of climate change, or by the force that we put into avoiding climate change. Now thankfully, there's still time to imagine a world that is made prosperous and fulfilling and just through climate action."

On trying to get the message across to politicians in the U.S.

"I haven't had any direct contact with the Trump White House. I've heard from a lot of political leaders on the other side of the aisle who are actually making quite enormous progress in this area. When I started working on climate a few years ago, it was conventional wisdom, which I'd sort of took for granted, that the public and our politics was quite inert on the subject, that it just wasn't moving at all and there wasn't much chance for rapid movement. But 73% of Americans now believe in climate change, 70% of them are concerned about it. Those numbers are up 15% since just 2015. They're up 8% since last year. Those are incredibly rapid movements by any political science standard, although they're a little too slow given how fast we need to take action to really avert some catastrophic change."

On the emotional burden of caring about climate change

"I think it's wearing on anyone who pays attention. It imposes an emotional cost on all of us to think about the world's suffering in all these ways. Thankfully though, I think it's all in front of us: If we get to some of these truly terrifying outcomes, it will be because of the choices we make from here on out. Nothing really is baked in stone besides a few more tenths of a degree of warming. Everything is up to what we do.

"You might feel some of these projections are overwhelmingly scary and they are, but they're also a reflection of how much power we have over the climate because we'll be the ones that bring those horrible eventualities into being, and that means we can also choose to not bring them into being if we make the right choices, adopt a new politics and produce a new set of policies that treat climate change as the story of our time, the story of our century, one that will dominate every aspect of our life &mdash which is how we need to think of it in order to bring about policy that makes the future happily livable for us all."


Close Calls: Three Times When Humanity Barely Escaped Extinction

Today it looks like humans will have to launch themselves into space to get enough room for our collective population, but we weren’t always so robust a species. There are three times in history during which humans nearly went extinct. Here’s what threatened us, and how we survived.

1.2 Million Years Ago: Humanity Before We Were Exclusively Homo Sapiens

In 2009 scientists spent some time analyzing two completely sequenced human genomes . They were looking for the time to most recent common ancestor, or TMRCA, and they knew what to look for in order to find it.

Mobile genetic elements are little sequences of DNA that don’t stay put. They move around, and multiply, within the genome. It’s much easier to copy and paste these elements than delete them, so once they’re in a gene, they tend to stay. As such, they’re genetic mile markers in individuals—signs that they have traveled a certain distance together. One of the most common of these elements is the Alu element. Scientists were looking for it because it separated “old DNA” from “new DNA.” According to the study, “the genealogy of a region that contains a mobile element is on average older than that of the rest of the genome. Because genealogies that contain polymorphic mobile elements are old, they are shaped largely by the forces of ancient population history and are insensitive to recent demographic events, such as bottlenecks and expansions.”

They read humanity’s history on its genes, and it seems that 1.2 million years ago, things weren’t looking good. Homo sapiens, Homo ergaster, and Homo erectus had, worldwide, a breeding population of about 18,000 people—no more than 26,000 people. This means that all over the world, every human-like species that could possibly contribute genes to a current human added up to a smaller population than that of gorillas today. Considering gorillas are only on one continent, and humans occupied Africa and Eurasia, that’s a very small population indeed.

This result came as a surprise because other evidence indicated that humans were doing very well. They occupied a great deal of territory. Scientists found stone tools in Turkey that date back 1.2 million years. In 2008 archaeologists found the jaw of a thirty-something human who lived in Atapuerca, Spain about 1.2 million years ago. We were all over the place. Why were we so very near extinction?

According to the Chad Huff, a co-author of the study, this might not have been a population anomaly. It might have been humanity’s normal state. He told one newspaper , “either the population got large and collapsed or the ancestors of modern humans were always a very small population for millions of years.” Human might just have been what we would consider now an “endangered species” for most of their history. The small world-wide population of humans suggests that the expansion of humans past the borders of Africa might be, if not an incorrect observation, then perhaps not genetically significant. It’s possible that those far-flung tool-makers died off, and only a core population which stayed close to home contributed to our genes.

If that’s the case, then the survival lesson is clear: stay put.

150,000 Years Ago: Homo Sapiens and the Big Chill

Around 195,000 years ago, the world changed. The temperature dropped in the winter, and then dropped in the summer as well. Glaciers expanded. Entire habitats were destroyed. The era is officially called Marine Isotope Stage 6 (because we know of its existence in part by analyzing oxygen isotopes from deep sea sediment samples), and informally called a “glacial stage,” but it was likely more of an “ice desert” stage . Deserts expanded as well as glaciers, and much of the world was cold and dry.