By Andy May
This is part four of our series on climate change costs and hazards. The first three parts were on humans and the environment, population and the food supply, and the cost of global warming. In this part we examine the assertion that man-made climate change, the growth of the human population, and other human activities are causing an increase in species extinctions. We also examine the polar bear controversy.
And we examine the assertion that man-made climate change will cause an influx of fresh water into the North Atlantic from melting glaciers on Greenland and shut down the North Atlantic thermohaline circulation and/or the Gulf Stream. This will then, supposedly, cause a major cooling akin to the one seen 8,180 to 8,340 years ago when the ice dam holding Lake Agassiz onto North America broke, spilling a huge amount of fresh water into the Atlantic.
Global warming is causing a “great extinction” event.
Besides the potential financial costs of global warming, some claim that the modest 0.8°C of warming we have experienced since the mid-19th century is causing more species to become extinct, others say it is the growth of the human population. In fact, National Geographic has claimed we are in the “sixth great extinction in the Earth’s history.” Nadia Drake proclaims that the current extinction rate may be 100 times the normal rate. This is also the subject of a book entitled The Sixth Extinction, by Elizabeth Kolbert. If true, this is a considerable cost of either global warming or human population growth.
Experts in the past five extinction events do not support this idea. Smithsonian paleontologist Doug Erwin, an expert on the Permian extinction that may have wiped out 90% of the species on Earth, says those claiming we are in a similar situation simply do not know what a mass extinction is (see here). Erwin points out that somewhere between 0 and 1% of species have gone extinct in recent human history. Consider what he told The Atlantic, in an interview:
“So, you can ask, ‘Okay, well, how many geographically widespread, abundant, durably skeletonized marine taxa have gone extinct thus far?’ And the answer is, pretty close to zero,” Erwin pointed out. In fact, of the best-assessed groups of modern animals—like stony corals, amphibians, birds and mammals—somewhere between 0 and 1 percent of species have gone extinct in recent human history. By comparison, the hellscape of End-Permian mass extinction claimed upwards of 90 percent of all species on earth.”
Daniel Botkin (UC Santa Barbara environmental scientist, bio here) has estimated that the extinction rate for animals and plants is about one per year. This is not an alarming rate and is very far from a “mass extinction” event.
“In the Danish press I pointed out that we had long been hearing figures for the extinction of the world’s species which were far too high – that we would lose about half of all species within a generation. The correct figure is closer to 0.7 percent in 50 years. This led to the Danish chairman of Greenpeace, Niels Bredsdorff, pointing out that Greenpeace had long accepted the figure of 0.7 percent.” Lomborg, Bjørn. The Skeptical Environmentalist: Measuring the Real State of the World (p. 17).
“Extinctions are always happening. Most species that have existed on Earth have gone extinct. As I mentioned before, the average rate for animals and plants has been about one a year (although some recent scientific papers argue that the average rate has been much higher, maybe up to six per year). The number of extinctions has varied over time, including five “mega-extinction” events since the evolution of multicellular life-forms, about 550 million years ago. During each of these mega-extinctions, the majority of species appear to have gone extinct in a (geologically speaking) comparatively short time. The greatest mass extinction was the Permian-Triassic, about 250 million years ago, when an estimated 80 to 90 percent of all species went extinct.” Botkin, Daniel B. 25 Myths That Are Destroying the Environment: What Many Environmentalists Believe and Why They Are Wrong (Kindle Locations 645-650).
The IPCC WGII AR5 report supports Lomborg and Botkin, in a bit of a back-handed way, with figure 1 below from page 43 of the Technical Summary:
Figure 1: Rates of change in distribution (km/decade) for several marine taxonomic groups for 1900 to 2000. Positive changes mean the taxa are present over a larger area, generally moving poleward.
While the IPCC AR5 report does not claim a “great extinction” is imminent they do claim that a “large” fraction of both terrestrial and freshwater species face an increased risk of extinction due to climate change. This prediction is entirely model-based and nothing like they predict has been observed. The report also acknowledges that there is very low agreement concerning the fraction of species at risk (AR5 WGII, technical summary, page 67).
The “Great” Quaternary Megafauna Extinction
After post #1, Javier included a reference to Barnosky, 2008 on the Quaternary megafauna extinction. The paper begins with the following:
“Earth’s most recent major extinction episode, the Quaternary Megafauna Extinction, claimed two-thirds of mammal genera and one-half of species that weighed >44 kg between ~50,000 and 3,000 years ago.”
After cleverly reducing his sample size to get to two-thirds, he proclaims:
“The Quaternary Megafauna Extinction (QME) killed >178 species of the world’s largest mammals, those weighing at least 44 kg (roughly the size of sheep to elephants). More than 101 genera perished. Beginning ~50,000 years (kyr) B.P. and largely completed by 7 kyr B.P., it was Earth’s latest great extinction event.”
So, the “Great” Quaternary megafaunal extinction event extirpated about 178 species of the world’s largest mammals, those weighing >44kg (roughly the size of sheep to elephants). According to Mora, 2011, there are a 1.2 million catalogued species today and there may be a total of 8.7 million species alive in the world today. So, while the extinction of 178 species over ~50,000 years of rapid climate change is distressing because the creatures are so interesting, geologically it is not a significant event. It is not remotely comparable to the five great extinctions. A “Great Extinction” is defined by the American Museum of Natural History as an event where more than half of all species go extinct in a short time, from the museum’s web site:
“Around 65 million years ago, … Fossils that are abundant in earlier rock layers are simply not present in later rock layers. A wide range of animals and plants suddenly died out, from tiny marine organisms to large dinosaurs.”
“Species go extinct all the time. Scientists estimate that at least 99.9 percent of all species of plants and animals that ever lived are now extinct. So, the demise of dinosaurs like T. rex and Triceratopssome 65 million years ago wouldn’t be especially noteworthy–except for the fact that around 50 percent of all plants and animals alive at the same time also died out in what scientists call a mass extinction.”
Thus, the Quaternary megafauna extinction is about three orders of magnitude too small to be a “Great Extinction” as claimed by Barnosky.
The Quaternary megafaunal extinction event began ~50,000 years ago and was mostly complete by 3,000 years ago. This was an extinction rate of 0.004 species per year, which is much lower than the average long term extinction rate of about one species per year (Daniel Botkin, see quote above). Obviously, the extinction of sabre toothed tigers, dire wolves, mammoths, and other megafauna is not particularly significant in geological history. But, these are fascinating creatures due to their size and we value them much more than a toad or insect that goes extinct. However, this is a value judgement, not a geological event.
Barnosky notes that humans fit into the large mammal category, yet humans have survived and thrived. They also claim that the gain in human biomass largely matches the loss of large non-human megafaunal biomass until 12,000 years ago, then total megafaunal biomass crashed as many megafauna went extinct. Sounds like classic “survivor guilt” to me. 12,000 years ago, was about when human civilization began, rice was already being cultivated in China and grains in the Levant (present day Syria and Israel). The construction of the large stone monuments at Gobekli Tepe in modern day Turkey began about this time. Humans were beginning to settle down and become farmers. Humans adapted quite well both during and after the Younger Dryas, other megafauna did not.
12,000 years ago, was very near the end of the Younger Dryas period. This was a 1,000-year return to glacial conditions after a brief warm period from 15,200 years ago until 13,000 years ago. The periods are labeled in figure 2. The figure plots the GISP2 Greenland ice core air temperature record by Alley, 2004.
Figure 2, data from Alley, 2004.
At least in Greenland, and probably over the whole Northern Hemisphere, it was very cold 12,000 years ago. A more detailed time line can be downloaded here. Below is a global reconstruction, using mostly marine temperature proxies that shows pretty much the same thing, although it only goes back to 12,000 BP.
Figure 3, source: A Holocene Temperature Reconstruction.
It was very cold 12,000 years ago and then the world warmed rapidly, especially in the northern hemisphere. This put a lot of stress on all species, undoubtedly some species went extinct, but the species we especially notice, in the fossil record, are the larger creatures. Some estimates suggest that air temperatures, on land, in the northern hemisphere, rose as much as 5-10°C in just a few decades (Severinghaus, et al., 1998). This extremely rapid warming could have affected many species as well. We have people concerned today because of a 0.8°C rise in 137 years, imagine a change of 5°C since 1990! This is what the world saw at the end of the Younger Dryas.
By 12,000 years ago, man had spread throughout Africa, Eurasia and the Americas. The rise of civilization and the development of new hunting tools (bows and arrows, spears, and spear throwers – all invented more than 30,000 years ago) made Upper Paleolithic hunters very formidable. We know that Upper Paleolithic humans hunted megafauna 12,000 years ago and earlier, and were present in areas where megafauna went extinct. In Australia, the megafauna disappeared within a few thousand years of man’s arrival on the continent and in a time of stable climate. But, elsewhere, like in Eurasia, the extinctions occurred during periods of dramatic climate change. It is likely that hunting by Upper Paleolithic humans and climate change both played a role in the megafauna extinction event. A summary of the geological evidence for both theories can be seen in Marianne Lehnert’s 2014 essay here as well as in Barnosky, 2008. Further, it seems clear that of the megafauna present 12,000 years ago, humans were the most adaptable to the changing world. To a large degree, humans simply outlasted and out-survived their competitors, evolution at work.
Barnosky mentions that some megafauna are at risk of extinction today, many of the species have only survived in Africa. This is not a surprise, Africa sits on the equator and is less vulnerable to severe climate change. Because of their size megafauna require a lot of land to live in the wild, this will restrict them to parks, private lands, and zoos; but as man becomes more prosperous, he is more interested in preserving them and they are unlikely to die off. Upper Paleolithic humans were only interested in surviving, humans today are affluent and secure, and will expend energy and resources to help species that we value survive. It is more likely that humans today will ensure the survival of megafauna, rather than threaten them.
Barnosky speculates that our current high level of large animal “biomass” is only being sustained by fossil fuels and is dominated by human “biomass.” Strange way of putting it, but it might be true. His next prediction is that another large animal “biomass crash” is imminent because we are running out of fossil fuels, this is unlikely mainly because his prediction that we only have an 83-year supply of oil and gas is much too pessimistic. The paper states we have a 50 year supply of oil and a 200 year supply of gas, I converted the gas supply to oil by using the USGS conversion of 6 MCF of natural gas to 1 barrel of oil equivalent.
Table 1, (from here), gives a much more realistic estimate of known hydrocarbon resources that are technically recoverable, it is very conservative and does not include all known hydrocarbons. All the hydrocarbon resources in table 1 can be produced economically at prices we have seen in the last 20 years, although some may not be economic at current (2017) prices. It appears that Barnosky was only counting “proven” or “probable” conventional oil and gas deposits, when most of the oil and gas known today are classified as “unconventional” (including oil shale and oil sand deposits). While the production of unconventional oil and gas is more expensive than conventional oil and gas, it is still an order of magnitude cheaper than solar and wind. Nuclear is even cheaper than coal or natural gas, see here. The bottom line is that available energy supply is not the problem.
Table 1, source here.
While Upper Paleolithic (roughly 40,000 to 10,000 years ago) man played some role in the Quaternary megafaunal extinction event, this was a very different human than we are. They were subsistence hunters in a very tough time, this caused physiological changes as they adapted to a very cold climate. During this period, they had barely learned to farm, and even then, only in the most primitive way. When food walked by, they killed it and ate it. We have already seen that taking care of the environment is only possible when our income and security needs are taken care of (see post 1, “Do Humans harm the Environment“), figure 2. Today when GDP in PPP$ exceeds about PPP$2,000 per person, the environment, in that country, improves rapidly.
Barnosky suggests that man’s rise and other megafauna going extinct is simply a trade off in biomass, thus as man’s population grows more extinctions will occur among existing megafauna. I find this highly speculative, considering our prosperity and our interest in preserving endangered species. There is a trade off in available land, but biomass? With modern farming we can feed many more people and animals than in the past, we can also use energy to create a nearly infinite amount of clean water. Further, man has an obvious interest in preserving existing megafauna for esthetic and humanitarian reasons. They will not be able to run wild in a fenceless wilderness, but I doubt we will allow large animal species to go extinct. The best insurance for the survival of megafauna is a prosperous and secure human population.
Polar Bears
As Dr. Susan Crockford has reported in detail on her site polarbearscience.com, USFWS researchers confidently predicted that polar bears would die off to dangerously low levels if sea ice dropped below 3-5 million square kilometers on a regular basis. The first prediction was made by the International Union for the Conservation of Nature (IUCN) in 2006. A second assessment was made by the United States Fish and Wildlife Service in 2008. On the basis of these predictions (see here for the ICUN listing), polar bears were put on the vulnerable species list.
It turned out that sea-ice extent has reached 3-5 million square kilometers on a regular basis since 2007, much earlier than expected and this is long enough to assess the predictions and Dr. Crockford has done so here. The “critical” level of ice was reached many times and, yet polar bears thrived, the population stayed stable or, perhaps, grew in number. The 2015 population of polar bears has been estimated to be about 26,000 (22,000 to 31,000). It has since been suggested that a low in the polar bear population was reached between 2004 and 2006 when the sea ice was thick and extensive (figure 2). The population of bears in 2005 has been estimated to be about 22,500 (the range is 20,000 to 25,000). The population increased after the ice melted and when polar bears were spending more time on land. Generally, the accuracy of the estimates of the bear population is not great, but a slight decline in 2001 to 2005 is quite possible. The population has remained stable since 2000, which suggests all the variation in sea ice has had little effect.
The loss of sea ice since 2007 has not affected the polar bear population, in the words of Atwood, et al., 2015:
“no causal link between the patterns in polar bear vital rates and increased use of terrestrial habitat“
The authors speculate that if the bears spend more time on land, due to the lack of ice, it may be a problem in the future. But, history has shown we should not make environmental decisions based upon speculation.
Once the lack of a link between sea ice extent and polar bear populations was established, Jeffrey Bromaghin (see Bromaghin, et al., 2015), said in an interview on the paper:
“The low survival may have been caused by a combination of factors that could be difficult to unravel,” said Bromaghin, “and why survival improved at the end of the study is unknown.”
The low point was 2004 to 2006, when the Arctic sea ice was extensive, the “survival of adults and cubs began to improve in 2007” when the Arctic sea ice declined rapidly. This is exactly the opposite of what the environmentalists predicted! The sea ice extent for the years discussed is shown in figure 4.
Figure 4, Data from JAXA, plot from Great White Con.
The polar bear story is a good example of what can go wrong when one bases policy on environmentalist’s predictions. In this case, the polar bear scientists concluded, erroneously, that polar bears needed sea ice to survive. Then they predicted if sea ice reached the 3-5 million square kilometer level or lower polar bears would suffer, this was also incorrect. Finally, they used a climate model to predict that the critical sea ice level would be reached in 2050 due to man-made climate change, also incorrect. It was reached a scant two years later and completely ignored by the bears who simply lived on land in the absence of ice. Not a single prediction was correct, but the polar bear made the “vulnerable” list anyway.
Global Warming will shut down the Gulf stream and cause a mini-ice age.
This hypothetical scenario where melting Greenland ice dilutes the Atlantic between Greenland and Norway and stops the North Atlantic thermohaline circulation (aka the “Atlantic conveyor”) causing a little ice age, such as the one 8,200 years ago, is very unlikely to happen. 8,200 years ago, an enormous fresh water lake (Lake Agassiz), in the area along the border between Canada and the U.S., broke through an ice dam, that was left over from the most recent glacial advance, and flooded the North Atlantic with fresh water. This lowered the salinity of the surface water and halted the thermohaline circulation in the North Atlantic and cooled the planet for hundreds of years (see more here by Michael Michalek). We often simply refer to one cooling, the 8,200 BP cooling period, but in reality, there were two, one was 8,490 years ago and the other from 8,340 BP to 8,180 BP. Per Lomborg’s Cool It:
“The Gulf Stream last shut down some 8,200 years ago, when the final glacial ice sheets in North America melted and a giant pool of freshwater built up around the area of the Great Lakes. One day, the ice dam broke, and an unprecedented amount of freshwater flooded the North Atlantic and disrupted the sinking salty water from the Atlantic conveyor. This pushed Europe into a little ice age for almost one thousand years. …
Yet the relevance of such a story crucially depends on the Greenland melt being on the same order of magnitude as the ancient freshwater pool—and it is not. Over the coming century, the IPCC expects Greenland to melt almost one thousand times less than what happened 8,200 years ago. A team of modelers looked at what would happen if Greenland melted at triple the rate expected by the IPCC—or, as they put it, at the “upper limit on possible melting rates.” Although they see a reduction in the Gulf Stream, they find “its overall characteristic is not changed” and that “abrupt climate change initiated by Greenland ice sheet melting is not a realistic scenario for the 21st century. …
This is also why the IPCC, in its 2007 report, is very clear about the Gulf Stream: ‘None of the current models simulates an abrupt reduction or shut-down.’ The IPCC’s models expect somewhere from no change to a Gulf Stream reduction of 50 percent over the coming century, but no models show a complete shutdown.” Lomborg, Bjorn. Cool It (Kindle Locations 1334-1394).
This idea was the inspiration for the 2004 film The Day after Tomorrow starring Dennis Quaid and directed and written by Roland Emmerich. This very imaginative film is filled with gross scientific inaccuracies, but did reasonably well at the box office. Critics panned it, as did most earth scientists I know who bothered to watch it.
Conclusions
Bottom line, there is no discernable trend in extinctions, up or down. But, we are certainly not in a “major extinction” event. The Gulf Stream and the world’s thermohaline circulation system are in fine shape and there is no “Lake Agassiz” waiting to spill into the North Atlantic to shut them down. Ice on Greenland cannot melt fast enough to affect the salinity to the degree necessary to repeat the 8,200 BP cold spell.
The Quaternary megafauna extinction was very sad, and both Upper Paleolithic humans and radical natural climate change played a role in those extinctions according to the data we have available. However, comparing this very minor extinction event to the five great extinctions, as Barnosky attempts to do, betrays a complete lack of proportion and an ignorance of the geological past. The true great extinctions were horrific events and the loss of 178 species of large animals is several orders of magnitude too small to qualify. For this event to be classified as a great extinction event would require the extinction of over half a million species and nothing like that is happening today or in the foreseeable future.
Dr. Susan Crockford has documented the saga of polar bears being erroneously declared “vulnerable” quite well and there are lessons to be learned from this fiasco. One cannot base public policy on unvalidated models and predictions. This recent trend of believing, without question, model results; or worse using model results as if they were data, needs to stop. At some point it will lead us off a cliff.
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WWF claims “The rapid loss of species we are seeing today is estimated by experts to be between 1,000 and 10,000 times higher than the natural extinction rate. MSNBC laments the “fact” that 100,000 species of flora and fauna will no longer be with us by next Christmas. And yet, WWF also estimates the number of identified unique species to be between 1.4 to 1.8 million, an uncertainty of 400,000. As someone said, “Anytime extinctions are claimed, ask for the names.” The debunking is done in detail here:
http://www.americanthinker.com/articles/2015/02/plenty_of_wiggle_room_in_scientific_certainty.html#ixzz3XIw5UJqd
Ron, Good link, thanks.
Andy, Thanks for digging into this topic. Another annoying alarmist thing is the imposition of globalized notions contradicted by local facts on the ground. Flora and fauna depend upon specific local and regional habitats defined by temperature and precipitation features, especially the Köppen climate zones, as they appear below in the 21st Century.
Researchers have analyzed changes to these zones, and found them to be quite stable, i.e.very small shifts in boundaries over periods of 30 years. Discussion and links are here:
https://rclutz.wordpress.com/2016/05/17/data-vs-models-4-climates-changing/
The whole modern mass extinction myth started with a Carl Sagan program. Sagan was down in Brazil for some conference. The conference was relative to the impacts of clearing tropical rain forest. Sagan met one of the presenters at dinner one night. Sagan has seen the presentation. The paper was basically about how many species there were in a hectare of Brazilian tropical rain forest, how many were new to science and how few of those species were found anywhere else.. Sagan and the presenter got into a discussion about extinctions. [I met the presenter a bit later in Miami, can’t remember his name.] They made an assumption in their discussion that all the species in that hectare if cleared would go extinct and they worked out the numbers on literally a napkin. Number in that hectare, times the number of hectares being cleared, etc. Next thing the presenter knows is Sagan is going around announcing to the world that we were on the verge of another mass extinction and quoted the gentleman as his source. The environmentalists pick up on Sagan’s speculation and have been running with it ever since. Anything that hints at “mass extinction” they run out as proof of the evils humans have done to the planet. Note I worked in the endangered species management game for a decade, it is intellectually and scientifically corrupt as you have found out on this site reading about such examples as polar bears, walruses, etc,
If people took the time to research co2 that climate crisis alarmists say is the cause for extreme weather and poses life threatening changes, they would see we have all be dooped/lied too/misled. Co2 levels are determined by Global Temperatures.
CO2. LEVELS FOLLOW GLOBAL TEMPERATURE. GLOBAL CO2 LEVELS FOLLOW GLOBAL TEMPERATURE OR LAG BEHIND GLOBAL TEMPERATURES BY 600-800 YEARS. SO ITS ACTUALLY MULTIPLES OF WATER VAPOUR THAT THE UN HAS USED TO THEIR MODELS TO GENERATE THEIR HUGE TDMPERATURE GUESSES.
OUR SUN GOES THROUGH AN 11YEAR CYCLE OF LOW ACTIVITY AND HIGH ACTIVITY. STAND IN THE SHADE AND THEN STAND IN THE SUN LIGHT. NOTICE ANY DIFFERANCE? The Sun controls Earths Temperature. Not Co2 which we all need to live and going below 180 ppm co2. Our trees begin to starve. High co2 means the Erath gets greener ehich means more oxygen output for us. People need to use their minds to look into this to see its all about money that the UN pays out to anyone willing to sellout their Morals to get free cash. Any Scientists who tell the truth that co2 is good and necessary for Life on Earth do not get funded, their research is not published and their careers are threatened to tell us we are all being fed complete B.S. Co2 ALARMISTS ARE PAID TO LIE …. STOP your Governments from funding the Unelected UN because the poor are dying and suffering because our Governments are giving Billions for a Huge Fraud pushed by the U.N…. Please do research….
The first few sentenes may be an error. The writer, while referring to Lake Agassiz, *may* have been thinking of the dramatic breakout of Lake *Iroquois* near Coveville NY, about 12,800 BP. Lake Iroquois had previously drained eastwards near Rome NY into the Mohawk and Hudson Rivers. When the ice dam provided by a lobe of the glacier at Coveville, was breached the Lake dropped at least 100 feet (estimates range from 100 to 400 feet). An incredible volume of water flushed into the Atlantic in about a half a year!
That event *may* have triggered the Younger Dryas in Europe. (Although the dates for either side are not an actual match).
(About 300-500 years later, deglaciation opened a route down what is now the St. Lawrence River Valley which was then (pre rebound) at sea level and there was another smaller flush of freshwater into the Atlantic. This event has also been postulated as the trigger for the Younger Dryas)
There was no similar breakout event for Lake Agassiz which covered the Dakotas and most of Manitoba. It drained, variously south, east and then north as deglaciation and isostatic rebound took place.
Dyspeptic Curmugeon, The Lake Agassiz outbreak in the Atlantic is well documented, see here: https://www.nature.com/articles/ngeo130
Although, the outbreak you describe may have also happened. I know less about the pre Younger Dryas event.
Barnosky doesn’t talk about a mass extinction. Mass extinction events are characterized by the loss of a widespread number of species and genera from many different taxa from many different locations in a relatively short span of time (geologically). The Quaternary Megafauna Extinction was the loss of only a few genera from a single taxon. Barnosky knows it isn’t a MEE. The term great extinction is arbitrary and subjective. It is clear that it was a rapid loss of a very specific group of mammals at a much higher rate than for the previous couple of million years. As far as we are concerned the QME hasn’t ended yet. We are still in the Quaternary and we are very likely to lose more megafauna species in the future.
There have been quite a lot of mass extinctions in the past. Bambach talks about 18. All of them involved the loss of 10-60% of genera. We usually talk only about the major five.
All of them with over 45% of marine invertebrate genera.
As far as I know we haven’t loss a single marine invertebrate genus and just a few genera in recent times. We are clearly not in a mass extinction.
Climate change currently is not causing extinctions. We know why we are losing species and the recent change in climate has nothing to do with it. We bear the responsibility of most extinctions. During the exploration age there was a peak of extinctions in island fauna due to the introduction of invasive species by mankind. We are still losing some due to that. Others have been hunted to extinction, and some more due to habitat loss.
Most of the species that we have lost in the last decades are river fishes. They have been lost due to river contamination. They are very vulnerable as many of them are very endemic and have no place to go.
Whether Barnosky is correct that the QME involved a biomass trade-off with expanding humans I don’t know. It is an interesting hypothesis that is congruent with the data.
To me the reason the African megafauna was spared is that humans developed their hunting skills progressively in Africa and the megafauna there had time to adapt and avoid humans as they would do with other predators. When humans reached other continents they were already highly efficient hunters facing a naive prey. Humans targeted the megafauna preferentially because you get a lot of food from a single kill. Once they killed the megafauna prey, competing predators became extinct from lack of prey, while humans switched to other food sources. Humans didn’t kill all the megafauna but clearly they were involved in killing a good part of it, and specially all competing hominins. Our tree got pruned to a single species, and that only because we could not extinct ourselves until very recently.
Javier, I agree with most of what you write, but not the thesis. My objection to Barnosky’s paper mostly lies in this phrase
“More than 101 genera perished. Beginning ~50,000 years (kyr) B.P. and largely completed by 7 kyr B.P., it was Earth’s latest great extinction event.”
101 genera, of any type or size, is not a “great extinction event.” It is very normal in geological history, especially over 43,000 years.
Upper Paleolithic and humans until around 150 years ago killed a lot of large mammals, but they were also very different from people today. We are affluent and food secure for the most part and the number food insecure and poor people are becoming fewer very rapidly due to modern technology. Thus, we now have rules and laws to protect the environment that would have been laughable in 1900. The more secure we are the better we will make the environment.
The last thing we want to do is restrict fossil fuel energy, make people poorer and more hungry, then who cares about the environment and preserving favored species and genera?
As I’ve said, prosperity creates a better environment. It will also preserve species that would die out in the modern world without man’s help. I don’t think a large animal has extirpated in over 70 years. I doubt you can count the Saudi gazelle as a species and the wallabys and other marsupials that are reported to have gone extinct in Australia may not be separate species either. Other than that we are talking about various varieties of rats and bats. A lot of these so-called “species” are really just distinctions based on adult size and coloring. How we define species is a complex problem.
Andy,
The definition of great extinction is personal, as science does not contemplate extinction categories other than mass extinctions, so your quibble with Barnosky on his terminology is personal. I go with the data.
Over 100 genera of a particular category (>44 kg) in just 50,000 years is highly unusual. That period is an instant compared to species average duration. To my knowledge no other period since the Pleistocene mass extinction 2.8 million years ago shows anything like that.
Several more species of large mammals are doing awfully in the last decades. Particularly the rhinos and some big cats. I really doubt we will be able to save all of them, specially in the wild, and out of the wild they are no longer natural species within ecological networks. Their adaptation and natural evolution ends.
“The last thing we want to do is restrict fossil fuel energy”
I have never proposed that. However, I think we should save fossil fuels for the future, as burning them all now might not be their best use. Chemically they are wonderful compounds with lots of uses. Burning them is a waste as none of their chemistry and only a part of their energy is used.
Javier,
Rhinos and indeed perissodactyls in general have been on their way out for tens of millions of years, outcompeted by artiodactyls.
The megafaunal extinctions have been over for thousands of years, unless you count large island species like moas. We’ve saved the bison and whales. We might bring back mammoths and woolly rhinos.
Forty years ago an oil exec buddy of mine stated that future generations would curse us for burning such rich molecules as in oil. Natural gas, not so much. And we can make rich molecules from coal, using nuke power if need be.
Javier, It’s OK to disagree, especially on this subject. Geologists, Biologists, and environmentalists cannot agree on what a species is, we do not know the current rate of extinctions (except in a very general way), we do not know the historical rate of extinctions with any accuracy, and we certainly cannot predict the future rate of extinctions. In my opinion, and in the opinion of others, like Daniel Botkin, we are not seeing anything unusual. Obviously, others, including yourself see otherwise.
Large animals, that require large areas of land to live in will either have to become domesticated (or live in enclosures of some kind), or their numbers will have to be reduced to the number that can live on land that humans can agree to give them. This distresses some people, they should donate to buy more land for them, I think there are places that take such donations. However, this is not a harbinger of any kind of grand natural disaster, it is just that they are animals, competing with humans for land. If we value humans more than animals, we’ll keep control of the land and protect the animals.
That said, I do not see many more going extinct as long as we remain prosperous and are willing to take care of them as we do now. I definitely do not agree that 100 genera in 50,000 years is unusual, in my understanding of paleontology this is orders of magnitude less than the normal rate of extinction (per Daniel Botkin) of 1 to 6 species per year, particularly for species whose habitat is shrinking. The world is changing, it has always changed, species adapt or go extinct. Humans take care of species they value, no other species does that, thus we are helping the environment, not hurting it, at least in my opinion. This argument is more point-of-view than data based.
Andy,
Ants farm aphids as we do cows.
Gulf Stream shut down? Quite the opposite:. it began to deliver warm water into the Arctic Ocean in the seventies. Arctic observers noticed this increase of warming and jumped on the bandwagon near the end of the seventies. There was just one problem: the warming they saw was twice as fast as their models were telling them. The discredited greenhouse warming sed by modelers is at fault most likely. They of course are being latecomrs, and have no idea of what preceded the warming they had just noticed. The fact is that at the turn of the century there was a rearrangement of the North Atlantic stream system that brought to an end to a two thousand year long stasis. Accoording to Kaufman et al. who observed it, there was nothing but a slight cooling for two thousand years, followed suddenly by an upsurge at the turn of the century. It is in my book which you obviously skipped. What folloered at the turn of the century was steady warming lasting for twenty years. To get a hang on that go and read my paper called “Arctic warming is not greenhouse warming.” By now there are two homewprks you missed and thereby failed.To continue, the initial warming of the twentieth century was followed by abrupt cooling that lasted for thirty years, frpm 1940 to 1970. It stopped there and the steady warming that is still active now started at that exact spot. By late seventies it was warm enough to attract the current crop of observers. I hate to tell you, but it is an ignorant bunch. They still think carbon dioxide did it and read the IPCC climate predictions that are way off the mark. The present Arctic warming is not caused by carbon dioxide and never was. As I mementioned before, there was a re-arrangement of the North Atlantic current system and what it did was to tweak the north-flowing Gulf Stream water that had been sp[lit between the North Sea and the Arctic to direct more of it into the Arctic. . That is the only way you can possibly start a steady long-term warming in 1970, the year of the peak of a cold wave. No amount of carbon dioxide can instantaneously overcome peak cooling. And if you have doubts about the Gulf Stream warming the Arctic, read Spielhagen et al. in Science, January 2011, pp, 450 to 453. They took a personal cruise into the Arctic and were able to scoop up warm water by hand from the Arctic ocean.
The greenies want to believe man has the ability to ruin the planet only because they want to feel powerful and then virtuous by stopping all the other “bad” people from exercising all that power.
In other words it’s all a power play.
Can’t we just sit back and watch what happens and log and correlate what happens and THEN make predictions based on FACTS instead of computer generated fairy tales? How hard could that be?
Cold extermination: One of greatest mass extinctions was due to an ice age and not to Earth’s warming
https://www.sciencedaily.com/releases/2017/03/170306091927.htm
Yogi, every single major mass extinction was during rapid changes in sea level. Which indicates ice ages. The cause of all the mass extinctions including the KT extinction event was caused by a major cooling event. I haven’t seen any other explanation that fits. Cooling, decreasing moisture in the air, massive decrease in food resources, mass extinction.
Meteor impact followed by major volcanism.
Polar Bears eat seals, as long as there are seals there are polar bears. There has been a 43% increase in biomass in the arctic since 1990, there be more seals, there be more polar bears. It’s pretty simple, Bears do not eat ice. They eat seals, and seals live on the edge of the ice where there is access to both food and water and air holes. Thick multi-year ice isn’t good, no breathing holes and places to go in and out of the water and no seals and no polar bears. Seals live on ice because land is much worse for predation, and there are literally millions of seals which populations are growing. Not sure how anyone who knows bears and seals and the arctic ecosystem should be surprised.
Not sure where you get the 43% increase, but I believe the gist of it — more sunlight penetrating the water (instead of being reflected), more zooplankton activity, which is the base of the food chain.
That 8.2 kyr cooling in Greenland must have been an intensely positive North Atlantic Oscillation regime. Which means a faster AMOC, and faster trade winds too.
No wonder Greenies are concerned about blocking the Gulfstream:
“DiCaprio took the private jet to Cannes, then back to New York to pick up the environmental award, and then shuttled back to Cannes…
Just how much fuel did that particular 12,000-kilometer environmental round-trip junket consume? No one knows for sure, but we can estimate it. The round trip involved around 16 hours of flight time – if not more – in a longer range private jet, e.g. a Gulfstream G450, which has a fuel capacity of 29,500 lbs, or approx. 16,000 liters. For the 16-hour long haul roundtrip, refueling once, such a jet would need close to 30,000 liters of fuel – fuel that gets burned right where greenhouse gases are claimed to be the most effective.”
http://notrickszone.com/2016/05/23/dicaprios-private-jet-junket-burned-30000-liters-of-fuel-enough-for-10000-cars-an-entire-day/#sthash.B8vJpgOS.dpbs
Does anyone know how many glacial periods have occurred during the current Quaternary ice age?
Warm periods are given odd numbers and cold periods even numbers. The Quaternary count ends at 104 2.6 million years ago. That would make 52 cold periods. However by eye I count only 45 periods that would qualify as glacial. Obviously in general the older they are the milder they appear, as there has been a progressive cooling of the planet.
When I was studying there were only four, that I had to learn their names in German. Würm, Mindel, Riss, and Günz. As a kid you believe everything you are told at school. Then you grow up and find many things you are told are not true, and learn to become skeptic.
Javier – Agreed.
But the names given [I believe, IIRC, those of small Alpine communities] were Günz; Mundell; Riss; & Würm [in alphabetical order]. The then namers [1920s???] suspected, at least, that there may have been ‘other’ interspersed, Ice Ages [of whatever duration] – so allowed future researchers considerable scope to intersperse names related to later discoveries.
But if there are 45 – or 52 – the early namers underestimated the complexity of the ‘Ice Ages’. Or Ice Ages, like nematodes [say] have splitters . . . . . . .
I have no expertise to judge!
Auto
Sorry – should have added –
“Günz; Mundell; Riss; & Würm [in alphabetical order] – earliest to latest”.
Apologies.
Auto
Problem was that the four most recent, more dramatic glacial advances extended farther than the prior ones, so that their traces upon the land were obscured, if not erased.
Auto,
Later on Würm and Riss were replaced by Weichsel and Saale with Eem in between.
The new numbers were not sufficient, for example, the Eemian has MIS number 5e.
Global map of human pressure free lands with a contiguous area >10,000 km².
Figure 2 : The extent of pressure free lands in 1993 (purple) and 2009 (green)
J.R. Allan, O. Venter & J.E.M. Watson. Temporally inter-comparable maps of terrestrial wilderness and the Last of the Wild. Scientific Data 4, Article number: 170187 (2017) doi:10.1038/sdata.2017.187
https://www.nature.com/articles/sdata2017187
There is less and less of the world left for nature as we expand and increase our numbers. Between 1993 and 2009 the decrease was of 10%.
Please tell the cougars, black bear, coyotes, whitetail deer and rats that they have less space now. They haven’t gotten the message. Thanks.
No. They are now living in places that are not free of human pressure.
They must like human pressure then, since their ranges and numbers are expanding.
Right on Gabro. You can add many species to that list. This map and the false thinking behind it assumes that wildlife cannot adapt. It is made worse by its simpleton human ‘pressure free’ basis.
This is just another example of the ‘humans bad/wildlife good’ story sold by the eco-crisis industry and their handlers.
Thanks for the link Javier, I don’t think I will agree with the thesis of the paper, but I want to read it anyway. We will accommodate favored species, but I doubt anyone wants to give up the rights to their private land. However, some environmental organizations buy land for wild animals. If they can raise the money and do so, good on them.
Hi Andy,
I find it surprising that you don’t agree with the thesis that unperturbed global land surface available to wildlife is in a long term decline trend. To me it is a very clear fact difficult to dispute.
At the Permian extinction event the world’s oceans turned anoxic. The entire ocean became a rancid yellow-orange at the surface, black below 10m depth. Marine species extinctions approached 100%, only scattered oxygenated refuges prevented total annihilation of marine flora and fauna.
It is hysterical and deeply ignorant / dishonest exaggeration to even imply that recent anthropogenic extinction come anywhere near the severity of the end Permian extinction. They did not.