Climate Dents in Humankind´s Family Tree

This is today as the latest Press Release by the Potsdam Institute for Climate Impact Research (PIK)

Climate dents in humankind´s family tree: new correlations discovered   

 Climate changes in Earth’s history have influenced the fate of modern man´s ancestors, but until now it has not been clear why some evolutionary variations developed or disappeared. Scientists of the Potsdam Institute for Climate Impact Research (PIK) and Potsdam University have now provided a novel view on human evolution during the past five million years. A nonlinear statistical analysis of sediments taken from the seafloor near Africa indicates that abrupt changes in climate variability could have had a significant impact on human evolution. In the first instance, the scientists have spotted three primeval tipping points.

“It has long been assumed that climate changes are significant for the history of humankind, but until now this has not been statistically proven,” says Jonathan Donges from PIK, lead author of the study published this week in the renowned Proceedings of the National Academy of Sciences. Now some evidence has been demonstrated. “For the first time we can show that the concurrence between changes in climate variability and those in early human evolution were probably not arbitrary,” says Donges. The transition between times of little and strong climatic fluctuations – “the changes within changes”– is crucial. Apparently they raise selection pressure.

Dust from the ocean bottom supplies data

Instead of long-term trends, the scientists examined comparably short-term changes that still cover a few thousand years. The mathematical analysis of time series spanning millions of years was based on data already published several years ago by marine geologists. The data is derived from drill cores from the seafloor of the Indian and Atlantic Oceans as well as the Mediterranean. The deposits of desert dusts contained in these sediments allow conclusions on what kind of climate prevailed at certain points in time.

In the process, the scientists were able to identify some of the mechanisms that possibly triggered climate changes. For example, the warm waters flowing from the Pacific towards Africa diminished due to shifting landmasses in the region of today´s Indonesia. Since ocean currents are conveyers of heat, as a result regional temperatures and rainfall over Africa changed. This in turn had impacts on the local vegetation and therefore also animal populations as well as early humans like Australopithecus, who became extinct about a million years ago. In contrast, other ancestors of man could suddenly flourish under the changed conditions, because they were more adaptive. “As an allrounder, Homo had better chances in a fluctuating climate than more specialized hominids,” says Donges.

Look into the past sharpens that into the future

To look into the past can help sharpen our view into the future. “Climate changes have impacts on the living conditions of humankind – and what took many hundreds of thousands of years in the past could now happen in fast motion because of the man-made greenhouse effect,” explains Jürgen Kurths, head of the research team and co-author of the study. Regarding temperatures, one of the three relevant periods about three million years ago can be considered a counterpart to a world with unabated CO2 emissions, such as may exist by the end of this century. “This is not a one-to-one equivalence, but about understanding essential mechanisms of climate changes,” says Kurths. “So-called paleoclimatology often serves to verify assumptions about the climate of today and tomorrow.”

“It is a big step ahead. Finally the methods of nonlinear physics are being utilized for research on the evolution of humankind,” says Hans Joachim Schellnhuber, PIK director and also one of the study´s co-authors. He is one of the pioneers in the application of this discipline – known as chaos theory – to Earth system research. “We are succeeding better and better in understanding complex dynamic systems,” says Schellnhuber. “It is becoming ever more clear that this is not a glass bead game, but an extraordinarily relevant field of research – especially in regard to climate change.”

Article: Donges, J., Donner, R.V., Trauth, M.H., Marwan, N., Schellnhuber, H.J., Kurths, J.: Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution. Proceedings of the National Academy of Sciences [doi:10.1073/pnas.0709640104] (Early Edition)

The article is available in PNAS’s Early Edition online the day it gets published this week. Until then it is available only on a protected website of PNAS/Eurekalert or via email:

For further information please contact the PIK press office:

Phone: +49 331 288 25 07


(Visited 71 times, 1 visits today)

You may also like...

1 Response

  1. Poo says:

    There are just so many studies/models and, as much as I love history, I do find it “odd” when it repeats itself. How long must I wait for the dinos to come back? And are we really trying to compare pre-man eras with those of man?

    Before I get to my point, and I do have one, lets take a brief look at just some of the dire predictions man has thus far faced down or missed completely.

    ‘The Population Bomb’ by Paul Ehrlich started screaming about overpopulation and resource consumption in 1968. Bombastic Ehrlich was, right he wasn’t.

    An article in the scientific journal ‘Nature’ has revealed the widely used and accepted mathematical method for estimating the rate by which species become extinct from loss of habitat is wrong. It overestimates the rate by approximately 160%. Not by much mind you, just 160%. The authors of the article, Fangliang He of Sun Yat-sen University in China and Stephen Hubbell of the Smithsonian Tropical Research Institute, reported the error results from the false assumption that the rate loss can be extrapolated by reversing a species area curve. Huh? This is a simple correlation between the area surveyed and the number of species found. When compared to actual data as opposed to assumptions, this extrapolation was found to consistently overestimate the loss of species.This result was,apparently, not completely unexpected among the scientific community. Previous extinction predictions have just not been observed in the wild. Estimates have ranged from one species lost per hour, to one per day, to Ehrlich’s (1980) doomsday prediction that 50% of all species would be lost by the year 2000. They weren’t. The U.S. Council on Environmental Quality and the National Research Council predicted a 33%-50% loss of species and a loss of half-to several million species by 2000. They weren’t either. The now laughable IPCC was , no surprise, even more oulandish. In 2007 it falsely warned that 20% to 30% of species assessed were at risk of extinction if increases in global average warming exceed 1.5°C to 2.5°C relative to 1980-1999. No comment.

    Curtis Flather of the U.S. Forest Service and his colleagues wrote an article which appeared in the journal ‘Trends in Ecology and Evolution.’ They clearly showed that widely used methods for predicting the extinction of individual species, based on minimum viable population size, was also erroneous.

    In other words, there is no magic bullet or matrix that can be used to predict the lifeline of a species. Scientists who have worked in the field with and among a wide variety of species know this and , no doubt, always have.

    Once published, however, falsehoods and out right distortions become urban legends and can be Googled as truths by those who look no further than the top 10 list. They should try Letterman. He is more accurate and funnier too! Google makes no account for poor scholarship or the selective use of research (see the IPCC) that supports a certain and restricted point of view. Scientific peer review is not all it is portrayed to be.This problem is widespread in the field of climate science where clear bias often favours preconceptions (see IPCC again).

    But even the IPCC says the CBC supported David Suzuki and others are wrong when they claim that hurricanes like Katrina are the product of man-made global warming.

    “There is low confidence in any observed long-term increase in tropical cyclone activity (i.e. intensity, frequency, duration), after accounting for past changes in observing capabilities,” says a recent report.

    There have been “statistically significant trends” in some regions of major rain/precipitation events although those trends have shown decreases as well as increases.” Oh boy, it works both ways. Droughts are also hard to identify. Some regions have experienced more intense and longer droughts. Some regions’ droughts have become “less frequent, less intense or shorter.” Hmmmm.

    Personally, I love quoting the guts of IPCC reports as they are so unlike their headlines. No one reads anymore. It’s all about blurbs and the 10 second sound bite. The IPCC report even downplays its support for the idea that floods are the result of global warming.

    Flooding is hard to assess at the best of times in any case because the available instrumental records of floods at gauge stations are limited in space and time. There is also the confounding effects of changes in land use and engineering.

    Most of the extreme-weather media coverage on global appears to have been wrong. Of course, the ever back pedaling IPCC waters down their message of what it means by climate change:

    “Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use.”

    So, is it man-made climate or natural forces or both with a few other things thrown in? And if past evidence is tepid what of the future?

    “Projected changes in climate extremes under different emissions scenarios generally do not strongly diverge in the coming two to three decades, but these signals are relatively small compared to natural climate variability over this time frame. Even the sign of projected changes in some climate extremes over this time frame is uncertain. For projected changes by the end of the 21st century, either model uncertainty or uncertainties associated with emissions scenarios used becomes dominant, depending on the extreme.”

    What the hell does that mean?

    Not exactly a go signal for the many exempt countries in Durban to write new environmental laws for the affected few.

    All the horror stories of rising seas, melting Himalayan glaciers, disappearing Amazon rainforests, severe storms and droughts, and other disasters have simply not come true. These headline grabbing claims are based on exaggerated computer models that deliberately excluded any contrary findings but included questionable air temperature station locations and “research” by environmental activists(World Wildlife Fund, Green Peace) as well as other lobbyists. Modelling is a tricky business and should be left to long legged girls on a ramp.

    Paul Ehrlich’s models were primitive yet he somehow decided to make quantum leaps. Species die (see dinos) and sometimes there are floods (see Noah).

    What about all the thousands of scientists associated with the UN’s IPCC who endorsed the IPCC’s global-warming theory? They were essentially peer reviewers of the IPCC reports, and even they regularly disagreed with the material they reviewed.

    Antarctic ice has always broken off. Satellites show it to be gaining ice overall and that it has been getting colder, not warmer, over the last half century.

    Several times over the last century the Arctic Ocean was actually navigable and today’s Arctic is no different from before.

    What about all the predicted hurricanes caused by global warming? The IPCC’s own hurricane expert said there is no evidence that global warming will cause an increase in hurricanes. He has since resigned form the organization. Maybe he was pushed for his heresy.

    What about all the submerged islands in the Pacific? That never happened either. The oceans have been rising for centuries but not because of recent carbon dioxide emissions. In fact, recent evidence shows the oceans’ rate of rise has been slowing.

    What about the correlation between carbon dioxide and global warming? In the last century it is hard to determine if there actually has been any. Carbon-dioxide emissions have steadily increased but the temperature has gone up and down like a toilet seat. In the 1970s it was so severe and cold that many scientists thought we were heading for a period of global cooling. In fact, there were headlines stating the next Ice Age was on the way. I know. I read them. Many scientists think the same thing today now that evidence shows the planet has stopped warming, once again.

    A professor at the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University, one Andreas Schmittner, recently headed up a major study which was published in ‘Science’ and funded by the U.S. National Science Foundation. It concludes that the doomsday scenario is simply not rooted in reality.

    Nobel laureate Ivar Giaever has also recently resigned from the 48,000 member American Physical Society, one of the world’s leading organizations for scientists. He did so in protest at the Society’s policy statement that, “The evidence is incontrovertible: Global warming is occurring.”

    Giaever’s response was scientific and to the point.”Incontrovertible is not a scientific word. Nothing is incontrovertible in science.”

    He has been joined by many other scientists such as Freeman Dyson, a Princeton physicist and such as America’s best known scientist, Antonino Zichichi, the president of the World Federation of Scientists and Italy’s best known scientist, Claude Allegre, a former socialist Minister of National Education, Research and Technology and France’s best-known scientist, and America’s Reid Bryson, known as the “father of scientific climatology” and judged “the world’s most cited climatologist” by the journal of the Institute of British Geographers.

    No scientist has been awarded a Nobel Prize in a science field for his work on global warming because no piece of science in the field has achieved a major scientific breakthrough. This despite the dominance of the issue on the scientific community for several decades plus loads of scientific funding and an inordinate amount of media coverage in scientific and popular publications. The only Nobel Prize conferred on global-warming advocates was awarded by the political wing of the Nobel Prize establishment. It was, in effect, a consolation prize for their failure to merit a prize for science. Talk about bending over backwards.

    NASA’s James Hansen testified in front of the the U.S. Senate in 1988. He brought the climate issue to the popular press. His computer models predicted dangerously high temperatures in the decades to follow. There was no Nobel Prize for him. His models proved to be duds.

    Michael Mann, developer of the infamous hockey stick model so beloved in Canada, showed temperatures on Earth to have shot up dramatically in the last century. This after some 900 years of relative stability. That model also proved to be a dud. Mann’s hockey stick is now the subject of court proceedings and an icon for deceit.

    Schmittner declared that, “the case for alarm regarding climate change is grossly overstated.”
    He was similarly clear in an interview with The Australian: “Very large changes can be ruled out. We have some room to breathe and time to figure out solutions to the problem.”

    The “problem” seems to fade under rigorous and agenda less scientific scrutiny. Schmittner predicts that even the doubling of CO2 concentrations would most probably result in temperature increases between 1.7 degrees Celsius and 2.6 degrees Celsius, not the 3-4 degree “alarming change” falsely predicted by the IPCC. That rise, of course, would occur nearly 100 years from now and presupposes no new improvements or innovations in technology or any negative impact that might result from natural and uncontrollable disasters (earthquakes, meteor strikes, tsunamis, volcanic activity, inordinate sun activity, unusual hurricanes or storms, etc.).

    Skeptical science is no longer confined to the margins by the discredited IPCC and its supporters. The discovery by no less than the CERN laboratories (based in Switzerland), arguably the most prestigious scientific group in the world, that fluctuations in the sun’s magnetic field have a very large and perhaps dominant effect on the Earth’s climate is game changing.

    I know Potsdam is credible but there are so many others that know their way around a laboratory that disagree or, at the very least, challenge. I read them too. Old people have time.

    As to the man made side in real time lets look at power plants. Over the next several years China, the United States and India will build 850 new coal-fired electricity plants. 562, or 66%, will be built in China. In fairness, it should be said that China is replacing their old, polluting plants with new more efficient ones that will reduce the rate of emissions. Still, less than half are equipped to remove sulfur compounds that cause acid rain and only 60% of these new plants are built using the newer, more highly efficient technology. Coal-fired plants supply 80 % of China’s electricity requirements and even their most efficient plants emit twice the carbon dioxide of those powered by natural gas. American coal-fired plants maintain a higher than the average efficiency than that of Chinese power plants.

    “No matter how much renewable or nuclear is in the mix, coal will remain the dominant power source,” said Ashok Bhargava, a China energy expert at the Asian Development Bank in Manila.

    By comparison, the United States produces almost 50% of its electricity and 21% of its total energy needs, from coal. India produces 70% of its electricity and 42% of its overall energy needs from coal.

    Bad guy Canada is a baby when compared to this group. We are responsible for only 2% of global greenhouse gas emissions. This includes the oil sands, at .01%. We generate 19% of our electricity by burning coal but unlike China, the U.S. and India, 75% of our electricity generation comes from hydro and nuclear power generation, non-emitting energy sources.

    China’s only interest in Kyoto or any similar agreement is the negative impact it will have on the industrialized economies of the developed world. Punitive environmental regulations will retard our growth and raise our prices thereby allowing China to continue its rapid expansion. According to the World Bank and UN statistics, approximately 200 million Chinese people live on less than US$1.25/day; a further 482 million people live on less than US$2/day. Who can blame their government for massive growth and social improvement planning?

    In short though, China’s pollution is six or seven times greater than ours but they don’t have any emission reduction targets under Kyoto. They’re exempt, along with India and its 500 million citizens who live below the poverty line. Most of the other freeloading Durban Do-Rights that comprise this latest in a seemingly endless series of environmental fun fests are also exempt. The United States is exempt too because they have steadfastly refused to ratify Kyoto going all the way back to the Bill Clinton/Al Gore administration. Yes, that Mr. Gore, another hypocrite. In fact, only 37 industrialized nations are covered by agreements these international partiers negotiate and sign. All they really want is our hard earned money. They call it redistribution. I call it theft.

    But coal, the biggest man made problem, is the world’s most abundant fossil fuel. Its reserves are enormous and its use in the developing world is rising, one reason total emissions there will surpass those of the industrialized world in our lifetimes.

    All nations big and small use whatever power sources are available to them. The idea is to raise the standard of living of those less fortunate not drag us down.

    In the meantime, they can call us what they want. We’re out of Kyoto and we’re not signing anything until all the major emitters and hypocrites do. You either pollute or you do not. How tough can that be?

    Someone should also tell poor old Desmond Tutu that his home country of South Africa receives 85% of its power from coal-burning plants. He should look around instead of reading what they put in front of him at these international gab fests. If he did he would learn about the two 4,800-megawatt power plants currently under construction right there in South Africa. Duh. Each one is nearly double the size of anything found in Canada or the U.S. The combined emissions from just these two plants alone will equal more than half the output of our Oil Sands. Can the man not Google? Tut, tut Tutu.

    Yes, I know about solar panels, wind mills and bio fuels. In my own Province (Ontario) the tax payers have eaten some $8 billion dollars on fool hearty attempts to get them off the ground. We are a Province not a country. We have blown more than the U.S. and we sell the resulting excess electricity we produce to the U.S. at a 50% discount. You’re welcome.

    I have learned much from this blog and have been happily forced to read more because of it. I like it and recommend it to others on a regular basis. On many topics I have changed long held opinions and on others I have softened. On climate change, not so much. But it’s early. We are learning more everyday. Even me.

Leave a Reply

Your email address will not be published. Required fields are marked *