PERMAFROST CAVE: The frost crystals at the entrance to the Ledyanaya Lenskaya cave in Russia denote the region's permafrost, which has been in place for roughly 400,000 years, according to the cave's speleothems.
Image: Vladimir V Alexioglo
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Permafrost is not so permanent. Across the Arctic, swathes of once-frozen-solid ground have begun to thaw. If the records preserved in Siberian caves are accurate, much more of the region could melt if temperatures continue to warm.
Geoscientist Anton Vaks of the University of Oxford led an international team of experts—including the Arabica Caving Club in Irkutsk—in sampling the spindly cave growths known as stalagmites and stalactites across Siberia and down into the Gobi Desert of China. Taking samples of such speleothems from six caves, the researchers then reconstructed the last roughly 500,000 years of climate via the decay of radioactive particles in the stone. When the ground is frozen above a cave no water seeps into it, making such formations "relicts from warmer periods before permafrost formed," the researchers wrote in a study published online in Science on 21 February.
The details of the study reveal that conditions were warm enough even in Siberia for these mineral deposits to form roughly 400,000 years ago, when the global average temperature was 1.5 degrees Celsius higher than present. It also suggests that there was no permafrost in the Lena River region at that time, because enough water seeped into the northernmost cave to enable roughly eight centimeters of growth in the formations.
That was, in fact, the last time the formations in the Ledyanaya Lenskaya Cave grew, although other caves further south showed multiple periods of growth coinciding with other warmer periods. "That boundary area of continuous permafrost starts to degrade when the mean global temperature is 1.5 degrees C higher than present," Vaks explains. "Such a warming is a threshold after which continuous permafrost zone starts to be vulnerable to global warming."
Since Vaks's present is the "preindustrial late Holocene," that means the planet is already more than halfway there, having experienced 0.8 degree C warming to date. Such a thaw is no small matter, given that permafrost covers nearly a quarter of the land in the Northern Hemisphere and holds roughly 1,700 gigatonnes of carbon—or roughly twice as much carbon as is currently trapping heat in the atmosphere. Much of that carbon would end up in the atmosphere if the permafrost was to thaw further.
That may not have occurred during the warm period 400,000 years ago, known as Marine Isotope Stage 11 to scientists, which featured elements such as boreal forest on Greenland and higher sea levels. "The thawing was probably very brief because the layer deposited in the northernmost cave stalactite was relatively thin," Vaks says—too thin in fact to determine how long the warm period lasted. "We don't see any extraordinary increase in atmospheric CO2 or methane during MIS-11." And the Gobi Desert might benefit, enjoying wetter conditions in the future if the record in these caves is accurate.
It's not clear how far north such thawing might extend if global average temperatures continue to warm until they match those from long ago. "Now we are looking for caves with speleothems in northern Siberia to answer this question," Vaks notes, adding that the northernmost cave is already much warmer than in the late 18th century based on historical reports. Further research could be done by taking sediment cores from Arctic river deltas or lakes, though this remains an epic task given the vastness and remoteness of the region. But, already, it is clear that global climates not much warmer than present are enough to thaw even more permafrost—as far north as 60 degrees latitude.
"The potential impact of these results extends to global policy: these results indicate the potential release of large amounts of carbon from thawed permafrost even if we attain the 2 degree [C] warming target under negotiation," says Kevin Schaefer, a scientist at the U.S. National Snow and Ice Data Center, who has also studied permafrost but was not involved in this, in his words, "great science" effort. "Permafrost thaws slowly and the carbon will be released into the atmosphere over two to three centuries."
Already, such thawing Arctic ice—whether underground or at sea—has further opened up the territory to exploration for resources, particularly oil. At the same time, the big thaw will make getting the oil out more expensive—billions of dollars in infrastructure investments in pipelines, roads and the like will be damaged as the ground shifts beneath them.
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Add CommentWe're warming up and the global consequences are not good. It's time to change the ways we generate and use energy for the sake of future generations. Contact your Congressional policy makers. Insist they work aggressively to reduce emissions.
Reply | Report Abuse | Link to thisIn addition, some are contacting the "experts" used by the fossil fuel industries to spread disinformation. The following link is being passed around with their email addresses. How can they morally justify working for or with those that willingly put profits before the health and safety of future generations?
http://heartland.org/experts
Climate change is inevitable and normal as this article specifically mentions. The fact that climate change is cyclical is something that is often ignored. While I completely agree that we need to find alternative energy sources I do not and will not buy into the premise that man is the cause of this instance of climate change. Regardless of the cause of the coming climate change we need to prepare for the effects that it will cause. Man is an exceedingly adaptable species and completely capable of making the necessary adaptations. Basically what I am saying is quit crying about the problem and let’s work towards finding a way to deal with the coming changes.
Reply | Report Abuse | Link to thisNo kidding climate has natural cycles and some degree of the human impact is indeed inevitable. But we can decrease the severity. If you really think we "need to find alternative energy sources" I would ask you, "Why?" Because the supply will run out or because pollution has consequences? Both are good reasons.
Reply | Report Abuse | Link to thisWe need cleaner alternatives mainly because our current fossil fuel burning endangers the biosphere’s long-term habitability. This isn't "crying" about the problem it's spreading the word, reducing ignorance and confronting denial. Humanity will not change course unless more of us know about the dangers. Sorry but apathy, ignorance, defeatism, and denial are all just business-as-usual.
As I agree that we need to prepare for the effects, man is the cause of the warming over the last 150 years, and I would like to read your refutation of said cause. Cyclical change has never been ignored; it has been focused on. The parameters of current change have been ignored by you. Although man is "adaptable", the man-made systems that have been put in place are much less so, and that may be the biggest quandary that faces mankind.
Reply | Report Abuse | Link to thisClimate change is cyclical over MUCH longer time scales than the change we are currently experiencing. A 1C increase over the last 150 years is unprecedented in the climatic record. And since ALL the natural forcings on the climate are either steady or should be causing cooling, human activities and GHG emissions in particular are the cause.
Reply | Report Abuse | Link to thisCO2 traps heat and we've increased its concentration in the atmosphere by 40%. We have a very good picture of its emissive properties and we have OBSERVED less radiation escaping to space. We have also OBSERVED more radiation coming back down to the surface from high in the atmosphere. The poles are warming faster than the tropics, nights are warming faster than days and the stratosphere is cooling while the troposphere is warming.
We have conclusively proven that human GHG emissions are the primary driver in the climate changes seen over recent decades. As the Earth warms, we will see increasingly negative impacts such as more frequent and intense storms, floods, fires and droughts. The abrupt disintegration of Earth's ice will continue and accelerate as temperatures climb. The world's ENTIRE scientific apparatus has united behind these conclusions and there is no significant objections to these conclusions.
But things don't look all bad. Solar power is plummeting in price and wind power is cheaper than basically all other energy sources already. Energy storage is becoming remarkably cheaper too and electric cars might be able to do double-duty as storage during the 23 hours a day they aren't being driven. Smart grid approaches will allow the electric grid to become more flexible and accommodate a wide range of energy sources. And to top things off, the cheapest source of new power is energy efficiency. The USA wastes about 1/2 of the energy it uses for no good reason. Energy efficiency can put some of that waste to good use, lowering costs for everybody while cutting greenhouse gas emissions and the nasty pollution that gets emitted along with it.
So has man been the cause of this?
Reply | Report Abuse | Link to this'Nothing off-limits' in climate debate
THE UN's climate change chief, Rajendra Pachauri, has acknowledged a 17-year pause in global temperature rises
http://www.theaustralian.com.au/news/nothing-off-limits-in-climate-debate/story-e6frg6n6-1226583112134
Much energy is wasted running backup generators for unreliable alternative energy schemes. We could save that for starters.
Reply | Report Abuse | Link to thisReasonable people will agree that there are people on both sides of the climate change issue. As I said earlier I do not buy into the premise that man is the cause of this climate change. Is it possible that man has added to this trend? Certainly, but man’s contribution to climate change is more in the order of adding a handful of sand to the back of a dump truck, it is there but there are many other contributors and many much larger than anything man has contributed. Global volcanism adds many times more greenhouse gases in a single year than all of mankind’s throughout history and unless someone here is going to argue that man causes volcanoes to erupt then I stand by my assertion.
Reply | Report Abuse | Link to thisSo with this said, why do I support developing alternative energy sources? Well the answer here is basically all of the reasons listed by the guys above. Even though I do not agree with their basic premise I do agree with their reasoning. It is possible to arrive at the correct answer by an incorrect path.
We must prepare for the coming effects of climate change. Global warming will cause sea level change and large sections of the population will have to relocate. Thankfully this is not something that will happen overnight but over the course several years. So as I said earlier, “Man is an exceedingly adaptable species and completely capable of making the necessary adaptations.” We may not want to change, we may resist this change but change we will.
Still haven't seen even one piece of evidence showing these mythical backup generators.
Reply | Report Abuse | Link to thisIt's a good thing they shut down all those SUVs and coal power plants 400,000 years ago!
Reply | Report Abuse | Link to thisLet's unpack all this denier bunkum, shall we?
Reply | Report Abuse | Link to this"Reasonable people will agree that there are people on both sides of the climate change issue."
Not really...
"National and international science academies and scientific societies have assessed the current scientific opinion, in particular on recent global warming. These assessments have largely followed or endorsed the Intergovernmental Panel on Climate Change (IPCC) position of January 2001 which states:
An increasing body of observations gives a collective picture of a warming world and other changes in the climate system... There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.[5]
The main conclusions of the IPCC on global warming were the following:
1.The global average surface temperature has risen 0.6 ± 0.2 °C since the late 19th century, and 0.17 °C per decade in the last 30 years.[6]
2."There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities", in particular emissions of the greenhouse gases carbon dioxide and methane.[7]
3.If greenhouse gas emissions continue the warming will also continue, with temperatures projected to increase by 1.4 °C to 5.8 °C between 1990 and 2100. Accompanying this temperature increase will be increases in some types of extreme weather and a projected sea level rise.[8] On balance the impacts of global warming will be significantly negative, especially for larger values of warming.[9]
No scientific body of national or international standing maintains a formal opinion dissenting from any of these three main points."
http://en.wikipedia.org/wiki/Scientific_consensus_on_climate_change
"Global volcanism adds many times more greenhouse gases in a single year than all of mankind’s throughout history..."
Again, more bunkum:
"...modern volcanic activity releases only 130 to 230 megatonnes of carbon dioxide each year,[13] which is less than 1% of the amount released by human activities (at approximately 29,000 megatonnes)."
http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere
Just because wildfires happened in the past doesn't mean that arson can't happen in the present. Logic FAIL.
Reply | Report Abuse | Link to this"Global volcanism adds many times more greenhouse gases in a single year than all of mankind’s throughout history and unless someone here is going to argue that man causes volcanoes to erupt then I stand by my assertion."
Reply | Report Abuse | Link to thisStandard denialist lie. Volcanoes emit less than 1% of what human activity does.
http://hvo.wr.usgs.gov/volcanowatch/archive/2007/07_02_15.html
http://news.discovery.com/earth/weather-extreme-events/volcanoes-co2-people-emissions-climate-110627.htm
http://www.scientificamerican.com/article.cfm?id=earthtalks-volcanoes-or-humans
A "Catastophe"? Really?? Some people having to move inland from the Jersey Shore over the next 50 years is not a "catastrophe". It is a reasonable adaptation to constantly changing conditions, and ongoing risks. Rebuilding there with public dollars is crazy. I am tired of the attempt to stampede the public into accepting big tax hikes in the name of "climate change". I am not buying. If you live in a low-lying area, it's time to think about your next move - inland. Time to change building codes and insurance coverages to get the move started, and let's save the seashores for day use only. No more building in areas prone to flooding during the "storm of the century", because it *will* happen, climate change or not.
Reply | Report Abuse | Link to thisI can't speak for Rajendra Pachauri, but if you separate the trends for La Nina, El Nino, and other years, you get a striking upward trend for each of them. For El Nino there have been only two data points bucking the trend in the past 60 years. For El Nina there has been only one data point out of order for the past 40 years, and that one point only a little. The remaining data is noiser, but much less that it was when combined with the two others. Look at the plot here:
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/File:Enso-global-temp-anomalies.png
How in the world could abandoning trillion$$$ in coastal infrastructure be cheaper than just making the switch over to clean energy during the next few decades? Since coal pollution causes between $100B and $500B in damages in just the USA, you have to put that on your accounting ledger too...
Reply | Report Abuse | Link to thisAnd you seem to lack an awareness of the moral hazards that climate change causes as well. Why should people living in low-lying areas have to lose their homes and livelihoods, especially in places like Bangladesh or small island states, so that people in developed countries can continue with their profligate lifestyle? How is that even remotely fair?
The war on weather continues, with truth the first casualty. I doubt the ability to model the infinite variables, direct interactions, and multi factor feedback effects of all life on earth, all mineral deposits, all subsea and ocean dynamics. Nothing has happened in 17 years, as the next IPCC report must reluctantly report. The hottest thing in climate change has always been the rhetoric.
Reply | Report Abuse | Link to thisThirty years of secretive government data, a small priesthood of insiders, the usual suspects beating the anti oil/coal/automobile drum, culminating in the futility of superpower intervention. Relying on a congress that borrows a tenth of a trillion $US monthly to stay current defines unsustainability.
Study worthy yes, regulation ready no, command and control impossible.
Stop market distorting incentives and subsidy. Since transit is quite efficient, work on poor residential and industrial energy waste.
Like global cooling, acid rain, and ozone depletion, this too shall pass.
Regardless of whether or not humans are contributing significantly to climate change, I believe the climate change policies are a good thing, as they help in reducing air and water pollution. I believe the climate change policies should be renamed to clean air/clean water polices to eliminate the debate.
Reply | Report Abuse | Link to thisWell then, you should be promoting nuclear. The only technology that could make a measurable difference.
Reply | Report Abuse | Link to thisThe reason it is cheaper to abandon the valuable coastal regions is that it is even more expensive to attempt to maintain them. There is no reasonable way to build dikes to hold back the oceans, as has been done in the Netherlands on a global scale; therefore, it is much more reasonable to migrate inland as necessary. The coming changes in sea level and weather patterns will change land usability globally it is likely that lands currently unusable due to arid conditions will become fertile again and currently fertile lands will also be affected. There is no reason to believe these changes will all be negative.
Reply | Report Abuse | Link to thisAs I have repeatedly stated climate change is not a man made occurrence. Has man had an impact on this current occurrence of climate change? Maybe yes, maybe no. Most likely man’s actions have added a bit of momentum to an event that was already in motion, kind of like a kid pumping a swing.
Many have suggested that America needs to make large adjustments to our energy policies. While I agree that going green is a good idea, I think we are looking in the wrong direction. There are several other industrialized countries that are much worse polluters than America, and whether or not America goes completely green or continues in our current direction these other countries impact is a much larger contributor to climate change.
In fact it could be argued that well-meaning green energy initiatives enacted here in America but not in other countries are actually hurting the environment and here’s why. People will always purchase the less expensive option that’s a basic economic premise. These American green initiatives cause American products to be more expensive thereby causing more and more manufacturing to move to the countries that do not use the green methods. Therefore, we should not be putting pressure on American industries about green technology as much as we should be putting pressure on all countries to enact these types of initiatives.
Be it as it may, there is an ongoing climate change and human activity is accelerating the process and making it more dangerous and potentially irreversible. But... You don't "buy" into the concept of anthropocentric climate change? How scientific of you! Don't be troubled by the results obtained by climatologists, physicists, etc. Bunch of liberals with an agenda to destroy the economy of the good old USA! Just ignore them, and don't forget to drink your tea while it is still warm. Smile, Ted Cruz and Marco Rubio love you!
Reply | Report Abuse | Link to thisI could make similar comments about your drinking the liberal Obama cool aid. There is well respected research on both sides of these issues you just refuse to accept any premise that contradicts your chosen view point. Admittedly I also refuse to refuse to accept any premise that contradicts my view point. The difference here is I have made a reasonable argument as to where we should be focusing green initiatives. You on the other hand just want to sling mud, how typically liberal of you. You lose an argument on logic so insult the opposition until the shut up. Make certain you are LOUD in your response that is what will make me wrong.
Reply | Report Abuse | Link to thisThere is no ancient climate record that is accurate to 150 years. Ice cores cover 12000 years in a layer. Statements about ancient highs and lows not being similar to today are made without any accurate data. Also, there tend to be extremes at the end of any long term build up in systems. Avalanches are the easy example. We can trigger them but not predict them with accuracy.
Reply | Report Abuse | Link to thisover the last fifty years, I have done soils drilling from the north side of the Chugach Range to the Arctic ocean. A couple of my recollections may be significant.
Reply | Report Abuse | Link to thisOver the last fifty years, i have worked on a number of soils investigations from the north side of the Chugach Range to the Arctic Ocean. significan observations that I would like to share. 1. Sedge Grasses tend to be a reliable indicator for ice rich permafrost and are easily mapped from aerial photography.with ice content ranging from 40 percent to a full hundred percent. I rarely drilled deeper than 10 or 15 meters (having identified a problem I needed to move on.)at a fair guess, I believe that probably 70 percent of the ground that i traversed was underlain by permafrost at least 10 meters thich. i never did find the bottom of the ice except on the alluvial plain of the Saganiverktok river at the edge of the arctic ocean. See the disappearing lakes for an explanation. My concern is that although the permafrost thaws slowly, the areal extent in alaska, canada and Siberia is so vast that it could contribute to sea level rise and has been largely ignored in comparison with the Greenland and antarctic ice sheets which are much more spectacular and newsworthy. Perhaps the output records from siberial numerous north flowing rivers could provice a clue.
Reply | Report Abuse | Link to thisAs Doyle had one of his characters state "When you have eliminated everything else whatever remains must be the truth". Everything else has been eliminated.
Reply | Report Abuse | Link to thisOnce again thank you Scientific American. Your ability to gather widespread articles of interest and bring them to the attention of the public is worthwhile and much appreciated. Thank you, as well, to the people that comment.
Reply | Report Abuse | Link to thisScience is about evidence, not belief. Ric, what is your investment in refusing to accept the evidence? What you don't mention is that there are short term social and economic costs to reducing our carbon output which some in our society do not want to pay. If human activity is not causing global warming, why look for alternative sources of energy?
Reply | Report Abuse | Link to this#5 sault is to be ignored. We may simply be in the midst of a warming cycle such as happens a few times every 1000 years. No one has proven or quantified the role of the current CO2 increase and there are conflicting views, so that is an irresponsible claim. Some parts of the world are enjoying the temperature increase so universal acceptance of CO2 decrease is not assured by any means. We would be well off with means for relatively local climate control.
Reply | Report Abuse | Link to thisI agree 100% Ric_Hornsby
Reply | Report Abuse | Link to thisWe simply do not have the (what we label Experts) That can convince the average Intellect what the Planet & Atmosphere will Do, is going to Do in a Span of even 100 Years. We can't even predict weather patterns with 100% certainty, or understand plate shifts which may or may not results in a potential devastating earth quack. When I observed the science geniuses within the Corporations for the last 30 years, I myself work for & with I can come up only with 1 conclusion.
It's Sad, but oh so True. When a scientist becomes Sauvé on politics and slowly mentor him/her self into a politician they lose basis with all reality & their basic knowledge of science.
Science Looks for Truth.
Politicians don't Care! We just Make it True.
Simon' View.
& I'm Stuck in the Middle Swimming to Safety.
Wow, where did all these deniers come from? The unscientific ignorance they bring is almost overwhelming! None of you have bothered to look at EVEN ONE scientific paper on this subject, have you! You probably think some blogger paid off by fossil fuel companies is smarter than the worlds ENTIRE SCIENTIFIC COMMUNITY too, right? Sorry, but Faux "News" and rightwing radio / blogs are NOT credible scientific sources! Either read some actual science on this issue and contribute to this discussion constructively or keep your denier bunkum restricted to the pile of trash where you picked it up!
Reply | Report Abuse | Link to thisVery good analyses Sault describe on the weather patterns. I assume, taken from the new Climate models scientist lately modified due to the observation satellites now supporting Us.
Reply | Report Abuse | Link to thisHowever, Co2 is not just the only and Main ingredient that increases Global warming. Methane for instant is a far greater threat, which I believe is more controlled by the Planet itself. For that matter so is the Carbon Cycle. Our few hundred year industrial revolution is nothing compare to what this planet our atmosphere combined with the Sun and our Galaxy is brewing for 5 billion Years or more.
Yes, we have polluted the Air, maybe altered the Microbes / bacterial growth concern found in the Upper atmosphere, and so on. The earlier planet's atmosphere was indeed warmer than it now is, and as this article describes, " 400,000 years ago, when the global average temperature was 1.5 degrees Celsius higher than present" Therefore, I simply deduct we do very little to that effect overall. We merely study the Universe, explore discover, learn and modify the energy flow that becomes available to Us sometimes by Luck or new discoveries. One comment I have to agree on, efficiency is hard to find and learn, a study by itself that covers almost everything we do. In people's daily lives on all factors and there is a lot to learn yet.
Too bad most of us will have to be forced to even consider that moderation and conserving energy supply for our daily needs will become a must. And that will be hard to do, because the less fortunate's always pay for it first.
To those who say let us adapt... indeed, as if there were a palatable alternative. For anyone not willing to accept humanity's contributions to global warming, so be it. Responsibility is such a dirty word these days; is it not? Let's avoid fixing blame; let us simply say that we have been unwitting. Consensus does seem to be in the arena that there is a problem however, and generating additional CO2, hardly part of the play book for winning the game. Let's put a finger on the solution, rather than pointing it at one another. We may be coming at this from different positions, but can we at least agree on a little teamwork... that smart play is what is in order here? Oh, and let's not forget that we are also playing against the clock. For sure, we may be a ways yet from the two minute warning. But does anybody seriously want to take it to that point?
Reply | Report Abuse | Link to thisI care less about what happens in the grand scheme of things than I do about what happens to my children, their children, and the people that they will share this planet with. And while humanity's actions are mostly insignificant compared to what's happened over the Earth's history, they are VERY significant over the course of human history.
Reply | Report Abuse | Link to thisYour apathetic mindset would lead somebody in the path of an oncoming tsunami to just sit and wait for the wave to wash over them instead of seeking higher ground. In the grand scheme of things, the water will eventually recede and it will be hard to tell whether the tsunami even happened, right? However, with the CLEAR evidence that disaster is on its way, it would be foolish for people caught on the beach on the day a tsunami strikes to not even try and save themselves!