NUMEROLOGY: Is there a right number to prevent "dangerous anthropogenic interference" in the planet's climate?
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This December, world leaders will meet in Copenhagen to add more hot air to efforts to combat climate change. That is so because although the impacts humanity would like to avoid—fire, flood and drought, for starters—are clear, the right numbers to halt global warming are not. Despite decades of effort, scientists do not know precisely what temperatures or greenhouse gas concentrations in the atmosphere constitute a danger.
When it comes to defining the climate's sensitivity to forcings like rising atmospheric carbon dioxide levels, "we don't know much more than we did in 1975," says climatologist Stephen Schneider of Stanford University, who first defined the term climate sensitivity in the 1970s. "What we know is if you add watts per square meter to the system it's going to warm up."
Greenhouse gases add those watts by acting as a blanket, trapping the sun's heat; they have warmed Earth by roughly 0.75 degree Celsius over the last century. Scientists can measure how much energy greenhouse gases now add (roughly three watts per square meter), but what eludes precise definition is how much other factors—the response of clouds to warming, the cooling role of aerosols, the heat and gas absorbed by oceans, human transformation of the landscape, even the natural variability of solar strength—diminish or strengthen that effect. "We may have to wait 20 or 30 years before the data set in the 21st century is good enough to pin down sensitivity," says climate modeler Gavin Schmidt of the NASA Goddard Institute for Space Studies (GISS).
Despite all these variables, scientists from Svante Arrhenius to those on the United Nations Intergovernmental Panel on Climate Change have noted that doubling preindustrial concentrations of CO2 in the atmosphere from 280 parts per million (ppm) would likely result in a world with average temperatures roughly 3 degrees C warmer.
But how much heating and added CO2 is safe for human civilization remains a judgment call. European politicians have agreed that global average temperatures should not rise more than 2 degrees C above preindustrial levels by 2100, which equals a greenhouse gas concentration of roughly 450 ppm. "We're at 387 now and we're going up at two ppm per year," says geochemist Wallace Broecker of Columbia University's Earth Institute. "That means 450 is only 30 years away. We'd be lucky if we could stop at 550."
The GISS's James Hansen argues that atmospheric concentrations must be brought back to 350 ppm or lower—quickly. "Two degrees Celsius [of warming] is a guaranteed disaster," he says, noting the accelerating impacts that have manifested in recent years. "If you want some of these things to stop changing—for example, the melting of Arctic sea ice—what you would need to do is restore the planet's energy balance."
Other scientists, such as physicist Myles Allen of the University of Oxford, examine the problem from the opposite side: How much more CO2 can the atmosphere safely hold? To keep warming to below 2 degrees C, humanity can afford to put one trillion metric tons of CO2 in the atmosphere by 2050, according to Allen and his team—and humans have already emitted half of that total. Put another way, only one quarter of the world's remaining known coal, oil and natural gas reserves can be burned. "To solve the problem, we need to eliminate net emissions of carbon dioxide entirely," Allen says. "Emissions need to fall by 2 to 2.5 percent per year from now on."
Climate scientist Jon Foley of the University of Minnesota, who is part of a team of researchers that defined safe limits for 10 planetary systems, including climate, argues for erring on the side of caution. "Conservation of mass tells us if we only want the bathtub [water level] so high either we turn down the faucet a lot or make sure the drain is bigger. An 80 percent reduction [in CO2 by 2050] is about the only path we go down to achieve that kind of stabilization."
The National Academy of Sciences, for its part, has convened an expert panel to deliver a verdict on the appropriate "stabilization targets" for the nation, a report expected to be delivered by summer 2010. Of course, perspectives on what constitutes a danger may vary regionally and locally, depending on whether one resides in coastal Florida or landlocked Minnesota, let alone in the U.S. or the Maldives.
Keeping atmospheric concentrations of greenhouse gases below 550 ppm, let alone going back to 350 ppm or below, will not only require a massive shift in human society—from industry to diet—but also, most likely, new technologies, such as capturing CO2 directly from the air. "Air capture can close the gap," argues physicist Klaus Lackner of the Earth Institute, who is looking for funds to build such a device.
Closing that gap is important as the best existing data—observations over the last century or so—show that the climate is sensitive to human activity. "There are thresholds of irreversible change out there, we don't know where they are," Stanford's Schneider notes. "What we do know is the more warming out there, the more dangerous it gets."
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27 Comments
Add CommentThe "trillion tonnes carbon" from CO2 Myles Allen says is 'safe', takes us to ~480 parts per million by volume [ppmv]. This value will help global temperature to rise beyond the average '2-degrees' still touted as 'safe' by some commentators.
Reply | Report Abuse | Link to thisAs stated by the UNFCCC executive in 2004, whatever value is the limit, a full-term emissions contraction-and-convergence [C&C] event is needed to theoretically keep within that limit.
In evidence to the UK House of Commons this year, Chairmain of the UK Climate Change Committee [CCC Chair Adair Turner] agreed that the UK Climate Act is based on C&C and agreed that "if, for reasons of urgency the rate of global contraction has to be accelerated, then for reasons of equity the rate of international convergence has to be accelerated relative to that."
Following this logic, the UK Met Office/Hadley Centre has confirmed - as shown in the images at the link below - [a] the CCC’s odds are worse than 50:50 for keeping within a maximum 2 degrees with their Contraction and Convergence [C&C] Scenario and that [b] the odds are better than 50:50 for keeping within a maximum 2 degrees with GCI’s accelerated Contraction and Convergence [C&C] Scenario.
http://www.tangentfilms.com/C&Csum27nov.pdf
Myles Allen gave evidence to the House of Commons Select 'Environmental Audit Committee' and will be aware of this.
Information concerning the above and C&C is here: -
http://www.tangentfilms.com/GCIEAC10nov09.pdf
Overall the world is probably in a lot worse shape than most of the climate models predict due to continuing depression of CO2 absorption from natural sinks . This depression means that even if emissions are reduced dramatically in the next 20-40 years the prospects for getting below 350 ppm, the number that is all the rage at the moment for averting serious climate disruptions, is remarkably small without technological assistance. Realistically air capture is probably the best bet over more risky pure geo-engineering strategies, but Klaus Lackner and other supports seem to underestimate how much we will really need to remove from the atmosphere.
Reply | Report Abuse | Link to thisI recommend reading these two posts if you want to have a better understanding of the real obstacles and advantages of air capture.
http://bastionofreason.blogspot.com/2009/07/turning-clock-back-reducing-atmospheric.html
http://bastionofreason.blogspot.com/2009/10/air-capture-update-is-grts-air-capture.html
"'To solve the problem, we need to eliminate net emissions of carbon dioxide entirely,' Allen says. 'Emissions need to fall by 2 to 2.5 percent per year from now on.'"
Reply | Report Abuse | Link to thisI find it strange that we are still talking in percentages. We will have to start removing carbon dioxide from the air and eventually (it will take a long time) get the concentration back down to 280 ppm.
If you go over the C&C proposals, you'll see that's what we've been culating and advocating with C&C for the last 15 years.
Reply | Report Abuse | Link to thisThere's no need to invent new technology for carbon capture. Nature has provided the optimal devices for removing CO2, and these devices are powered by sunlight and water. Plants have been evolving to maximize their growth potential for hundreds of millions of years, from plankton to trees. We should harness that efficiency to capture carbon.
Reply | Report Abuse | Link to thisHow many warmist PR articles can Un-Scientific American put out in a day?
Reply | Report Abuse | Link to thisWhat a rag - and an embarrassement that "American" is in your title.
I'm really shocked. Can't wait to look up your list of advertisers, to see who are supporting this propaganda.
"Air capture can close the gap," argues physicist Klaus Lackner of the Earth Institute, who is looking for funds to build such a device.
Reply | Report Abuse | Link to thisI wonder how many 100s of billions of dollars he will need for this boon doggle. These people need professional help, not more funds and print space..
What a load. You guys still bangin that drum? You guys are making Scientific American a contradiction of terms
Reply | Report Abuse | Link to thisMr Rational, Sciam is reporting the science and the arguments. You appear to support irrational thinking in this "debate". If you can say why all the climate scientists are wrong and point to some peer reviewed corroborated research, then you may have reason for doubt. Without that, a reason of "I don't want it to be so" is hardly good enough. It's certainly not good enough for this "rag", which is why we get balanced reporting (look at the number of articles about energy and geo-engineering that purpote to keep an unsustainable global society going a bit longer, for evidence).
Reply | Report Abuse | Link to thisWhat a crock. This article "reports" only the comments that fit the non-scientific warmist agenda.
Reply | Report Abuse | Link to thisFor me to post a thoughtful response to the bushels of crap in this article would take days. Because unlike the author, just finding one quote from one biased "scientist" is not a basis for me to mke a declarative statement.
Your education is not my responsibility. I have done you the trouble of pointing out that this is a propanda article. You are free to continue to drink the cool aid - but the "deniers" have been pointing out the junk science for a decade now.
The August 2009 NOAA Climate Assessment Update has a chapter that discusses the past 10 years of no warming. In the analysis NOAA stated that a 10 year trend was not enough to falsify the GCMs but that a 15 year trend would falsify them at a 95% level of significance. So if no more warming occurs through 2014 the theory of CO2 as the primary cause of our warming planet would be falsified.
Reply | Report Abuse | Link to thisIf the NOAA analysis is wrong, I would be interested in knowing what benchmark would be needed to falsify the theory of CO2 driven warming in Earth's open system.
Mr Rational,
Reply | Report Abuse | Link to thisThanks for confirming that you have no argument other than belief.
windy city kid,
This graph from the NOAA certainly shows warming in the last 9 years. The 1998 temperature was a spike, which was actually exceeded by the 2005 data. Overall, the trend is still clear.
http://www.ncdc.noaa.gov/img/climate/research/global-jan-dec-error-bar-pg.gif
I am saddened and alarmed by the agression this topic seems to have raised in those of differing opinions. Perhaps that is the difference between discussion and debate. The latter seeks a victor and a vanquished. This topic is too serious to decend into the realms of who's ego is more worthy.Agression is often a symptom of fear, and it is what we fear that probably divides us. It is also a red herring, because other long term trends which threaten human culture also point to the imperative of changing the way we operate, or wait and have catastrophic change forced upon us. Quite a few key natural resources supplies, including oil, are set to fall short of the demand that we will place on them if we continue on our present course. Originally the study of economics was about optimising resources to meet human needs and aspirations. It has now been largely hijacked by a greed obsessed financial system which, through a gradual , but relentless pressure demanded and got ever more reward for it's contribution to the operation of civilisation. People have noted this and joined in, and as a result the financial sector is probably much larger than it actually needs to be, but is maintained by a complicated system of market distortion and buckpassing, so that the weakest individuals and nations pay for the excesses of the strong. This eventually breaks down when someone drops the parcel, or the poor have not enough left to mortgage. The major economies have put their populations into hock for years ahead to sustain a faulty system. If "time out" were declared all over the world and a balance sheet drawn up, a huge entry on that document would be a debt supposedly owing to the financial industry by the real economy. If some benevolent alien wiped out all financial records at a stroke, would we as a species be worse of, or just a percentage who have power as a consequence. All the actual physical capital would still be intact and the capacity to produce, but banks and other money custodians would have to start afresh. The banks effectively told the world leaders we can't be allowed to fail, but the price for letting them survive should have been a re appraisal of what their limits should be. We won't sort the emissions problem without sorting out the emitters. The money system limits the freedom of action of the real economy to make and sustain the necessary changes, but both need to know where they are going and what they are really worth.
Reply | Report Abuse | Link to this'Capturing Co2 directly from the air' : I clicked on this link, but there was no mention of Biomass Pyrolysis, which converts any wet or dry biomass into biogas, biofuels, hydrogen or biochar.
Reply | Report Abuse | Link to thisThe technology has been developped for over ten years and is now fully operational. See www.eprida.com for details.
Why look elsewhere when economical solutions already exist?
Maybe the big lobbies get too much airing...
Windy city kid:
Reply | Report Abuse | Link to thisThis central issue is the concept of "positive feedback forcings", in which water vapour allegedly multiplies the effect of the CO2. This is a crucial issue as experiments show that the physics of CO2 alone are unable to create any signficant warming per se.
The question I have asked numerous times is whether "positive feedback forcing" has ever been demonstrated in nature or does it only exist in computer models? So far the only information I have seen on the subject show that forcing is, if anything, slightly negative, meaning that significant increases in CO2 would have little effect or possible a slight cooling effect.
I've asked this question several times and I'll ask it again does anybody know of any data that demonstrates positive feedback forcing supported by real world data? Not computer models, but real live actual data?
Sofistek - You completely missed my point so I'll try again. The MET Office in the UK released an analysis of recent GMST trend and its divergence with MET model forecast. Here is the analysis:
Reply | Report Abuse | Link to thishttp://www.metoffice.gov.uk/corporate/pressoffice/2009/global_temperatures_09.pdf
The MET scientists clearly state that the GMST trend is zero and here is the quote:
"The trend in the ENSO-related component for 1999–2008 is +0.08±0.07°C decade–1, fully accounting for the overall observed trend. The trend after removing ENSO (the "ENSO-adjusted" trend) is 0.00°±0.05°C decade–1, implying much greater disagreement with anticipated global temperature rise."
The MET office clearly states that a zero trend for 10 years is still within internal model variance parameters here:
"Near-zero and even negative trends are common for intervals of a decade or less in the simulations, due to the model’s internal climate variability."
Then they continue with:
"The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate."
This is good news as climate scientist very rarely offer a measurable indicator that would falsify the models that they provide as evidence for future claims. I prefer empirical evidence to consensus and there should be more measurable indicators of falsification so that climate scientists aren't just adjusting historic raw data to fit their models like the GISS adding .5 degrees F onto the raw temperature data since 1940.
So if the zero trend for GMST continues 4 more years, the MET forecast of 2 degree Centigrade for 2100 would be outside model variability and the forecast would be too high.
It is important to note here that if all model parameters other than man made CO2 are removed from the model, there is no warming correlation for man made CO2. Rise in MGST forecasts rely on positive feedback systems and the understanding of those feedbacks is not well understood.
Is our best guess of 2100 GMST good enough? We'll see but at least now it can be measured in 4 years.
Again if you have an alternate method of showing falsification for a hypothesis as related to climate change let me know.
Shoshin - Good question and you should keep asking it until it's answered to your satisfaction. My answer is that I don't know. I can tell you that I believe your answer will come from satellites supplying empirical data on climate that is starting to shed more light on correlating open system measurement with closed system replications (models). I suggest you do a Google Scholar search on the topic. Here is one recent peer reviewed paper that compares modeled feedback with satellite measurement as a start. Good luck!
Reply | Report Abuse | Link to thishttp://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
I thought the Obamster was elected 'cause we needed "change".
Reply | Report Abuse | Link to thisHow soon we forget. The little ice age ended only a little over 300 years ago, and as a surrvivor of it I'd much rather see warmer than colder.
Seriously, we're going to havc change one way or the other. As I said, warm is better than cold.
Reply | Report Abuse | Link to thisBiello wrongly states:
Reply | Report Abuse | Link to this"Despite all these variables, scientists from Svante Arrhenius to those on the United Nations Intergovernmental Panel on Climate Change have noted that doubling preindustrial concentrations of CO2 in the atmosphere from 280 parts per million (ppm) would likely result in a world with average temperatures roughly 3 degrees C warmer"
Sheesh, even SA writers should know the difference between the warming that will come from a doubling of CO2 (1 degree C) and the warming at equilibrium that comes when you add the CO2 doubling to the feedbacks resulting from the doubling. That value is known as the "climate sensitivity" and it's what Biello is talking about when he says 3 degrees C.
All we know for sure is that a doubling of C02 will raise temps about 1 degree C (by the way, Arrhenius stated 1.6 deg C, not 3). The warming is logarithmic, so much of it has already occurred, i.e. we've seen the worst of it already.
The remaining 2 plus degree C will come from feedbacks and, since we've been doubling the CO2 for quite a while now, we can safely say that the feedbacks must be strongly negative for temps to have stayed so stable.
Look at the satellite data since 1978:
http://www.flickr.com/photos/toptechwriter/4158824792/in/photostream/
The green and blue trend lines show that temps have been increasing at a nearly flat level for at least 30 years. The temp spike that happened in 1998 & 1999 did not follow the pattern of warming caused by GHG, so it was caused by something else.
So where's the warming? What's the crisis?
Hi sofistek,
Reply | Report Abuse | Link to thisI'll see your NOAA graph and raise you this UAH satellite temps graph:
http://www.flickr.com/photos/toptechwriter/4158824792/in/photostream/
You can see the trend lines have nearly flat except for the 1998 & 1999 spike you mentioned. It shows that the negative feedbacks have restrained the warming caused by the CO2 doubling to within natural variability.
You can't trust NOAA's numbers, they use the USHCN and there are severe siting problems and urban heat island issues that compromise its validity. Right now, the satellites are our most accurate measurement of global temps and they're showing no excessive warming.
Shoshin writes : 'experiments show that the physics of CO2 alone are unable to create any significant warming per se'
Reply | Report Abuse | Link to thisIf this were true, how would you explain that without CO2 the average world temperature would be approxiately minus fifteen degrees centigrade...
Come on, quote your sources....
Hi eco-steve
Reply | Report Abuse | Link to thisCO2 by itself adds 3 degrees C to the total GHG effect warming the planet. When the current doubling is finished, temps from CO2 alone will have risen another 1 degree C.
LoL. Exactly. I hope nothing gets done in Copenhagen.
Reply | Report Abuse | Link to thisOur economy is obviously more fragile than our climate. A strong economy and opportunity is more important than saving the planet. Your planet will definitely not be "saved" by a bunch of broke people with no jobs. The government is only as rich as it's tax base. Not that the government was ever a very good answer for anything. Most great things are done privately.
Go plant some more trees if you want to get CO2 out of the air. Killing people in tiny little cars saves CO2 emissions per car and per life, but at what cost?
Let's make more money and increase innovation. That will allow us to tackle whatever problems the future holds.
the bottom line is that whether climate change is affected by human activity or not is irrelevant...
Reply | Report Abuse | Link to this"Right now far too much time is being wasted discussing the validity of scientific evidence that an abstract process called 'global warming' is caused by human activity. Wouldn't it be more straightforward to argue instead that pollution is caused by human activity, and that with an ever-increasing global population there is an urgent need to adopt better stewardship skills in order to successfully coexist? This is a tangible concept that requires no data or leap of faith - only gut instinct and observation."
please see the following link for the remainder of this article "(climate)change is dead, long live change":
http://www.truthout.org/change-is-dead-long-live-change57879
Yes the amount of positive feedbacks is important.
Reply | Report Abuse | Link to thisToo bad the whole feedback analysis is false.
The amount of GHE depends on the number of absorbable photons AND the number of available GHGs.
In our world, the number of absorbable photons is limited. The number of GHGs is in excess of those required to maximize the use of all the avilable photons. There is EXCESS Water vapor in the air (& in the ocean). There are no more photons that can be absorbed by the WV because they are all already in use creating the 32C greenhouse effect. The same applies to CO2. There is excess in the air. Adding more addsmore excess CO2, it does not add warming. If there is excess GHGs in the air, then why would the GHE WAIT intil man adds more to increase the GHE. Why not just maximize out using the already available excess?
Also when the amount of energy coming in decreases (every night) then the GHE also decreases- (fewer photons available!) So nightly cooling also adds more excess CO2 and WV which is then available for an increase in photons the next morning.
If there are no more photons, then no matter how much extra feedback water vapor is created it will NOT cause more warming because there are no photons left to warm it. When it rains and the excess WV triples, the temperature from the (local) GHE does NOT rise because there are no more photons available.
The IPCC global warming analysis & feedback is false. It mis-applies the GHE, by saying more GHGs cause more warming regardless of the number of absorbable photons. This just AIN"T true.
See http://www.scribd.com/doc/27343303/Gravity-Causes-Climate-Change, for an alternate theory of how gravity causes climate change.
One can only wonder if 'Mr Rational' is still as uninformed now as in '09.
Reply | Report Abuse | Link to thisIgnorance is the ball and chain, education is the key. Your born with the former, you earn the the latter.