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The New Climate Data: So What?

The views expressed are those of the author and are not necessarily those of Scientific American.

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After much anticipation, the Intergovernmental Panel on Climate Change on Friday revealed it’s new assessment of climate change, after two years of deliberation. The bottom line: global temperatures and sea levels will rise even faster than everyone thought. At a long press conference held after IPCC released its report, Climate Change 2013: The Physical Science Basis, U.S. climate experts explained what the new data boil down to for the U.S. and the world. Here are the facts they emphasized, and the comments they made on what the findings mean for policy and the planet.

Temperature. If the world aggressively cuts back on CO2 emissions, the global mean surface temperature by 2100 could be kept below a 2 degree Celsius rise (compared with 1986-2005), considered the limit beyond which severe consequences will arise. But if nations continue on the present course, temperature could rise by up to 4.8 degrees C. “We do have a choice,” said Gerald Meehl, a senior scientist at the National Center for Atmospheric Research and a lead author of the IPCC report, during the press conference. “We can choose to mitigate, which will keep us on the lower curve. If we don’t do anything, we’ll end up on the higher curve.” Even a 3 degree C rise, Meehl said, “will have serious impacts on agriculture and water resources—major disruptions to systems that are important to human welfare.”

Sea level. Under the same two scenarios, sea levels would rise by a minimum of 0.26 meter, or a maximum of 0.98 meter. The rate of sea level rise from 1993 to 2010 was 3.2 millimeters per year, higher than the IPCC’s last assessment in 2007. The panel also predicts that under the “business as usual” scenario, sea level rise would soar to 8 to 16 mm/yr by 2100. These estimates are the most dramatic change from 2007.

U.S. temperature and precipitation. Starting now and continuing into the future, there will be fewer cold days and more extremely warm days all across the U.S. Winters will be warmer. Extreme rains will increase. General precipitation will rise in the northern half of the country. In prior years the IPCC thought precipitation in the Southwest would decrease but now it concludes that precipitation may remain somewhat similar. However, because rising temperatures mean more evaporation and because less snow will fall at high elevations, the net effect will be less water in the region.

Atlantic hurricanes. Scientists have been saying for some time that Atlantic hurricanes will increase in intensity but not necessarily in number—although very recent research, which the IPCC did not consider, indicates that the number may increase too. Regardless, any increase in intensity will not be driven by overall global temperatures but by rising water temperature in certain regions of the oceans. The IPCC says more work is needed to identify those hot spots, which could improve forecasting if tropical storms cross those regions.

Arctic sea ice. “The “summer minimum ice cover”—the amount off ice remaining on the water at the height of summer warming—has dropped by 9 to 14 percent each of the past three decades. By 2100 the minimum could be 43 to 94 percent of what it is now—meaning that we could see an ice-free Arctic in summer by that year.

“The pause.” Climate deniers and skeptics in recent months have been claiming that global warming is over because the rise in atmospheric temperatures has slowed from 1998 to 2012. But the so-called pause or hiatus means the rate of increase has slowed—temperatures are still rising. The IPCC confirmed what other scientists have been maintaining: that a decade-long spell of climate conditions in the tropical Pacific Ocean caused more heat than normal to be stored in the ocean, helping to lessen heat rise in the atmosphere. This kind of spell, they also maintain, is a common part of the natural variability in global atmospheric and ocean patterns. The pattern, in which so-called La Nina conditions predominate more so than El Nino conditions, happens somewhat regularly over time; the most recent spell ended in the 1970s. Soon enough, the condition will end again. But even during this time, global temperatures have continued to rise. The decade 2000-2010 was the hottest ever recorded.

Policy. So will world leaders be more likely to act on the news that climate change will continue to worsen? “In 1990 the IPCC had already released compelling evidence,” Meehl said. “Since then I would have thought that more would have happened by policymakers in addressing this problem. The hope now is that with more information—and more detailed information—policymakers will think now is the time to do something with it.” Tad Pfeffer, from the University of Colorado, also warned politicians and the public to not misinterpret predictions. “It is important to understand what really constitutes a threat,” said Pfeffer, also a lead IPCC author. “A half-meter rise in sea level will be very disruptive, but people may discount it because it’s not the dramatic worst-case scenario. The smaller predictions tend to get ignored.” And that, Pfeffer said, would be a costly mistake.

You can hear an audio recording of the press conference, including the Q&A with journalists, here.

Graph courtesy of Intergovernmental Panel on Climate Change

Mark Fischetti About the Author: Mark Fischetti is a senior editor at Scientific American who covers energy, environment and sustainability issues. Follow on Twitter @markfischetti.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Shoshin 9:46 am 10/2/2013

    Not sure what IPCC report you read. Certainly not the one that the IPCC published. I think you only cut and pasted the Alarmist talking points. Virtually everything that you state is wrong and not in the IPCC report.

    Care to try reading it this time before you comment?

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  2. 2. cls42 10:58 am 10/2/2013

    It’s a strategic mistake for climate scientists to “explain” a 15-year slowdown in global average surface temperature. Climate trends begin to emerge above weather noise in moving averages over thirty years or more. We’re only halfway to being able to say whether the hundred-year trend suddenly ended in 1998. When we make excuses for a nonsensical claim, we accept the agenda and the frame of reference presented by the fossil fuel industries’ anti-science public relations campaign. You can’t teach science in a frame of nonsense.

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  3. 3. sault 11:27 am 10/2/2013

    Sorry Shoshin, but you probably just confused the real IPCC report with all the fossil fuel propaganda you read. Seriously, Exxon and Koch Industries have a HUGE financial conflict of interest when it comes to telling the truth on climate change, so you shouldn’t take their word at face value.

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  4. 4. abhishekloser 11:28 am 10/2/2013


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  5. 5. evosburgh 1:52 pm 10/2/2013

    What is interesting is the use of the word ‘could and would’ in terms of the science. I recall being trained, during the writing of my thesis, that these are words that are not used in the reporting of scientific findings. You state what the evidence indicates as a fact supported with the data and data analysis.

    The use of these word leads me to believe that: (1) the analysis is not definitive or (2) the politicians are playing games to be able to deflect blame later if/when the predictions do not come to pass. Playing both sides of the fence is not only reprehensible but also a sign of weakness in ones work.

    Sure temperatures could go up or down or hurricane frequency and intensity could increase or decrease. These are not Earth shattering predictions and these processes will occur with or without the intervention of mankind. The question is what sort of forcing can we cause in the system. Thus far the models have failed to predict the 15 year trend and that is acceptable as they are mathematical models and they need to be reworked.

    There is no shame in the failure of a model but I take issue with going on parroting that the models predict this and that and the baseless postulation of reasons for the mispredictions. Once the problems with the models are identified and newer models are constructed to sucessfully address those issues then we discuss what the results mean.

    As far as this time frame discussion goes: it is EXTREMELY dodgy to start and stop your time frame analysis on a whim. You need to be well aware of the entire data set and be able to reproduce the measurements, within a reasonable range of error, with your mathematical constructs. If the cycle really is 30 years then we should be seeing the 15 current years and we are not.

    As far as the fossil fuel people go: they have a very valid opinion with repect to modeling these types of systems. You can try to spin what they say as biased due to the source but the methodologies are not biased by the source. I would say they have had a pretty stellar track record of modeling and using the results of those models to make a lot of money so maybe the AGW crowd could close their mouth long enough to consider what others have to say when it comes to predicting the behavior natural systems.

    In the end back to the point: if you are going to say would or could then you had better have some sort of probability attached to those statements such as: there is a 90% chance of a 2 degC rise in surface temperature in the next 100 years and then have the conviction to stand by that prediction.

    What I have seen thus far is we predict X plus or minus Y and since X did not occur within the range of Y we lowered the range of Y to fit the data. Seems defensible to me (sarcasm intended). Therefore, the predictive tools have failed and now it is time to retool. However, if we admit that we were not correct will we still get the funding to retool? It seems that those people who gave us the money to start with expected results and if we tell them the results we presented are not defensible will they give us more money to make more predictions? Maybe we should have been more thoughtful about the ranges we used and communicating the uncertainies. Oh well … too late and now we are backed into a corner. Just keep telling the same story and make a concerted effort to stiffle anyone who contradicts us and we will survive (at least until the end of our career).

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  6. 6. Owl905 2:07 pm 10/2/2013

    evosburgh, climb back under the blarney stone you’ve over-kissed. ‘Could’ and ‘may’ and ‘% chance of’ are common, almost pre-req, terms in science forecasting. It’s street talk for ranges and error-bars and current evidence. You certainly don’t take evidence-to-date and present it as “fact”. My guess is you have no training in science whatsoever, and your expertise is self-annointed from reading more than two blogs trashing AGW.
    Your conclusion doesn’t even relate to the evidence, it’s just sleazy opinion. You understanding of the timeframe issue is basically zero. You know squat about what the GCMs are or do. Your failure to relate the likelihoods to % ranges is a clear indication you didn’t read the report. The predictive tools haven’t failed – you have failed to understand them.
    “Maybe we should have been more thoughtful about the ranges we used and communicating the uncertainies.” They did. You didn’t look for them, but created a bogus non-entity to vent at. Your comment is pathetic rubbish. You deserve an oil-rag award.

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  7. 7. Noone 2:31 pm 10/2/2013

    Sorry sault, but WE finally figured out who YOU are: Robin Hood with an outwardly green cap (red on the inside), who steals from “the rich”, i.e., those non-governmental persons who own either two cars or two cows, and then composts everything he steals.

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  8. 8. Owl905 2:32 pm 10/2/2013

    It’s not that temps and sea-levels will rise faster than anyone thought, it’s that the high-end of the ranges are being locked in by the failure to respond to the GHG-pollution. The pollution is growing at rates 30% faster than the BAU scenarios.
    Temperature will not be kept below 2dC. It’s .8 with .4 in the pipeline, and pollution is still growing … faster. Annual concentrations are now increasing by 2.5ppm. Perspeive – 25 years ago, 351.5; 2012, 393.9.
    Sea levels – .4 meters this century is a conservative mainstream estimate. Coastlines, and coastal habitats will not avoid significant widespread damage that increase.
    Arctic sea-ice cover – it’s still in line for ice-free with an ecosystem collapse in a quarter of a century. The open ocean will accelerate the stability failure of the Greenland ice-mass.
    ‘The Pause’ doesn’t exist as anything more than a measurement anomaly. It joins the previous five stats games with ranges and noise-swamp. It’s as valid to the discussion as all the fence crows squawking about Maunder and Dalton minimums when Solar Cycle 24 arrived late and weak.
    Further reading – Samalas Volcano – new research has matched the volcano’s isotope signature to the start of the Little Ice Age – 1315 crop failures. Samalas matches the tip that started about 1260, and had a bang bigger than Krakatoa.

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  9. 9. Owl905 2:34 pm 10/2/2013

    Noone reveals a lack of character that can only fire blanks at messengers instead of addressing the subject content. Actually, have you ever contributed any content to the threads?

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  10. 10. Noone 2:37 pm 10/2/2013

    Owl905, you need to climb back under the toilet seat lid you’ve over-kissed, evosburgh is quite right. When ALL the models fail, you come up with a new hypothesis, not condemn the results. Your comment is bathetic waste. You deserve a used-TP award.

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  11. 11. jimmywat 3:05 pm 10/2/2013

    “I think that the latest IPCC report has truly sunk to level of hilarious incoherence,” Dr. Richard Lindzen told Climate Depot.

    Lindzen, a top climate scientist from the Massachusetts Institute of Technology lambasted a new report from the UN’s climate bureaucracy that blames mankind as the main cause of global warming while whitewashing the fact that there has been no warming for the last 15 years.

    “They are proclaiming increased confidence in their models as the discrepancies between their models and observations increase,” said Lindzen.

    “Their excuse for the absence of warming over the past 17 years is that the heat is hiding in the deep ocean,” Lindzen said. “However, this is simply an admission that the models fail to simulate the exchanges of heat between the surface layers and the deeper oceans.”

    “They now, somewhat obscurely, admit that their crucial assumption was totally unjustified.”

    “It is quite amazing to see the contortions the IPCC has to go through in order to keep the international climate agenda going,” says Lindzen.

    Freeman Dyson, professor emeritus of the School of Natural Sciences, Institute for Advanced Study; Fellow of the Royal Society [10]
    Richard Lindzen, Alfred P. Sloan professor of atmospheric science at the Massachusetts Institute of Technology and member of the National Academy of Sciences[11]
    Nils-Axel Mörner, retired head of the Paleogeophysics and Geodynamics department at Stockholm University, former chairman of the INQUA Commission on Sea Level Changes and Coastal Evolution (1999–2003), and author of books supporting the validity of dowsing[12]
    Garth Paltridge, retired chief research scientist, CSIRO Division of Atmospheric Research and retired director of the Institute of the Antarctic Cooperative Research Centre, visiting fellow ANU[13]
    Philip Stott, professor emeritus of biogeography at the University of London[14]
    Hendrik Tennekes, retired director of research, Royal Netherlands Meteorological Institute [15]

    Scientists arguing that global warming is primarily caused by natural processes

    Graph showing the ability with which a global climate model is able to reconstruct the historical temperature record, and the degree to which those temperature changes can be decomposed into various forcing factors. It shows the effects of five forcing factors: greenhouse gases, man-made sulfate emissions, solar variability, ozone changes, and volcanic emissions.[16]
    Scientists in this section have made comments that the observed warming is more likely attributable to natural causes than to human activities. Their views on climate change are usually described in more detail in their biographical articles.
    Khabibullo Abdusamatov, mathematician and astronomer at Pulkovo Observatory of the Russian Academy of Sciences[17]
    Sallie Baliunas, astronomer, Harvard-Smithsonian Center for Astrophysics[18][19]
    Ian Clark, hydrogeologist, professor, Department of Earth Sciences, University of Ottawa[20]
    Chris de Freitas, associate professor, School of Geography, Geology and Environmental Science, University of Auckland[21]
    David Douglass, solid-state physicist, professor, Department of Physics and Astronomy, University of Rochester[22]
    Don Easterbrook, emeritus professor of geology, Western Washington University[23]
    William M. Gray, professor emeritus and head of the Tropical Meteorology Project, Department of Atmospheric Science, Colorado State University[24]
    William Happer, physicist specializing in optics and spectroscopy, Princeton University[25]
    William Kininmonth, meteorologist, former Australian delegate to World Meteorological Organization Commission for Climatology[26]
    David Legates, associate professor of geography and director of the Center for Climatic Research, University of Delaware[27]
    Tad Murty, oceanographer; adjunct professor, Departments of Civil Engineering and Earth Sciences, University of Ottawa[28]
    Tim Patterson, paleoclimatologist and professor of geology at Carleton University in Canada.[29][30]
    Ian Plimer, professor emeritus of Mining Geology, the University of Adelaide.[31]
    Nicola Scafetta, research scientist in the physics department at Duke University[32][33]
    Tom Segalstad, head of the Geology Museum at the University of Oslo[34]
    Fred Singer, professor emeritus of environmental sciences at the University of Virginia[35][36][37]
    Willie Soon, astrophysicist, Harvard-Smithsonian Center for Astrophysics[38]
    Roy Spencer, principal research scientist, University of Alabama in Huntsville[39]
    Henrik Svensmark, Danish National Space Center[40]
    Jan Veizer, environmental geochemist, professor emeritus from University of Ottawa[41]

    Scientists arguing that the cause of global warming is unknown

    Scientists in this section have made comments that no principal cause can be ascribed to the observed rising temperatures, whether man-made or natural. Their views on climate change are usually described in more detail in their biographical articles.
    Syun-Ichi Akasofu, retired professor of geophysics and founding director of the International Arctic Research Center of the University of Alaska Fairbanks[42]
    Claude Allègre, politician; geochemist, emeritus professor at Institute of Geophysics (Paris)[43]
    Robert C. Balling, Jr., a professor of geography at Arizona State University[44]
    John Christy, professor of atmospheric science and director of the Earth System Science Center at the University of Alabama in Huntsville, contributor to several IPCC[45][46]
    Petr Chylek, space and remote sensing sciences researcher, Los Alamos National Laboratory[47]
    Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology[48]
    David Deming, geology professor at the University of Oklahoma[49]
    Ivar Giaever, professor emeritus at the Rensselaer Polytechnic Institute.[50]
    Antonino Zichichi, emeritus professor of nuclear physics at the University of Bologna and president of the World Federation of Scientists[51]

    Scientists arguing that global warming will have few negative consequences

    Scientists in this section have made comments that projected rising temperatures will be of little impact or a net positive for human society and/or the Earth’s environment. Their views on climate change are usually described in more detail in their biographical articles.
    Craig D. Idso, faculty researcher, Office of Climatology, Arizona State University and founder of the Center for the Study of Carbon Dioxide and Global Change [52]
    Sherwood Idso, former research physicist, USDA Water Conservation Laboratory, and adjunct professor, Arizona State University[53]
    Patrick Michaels, senior fellow at the Cato Institute and retired research professor of environmental science at the University of Virginia[54]

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  12. 12. Carlyle 4:46 pm 10/2/2013

    The claim by the IPCC was that a rise in ocean temperature MIGHT be occurring. They are talking about hundredths of a degree more than previously recorded. Levels below the ability to measure, particularly for earlier times. The other point with using this as an excuse for the pause does not explain why would it suddenly be happening now? By the way, the hot denials we have endured for years that there was any pause have been demolished.
    The IPCC reminds me of the old joke about the camel. it could only have been designed by a committee.

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  13. 13. sault 5:02 pm 10/2/2013

    LOL – jimmy’s back posting his garbage about how mostly NON climate scientists and some hucksters paid off by fossil fuel companies (like Patrick Micheals and his paychecks that come from the Cato Institute) actually means anything when 98% of REAL climate scientists and EVERY SINGLE scientific organization of national or international standing on the planet agrees that human greenhouse gas emissions are dangerously changing the climate.

    Regardless of what you would like to believe, but you can’t expect to dump billions of tons of CO2 into the atmosphere every year and expect nothing bad to happen. Ice is still melting around the globe, sea levels are rising much faster than what we predicted even just 6 years ago, the pH of the oceans is still dropping, permafrost is still melting, and the Earth is accumulating the heat energy equivalent of 10 nuclear bombs going off every second of every day due to all the crap we spew into the air. Either join the reality-based community or find some other website where illogical behavior is more welcome.

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  14. 14. sault 5:08 pm 10/2/2013


    You do understand that 90% of the extra heat that Earth accumulates because of our greenhouse gas emissions goes into the oceans, right? And you DO understand that water has hundreds of times greater heat capacity than air, right? And you DO understand that La Nina has dominated El Nino in the ENSO cycle for the past decade or so, or that aerosol and stratospheric water vapor forcing has worked to mask the anthropogenic warming signal over a similar timeframe, correct?

    In short, are you familiar with the fallacy of mistaking short-term noise for long-term trends? I mean, you are utterly clueless in this same department concerning arctic sea ice extent, thinking ONE YEAR of non-record-low extent translates to a “recovery” even though the long-term trends in ice extent show you to be hilariously wrong? Can you honestly say that you’re interested in discussing the same reality the rest of us live in?

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  15. 15. Carlyle 5:52 pm 10/2/2013

    Garbage. The ocean heat argument has been trotted out as a POSSIBLE explanation for the lack of surface warming. You do not read other peoples posts. Or look at non AGW friendly sites to obtain alternative views or data. Even the IPCC only claimed it was a possible answer. They & you, fail to explain why, if this were the case, it is only happening now & not previously, nor how they can claim they know the baseline ocean temperatures from earlier eras when even todays instruments are incapable of the accuracy required. as usual, raw data is not used. It is manipulated by models until the desired result is obtained.

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  16. 16. bongobimbo 7:14 pm 10/2/2013

    An honest report by the leading climate scientists. Forget the deniers. They will keep on denying evidence till they drown in De Nial.

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  17. 17. Carlyle 9:36 pm 10/2/2013


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  18. 18. ErnestPayne 4:20 pm 10/3/2013

    Interesting if depressing reading in the article and comments. Apparently academic pissing contests still continue.

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  19. 19. Dr. Strangelove 11:11 pm 10/3/2013

    The new climate data: all IPCC climate models fail to predict the warming pause since 1998.

    So what? IPCC insists – nevermind the data, believe what we say: temperature will increase by 4.8 C, sea will rise by 0.98 m, extreme rains but less water in US, more hurricanes, Arctic sea ice will disappear, cut CO2 emissions now to avert global catastrophe!

    Nothing new there except the new climate data.

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  20. 20. Son of Liberty 3:06 pm 10/4/2013

    “The bottom line: global temperatures and sea levels will rise even faster than everyone thought.”

    That’s not what the report says

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  21. 21. slbolfing 12:24 pm 11/3/2014

    Reading the actual report has generated several comments:
    1) Although the data occasionally seem to be contradictory, taken as a whole, there is strong evidence of a changing climate. However, the data cover a relatively limited time frame (with reasonable extrapolation to larger time frame).
    2) The graphs for ocean level rise all seem to be relatively linear; I could not find the reason for the slope to suddenly begin to increase to the rates predicted.
    3) There is a lot more evidence for warming in the northern hemisphere than in the southern (probably a function of land mass vs oceanic mass)
    4)There is no comment regarding the impact of sunspot activity and the associated increase radiation on the impact of the atmosphere/climate.
    5)There is little direct evidence correlating change from human activity vs natural activity (volcanic, etc.)
    6) The largest areas of the globe that seem to be showing the most amount of warming are primarily in Asia, Africa and other areas that have proven to be very difficult to police
    7) The complexity of climate is beyond any current capability to report with >95% certainty (there are simply too many non-linear variables requiring complex differential analysis) – however, we are continually improving are models, as computer technology evolves.
    Finally, regardless of how anyone feels about the data and conclusions, there is certainly nothing wrong with striving to minimize the environmental impact human activity has on the climate (or world in general). Dependence on fossil fuels is, by definition, of limited time – long term goals should be investigating safe, reliable alternatives (and there are obvious financial and political gains available). Why NOT try to make a change? Can we use this a way to generate a globally common goal for all humanity? Of course, these are just my opinions.

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  22. 22. slbolfing 12:27 pm 11/3/2014

    I left out one other thought – there has been considerable evidence indicating a shift in the Earth’s magnetic poles is imminent (within a millennium or sooner). Because changing the magnetic fields impacts the protection we receive from solar radiation, how will this impact climate?

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