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Did global warming stop in 1998? (basic version)

Posted on 16 August 2010 by John Russell

This blog post is the Basic version, written by John Russell, of the skeptic argument "It hasn't warmed since 1998":

No, it hasn't been cooling since 1998. Even if we ignore long term trends and just look at the record-breakers, that wasn't the hottest year ever. Different reports show that, overall, 2005 was hotter than 1998. What's more, globally, the hottest 12-month period ever recorded was from June 2009 to May 2010.

Though humans love record-breakers, they don't, on their own, tell us a much about trends -- and it's trends that matter when monitoring Climate Change. Trends only appear by looking at all the data, globally, and taking into account other variables -- like the effects of the El Nino ocean current or sunspot activity -- not by cherry-picking single points.

There's also a tendency for some people just to concentrate on air temperatures when there are other, more useful, indicators that can perhaps give us a better idea how rapidly the world is warming. Oceans for instance -- because of their heat-storage abilities, or 'thermal mass -- tend to give a much more 'steady' indication of the warming that is happening. Here records show that the Earth has been warming at a steady rate before and since 1998 and there's no signs of it slowing any time soon.

Note: we're currently going through the process of writing plain English versions of all the rebuttals to skeptic arguments. It's a big task but many hands make light work. If you're interested in helping with this effort, please contact me.

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Comments 1 to 14:

  1. For a simple method, easily verifiable by lay people, just average each 5 years or decade for the last few. Using Hadley data (a few months old since I haven't updated the values I keep in Excel) the results for the last few decades are: (anomalies in degrees Celsius) 1970 – 1979 = -0.0772 1980 – 1989 = 0.0843 1990 – 1999 = 0.2307 2000 – 2009 = 0.4041 For 5-year averages: 1980 - 1984 = 0.0596 1985 - 1989 = 0.0856 1990 - 1994 = 0.1544 1995 - 1999 = 0.3070 2000 - 2004 = 0.3968 2005 - 2009 = 0.4114 Calculated using annual values. I don't know how valid the method is, but there has been no global cooling or flat-lining since 1998 using this simple calculation.
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  2. Tony Abbott stated tonite 16/8/2010 on ABC Four Corners that 1998 was the hottest year on record and that there was an equal scientific arguement that co2 from humans was not responsible for the warming thats not happening. I think it has moved passed stopping or even slowing GW onto working out how to deal with it . this site has evolved into prob the best site for info on this subject THANK YOU !! to John and ALL who help him .
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  3. “... like the effects of the El Nino ocean current or sunspot activity -- not by cherry-picking single points.” “The slope of NCDC (NOAA) for the past 13 years indicates a warming of a mere 0.08°C although the graph ends during the ongoing El Nino.” I recommend of this very interesting analysis. Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming: “However, the trend in global surface temperatures has been nearly FLAT since the late 1990s despite continuing increases in the forcing due to the sum of the well-mixed greenhouse gases (CO2, CH4, halocarbons, and N2O), raising questions regarding the understanding of forced climate change, its drivers, the parameters that define natural internal variability, and how fully these terms are represented in climate models.” “the decline in stratospheric water vapor after 2000 should be expected to have significantly contributed to the flattening of the global warming trend in the past decade, and stratospheric water increases may also have acted to steepen the observed warming trend in the 1990s.” That, however, even if the warming is still present, this is it: "Flattening" ... because “stratospheric water vapor ...” ... but on the “stratospheric water vapor” we have no influence. Here you have the greatest impact Quasi Biennial Oscillation. Because the QBO affects [short wave radiation] ozone - steam - high clouds. In this way (short wave radiation), we “arrive” at: “Oceans for instance -- because of their heat-storage abilities ...” from Victor de Vries comment - on this website - The role of the Sun “Another point is that shortwave radiation penetrates deeper in the ocean as longwave radiation does (this effect gives the typical blue light in deep waters).” “The oceans absorb most solar energy in the tropics. The small zenit-angle results not only in a high net radiation but also in a deeper penetration of UV-light, and the ozone layer is thinner around the equator.” Very interesting (w tym kontekście) is the change in temperature in the tropics:
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  4. "w tym kontekście" - "in this context", of course, sorry
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  5. Solomon: It shows that we shouldn't over-interpret the results from a few years one way or another.
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  6. Arkadiusz Semczyszak wrote : "Solomon: It shows that we shouldn't over-interpret the results from a few years one way or another." I doubt if you will find many here who would disagree with that but, unfortunately, most so-called skeptics use such 'over-interpretations' as a basis for their beliefs. By the way, could you post a link to that quote from Solomon ? Also, that paper has been discussed on this site before (here, where you only made the briefest of interventions), and the pertinent statement about it is this : The paper doesn't draw any conclusions regarding cause, stating that it's not clear whether the water vapor changes are caused by a climate feedback or decadal variability (eg - linked to El Nino Southern Oscillation). The radiative forcing changes (Figure 3 above) indicate that the overall effect from stratospheric water vapor is that of warming. The cooling period consists of a stepwise drop around 2000 followed by a resumption of the warming effect. This seems to speak against the possibility of a negative feedback.
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  7. Phil Jones would disagree. From BBC interview: Q:Do you agree that from 1995 to the present there has been no statistically-significant global warming A: Yes
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    Response: To understand the context of both this loaded question and Phil Jone's answer, you need to read Phil Jones' words and understand the nature of the statistics discussed. The issue is also discussed in more detail in this blog post by Alden Griffiths which was adapted from his video addressing the argument: 'Global warming has stopped'.
  8. Paul, how about just a graph? (from GISS Surface Temperature Analysis ) Lots of places there where we could bridge two data points with a plateau, a steep decline, a steep rise, whatever we want as long as the big picture is no concern.
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  9. It's funny how the skeptics attacked Phil Jones credibility relentlessly, and still make snide references to "climategate," but they're only too happy to cite him as an expert over and over again for this one quote. It's just another bit of evidence that even they don't believe most of what they're saying.
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  10. It doesn't matter that they don't understand the quote. Jones' comment is an 'admission'. The rest of his work is 'fraudulent'. Agreeable propaganda is to an ideologue what a toy is to a child.
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  11. Paul Bell wrote : "Phil Jones would disagree. From BBC interview: Q:Do you agree that from 1995 to the present there has been no statistically-significant global warming A: Yes" Surely this can't be left hanging like that, just in case anyone reads it but can't be bothered to go to the other thread ? I hope I can be allowed to post the full response from Phil Jones, for clarification - especially as Paul Bell has not quoted Jones properly, for some strange reason : Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.
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  12. By the way, could you post a link to that quote from Solomon ? This is a very famous article - an interview with Solomon - The Guardian (29.01.2010) Water vapour caused one-third of global warming in 1990s, study reveals As a reminder - Solomon: “An atmospheric chemist ... ... was one of the first to be stirred into action by reports in the 1980s of deterioration of the planet's OZONE layer.” “ As a co-chair with Dr. Qin Dahe of Working Group 1 of the UN's Intergovernmental Panel on Climate Change (IPCC), she played a key role in producing the report ...” The paper doesn't draw any conclusions ... ? “Satellite measurements were used to show that water vapour levels in the stratosphere have dropped about 10% since 2000. When the scientists fed this change into a climate model, they found it could have reduced, by about 25% over the last decade, the amount of warming expected to be caused by carbon dioxide and other greenhouse gases.” No 90% “over the last decade” but 90% - 25% ? Merely 65% ? a negative feedback ... ? “She said it was not clear if the water vapour decrease after 2000 reflects a NATURAL shift, or if it was a consequence of a [anthropogenic] warming world [natural - The stratospheric cooling events at the equator ... “Stratospheric temperature is driven by the QBO of magnetic and irradiance activity on the sun.” “The temperature response at 10hPa was about 7.5 degrees.” “The change in total solar irradiance is immaterial.”]. If the latter [AGW feedback] is true, then more warming could see greater decreases in water vapour, acting as a negative feedback to apply the brakes on future temperature rise.” ... they don't believe most of what they're saying? He would like to point out that such skeptics such as Spenser, the two gentlemen Pielke, Segalstad even Lindzen, Lomborg, especially Korhola and von Storch (type of semi-sceptics) does not negate the role of CO2 in the current temperature change, say only that this role - CO2 - In the process of temperature change - by the IPCC - is far too highly estimated. I recently studying how very slowly (but still!) over the past three years to change the views of other "icons" AGW theory - F. Joos. Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate: “Our results are incompatibly lower (P,0.05) than recent pre-industrial empirical estimates of 40 p.p.m.v. CO2 per 6C, and correspondingly suggest 80% less potential amplification of ongoing global warming.” “Coupled carbon–climate models show a wide range in feedback strength, with 20–200 p.p.m.v. [?!] of temperature-driven CO2 ...” “Approximately 40% of the uncertainty related to projected warming of the twenty-first century stems from the unknown behaviour of the carbon cycle ...” If it is not (even slightly) skepticism ...
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  13. Arkadiusz Semczyszak wrote : "This is a very famous article - an interview with Solomon - The Guardian (29.01.2010) Water vapour caused one-third of global warming in 1990s, study reveals" Very famous ?! Maybe amongst those who spend all their time thinking about AGW, perhaps ? Anyway, good to see the bit you quoted, in its full context, i.e. : Solomon said the new finding does not challenge the conclusion that human activity drives climate change. "Not to my mind it doesn't," she said. "It shows that we shouldn't over-interpret the results from a few years one way or another."
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  14. "... does not challenge the conclusion that human activity drives climate change." - and if I and the aforementioned (through me) of scientists - with the great achievements - a lot of significant - “pre-reviewed” - the papers, we agreed with that. We disagree only on the actual "severity - weight " Human activity drives in relation to natural climate variability (estimated by IV IPCC report) - and looking at the "flat" trend in the last decade, especially in the tropics, it seems to us that we have “full” right ..., ... and S. Solomon says: it might really we (maybe) have “partly” right... - this is a small, but - comparison the last period - great progress towards an agreement.
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