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What has global warming done since 1998?

What the science says...

Select a level... Basic Intermediate

Every part of the Earth's climate system has continued warming since 1998, with 2015 shattering temperature records.

Climate Myth...

It hasn't warmed since 1998

For the years 1998-2005, temperature did not increase. This period coincides with society's continued pumping of more CO2 into the atmosphere. (Bob Carter)

Even if we ignore long term trends and just look at the record-breakers, 2015, 2014, 2010, and 2005 were hotter than 1998.

The myth of no warming since 1998 was based on the satellite record estimates of the temperature of the atmosphere.  However, as discussed in the video below by Peter Sinclair, even that argument is no longer accurate.  The satellites show warming since 1998 too.

There's also a tendency for some people just to concentrate on atmospheric or surface air temperatures when there are other, more useful, indicators that can give us a better idea how rapidly the world is warming. More than 90% of global warming heat goes into warming the oceans, while less than 3% goes into increasing the atmospheric and surface air temperature.  Records show that the Earth has been warming at a steady rate before and since 1998 and there is no sign of it slowing any time soon (Figure 1). 

Fig 1

Figure 1:  Land, atmosphere, and ice heating (red), 0-700 meter ocean heat content (OHC) increase (light blue), 700-2,000 meter OHC increase (dark blue).  From Nuccitelli et al. (2012).

Even if we focus exclusively on global surface temperatures, Cowtan & Way (2013) shows that when we account for temperatures across the entire globe (including the Arctic, which is the part of the planet warming fastest), the global surface warming trend for 1997–2015 is approximately 0.14°C per decade.

Ultimately, every part of the Earth's climate system is warming, and has continued warming since 1998.

Last updated on 29 September 2017 by dana1981. View Archives

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Further reading

Tamino further explores the warming trend since 1998 in Garbage is Forever and Wiggles.

I've kept my original treatment of the subject as other websites hotlink to the images. My original treatment uses similar arguments to Fawcett and Jones 2008 although their analysis is much more rigorous (as you'd expect in a peer-reviewed paper).

Further viewing


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Comments 401 to 407 out of 407:

  1. Guym @400 , [and my apologies for the long post]

    the "hiatus" still lives on — at least in the minds of the climate denialists.  (The less-educated denialists often refer to it as "the Pause" . . . and seem to wish to genuflect at its mention.)   Although the hiatus disappeared 4 years ago, many denialists feel that the recent record-hot years [2014/2015/2016/2017] are a transient aberration; and that within a very few years, planet Earth will return to another prolonged halt in warming (and thus all the scientists will conclusively be proven wrong).   And moreover, the Earth will probably cool down, back to its rightful & divinely ordained un-warmed condition.   That is their faith.   But they have zero mechanism to point to, which could produce such a change (they sometimes point to the future possibility of a Grand Solar Minimum . . . but they refuse to acknowledge that such an event, if it would occur at all, could only produce a feeble/ineffectual counter to the ongoing rapid warming caused by the Greenhouse Effect — an Effect which many denialists still refuse to believe CO2 has any place in).

    I am fairly sure I am not telling anything you aren't already aware of.

    Denialists will only look at planetary surface temperatures: and even there, they have an extreme preference for the satellite record of temperatures limited to to the upper troposphere, rather than the actual planetary surface temperatures down here at ground level.   They have a blind spot for other surface changes such as ice melting and sea levels rising — or at least, they will consider such changes only in isolation (and will quibble about those changes individually, rather than putting it all together in the big picture).

    Where denialists do pay attention to real surface conditions, they usually restrict their mental focus to the region around Latitude 40 North and Longitude 80 West.   Other regions receive attenuated or non-existent concern.

    Denialists mentally refuse to look at the ongoing continuous warming of the ocean, and they have a massive blind spot for the 90+% of global warming energy which goes into the ocean.   For them to acknowledge that fact, would mean acknowledging it is impossible for a genuine hiatus to exist (short of the Earth reaching thermal equilibrium as a new higher plateau of GH Effect).

    Consequently, they still agonize over the so-called Hiatus/Pause; they discuss it as though it never terminated, and they still put enormous effort into statistical analysis "proving" that the Hiatus was/is real.   They denounce the scientific view that there never was a real post-1998 hiatus . . . and they are still buoyed by the way that some real scientists were embarrassed (and insecure) enough to name a "hiatus" (as well devoting some discussion & research time to it.   Surely there can be no smoke without fire !!  Nor can there be any ocean warming, or even Greenhouse Effect !!  The existence of an unpredicted Hiatus must mean that the scientists' models from the 80's and 90's . . . are false & invalid.  Likewise all the rest of the Warmist/Alarmist blather & propaganda).


    Guym, for my sins (and for my entertainment) I sometimes look at the WhatsUpWithThat website.   The actual articles are a complete waste of time — being either crazy stuff, or semi-real stuff which has received ferocious "spin".   But in the comments column under each article, you find a 100 or so "comments".    95% of them, you should slide straight past — they are the usual deluded/toxic/extremist nonsense spouted by angry denialists who are using the WUWT site as an echo-chamber to bolster their strange/bizarre beliefs.   But there are a few gems.

    Keep your eye alert for (A) posts by Nick Stokes — a real scientist, with saintly patience, who infuriates the denialists by his cool corrections of their nonsense (they just can't win a trick against him)

    . . . and (B) a couple of denialists [I won't name them] who have enough science & math to produce umpteen paragraphs of equations & analyses — all of it ultimately fruitless in reality; yet they lack the insight to see that they are willing victims of severe Motivated Reasoning.  If they were sane, then they could achieve a considerable amount if they turned their talents to actual real science, I'm sure.  Ah, what a waste.   One of them asserts that the CO2 / Greenhouse Effect does not exist, and that "AGW" is truly just a result of long-cycle ocean oscillations.   Quite crazy.

    The other [and here I finally address the main point of your post] goes in for lengthy statistical analyses to demonstrate that the recent "hiatus" must have been genuine because he can find "no statistically significant" upward trend in (surface) temperature.   He does sometimes admit that there seems to be a very slight positive trend during the hiatus — but since it is statistically not significant in its difference from zero trend, then he concludes that there was no actual warming during that period (and therefore the scientific climate consensus is wrong in its entirety).

    Not only does he ignore the ongoing melting and sea level rise, but he seemingly cannot conceive that the real purpose of statistical analysis is to reflect reality, rather than conceal it.  He prefers to look at his figuring, rather than look at the reality of the physical processes affecting climate.

  2. guym @400,

    I have long  pondered the "hiatus" nonsense from contrarians. My take on it is perhaps more clinical than Eclectic @401, and a smidgen shorter.

    One of the difficulties we face addessing the "hiatus" is that contrarians define the "hiatus" to mean vastly different things, from silly nonsense from Rose of the Daily Rail (Temp(Jan1996)=Temp(Aug2012) => global warming stopped 16 years ago) to more allegedly-grown-up versions comparing modeled & measured temperatures. Which ever version is used, their take-away is "Global Warming has stopped" or "Models are badly wrong". And any attempt to sensibly address the issue like in the AR5 Box 9.2 or for instance Hansen et al discussing the 'Global Warming Standstill' in 2012 results in a contrarian 'we told you so!!' response which is then grafted onto nonsense by even the more respected of contrarians to beat the "Global Warming Has Stopped!!!" drum (eg ex-clomatologist Judith Curry).

    So you really do have to be careful when addressing the issue of the "hiatus" and that means more than using a title that calls it the "Hiatus in Global Mean Surface Warming of the Past 15 Years" as per AR5 Box9.2.

    I think the AR5 Box9.2 use of OLS analysis over the period 1998-2012 was poorly contrived. (For the record, the resulting SAT trend roughly doubles if you use 1999-2012, to +0.09ºC/decade, instead of  1975-1996.) What was poor was firstly comparison of 1998-2012 with 1951-2012. The start period should have been roughly 1975, the start of the recent strong AGW. Contrarians who exaggerate the significance of the "hiatus" would be surprised to hear that if you compare 1975-1996 with 1975-2012 you get almost identical trends. The reason for 1998-2012 being so different from the longer-term SAT trend is because the 1998-2012 SAT trend relies on one of those reality-busting steps as in the SKS Escalator. So a second criticism of AR5 Box9.2 is giving credance to the 1998-2012 reality-busting OLS analysis.

    SKS Escalator

    Simply-put, anybody who (a) supports a "hiatus" 16-years long or (b) uses the "flatness" in surface temperature record to create a 16-year long "hiatus" by for instance saying "I predict we will see continuation of the ‘standstill’ in global average temperature for the next decade" (and good old Judy Curry manages both a & b) show they have departed from truthful analysis of AGW.

    I myself feel the way to take command of the "hiatus" is by setting its true length. This analysis of HadCRUT data (usually 2 clicks to 'download your attachment') finds it was just 32 months long. And a message that must always be included in "hiatus" talk - thoroughout these years, AGW did not show any signs of faltering as the Ocean Heat Content data surely demonstrates.

  3. Correction to #402.

    Para 3 should read "... instead of 1998-2012."

  4. I am not a climate scientist and have no knowledge of the sophistication of the models. But is there a way to explain the 'Hiatus' when considering the melting of ice?

    Doesn't the ice absorb a lot more heat going through the phase change to water? So once the world has warmed up enough to initiate a lot of ice melting, the large scale ice melting would then absorb a lot of heat energy and keep temperatures relatively stable, until a significant amount of ice has melted.  Then everything would continue heating up more linearly.

    Basically the world is acting like a big old glass of iced water with a lid on top, left out in the sun!?

    The scary thing is what happens when the stabilising effect of melting is over and all those previously white, heat reflecting surfaces have gone to reveal plenty of dark rock and gravel...  

  5. andyred3D, there is really no "hiatus" to explain. Statistical analysis of the time series of global surface temperature anomalies does not show a significant departure from the trend; correcting for El-Nino/La Nina and volcanic activity makes it even more obvious. The so-called hiatus is entirely dependent on selecting 1998 as a start date, and as we all know, that year saw a massive El-Nino. What is remarkable is that it took only a few years for global temps to set a new normal at or above the extraordinary 1998 level. Moderate or non El-Nino years then beat 1998 and finally when a comparable El-Nino came, the 1998 record was shattered. There was no pause. 


    [DB] To illustrate the overall trend, here's the NASA GISS temperature record with a 132-month filter applied:

    132-month smooth

    The overall long-term trend continues upward, inexorably, as Philippe notes.

  6. andyred3D @404,

    There are big amounts of energy required to melt Arctic Sea Ice each spring/summer, also the amount released with the winter freeze-up. Of course this cycle has been happening for millenia and involve lots of energy. So such energy fluxes are already part of global climate and even then they fall far short (perhaps just 10%) of that which would be released by global surface temperatures falling modestly behind the long-term upward trend.  If you are interested, numbers can be presented but they are a mite too involved to pop into the thread without an audience.

  7. to Philippe at 405: 

    Thank you so much for the updated temperature plot. It is the best "Hiatus Killer" I've seen.

    For years I have been waiting to see the SKS escalator brought up to date, showing 2019. 

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