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As Scientists Predicted, Global Warming Continues

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"As Scientists Predicted, Global Warming Continues"

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Most of manmade global warming is ending up in the ocean, just as scientists had predicted (see “Global Warming Has Accelerated In Past 15 Years“). And while recent “observations support predictions of extreme warming” this century, even sophisticated media outlets, like “The Economist,” get the story wrong (see “Memo To Media: ‘Climate Sensitivity’ Is NOT The Same As Projected Future Warming, World Faces 10°F Rise“). Former Hurricane Hunter Jeff Masters has a good chart-filled piece reviewing the latest temperature observations.

Tavurvur volcano in New Guinea erupting in 2009. A 2011 study found its 2006 eruption, combined with one on Montserrat Island, hurled a huge amount of sulfur into the stratosphere, helping reduce global temperatures. Image: Taro Taylor.

By Dr. Jeff Masters, via Weather Underground

One often hears the statement in the media that global warming stopped in 1998, or that there has been no global warming for the past 16 years. Why pick 16 years? Why not some nice round number like 20 years? Or better yet, 30 years, since the climate is generally defined as the average weather experienced over a period of 30 years or longer?

Temperatures at Earth’s surface undergo natural, decades-long warming and cooling trends, related to the La Niña/El Niño cycle and the 11-year sunspot cycle. The reason one often hears the year 1998 used as a base year to measure global temperature trends is that this is a cherry-picked year.

An extraordinarily powerful El Niño event that was the strongest on record brought about a temporary increase in surface ocean temperatures over a vast area of the tropical Pacific that year, helping boost global surface temperatures to the highest levels on record (global temperatures were warmer in both 2005 and 2010, but not by much.) But in the years from 2005 – 2012, La Niña events have been present for at least a portion of every single year, helping keep Earth’s surface relatively cool.

Thus, if one draws a straight-line fit of global surface temperatures from 1998 to 2012, a climate trend showing little global warming results. If one picks any year prior to 1998, or almost any year after 1998, a global warming trend does result. The choice of 1998 is a deliberate abuse of statistics in an attempt to manipulate people into drawing a false conclusion on global temperature trends. One of my favorite examples of this manipulation of statistics is shown an animated graph called “The Escalator”, created by skepticalscience.com (Figure 1).

Figure 1. Average of NASA’s GISS, NOAA”s NCDC, and the UK Met Office’s HadCRUT4 monthly global surface temperature departures from average, from January 1970 through November 2012 (blue), with linear trends applied to the time frames Jan ’70 – Oct ’77, Apr ’77 – Dec ’86, Sep ’87 – Nov ’96, Jun ’97 – Dec ’02, Nov ’02 – Nov ’12. Climate change skeptics like to emphasize the shorter term fluctuations in global temperatures (blue lines) and ignore the long-term climate trend (red line.) The global surface temperature trend from January 1970 through November 2012 (red line) is +0.16°C (+0.29°F) per decade. Image credit: skepticalscience.com.

Correcting for natural causes to find the human contribution to global temperature changes

We know that natural global warming or cooling on time scales of 1-11 years can be caused by changes in the El Niño-Southern Oscillation (ENSO) cycle, dust from volcanic eruptions, and changes in solar energy. For example, a study published in March 2013 in Geophysical Research Letters found that dust in the stratosphere has increased by 4-10 percent since 2000 due to volcanic eruptions, keeping the level of global warming up to 25 percent lower than might be expected. So, it is good to remove these natural causes of global temperature change over the past 34 years for which we have satellite data, to see what the human influence might have been during that time span.

The three major surface temperature data sets (NCDC, GISS, and HadCRU) all show global temperatures have warmed by 0.16-0.17°C (0.28-0.30°F) per decade since satellite measurements began in 1979. The two satellite-based data sets of the lower atmosphere (UAH and RSS) give slightly less warming, about 0.14-0.15°C (.25-.27°F) per decade (keep in mind that satellite measurements of the lower atmosphere temperature are affected much more strongly by volcanic eruptions and the El Niño phenomena than are surface-based measurements taken by weather stations.) A 2011 paper published by Grant Foster and Stefan Rahmstorf, “Global temperature evolution 1979-2010“, took the five major global temperature data sets and adjusted them to remove the influences of natural variations in sunlight, volcanic dust, and the El Niño/La Niña cycle. The researchers found that adjusting for these natural effects did not change the observed trend in global temperatures, which remained between 0.14-0.17°C (0.25-0.31°F) per decade in all five data sets.

The warmest years since 1979 were 2010 and 2009 in all five adjusted data sets. Since the known natural causes of global warming have little to do with the observed increase in global temperatures over the past 34 years, either human activity or some unknown natural source is responsible for the global warming during that time period.

Figure 2. Departure from average of annual global temperatures between 1979 – 2012, adjusted to remove natural variations due to the El Niño-Southern Oscillation (ENSO) cycle, dust from volcanic eruptions, and changes in solar energy. The five most frequently-cited global temperature records are presented: surface temperature estimates by NASA’s GISS, HadCRU from the UK Met Office, and NOAA’s NCDC, and satellite-based lower-atmosphere estimates from Remote Sensing Systems, Inc. (RSS) and the University of Alabama Huntsville (UAH.) Image is an update (via realclimate.org) of one from a 2011 study, Global temperature evolution 1979-2010 , by Grant Foster and Stefan Rahmstorf, Environ. Res. Lett. 6, 2011, 044022 doi:10.1088/1748-9326/6/4/044022.

Figure 3. Average of NASA’s GISS, NOAA”s NCDC, and the UK Met Office’s HadCRUT4 monthly global surface temperature departures from average, from January 1970 through November 2012 (blue), with linear trends applied to the time frames Jan ’70 – Oct ’77, Apr ’77 – Dec ’86, Sep ’87 – Nov ’96, Jun ’97 – Dec ’02, Nov ’02 – Nov ’12. Climate change skeptics like to emphasize the shorter term fluctuations in global temperatures (blue lines) and ignore the long-term climate trend (red line.) The global surface temperature trend from January 1970 through November 2012 (red line) is +0.16°C (+0.29°F) per decade. Image credit: skepticalscience.com.

Video 1. An animated description of how correcting for El Niño-Southern Oscillation (ENSO) cycle, dust from volcanic eruptions, and changes in solar energy shows that global warming has continued. Video credit: skepticalscience.com.

Where is the missing heat going? Into the oceans

The preponderance of La Niña events in recent years has caused a large amount of heat from global warming to be transferred to the deep oceans, according to a journal article published earlier this week by Balmaseda et al., “Distinctive climate signals in reanalysis of global ocean heat content“.

The warming at the surface has slowed down in recent years, but the total amount of heat going in the atmosphere/oceans/surface has continued unabated. The next big El Niño event will be able to liberate some of this stored heat back to the surface, but much of the new deep ocean heat will stay down there for hundreds of years. As far as civilization is concerned, that is a good thing, though the extra heat energy does make ocean waters expand, raising sea levels.

Figure 4. Land, atmosphere, and ice heating (red), 0-700 meter ocean heat content (OHC) increase (light blue), and 700-2,000 meter OHC increase (dark blue). From Nuccitelli et al. (2012), described at skepticalscience.com.

Links
In October 2012 Carbonbrief.org published a list of six blogs and videos done to debunk the claim that the Earth hasn’t warmed since 1998.

Balmaseda et al., 2013, “Distinctive climate signals in reanalysis of global ocean heat content,” Geophysical Research Letters, DOI: 10.1002/grl.50382.

The 2013 realclimate.org annual adjusted global temperature analysis, for 1979 – 2012, concludes: “the models are on the low side of some changes, and on the high side of others, but despite short-term ups and downs, global warming continues much as predicted.”

To answer frequently cited challenges to climate change science, see the wunderground.com webpage, Top Ten Skeptic Arguments, as debunked by skepticalscience.com.

Jeff Masters co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990. This piece is reprinted with permission.

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17 Responses to As Scientists Predicted, Global Warming Continues

  1. David Goldstein says:

    Hey all: I could use some help. I am about to have an article posted in Huffington Post about this very topic. I am referring to the “90% problem” and highlighting the Balsameda, Trenberth study to point out that warming continues unabated. Here’s my question: I do reference the ‘it has stopped warming’ myth in 2 manners: 1) I say it is wrong, that, in fact, global temps have not stopped rising.- but here, I do reference the fact that ‘the warming at the surface has slowed down in recent years’ (from the above article). My best research has shown that surface temps have risen about .04C per decade during this ‘slow-down period’. Can somebody tell me if this is accurate? 2) I then quickly and strongly emphasize that this myth considers only surface temps and we have a “90%” problem (playing off of Romney’s ’47%’ problem’) with the ocean heat. Any help would be appreciated. fwiw- the article is to be titled “The First Level of Disruption: Our 90% Problem” I’ve had 3 articles posted so far. One of them got a couple hundred comments. This one seems to have gotten the best qualitative feedback: http://www.huffingtonpost.com/davidgoldstein/adult-response-climate-change_b_2832052.html

    • BlackDragon says:

      I can’t source the accuracy of that number myself, but given the point of your article, my question would be: does it even matter, for that short period, if there was any increase at all? It could be a slight increase, decrease, or exactly flat (and given the measurement error bars on all temp records of that short period, one could probably make a case that the actual temp change was any of those three possibilites). It is not, perhaps, something you want to get too distracted by in your article.

      Getting across the idea of ocean heat storage and the longer term possible surprises (a big El Nino kicking some of that heat back out, warmer oceans decreasing overall CO2 uptake, etc) is the key thing.

      Ocean CO2 uptake:
      http://carboncycle.aos.wisc.edu/ocean-uptake/

      Try and stay away from waffly things. That personally drives me nuts. As good as Masters’ article is, why does he need to say: “…but much of the new deep ocean heat will stay down there for hundreds of years. As far as civilization is concerned, that is a good thing…”

      Yes, he mentions sea level rise, but who is to say there is any “good thing” in the long run about the oceans storing so much heat? On balance, given the potential changes in CO2 uptake, and many other “unknown unknowns” out there, it could be the most horrible long term thing ever for civilization that the oceans are storing so much heat! (as opposed to say the heat just radiating back out to space) That statement is totally unnecessary.

      • Alex P says:

        I agree. And what happens to the middle to upper ocean as the deep ocean warms, in terms of future heat uptake and circulation patterns? Presumably those effects will unfold more or less in real time, and not conveniently wait a few centuries.

      • Mulga Mumblebrain says:

        A very keen observation. I agree, but perhaps we can grant the author the benefit of our hindsight in that he might not have thought through his statement in the way that you have done. I really cannot think of any beneficial effect that might eventuate from storing so much heat deep in the oceans.

    • BlackDragon says:

      Also wanted to say, David, I really enjoyed the article you linked above. Great stuff.

      • David Goldstein says:

        thanks, Dragon. No worries- no waffling for me- if anything, I feel we should be more assertive than ever.

    • Duncan Noble says:

      It’s important to recognize the chaotic nature of these systems we are attempting to understand and model. According to this quote, looking at “climate trends” of less than 30 years or so may be meaningless:

      “Distinguishing the forced response of the climate system from its chaotic natural variability requires a detailed understanding of the character of the latter, often referred to as “climate noise.” Current estimates of this noise come largely from climate models run for a long time with constant forcing. These estimates suggest that the current global warming trend is clearly distinguishable from climate noise on time scales of around 30 years and longer. Just as a particular week in mid spring may be colder than a particular week in late winter, there can be stretches as long as 30 years during which, owing to natural chaotic variability, the global mean temperature cools. Thus, for example, the lack of appreciable global warming over the first decade of the current millennium is, contrary to the claims of some, entirely consistent with the simultaneous occurrence of climate noise and greenhouse gas-induced warming.”

      Emanuel, Kerry (2012-10-26). What We Know About Climate Change (Boston Review Books) (pp. 36-38). MIT Press. Kindle Edition.

    • Joan Savage says:

      David Goldstein,
      Please clarify what you mean by your “best research has shown that surface temps have risen about .04C per decade.” I tend to be literal about the word research, expecting data, methods, references.

      From UCAR:
      Global warming does not mean that temperature increases are spatially uniform or monotonic: some places warm more than the average and some places cool because of accompanying changes in the circulation of the atmosphere and oceans. Land regions have warmed the most (0.7°C since 1979), with the greatest warming in winter and spring over the Northern Hemisphere continents.

      http://www2.cgd.ucar.edu/research/cgd-climate-highlights/surface-temperature

    • The last hottest year on record was 2010, not 1998. We don’t even need to quibble with the deniers about rate of warming since 1998. We haven’t even had a powerful El Nino since then and we still have record years. We have SO2 eruptions via volcanoes (which would cause cooling) and we still have record years. We have low solar activity and we still have record years. We have multiple La Ninas and we still have record years.

      Everything in nature pushes us toward cooling. But that signal is being over-ridden by human warming enough to, not only keep temps steady, but to increase them.

      The deniers grasp at straws, but last year was a La Nina year and still the 9th hottest on record. Anyone who thinks this means cooling isn’t using a human brain.

    • Colorado Bob says:

      DG -
      Speaking to the 90% -
      The scale we use to measure a substance’s ability to store heat is called, “specific heat”.
      Water has a value of 1 on this scale . It is the bench mark by which everything else is measured. Almost everything in nature is below this number. And the gases are some of the weakest things in nature when it comes to storing heat , water only gets beat by things that can go through a phase change as it can.
      So when you, explain this ocean warming , and why the heat in the oceans matters, use this example:
      One cubic foot of air. One cubic foot of granite. One cubic foot of sea water. All are heated to 110F degrees. Which one is holding the most heat ?

      The numbers are mind bending, Live Science had a great example today. …….

      During the 2000s, we and our fellow oceanographers returned and re-measured ocean properties at many of those sites. We detected a consistent warming signal in the abyssal ocean around the globe. The strongest warming is occurring in the Southern Ocean, aroundAntarctica, at a rate of approximately 0.03 degrees Celsius per decade. [Warming in Deep Southern Ocean Linked to Sea-Level Rise]
      Further north, abyssal ocean waters are also warming, but at a rate of about one tenth of what we see in the deep Southern Ocean. Even though the temperature increases are small, because they are spread over huge ocean basins in layers a few kilometers thick, they quickly add up.
      The warming in the deep Southern Ocean alone accounts for 34 terawatts of warming, roughly equivalent to the continuous operation of three 1,500-watt electric teakettles for each of the 7 billion people on the planet. This warming could offset some of a recently reported slowdown in the upper ocean’s warming rate.

      http://www.livescience.com/28248-deep-ocean-warming.html

  2. Jack Burton says:

    I have heard any number of deniers use their no global warming since 1998 talking point, or global warming stopped in 1998 talking point.
    Of course any fool can see that this is cherry picked, you see the same type of cherry picking of starting points in the economic news in the main stream media. The main stream economist use this method in order to alter the economic perception of the current recession/depression. It is only natural that the climate change deniers would go wild over the chance to pick a date 1998 and use it to show a halt to global warming. Kinda funny tactic though, as by using it, they tacitly are admitting that before their cherry picked date these WAS global warming.
    But we know this denial is not about facts, it is about lies and liars. Paid liars. They are not about showing that global warming stopped in 1998, they know it has not, they simply need a convenient lie to divert the public. This date, 1998, is all over the internet and comments sections to blogs and news sites. Why, because the Public Relations firms working for the fossil fuel companies have chosen this bit of useable data to lie. Simple object is to fool average people and delay or prevent any political pressure to arise against the CO2 emissions business as usual model.

    • Mulga Mumblebrain says:

      Thank-you for calling the deniers by their correct name. Getting the terminology right is crucial. ‘Skeptic’, even inside inverted commas, is surrendering to their phony nomenclature, and we might as well call the climate rationalists ‘warmists’ or ‘alarmists’ and adopt their entire narrative. There are two types of denier in my opinion. The ignorant moron type and the cynically duplicitous type. Both are heads of the Rightwing Hydra.

  3. Martin Vermeer says:

    My best research has shown that surface temps have risen about .04C per decade during this ‘slow-down period’.

    That number is not wrong, but certainly not “accurate”. See this graph. An appreciation of the impact of natural variation, as here illustrated by the choice of starting year, could be a welcome extra for your article.

    I don’t know if ‘in recent years’ as meant by you corresponds to my assumed ca. 16 years, but for shorter periods this issue is even more salient.

    …and of course ‘random’ natural variations have physical mechanisms too…

  4. Just one point RE this article…

    Deep ocean warming really isn’t such a good thing for civilization. Methane hydrate destabilization. That’s what deep ocean warming gives us.

  5. Colorado Bob says:

    Dr. Master’s -
    Nice job. But the lie from the Mail Online has circled the Earth for weeks.
    Mark Twain was right .
    A lie can circle the Earth, while the truth is putting on it’s shoes.