The climate conundrum - why aren't global temperatures higher?

Friday 28 June 2013, 17:48

Paul Hudson Paul Hudson

News that carbon dioxide levels have reached 400 parts per million – a level widely thought by scientists not seen for at least 3 million years – caught the headlines last month.

 

It comes at a time when global temperatures have remained largely flat since the late 1990s, despite climate forecasts of a rise of 0.2C per decade.

 

Through the 1980s and 1990s, as carbon dioxide levels rose, so did global temperatures, until a peak in 1998.

 

Since then it’s become increasingly clear that the science is not as straightforward as it seemed, and after 15 years of flat-lining temperatures, scientists are trying to work out what has caused this apparent halt in global warming.  

 

One of the criticisms of mainstream climate scientists, by sceptics, is that they have been very slow in acknowledging this obvious levelling-off in global temperatures.

 

So why have we seen very little warming in recent years? Is the science in which global warming projections are based flawed?

 

Calculations based on simple physics show that if levels of carbon dioxide double, the earth’s temperature should rise by approximately 1C.

 

Mainstream climate scientists believe that this initial rise will then lead to further global warming due to feedback mechanisms.

 

For example, melting ice and permafrost could potentially release billions of cubic feet of natural methane gas, which is around 20 times more powerful a greenhouse gas than carbon dioxide.

 

Levels of water vapour in the atmosphere are likely to increase, itself a much more powerful greenhouse gas than carbon dioxide.

 

Some climate sceptics argue that a warmer earth with more water vapour in its atmosphere will lead to a cloudier planet; more cloud cover will act to cool the planet by reflecting some of the suns warmth back onto Space; the earth is in equilibrium with itself, and will adjust itself accordingly, according to this theory.

 

Climate sceptics, though, have yet to come forward with a plausible reason as to why carbon dioxide wouldn’t increase the earth’s temperature; in other words, why in this instance would basic physical laws not apply?

 

But assuming that the science is sound, an explanation is still required as to why the rise in global temperatures has ground to a halt and why it wasn’t forecast.

 

Because according to data used by Climate lab book in association with the National Centre for Atmospheric Science (based at Leeds University) ‘global temperatures are tracking at the bottom of the range in which 90 per cent of the model simulations lie’.

 

Put simply, the vast majority of climate models predicted that global temperatures would be higher than they are today.

 

So why are global temperatures not higher?

 

One explanation put forward lies in the oceans, which cover 70% of the earth’s surface.

 

The top two and a half metres of the ocean can hold as much heat as the atmosphere. So could the missing global warmth be here?

 

Some scientists believe it's buried deep in the oceans, but if this is the case, measuring it is a real problem.

 

Some recent research has suggested that the earth may not be quite as sensitive to increased levels of carbon dioxide as scientists previously thought.

 

 But whatever the explanation as to where the ‘missing heat’ is, and whatever the actual level of warming turns about to be, with carbon dioxide levels continuing to rise year on year, altering the chemical composition of the atmosphere, most scientists believe that further global warming is only a matter of time, but by how much and how fast is the real conundrum.

 

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Comments

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  • rate this
    0

    Comment number 1.

    It's a fair enough appraisal by Paul overall, but I wonder sometimes about comments like: "Through the 1980s and 1990s, as carbon dioxide levels rose, so did global temperatures, until a peak in 1998."

    The period 1981-1998 is still just a snapshot of a longer period. Likewise, the period from 1999 to the present is really too short a period from which to draw meaningful conclusions about climate change.

    Why not consider the entire period from 1981 to the present, and compare CO2 concentrations and temperature rise over this longer term?

    It's over longer periods (+3 decades) such as this that we are supposed to see a statistically significant correlation between rising CO2 concentrations and rising surface temps.

    Effectively Paul is just doing the 'same-old-same-old' of dividing a long term trend into short term pieces.

  • rate this
    +5

    Comment number 2.

    "Climate sceptics, though, have yet to come forward with a plausible reason as to why carbon dioxide wouldn’t increase the earth’s temperature; in other words, why in this instance would basic physical laws not apply"

    Doesn't a scientist have to prove his hypothesis??

    Why should someone have to disprove someone else s hypothesis??

  • rate this
    0

    Comment number 3.

    #1 newdwr54

    Why limit the start date to 1981?
    What's so special about this period?
    There is nothing outstanding that should warrant attention so go for the full historical record, the more data the better.

  • rate this
    0

    Comment number 4.

    One argument by the "modellers" is that periods of up to 15 years with no increase in observed temperature are not unusual and there are some models which forecast such a hiatus.
    In an attempt to track down these elusive models, I have recently reviewed the 21 models which make up IPCC AR4 scenario A1B, using data obtained from the IPCC website, to see if any of those models show warming trends of zero or less over any 15 year periods since 2000.
    If my calculations are correct, only 2 of the 21 models (9.5%) show negative trends over any 15 year period since 2000. These are:

    gfdl_cm2_0

    A trend of -0.085c/decade for the period to 2092.
    The 15yr trend to 2012 in this model's projections is +0.938c/decade and the maximum 15 year trend is +6,31c.decade in 2057.

    mri_cgcm2_3_2a

    A trend of -0.020c/decade for the period to 2009, and one of -0.015c/decade for the period to 2010.
    The 15yr trend to 2012 in this model's projections is +1.06c/decade and the maximum 15 year trend is 4.00c/decade in 2065

  • rate this
    0

    Comment number 5.

    It's the feedback mechanisms involving water vapour which are the problem. All of the 'dangerous' global warming predicted by the IPCC models is based on these feedbacks and the really catastrophic scenarios are largely based on huge releases of methane from melting permafrost. Also, little mentioned in the literature is the fact that the warming directly attributable to accumulations of CO2 in the atmosphere does not follow a linear relationship; it is logarithmic, meaning that the more CO2 which accumulates, the less heating effect it will have.

    The IPCC models have, in the past, evidently seriously over-estimated climate sensitivity to CO2, both equilibrium climate sensitivity (long term) and the shorter term transient climate response, both of which have been recently pegged downwards in a peer-reviewed study authored by IPCC scientists (Otto et al).

    The current 15 year hiatus in warming is proving to be problematic for the scientists who originally forecast a steady upward rise and as Paul says, attempts to model and account for this lack of warming are being put forward by climate scientists, none of which look particularly convincing in my opinion. Meanwhile, the heretical possibility that most or all of the global warming occurring during the 20th Century is due to natural causes still seems to attract little attention and funding from the wider climate science community.

  • rate this
    +7

    Comment number 6.

    The simple answer is that CO2 is a bit player in the drama of the climate. Such effects as it has in theory are dwarfed by the main actors - wind, rain, cloud. Radiative physics only dictates the big picture - energy in and energy out. The distribution of the energy is in the hands of much more powerful forces. It is a tragedy for mankind that climate science was betrayed by activists in its early years and has yet to recover.

  • rate this
    +1

    Comment number 7.

    Have we forgotten the Murray Salby presentation that appeared in Paul's previous comments section following hs 10 June article? I await any plausible rebuttal of his arguments that temperature drives CO2 rather than vice versa, or that their is a no man-made signature to the rise in CO2 concentration.

  • rate this
    +4

    Comment number 8.

    The basic problem is that the science is not sound. That is why there are so many sceptics and why such a large percentage of them are scientifically literate. The CO2 warming effect is accepted but the feedback amplification grossly exaggerated to support political ambitions. And now inevitably the cracks in that dubious deceit are beginning to show.

  • rate this
    0

    Comment number 9.

    I normally wait for an appropriate topic to re-publish out 2013 forecasts for HadCRUT4 submitted
    Met Office WMO forecast is +0.57
    The figures in brackets show the degree of error for 2012 and 2011 entries

    “Warmists”
    +0.57 * Met Office (+0.08,+0.09)
    +0.5 Newdwr54 (+0.05:N/A)
    +0.51 John Cogger (+0.03:N/A)

    “Neutralists”
    Mr Bluesky (+0.02:N/A)
    Lazarus (+0.02:N/A)
    +0.49 quake (+0.01:+0.36)
    Paul Briscoe (0:2012 winning entry 0.4)
    Gagetfriend (0:+0.30) (2012 winning entry 0.4)
    +0.48 NeilHamp (0:-0.08)(2012 winning entry 0.4)
    “Coolists”

    +0.41 QuaesoVeritas (-0.06:+0.31)
    +0.38 ukpahonta (-0.12:0) (2011 winning entry 0.35)
    +0.35 Lateintheday’s Holly Bush (-0.03,No entry)
    millinia (-0.11:+0.24)
    LabMunkey (-0.11:+0.25)

  • rate this
    0

    Comment number 10.

    The problem fro warmists is that the "greenhouse effect" hypothesis is a complete fraud, based on a flat model of the earth. Hence compuiter models based on the fraudulent physics will never predict the real behaviour of the climate.

  • rate this
    +2

    Comment number 11.

    "Climate sceptics, though, have yet to come forward with a plausible reason as to why carbon dioxide wouldn’t increase the earth’s temperature; in other words, why in this instance would basic physical laws not apply?"

    Whoa, Paul, steady on there. Sceptics' POINT is that basic physical laws DO apply, and a climate sensitivity of ~1.2C is what should be expected - a figure we're just about exactly on track for.

    It's for "consensus" scientists to justify their tipping point and positive feedback mechanism hypotheses - something that hasn't happened, despite being (at least in other scientific disciplines) the first order of business through observation and collection of empirical data.

    Fundamentally, this is the distinction between sceptics (i.e. geologists, physicists et al - known as "hard" sciences) and the rather woolly, more socio-politically oriented "soft" sciences like climatology.

  • rate this
    +2

    Comment number 12.

    #5.JaimeJ

    "It's the feedback mechanisms involving water vapour which are the problem. All of the 'dangerous' global warming predicted by the IPCC models is based on these feedbacks and the really catastrophic scenarios are largely based on huge releases of methane from melting permafrost. Also, little mentioned in the literature is the fact that the warming directly attributable to accumulations of CO2 in the atmosphere does not follow a linear relationship; it is logarithmic, meaning that the more CO2 which accumulates, the less heating effect it will have."

    I agree. I don't think that most people realise that a large part of the temperature increases predicted by models are as a result of feedback mechanisims, rather than CO2 as such and the non-linear effect of CO2.
    Also, as Paul says, the increase in water vapour and clouds is being used as a possible explanation for the lack of temperature increase, which even suggests that the feedback from water vapour may be negative.
    If we have reached a new state of equilibrium, that could go a long way to explaining the recent lack of warming.
    The strange thing is, that when you hear advocates of "climate change" talking in the media, they seem to be totally oblivious to the fact that there has been any pause in the increase in global temperatures. Are they in denial?

  • rate this
    0

    Comment number 13.

    #10.PAWB46

    "The problem fro warmists is that the "greenhouse effect" hypothesis is a complete fraud, based on a flat model of the earth. Hence compuiter models based on the fraudulent physics will never predict the real behaviour of the climate."

    I'm not sure whether it is valid to talk of this as "fraud".
    I think that most advocates of "climate change" genuinely believe what they are saying, it's just that they don't seem to be aware of the limitations of the models and have become convinced by their own propaganda.

  • rate this
    +2

    Comment number 14.

    #12 QuaesoVeritas

    Paul says: "Some climate sceptics argue that a warmer earth with more water vapour in its atmosphere will lead to a cloudier planet; more cloud cover will act to cool the planet by reflecting some of the suns warmth back onto Space; the earth is in equilibrium with itself, and will adjust itself accordingly, according to this theory" which is what you referred to in your post above, suggesting that the feedback from water vapour may in fact be net negative which would explain the lack of warming.
    Personally, I'm not convinced by this explanation which warmists could use to justify their basic 'CO2 is a climate pollutant' theory, pointing out that 'warming' is still happening but is being masked by consequent reflective cooling from increased cloud cover, conveniently of course forgetting to mention that the main thrust of CAGW is based upon POSITIVE water vapour feedbacks. That's how a lot of these people think.

    Also, it is not necessarily given that higher temps will lead automatically to increased evaporation, more humidity and hence more cloud formation. Warmer air is able to hold more water vapour without it condensing to form clouds; in fact lowering the temp of air whilst keeping the water vapour constant will lead to increased condensation (Dew Point) and hence more cloud cover. So in actual fact, increased evaporation will be compensated in some measure by the increased saturation vapour pressure of warmer air. You also need to look at the availability of condensation nuclei in the atmosphere which will also determine the rate at which clouds form.

    Global warming advocates ARE in a state of denial. They have consistently labelled the sceptics as the deniers, but the truth is, reality is rudely intruding upon their computer generated climate apocalypse nightmare. The smarter ones - and those not joined at the hip to an ideological dream of a carbon-free future - are waking up (slowly). People like our Energy Secretary Ed Davey will NEVER shift into reverse and this is the current tragedy of the situation in the UK, where our insane energy policy is driven by illusory goals generated from the wish to avoid an illusory future.

  • rate this
    0

    Comment number 15.

    What ''simple physics'' shows that doubling atmospheric levels raises temperatures by 1C? One law of physics proves that the theory of the GHE cannot work ie., the 2nd law of Thermodynamics. Radiation from a cool body cannot raise the temperature of a warmer body. this basic fact is 1st year A level let alone university level. The 2nd law also means that a system cannot heat itself. Would that it could and we would be using free energy.
    The reason why models show a temperature rise when reality has plateaued is because the models are wrong. How many years do we wait for the realization that if models fail to follow reality it is the model that is wrong not reality.
    You keep on about physical laws proving the CO2 conjecture but fail to name them. Perhaps they are actually ''climate science physics'' which with the model output is wrong. Your physics is based on a flat earth with no day/night cycle and cold insolation. reality is the earth is a rotating sphere with insolation on one face only and a cooling night side. if your model does not follow reality your model is wrong and will lead to your wrong conclusions about CO2 supplying heat that it cannot do.
    Get real Paul.

  • rate this
    0

    Comment number 16.

    You are incorrect about past CO2 atmospheric levels in the recent past not being above 400ppmv. Measurements in Victorian times show levels up to and possibly over 490ppmv. These levels were taken in UK, Germany, Italy so over a wide area.
    It is very difficult to obtain accurate proxy temperature/CO2 levels from ice cores. Entrapped gas gets squashed out of the progressively compressed ice so level figures tend to be too low. What ice core data does show is that temperature increased BEFORE CO2 levels which is ocean outgassing due to temperature rise. This takes about 800 years. Most atmospheric CO2 comes from the oceans and volcanoes animal respiration is also high. Our bit from burning fossil fuels is but 3% of the total.
    Please answer this question Paul--- why are deserts (dry) hotter than same latitude rainforest (wet) when your favorite theory claims that the reverse should be true because of the GHG water vapour. Both areas are getting the same insolation.

  • rate this
    +2

    Comment number 17.

    I would like to reiterate the point made by Simon H @ 11. Mainstream Skeptics expect CO2 emissions to increase temperatures.

    The problem is that the 'consensus' has grossly underestimated natural variability and hence overestimated the effect of CO2. This has been compounded by flawed statistics that have greatly exaggerated the possibility of extreme warming.

    The sorry state of climate science means that the 'thermo guys' who say there is no GHE and who have been banned from most Skeptic blogs may end up being closer to the final figure than James Hansen with his 4.2C. Is anyone calling Hansen anti-science?

  • rate this
    +2

    Comment number 18.

    Why is the present hiatus in the previous increase in global average temperatures so difficult for the scientific community to accept?

    My tutor was a PhD in the study of the surface levels of the seas and oceans and the rate of evaporation. He did not accept the general consensus about the hypothesis of man-made global warming, although did concede that further study may lead to such possible conclusions.

    A Professor at a well-known Northern University, but at a different establishment, who was chairing a debate, volunteered the thought that academics are always reluctant to concede that their previous studies and some published papers may be flawed in some way.

    Surely scientific method always allows for changes of opinion?

    What I find most difficult to accept is that a dogmatic view can be taken as being fact, either way. What is so wrong with keeping an open mind on the subject?

  • rate this
    +1

    Comment number 19.

    #17 RobWansbeck

    Yes Sir, the most accurate comment of the state of climate science made on this site for days.

    Whoever is negative rating you in the background for this obviously cannot format an argument against the bleeding obvious.

  • rate this
    +2

    Comment number 20.

    CET still showing below normal at -0.2c to the 27th.
    If that continues, which seems quite likely, that will be the the first 6 months of 2013 with below the 1961-90 average temperature.
    I think that would be the first time that has happened since 1979.
    July 1979 was above the 1961-90 average and the last year I can find with the first 7 months below the 1961-90 average was 1888.
    Only done by "eyeball", so I will need to double-check.

 

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I worked as a forecaster with the Met Office for nearly 15 years locally and at the international unit, after graduating with first class honours in Geophysics and Planetary physics at the University of Newcastle upon Tyne in 1992. I then joined the BBC in October 2007, where I divide my time between forecasting and reporting on stories about climate change and its implications for people's everyday lives.

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