Should climate models have predicted the pause?

27 09 2013

Media coverage today of the launch of the 5th Assessment Report of the IPCC has again said that global warming is “unequivocal” and that the pause in warming over the past 15 years is too short to reflect long-term trends.

Over recent days some commentators have criticised climate models for not predicting the pause. It’s good to see this being addressed, and so begin to clarify the difference between climate model projections and predictions.

We should not confuse climate prediction with climate change projection. Climate prediction is about saying what the state of the climate will be in the next few years, and it depends absolutely on knowing what the state of the climate is today. And that requires a vast number of high quality observations, of the atmosphere and especially of the ocean.

Whilst the last decade has seen a rapid increase in good observations of the surface and upper ocean, thanks to Argo floats, we have very few for the deep ocean. Without these requisite observations to initialise, i.e. set running, a climate prediction, it is impossible to have predicted the current pause, however good the climate models.

On the other hand, climate change projections are concerned with the long view; the impact of the large and powerful influences on our climate, such as greenhouse gases. Projections capture the role of these overwhelming influences on climate and its variability, rather than predict the current state of the variability itself.

The IPCC model simulations are projections and not predictions; in other words the models do not start from the state of the climate system today or even 10 years ago. There is no mileage in a story about models being ‘flawed’ because they did not predict the pause; it’s merely a misunderstanding of the science and the difference between a prediction and a projection.

As the IPCC states in line with our three papers on the pause, the deep ocean is likely a key player in the current pause, effectively ‘hiding’ heat from the surface. Climate model projections simulate such pauses, a few every hundred years lasting a decade or more; and they replicate the influence of the modes of natural climate variability, like the Pacific Decadal Oscillation (PDO) that we think is at the centre of the current pause.

The Daily Telegraph today also covers the science of the pause.

Critically there is ever more confidence that the world is warming as a result of human actions, and limiting climate change would require substantial and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases.


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11 responses

27 09 2013
jbenton2013

This is unscientific claptrap. Whoever wrote this article should have just owned up to the fact, “our models failed to predict the stop in global warming over the last 15 years and we haven’t got a clue why”.

Trying to reframe the models failure in such deceptive terms is simply making the Met Office look even more foolish. Simply more obfuscation from an already discredited organisation which has even failed to accurately predict anything over a few days into the future.

It’s time for politicians to defund this failing organisation and limit their scope to producing accurate weather forecasts for the next few days. Once the Met Office can do that then they can try producing forecasts for the next month, but don’t try to con anyone that you can predict, or is it project, the climate years in advance. Do you think the public are fools, no one is listening anymore to your scare stories.

27 09 2013
mpcraig

Just this morning, I listened to an IPCC spokesman who said climate models are “policy relevant”.

From what I have read here (and elsewhere), climate models are anything but “policy relevant”. My confidence in the IPCC is very low and uncertainty is high. IMO, you’d have to have some sort of dogmatic mindset to think any different (or be uniformed).

28 09 2013
Lord Beaverbrook

So which category does the change in the UK to a Mediterranean climate fall?

4 10 2013
jeremyp99

Yes. We’ve had to replant our Mediterranean garden. And whatever happened to “no more snow”. It wouldn’t be so b\ad were not this claptrap being paid for by us. That the Met Office got bonuses this year just adds to my contempt for the warming establishment and their corruption of science.

28 09 2013
James Evans

“Over recent days some commentators have criticised climate models for not predicting the pause. It’s good to see this being addressed…”

So, you mean it’s good to see some commentators addressing this. If they hadn’t, would you have mentioned it?

“Without these requisite observations to initialise, i.e. set running, a climate prediction, it is impossible to have predicted the current pause, however good the climate models.”

So what’s the point of the models then? You can’t predict a 15 year pause – it’s impossible. So what on earth could you predict? If it is impossible to predict a massive feature like that then there really is no hope for the models, surely.

“Projections capture the role of these overwhelming influences on climate and its variability, rather than predict the current state of the variability itself.”

But, it remains an assumption (of yours) that the models are reflecting these overwhelming influences. Because reality has never followed the line of your projections. We all know you are super confident (95%?) that your assumptions will turn out to be correct in the long run. But they can ONLY turn out to be correct in the long run. In the short run you fail. Again and again. There is absolutely nothing to convince us that your assumptions will turn out to be right, other than your “confidence”.

There are lots of rational, logical people who are following this issue. Do you see, at all, how silly your arguments might seem?

29 09 2013
Martin A

From a Met Office publication:

“Are computer models reliable?

Yes. Computer models are an essential
tool in understanding how the climate will
respond to changes in greenhouse gas
concentrations, and other external effects,
such as solar output and volcanoes.

Computer models are the only reliable
way to predict changes in climate. Their
reliability is tested by seeing if they are able
to reproduce the past climate, which gives
scientists confidence that they can also
predict the future.”

Reproducing the past is a very weak test of a model. If a model could not even reproduce the past it would have failed completely. But reproducing the past is not a test that a model has correctly modelled all the necessary physical effects to predict future behaviour.

“Computer models are the only reliable way to predict changes in climate” – their failure to predict the pause shows this is wishful thinking.

30 09 2013
Barry Woods (@BarryJWoods)

yes they should…
climate predictions made on the short term by the Met Office below (2007 aroundthe time of AR4)

http://web.archive.org/web/20080708230357/http://www.metoffice.gov.uk/corporate/pressoffice/2007/pr20070810.html

Met Office 10 August 2007
The forecast for 2014…
Climate scientists at the Met Office Hadley Centre will unveil the first decadal climate prediction model in a paper published on 10 August 2007 in the journal Science. The paper includes the Met Office’s prediction for annual global temperature to 2014.

Over the 10-year period as a whole, climate continues to warm and 2014 is likely to be 0.3 °C warmer than 2004. At least half of the years after 2009 are predicted to exceed the warmest year currently on record

These predictions are very relevant to businesses and policy-makers who will be able to respond to short-term climate change when making decisions today. The next decade is within many people’s understanding and brings home the reality of a changing climate.

The new model incorporates the effects of sea surface temperatures as well as other factors such as man-made emissions of greenhouse gases, projected changes in the sun’s output and the effects of previous volcanic eruptions — the first time internal and external variability have both been predicted.

Team leader, Dr Doug Smith said: “Occurrences of El Nino, for example, have a significant effect on shorter-term predictions. By including such internal variability, we have shown a substantial improvement in predictions of surface temperature.” Dr Smith continues: “Observed relative cooling in the Southern Ocean and tropical Pacific over the last couple of years was correctly predicted by the new system, giving us greater confidence in the model’s performance”.

Notes

Total global warming, on a decadal average, is 0.8 °C since 1900 (IPCC 2007)
1998 is the current warmest year on record with a global mean temperature of 14.54 °C

30 09 2013
Barry Woods (@BarryJWoods)

10 year climate predictions were confidently being made in 2007 (AR4 time) were the policymakers badly advised then?

Met Office – News release
10 August 2007
The forecast for 2014…
Climate scientists at the Met Office Hadley Centre will unveil the first decadal climate prediction model in a paper published on 10 August 2007 in the journal Science. The paper includes the Met Office’s prediction for annual global temperature to 2014.

Over the 10-year period as a whole, climate continues to warm and 2014 is likely to be 0.3 °C warmer than 2004. At least half of the years after 2009 are predicted to exceed the warmest year currently on record

These predictions are very relevant to businesses and policy-makers who will be able to respond to short-term climate change when making decisions today. The next decade is within many people’s understanding and brings home the reality of a changing climate.

The new model incorporates the effects of sea surface temperatures as well as other factors such as man-made emissions of greenhouse gases, projected changes in the sun’s output and the effects of previous volcanic eruptions — the first time internal and external variability have both been predicted.

Team leader, Dr Doug Smith said: “Occurrences of El Nino, for example, have a significant effect on shorter-term predictions. By including such internal variability, we have shown a substantial improvement in predictions of surface temperature.” Dr Smith continues: “Observed relative cooling in the Southern Ocean and tropical Pacific over the last couple of years was correctly predicted by the new system, giving us greater confidence in the model’s performance”.

Notes

Total global warming, on a decadal average, is 0.8 °C since 1900 (IPCC 2007)
1998 is the current warmest year on record with a global mean temperature of 14.54 °C
For further information:
Met Office Press Office

2 10 2013
ntropyalwayswins

“On the other hand, climate change projections are concerned with the long view; the impact of the large and powerful influences on our climate, such as greenhouse gases. Projections capture the role of these overwhelming influences on climate and its variability, rather than predict the current state of the variability itself.”

Eventually it will occur to you that greenhouse gasses do not have ‘a large and powerful influence’ on our climate nor are these ‘overwhelming’ influences. If you were to take Occam’s razor to the problem of the so-called missing heat you would find that it is not missing. It has been hypothesised by a politicised science elite.

The greenhouse effect is governed by radiative physics. Beautiful and elegant radiative physics explains the energy in and the energy out. But the amount of energy that enters the earth system and the distribution of the energy within the earth system is governed by much greater forces. Just to give one example – the effect of clouds. You do not understand and therefore cannot model clouds. Here is what AR5 says on clouds:

“• Substantial ambiguity and therefore low confidence remains in the observations of global-scale cloud variability and trends. {2.5.7}

• There is low confidence in an observed global-scale trend in drought or dryness (lack of rainfall), due to lack of direct observations, methodological uncertainties and choice and geographical inconsistencies in the trends. {2.6.2}

• There is low confidence that any reported long-term (centennial) changes in tropical cyclone characteristics are robust, after accounting for past changes in observing capabilities. {2.6.3}”

In spite of low confidence (which is IPCC-speak for little understanding) in how clouds affect the climate the IPCC and the Met Office have high confidence that they do understand the climate system sufficiently well to find CO2 guilty as charged (which let us not forget is the ultimate purpose of the charade that is the IPCC process).

Are clouds a feedback or a forcing? Or sometimes one and other times the other. Do you know?

When you talk about ‘overwhelming influences’ on climate those influences are sun, clouds, the ocean currents and the hydrological cycle. In comparison to these known overwhelming influences the proportion of CO2 put in the atmosphere by man’s activities is a puny bit player.

This is what Judith Curry has to say about the pause and the IPCC:

“What is wrong is the failure of the IPCC to note the failure of nearly all climate model simulations to reproduce a pause of 15+ years.

Yes, Dana Nuccitelli, climate models are just as bad as we thought – and even worse than most people think, since the inability of most models to reproduce the Earth’s average temperature is not well known.”

see http://judithcurry.com/2013/10/02/spinning-the-climate-model-observation-comparison-part-ii/#more-13193 for full comment.

You end your post above with the following words:

“Critically there is ever more confidence that the world is warming as a result of human actions, and limiting climate change would require substantial and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases.”

The confidence you refer to is a political construct and has no scientific basis and it reflects very badly on a national meteorological office to make such a statement. You should be doing science not politics.

4 10 2013
jeremyp99

Well put. Thank you.

6 10 2013
clivebest

“We should not confuse climate prediction with climate change projection.”

This sounds to me more like some medieval argument about transubstantiation than science ! Art its core AR5 shows clearly that models are now running a little too hot. Equilibrium climate sensitivity is most likely lower than feared at between 2 and 2.5C. Dangerous climate change is very unlikely and we have at least 30 years to find a long term solution.

DWBH.

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