The 2013 global mean temperature

29 01 2014

In December 2013 we published an estimate of the global mean temperature up to the end of October 2013, based on an average of the three main global temperature datasets – Met Office and University of East Anglia (HadCRUT4), NOAA National Climatic Data Center (NOAA NCDC) and NASA Goddard Institute of Space Studies (NASA GISS).

The United Nations’ World Meteorological Organisation (WMO) and the IPCC’s provisional estimate global mean temperature for 2013 is 0.5 °C ± 0.1 °C above the long-term (1961-1990) average.

For HadCRUT4, the provisional estimate for the whole of 2013 is between 0.39 °C and 0.59 °C above the long-term (1961-1990) average of 14.0 °C, with a central estimate of 0.49 °C.

This means 2013 is in the top ten warmest years on record and we continue to see near record global temperatures like those which resulted in 2000-2009 being the warmest decade in the instrumental record.

As always the latest figure has generated interest in the media, which focuses on how it relates to previous forecasts from the Met Office.

The global mean temperature is just one of many indicators – including sea level rise, shrinking glaciers and reducing Arctic sea ice – that give even more confidence that the world is warming. Climate models are an invaluable tool in helping us to understand past changes and predict how temperatures may change in the future; they have provided overall good advice capturing and representing the warmer world we now live in.

We can see from the IPCC AR5 report figure below how global temperatures have risen since 1860 and how the latest provisional observational estimates still lie within the range of the forecast models. This figure also shows that, looking back over the entire observational record there are a number of occasions where the observations lie close to both the upper and lower bounds of the model simulations, so what we are seeing at the moment is nothing new.

Time series of global and annual-averaged surface temperature change from 1860 to 2012 showing results from two ensemble of climate models driven with natural forcings and human-induced changes in greenhouse gases and aerosols compared to observations of global mean temperature from three different datasets relative to 1880-1919. CMIP3 relates to the suite of climate models used in IPCC AR4 and CMIP5 those models used in IPCC AR5.*

Time series of global and annual-averaged surface temperature change from 1860 to 2012 showing results from two ensemble of climate models driven with natural forcings and human-induced changes in greenhouse gases and aerosols compared to observations of global mean temperature from three different datasets relative to 1880-1919. CMIP3 relates to the suite of climate models used in IPCC AR4 and CMIP5 those models used in IPCC AR5.*

So, why might the global mean temperature be different from forecasts? Well, we know that, due to the lack of long-term observing sites in polar latitudes, HadCRUT4 underestimates the contribution from Arctic warming which has accelerated in recent years.

There is also increasing scientific evidence that the current pause in surface warming is associated with natural variability in the global oceans, as they absorb heat from the atmosphere. Changes in the exchange of heat between the upper and deep ocean appear to have caused at least part of the pause in surface warming, and observations suggest that the Pacific Ocean may play a key role. You can find out more about the recent pause in warming here.

*Figure modified from Bindoff, N. L., P. A. Stott, K. M. AchutaRao, M. R. Allen, N. Gillett, D. Gutzler, K. Hansingo, G. Hegerl, Y. Hu, S. Jain, I. I. Mokhov, J. Overland, J. Perlwitz, R. Sebbari and X. Zhang, 2013: Detection and Attribution of Climate Change: from Global to Regional. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, in press.


Actions

Information

16 responses

29 01 2014
Kav

Reblogged this on and commented:
Great and simple article regarding how the climate has changed in recent times through the use of scientific data.

31 01 2014
jbenton2013

Not quite the “scientific data” you may think it is Kav.

31 01 2014
jbenton2013

This must rank as one of the most misleading and disingenuous articles from the Met Office recently.

The centrepiece of this article is the graph of averaged surface temperature change from 1860 – 1912. This entire graph, or more usually the most recent 50 year period, has been reproduced in many scientific and media articles dealing with climate change over the last few years. However in reputable publications the graph includes an extremely significant additional vertical line through the year 2005 to indicate to readers that after 2005 the graph shows model FORECASTS, whereas prior to 2005 the graph shows HINDCASTS (curve fitting to historical temperature data).

Unless the reader was aware of how this graph was compiled, and what it represented, it could easily be assumed that the climate models had done a fairly good job of modelling the temperatures from 1860 to around the early 2000’s, whereas in reality these are hindcasts where modellers have fitted their models to empirical data.

It is therefore clear that over the true FORECAST period 2005 – 2012, the models have done an incredibly poor job of forecasting the observed temperatures.

The Met Office claim in the paragraph immediately prior to the graph above is extremely disingenuous by suggesting that readers should place credence on the modelled results “over the entire observational record”. My goodness, are they really expecting credit for fitting a curve to historical data prior to 2005. If they can’t even get that right, what confidence could we possibly place on actual forecasts post 2005.

Remarkably though, post 2005 we see that the models have done an incredibly poor job of forecasting the temperature to 2012. The Met Office claim that the “latest provisional observational estimates still lie within the range of the forecast models”. Again this is at best a disingenuous claim. The reality is that of the nearly EIGHTY models included in the ensemble, the observed temperature has now fallen outwith the uncertainty bounds of all but THREE models, and unless the observational temperatures increase significantly will also fall outwith the outer uncertainty limits of even those three models very soon. Furthermore when you examine the predictive capabilities of those three models in respect to other criteria, other than temperature, it becomes clear their credibility is further eroded. In essence 97% of the models have already failed and the remaining 3% are on the verge of failing to demonstrate any predictive qualities. Not quite the message the above article seeks to portray, or one the average reader is likely to deduce from the article.

The article also states that other indicators offer confidence of warming. No one disputes that the world has warmed since the Little Ice Age over 300 years ago, or that the direct radiative effect from a doubling of CO2 (280ppm – 560ppm) should (all else being equal, which it rarely is), increase temperature by around 1 deg C. However the article above also fails to acknowledge a number of other inconvenient facts.

Global sea ice is presently at an all time high since reliable satellite records began, and Arctic minimum sea ice in 2013 staged a massive recovery in over 2012 levels, up over 50% in a single year. I’m not too surprised the Met Office once again failed to mention Antarctic sea ice, which has been expanding for at least 35 years since satellite records began. It is correct, but not too surprising that more glaciers have been shrinking than expanding since the end of the Little Ice Age, but there is no evidence of any alarming sea level rise, and certainly NO EMPIRICAL EVIDENCE of any increase in ‘extreme weather events’ despite spurious claims by the Met Office chief alarmist Peter Stott, who has failed to produce any supporting data despite repeated requests.

With articles like this, it is hardly surprising that the Met Office is currently held in low regard by large numbers of the public.

4 02 2014
Bob Smith

There’s a lot wrong in that comment, but this one stood out:
“Global sea ice is presently at an all time high since reliable satellite records began”

Not remotely true.

5 02 2014
jbenton2013

No data to support your claims.

31 01 2014
jbenton2013

Despite what the article claims there is no credible empirical evidence to support the claims that the hiatus in temperatures over the last 16 years can be accounted for by claims that the ‘missing heat’ has suddenly decided to ‘hide away’ in the ocean depths. This claim is based on reprocessed modelled data in the Balmesada et al paper, which even many warmists acknowledge is extremely unlikely, given that no credible mechanism has been postulated as to how it got there without having been detected by the ARGO system in the 0 – 700m level.

The Met Office would also have to explain why the Pacific Ocean had absorbed heat when others had not.

Another disingenuous claim that the ‘missing heat’ has taken up residence in the Arctic where there are conveniently fewer thermometers is to say the least suspicious, and smacks of desperation, particularly with the massive increase in Arctic ice in 2013.

A much more likely explanation is that the heat never existed in the first place and the models are running far too hot. It is well known that the CMIP 5 models fail to accurately account for aerosols correctly, which will inevitably have this effect.

4 02 2014
Bob Smith

“This claim is based on reprocessed modelled data in the Balmesada et al paper”

It’s based on far more than that. Sea level rise for example is strong evidence of continued thermal expansion.

“which even many warmists acknowledge is extremely unlikely, given that no credible mechanism has been postulated as to how it got there without having been detected by the ARGO system in the 0 – 700m level.”

I haven’t seen any scientist acknowledge anything of the sort. Your claim that it must be “detected by the 0 – 700m level” is unjustified as it’s based on an overly simplistic notion that heat is some moving blob.

“Another disingenuous claim that the ‘missing heat’ has taken up residence in the Arctic where there are conveniently fewer thermometers is to say the least suspicious”

There’s plenty of evidence that the Arctic is warming up faster than lower latitudes. There are satellites and buoys for example.

“particularly with the massive increase in Arctic ice in 2013.”

What does that prove? You think one year of increase implies the Arctic hasn’t warmed sharply in recent decades?

“A much more likely explanation is that the heat never existed in the first place”

Then you have to explain the sea level rise without thermal expansion. Perhaps you are suggesting the ice sheets in the last decade have slipped into a sharp accelerated melt and that’s where the sea level rise has come from?

Your position is entirely based on wanting a certain outcome rather than thinking it through.

5 02 2014
jbenton2013

There has been no acceleration in sea level rise whatsoever. In fact it has remained remarkably stable, but since we are still emerging from the Little Ice Age it’s completely unremarkable that sea levels have been rising at a constant 3mm/year.

There was a fairly lengthy discussion about the Balmesada et al paper at the warmist Climate Etc site which dismantled the ‘ocean ate our missing heat’ theory which Trenberth has been pedalling. However even if I were to accept your premise that the deep oceans had warmed by the few thousandths of a degree that the Balmesada paper claims, which I certainly do not, it’s going to be very hard to get anyone excited about that given the second law of thermodynamics.

Since you have offered no data to support your other claims i’ll assume they’re nothing more than hand waving.

31 01 2014
nuwurld

Oh dear Met.

Still sticking to “everything is going to plan”!

You have around two years to modify your models before the measured temperatures escape below your “far too warm” error bars. Unfortunately nature is unaware of your models’ sensitivity to greenhouse gases.

The modern warm period due to natural forcings is over, period.

The PDO has peaked, the AMO has peaked and all solar metrics show a multi decadal decline in both the total solar irradiance and the portion thermalised. The world will cool. Sorry.

4 02 2014
Bob Smith

Actually the PDO has not peaked, it’s well past peak. It has bottomed out, and the Sun has plummeted back to early 20th century levels.

So why is the world still heating up? Where’s the cooling?

Keep hanging onto the AMO, but you’ll find that’s a damp squib too.

Man is driving global temperature now, nature is in the back seat.

5 02 2014
jbenton2013

More hand waving. The world has not warmed for the last 17 years.

5 02 2014
nuwurld

Hi Bob.

Bob I have said that the PDO has peaked and I stand by that statement. The cycle length of the PDO is 60 to 65 years. Last century the PDO peaked around 1940 and then again around the year 2000. As a surface temperature anomaly with an approximate 30year positive phase centred around the year 2000, we can expect little assistance from this natural oscillation for at least 30 years. It has peaked.

You ask,
“So why is the world still heating up? Where’s the cooling?”

Well the data says it isn’t heating up!
The oceans lag by around 400 years due to their thermal inertia. The oceans continue to expand because of this. They are not in equilibrium with the surface or atmosphere. They’re playing “catch up”.

Temperature peaking after peak input is a classic signature of a thermal storage oscillator. Equilibrium is never achieved due to lag.

The AMO will prove more significant than you think. The warm phase of the AMO is largely the cause of the recent multi decadal reduction in Arctic sea ice. Altered atmospheric circulation patterns are set to work with the imminent decline of the AMO and reduce the surface flow of warm Atlantic waters into the Norwegian and Barents seas. This will increase the Arctic winter sea ice area and the increased ice albedo feedback will then start to drive the Earth cooler.

At present this is the weakest peak of solar activity for 100 years as you have stated. However, recent activity has been around 100 spots/day. Today it’s normalised value is 122. Due to the “darkening” effect of very large spots total solar irradiance peaks at around 100 spots/day. So TSI is still quite high. However, extreme UV is relatively low, diminishing upper atmospheric energy and changing upper atmospheric chemistry and advection poleward. By the end of this year both TSI and extreme UV will be low and stay low. Then you will see what the Sun has been providing under the cloak of apparent invariance. The Earth will cool.

12 02 2014
nuwurld

I don’t expect you to print this Met, but I fail to comprehend why it should take a week for a comment to pass through ‘moderation’. You have started two new topics since that are open for replies yet still I wait for my comment from the 5th Feb to appear. Either you want to delay some comments or you are happy to run a pedestrian blog. Why not just delete the comments option? That way only your views are read. Just a thought.

13 02 2014
Met Office Press Office

Hello Geoff

Thank you for your comments and apologies for the delay in moderating in general. We will endeavour to do better in future.

13 02 2014
nuwurld

Dear Met, as a proponent of the truth I accept this accolade of recognition positively. I trust without question that your promise will be upheld. Thank you for taking the time to research.

Btw. This is still totally offensive,

http://www.metoffice.gov.uk/news/releases/archive/2009/science-community-statement

Without fully understanding natural variation no portion can be attributed to mankind’s actions.

Plants/animals, CO2/O2 is symbiosis.

CO2 and temperature are proving to be uncorrelated. Around 18 months left.

Looking after our planet, caring for its life forms is essential. Efficiency and respect for our environment unquestionable.

The rest is economics.

Thanks for replying.

Geoff.

1 02 2014
craigm350

Reblogged this on CraigM350 and commented:
There is also increasing scientific evidence that the current pause in surface warming is associated with natural variability in the global oceans, as they absorb heat from the atmosphere.
We just won’t say natural variability caused the warming.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




Follow

Get every new post delivered to your Inbox.

Join 6,192 other followers

%d bloggers like this: