Central England Temperature has fallen out of favour at WUWT

Some of you might remember how various WUWT-ers were hailing the temperature in Central England (HadCET) as heralding in an ice age. Two years ago a denier at WUWT was claiming that an ice age cometh, and pointed to HadCET - which, as you'll see below, indicated no such thing.  In June that year, David "funny sunny" Archibald made one of his famous failed predictions, that Central England was in for a cold spell. A few months later, a chap called Tony Brown claimed that HadCET showed temperatures were back to those of the 1730s, which was utter nonsense. (That is, they weren't!)

Now that particular temperature record has fallen out of favour. Not even the most ardent denier can deny it's got a lot hotter there in the past few years. I say they can't deny it, but they do, still.

Heat, Heat Waves and Angry Australian Summers (and Years)

I recently wrote a short article about the summer of 2012-13 in Australia. It got some reaction from one person in particular who was claiming the record heat couldn't be attributed to global warming, he postulated that it was caused by the Pacific Decadal Oscillation (eventually having some comments moved).

Rum Runner's challenge

He also posed a challenge. Rum Runner wrote: (October 9, 2014 at 2:26 AM)

@Lou "Why do you think I run this blog?"
A sense of empowerment I suppose. On other people's blogs you'd have your ass handed to you on a plate in an open debate. But here you can just *pop* delete any responses that are a bit too challenging for you.

I assume that by Lou he meant Sou. Here are the comments Rum Runner would have been talking about.

Now since Rum Runner regards the prestigious Bulletin of the American Meteorological Society as "political advocacy", and says that therefore doesn't take his information from there; and since he doesn't seem to have recognised as Australians, the scientists who wrote the papers I referred him to, I'll admit it's not much of a challenge.

Still, I thought it worthwhile doing two things. First, reporting some of the latest scientific findings about the weather Australia experienced in 2012 and 2013. And secondly, briefly touching on the Pacific Decadal Oscillation (PDO) - what it is and what is known about it and its effects on weather - in Australia and elsewhere. (I've written about the PDO a couple of times - here and here.) This article is about the former. I'll be writing a separate article on the PDO in the near future.

Australia looks forward to still hotter from the extra CO2

There are four papers in the BAMS supplement relating to the years 2012 and 2013.

The first one is: "The role of anthropogenic forcing in the record 2013 Australia-wide annual and spring temperatures" by Sophie C Lewis and David J Karoly.

What they did was investigate the roles of anthropogenic climate change and natural variability in regard to the record-breaking heat of 2013.

(Not) looking forward to hotter and drier...

Tonight I stopped by an AMOS presentation at which some of our top climatologists talked about the state of Australia's climate.  (Thanks all.) The strongest message was about where our climate is heading.

If the numbnuts at WUWT and Jo Nova's place and those who float around Andrew Bolt's blog waiting for a chance to proclaim AGW is a myth had seen what these people see, they'd be marching the streets campaigning for Tony Abbott to get off his bum and do something to cut carbon emissions.

Here is a slide that Dr Sophie Lewis of the University of Melbourne put up.

Sophie Lewis, AMOS presentation Melbourne, March 2014

She explained that she and David Karoly ran some experiments that demonstrated that the chance of having a year like last year in Australia without AGW would have been once only - in 13,000 years!  And last year wasn't even an El Nino year.

Later, she told us that years like last year's record hot year will be the norm by 2050.  By the end of this century, years like last year will be considered cold.  Well, not cold of course, but a reprieve of sorts from the stinking heat that will be the norm if we keep emitting CO2 at the rate we are.

Sophie Lewis at AMOS presentation
How the record hot 2013 will soon be the norm and by 2070 will seem "cold"

Other speakers were Dr. Karl Braganza (BoM), Dr. Scott Power (BoM), Dr Penny Whetton (CSIRO) and Dr. Ailie Gallant (Monash).  I was held up at a meeting and missed Karl and Scott's talks, but Ailie's presentation was every bit as good as expected and so was Penny's.

It's one thing to read reports like the State of the Climate 2014.  It's quite another to see and hear climate scientists discuss what is happening.  We know what is happening because we are living it.  But seeing what's before us is something else altogether.

Here is a graphic from the State of the Climate report, showing how much different parts of the country have warmed over the past century or so.

Source: State of the Climate 2014, CSIRO and BoM

As for the future, the report states:

Australian temperatures are projected to continue to warm, rising by 0.6 to 1.5°C by 2030 compared with the climate of 1980 to 1999; noting that 1910 to 1990 warmed by 0.6°C. Warming by 2070, compared to 1980 to 1999, is projected to be 1.0 to 2.5°C for low greenhouse gas emissions and 2.2 to 5.0°C for high emissions.

There's a chance of Australia being five degrees Celsius hotter by 2070! Sheesh.  Last year was bad enough, I cannot imagine the world that my great nieces and nephews and their children will have to learn to live with if we keep going the way we are.

Here is a chart from the same report showing the changes in rainfall:

Source: State of the Climate 2014, CSIRO and BoM

We live down in the south east corner - the bit where it says "very much below average" to "lowest on record".  With an El Nino maybe coming, I figure it's time to get the water tank connected properly.  In south eastern Australia it's going to continue to get drier and hotter.  Could be a drought coming, it might not be this year or next.  Then again, it might.  Time to resurrect that old motto: "Be prepared."


More in keeping with HotWhopper was what was waiting for us outside the theatre - some chemtrail kooks.  Yes, I guess we have them too :(

Credit: Sou at HotWhopper

Australia's hottest year was no freak event: humans caused it

By Sophie Lewis, University of Melbourne and David Karoly, University of Melbourne

The Bureau of Meteorology has confirmed that 2013 was the hottest year in Australia since records began in 1910.

Unusual heat was a persistent feature throughout the year. For the continent as a whole, we experienced our hottest day on record on January 7. Then January was the hottest month on record, and the 2012-13 summer was the hottest recorded for the nation.

The nation-wide temperature record set for the month of September exceeded the previous record by more than a degree. This was the largest temperature anomaly for any month yet recorded.

Averaged across all of Australia, the temperature for 2013 was 1.2C above the 1961-1990 average, and well above the previous record hot year of 2005 of 1.03C above average.

What caused these extreme temperatures? Climate scientists have a problem: because climate deals with averages and trends, we can’t attribute specific records to a particular cause.

But our research has made significant headway in identifying the causes of climate events, by calculating how much various factors increase the risk of extreme climate events occurring. And we have found sobering results.

We previously analysed the role human-caused climate change played in recent extremes across Australia.

For various record-breaking 2013 Australian temperatures, we investigated the contributing factors to temperature extremes using a suite of state-of-the-art global climate models. The models simulated well the natural variability of Australian temperatures.

Using this approach, we calculated the probability of hot Australian temperatures in model experiments. These incorporated human (changes in greenhouse gases, aerosols and ozone) and natural (solar radiation changes and volcanic) factors. We compared these probabilities to those calculated for a parallel set of experiments that include only natural factors. In this way, natural and human climate influences can be separated.

In our previous studies, we then applied an approach (known as Fraction of Attributable Risk) widely used in health and population studies to quantify the contribution of a risk factor to the occurrence of a disease. Health studies, for example, can quantify how much smoking increases the risk of lung cancer.

Using the climate models, the Fraction of Attributable Risk (FAR) shows how much the risk of extreme temperatures increases thanks to human influences.

In our earlier study of our record hot Australian summer of 2012-13, we found that it was very likely (with 90% confidence) that human influences increased the odds of extreme summers such as 2012-13 by at least five times.

In August 2013, Australia broke the record for the hottest 12-month period. The odds of this occurring increased again from the hottest summer. We found that human influence increased the odds of setting this new record by at least 100 times.

Recent extreme temperatures are exceeding previous records by increasingly large margins. The chance of reaching these extreme temperatures from natural climate variations alone is becoming increasingly unlikely. When we considered the 12-month record at the end of August, it was nearly impossible for this temperature extreme to occur from natural climate variations alone in these model experiments.

We have just completed a preliminary investigation of contributing factors for the record Australian temperature in the 2013 calendar year.

In the model experiments, it is impossible to reach such a temperature record due to natural climate variations alone. In climate model simulations with only natural factors, none of the nearly 13,000 model years analysed exceed the previous hottest year recorded back in 2005.

Australian annual temperature changes (relative to 1911-1940 average) for observations (dashed black) and model simulations with natural influences only (green) and with both human and natural influences (red). The grey plumes indicate the range of values simulated across nine global climate models used. Average Australian temperature anomalies are indicated for 2013 and the previous hottest year on record in 2005. David Karoly & Sophie Lewis.

In contrast, in model simulations including both natural and human factors, such as increasing greenhouse gases, record temperatures occur approximately once in every ten years during the period 2006 to 2020. (On a mathematical note, as there is no instance in which the record hot yearly temperature occurred without human contributions, the FAR value is one.)

Probabilities of annual average temperatures for Australia from climate model simulations including natural influences only (green) and both natural and human climate influences (red) for model years 2006-2020. The vertical lines show the temperature anomalies observed in 2013 and in 2005 (the previous hottest year observed). David Karoly & Sophie Lewis

Clearly both natural climate variability and global warming from humans contribute to recent temperature records. Natural variability always plays a major role in the occurrence of weather and climate extremes. But in the case of our recent hottest year on record, human-caused global warming made a crucial contribution to our extreme temperatures.

Our extensive catalogue of 2013 record-breaking events in Australia occurred in a global context of increasing temperatures that must be considered. Globally, 2013 will likely rank as the 6^th hottest year recorded.

So to return to our question, what caused the 2013 record hot year across Australia? Simply put, our climate has changed due to human activities. Recent extremes, such as this hot year, are occurring well outside the bounds of natural climate variations alone.


Sophie Lewis is a Research Fellow at the University of Melbourne node of the ARC Centre of Excellence for Climate System Science.

David Karoly receives funding from the Australian Research Council Centre of Excellence for Climate System Science and the Australian Antarctic Division. He is a member of the Climate Change Authority and the Wentworth Group of Concerned Scientists.


This article was originally published at The Conversation. Read the original article.