Our warmest year on record

The Bureau of Meteorology recently released its Annual Climate Statement for 2013. Here are its key points: 

Data collected and analysed by the Bureau of Meteorology show that 2013 was Australia’s warmest year on record while rainfall was slightly below average nationally.

  • Summer 2012–13 was the warmest on record nationally, spring was also the warmest on record and winter the third warmest
  • Overall, 2013 was Australia’s warmest year on record: annual national mean temperature was +1.20 °C above average
  • All States and the Northern Territory ranked in the four warmest years on record
  • Nationally-averaged rainfall was slightly below average for the year, with 428 mm (1961–1990 average 465 mm)
  • Rainfall was mostly below average for the inland east and centre, and above average for the east coast, northern Tasmania and parts of Western Australia.*


  • 2013 was Australia’s warmest year since records began in 1910. Mean temperatures across Australia have generally been well above average since September 2012. Long periods of warmer-than-average days have been common, with a distinct lack of cold weather. Nights have also been warmer than average, but less so than days.
  • The Australian area-averaged mean temperature for 2013 was +1.20 °C above the 1961–1990 average. Maximum temperatures were +1.45 °C above average, and minimum temperatures +0.94 °C above average. Temperatures were above average across nearly all of Australia for maximum, mean and minimum temperatures, with large areas of inland and southern Australia experiencing the highest on record for each.
  • Australia has experienced just one cooler-than-average year (2011) in the last decade.

* Most of the above-average rainfall on the east coast was due to just one extreme event, cyclone Oswald in late January, as per Special Climate Statement 44 – extreme rainfall and flooding in coastal Queensland and New South Wales (pdf).

The BoM also releases annual statements covering weather at state level in more detail. Key points of the Queensland report: 

Queensland in 2013: Record heat, dry in the west

Queensland’s mean maximum temperature was highest on record in 2013. The year started with some exceptionally hot weather, with high temperature records broken. Locally, there was very heavy rain, especially in January, but it was generally a dry year west of the Great Dividing Range. Mt Isa and Tambo had their lowest annual rainfall on record.

  • Mean maximum temperature highest on record
  • Record hot start to the year
  • Record rain in the east in January from ex-tropical cyclone Oswald
  • Four tropical cyclones
  • Severe thunderstorms in November and December
  • Dry west of the Great Dividing Range
  • Record low rainfall in the west and southern interior

None of the above is necessarily due to global warming but it is all entirely consistent with global warming, and we can expect that weather like this will become normal as global warming progresses. Bearing in mind that this year represents, as the BoM says, temperatures [only] 1.2 C above the baseline and medium-term predictions are in the range of  2 – 6 C above the baseline, I think we should be more worried than most of us are; but I will deal with those issues on their own in another post as soon as I can find time.

Warning: climate change ahead

climate-crisis-aheadThe really short version of the climate change story hasn’t changed much for the last ten years or more, of course: we know we are cooking the earth and things are going to get very uncomfortable, if not catstrophic, unless we stop pumping CO2 into the atmosphere. (NASA’s version is one of the simplest, clearest and most authoritative if you need to direct anyone to such a resource.) However, the scientific work continues to improve our knowledge every year. Two significant recent publications are discussed in not-too-technical terms in two highly regarded blogs, RealClimate and ThinkProgress.

Should we trust the bloggers? These bloggers, yes. Stefan Rahmstorf, who discusses Marcott’s paper in Science, teaches physics of the oceans as a professor at Potsdam University, is a member of the Advisory Council on Global Change of the German government and is a lead author of the paleoclimate chapter of the 4th assessment report of the IPCC. Joe Romm, who discusses Hansen’s paper, worked at the highest levels of the US Department of Energy in the 1990s before moving into full-time environmental campaigning. (For more about them, see Wikipedia: Rahmstorf, Romm.) From here on, this summary uses their words, drastically condensed; follow the links at the end for the full versions.

Marcott study: The End of the Holocene

by Stefan Rahmstorf

Recently a group of researchers from Harvard and Oregon State University has published the first global temperature reconstruction for the last 11,000 years – that’s the whole Holocene (Marcott et al. 2013). The results are striking.

Over the last decades, numerous researchers have painstakingly collected, analyzed, dated, and calibrated many data series that allow us to reconstruct climate before the age of direct measurements. Such data come e.g. from sediment drilling in the deep sea, from corals, ice cores and other sources. Shaun Marcott and colleagues for the first time assembled 73 such data sets from around the world into a global temperature reconstruction for the Holocene [i.e. the 11,700 years since the last Ice Age].

Marcott s

Global temperature reconstruction from proxy data by Marcott et al, Science 2013

The climate curve looks like a “hump”. At the beginning of the Holocene global temperature increased, and subsequently it decreased again by 0.7 ° C over the past 5000 years. The well-known transition from the relatively warm Medieval into the “little ice age” turns out to be part of a much longer-term cooling, which ended abruptly with the rapid warming of the 20th Century. Within a hundred years, the cooling of the previous 5000 years was undone. (One result of this is, for example, that the famous iceman ‘Ötzi’, who disappeared under ice 5000 years ago, reappeared in 1991.)


The curve of Marcott et al. will not be the last word on the global temperature history during the Holocene; like Mann et al. in 1998 [the famous “Hockey Stick” which was a similar temperature record for the last 1,000 years] it is the opening of the scientific discussion. There will certainly be some corrections and improvements. However, I believe that (as was the case with Mann et al.) the basic shape will prove correct: a relatively smooth curve with slow cooling trend lasting millennia from the Holocene optimum to the “little ice age”, mainly driven by the orbital cycles. At the end this cooling trend is abruptly reversed by the modern anthropogenic warming. …

Just looking at the known drivers [factors affecting climate change] and the actual temperature history shows it directly, without need for a climate model: without the increase in greenhouse gases caused by humans, the slow cooling trend would have continued. Thus virtually the entire warming of the 20th Century is due to man. This May, for the first time in at least a million years, the concentration of carbon dioxide in our atmosphere has exceeded the threshold of 400 ppm. If we do not stop this trend very soon, we will not recognize our Earth by the end of this century.

Hansen study: Climate Sensitivity is High, Burning All Fossil Fuels Would Make Most of Planet ‘Uninhabitable’

by Joe Romm, Sept 17, 2013

James Hansen, the country’s most prescient climatologist, is out with another must-read paper, “Climate sensitivity, sea level and atmospheric carbon dioxide,” … co-authored by a number of Hansen’s former colleagues at NASA. … The key findings are:

• The Earth’s actual sensitivity to a doubling of CO2 levels from preindustrial levels (to 550 ppm) — including slow feedbacks — is likely to be larger than 3–4°C (5.4-7.2°F).
• Given that we are headed towards a tripling (820 ppm) or quadrupling (1100 ppm) of atmospheric CO2 levels, inaction is untenable.
• “Burning all fossil fuels” would warm land areas on average about 20°C (36°F) and warm the poles a stunning 30°C (54°F). This “would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.”

Burning all or even most fossil fuels would be a true scorched Earth policy.

Given that James Hansen has been right about global warming for more than 3 decades, his climate warnings need to be taken seriously. [The] whole paper is worth reading. The authors conclude:

Most of the remaining fossil fuel carbon is in coal and unconventional oil and gas. Thus, it seems, humanity stands at a fork in the road. As conventional oil and gas are depleted, will we move to carbon-free energy and efficiency—or to unconventional fossil fuels and coal?

If fossil fuels were made to pay their costs to society, costs of pollution and climate change, carbon-free alternatives might supplant fossil fuels over a period of decades. However, if governments force the public to bear the external costs and even subsidize fossil fuels, carbon emissions are likely to continue to grow, with deleterious consequences for young people and future generations.

It seems implausible that humanity will not alter its energy course as consequences of burning all fossil fuels become clearer. Yet strong evidence about the dangers of human-made climate change have so far had little effect. Whether governments continue to be so foolhardy as to allow or encourage development of all fossil fuels may determine the fate of humanity.

That’s the end of my quote from Romm’s blog, and now you know the considered opinion of the experts. But we will be all right here in Oz, of course:



Realclimate post on Marcott: http://www.realclimate.org/index.php/archives/2013/09/paleoclimate-the-end-of-the-holocene/

Marcott’s paper on Science: http://www.sciencemag.org/content/339/6124/1198.abstract
Science 8 March 2013
A Reconstruction of Regional and Global Temperature for the Past 11,300 Years
Shaun A. Marcott1, Jeremy D. Shakun, Peter U. Clark, Alan C. Mix

ThinkProgress post on Hansen: http://thinkprogress.org/climate/2013/09/17/1892241/hansen-climate-sensitivity-uninhabitable/

Extreme weather around the world

For a while now the climate scientists have been warning that global warming isn’t simply a matter of the weather getting a little warmer everywhere. Rather, the warming will vary from place to place and be accompanied by changes of weather patterns, especially rainfall. That is already happening. I have mentioned extreme weather events here before over the last year or so, and in fact the last few months have seen a cluster of extreme events which are causing great suffering across the Northern hemisphere.

We know that none of these can be ascribed to climate change with any certainty but there is a growing body of knowledge (e.g. IPCC, Climate Communication, Union of Concerned Scientists) which shows that we can confidently give the odds that a particular event would have happened without global warming, and the experts are quoting high odds against any of these happening under our old weather patterns. The combined odds against all of them happening by chance are infinitesimal.

The silver lining to this litany of disaster is that ordinary people are beginning to see for themselves that weird things are happening to their weather and are more willing to acknowledge that climate change is indeed here already, that it is looking scarier every year, and that we really should try harder to avert it.

Smile: In what seems like poetic environmental justice, a brown coal mine in Victoria’s Latrobe Valley has also been flooded after unusually heavy rain.

Don’t smile too broadly: James Hansen, one of the world’s pre-eminent climatologists, has warned that the future he predicted is here here already and it is worse than he expected, sooner than he expected – almost entirely because of extreme weather events:

In a new analysis of the past six decades of global temperatures, which will be published Monday, my colleagues and I have revealed a stunning increase in the frequency of extremely hot summers, with deeply troubling ramifications for not only our future but also for our present.

This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened. Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.

The rest of his Washington Post article is here and if you want the whole scientific  paper you can get it – free – here.

Our very own hockey stick

Everyone with even the slightest interest in climate change has heard of the ‘hockey stick’ which showed in 1998 that recent warming is unprecedented in human history (the background is here, on wikipedia, if you want it).

What we may not have been particularly aware of was that it was based primarily on Northern hemisphere data. In hindsight, that meant there was the ghost of a hope that the temperature trend didn’t apply to Australia, but a team led by Joelle Gergis of Melbourne University has just laid that phantasm to rest: we now have our very own hockey stick.

Temperature reconstruction graph
Fig. 4 from Gergis et al.

The temperature reconstruction uses 27 proxy records, relying equally on tree rings and coral cores, and concludes that summer temperatures in the post-1950 period were warmer than anything else in the last 1000 years at high confidence, and in the last ~400 years at very high confidence.

RealClimate introduces the study here (that’s where I found out about it, in case you hadn’t guessed) and the full study is here.

Update, 25 March 2013: A reader recently alerted me to the fact the Gergis et al’s paper was withdrawn before publication. It appears that there were technical flaws in it which meant it didn’t meet the expected standards of proof.

As far as I can determine, however, its conclusions were still probably correct – as one would expect, given that it was only extending northern hemisphere records into the southern hemisphere and one would not expect to find any great north-south difference.

Merchants of Doubt

cover of Merchants of DoubtMerchants of Doubt by Naomi Oreskes and Erik M Conway (Bloomsbury, 2010)

Merchants of Doubt tells the story of ‘How a handful of scientists obscured the truth on issues from tobacco smoke to global warming,’ as its subtitle says. It is a very strange and disturbing story of collusion between scientists, science administrators, right-wing politicians and big business in pursuit of an agenda which was ostensibly libertarian but in fact unscrupulously pro-business. One of its strangest, saddest aspects is that their programme gradually became a broadside attack on all science.

Anyone with any interest in the politics and sociology of climate change soon becomes aware that there is a very vocal but very small group which denies the overwhelming expert evidence that climate change is real, that is happening now and that it is man-made. They are today’s merchants of doubt: Bolt, Carter and Plimer in Australia, and Monckton, Lindzen, the Pielkes (father and son), Curry, Spencer, Lomborg, Watts and a few others overseas, mostly in the US. Most of the scientists on that list are not climate scientists, and some of the most vocal deniers are not scientists at all.

Oreskes and Conway show how this situation developed from the US politics of the Cold War era. First, the hard-science establishment was identified with the war effort; second, its already-hawkish leaders were promoted into science policy-making; third, some of them convinced themselves that any regulation of the free market was equivalent to creeping communism; and fourth, industry tacticians began recruiting scientists willing to cast doubt on any science which led to government policies which would cost them money.

The industries concerned were tobacco, agricultural and industrial chemicals (opposing bans on DDT and CFCs) and most recently fossil fuels – fighting, of course, the idea that global warming is a problem. In each case they funnelled money to scientists and opinion-makers through lobby groups, ‘philanthropic’ foundations and so on – bodies with names like ‘Heartland Institute,’ ‘Freedom of Expression Foundation’ and ‘Hudson Institute.’ Names are named and evidence is methodically documented.

The original merchants of doubt, Frederick Seitz, S. Fred Singer, William Nierenberg and Robert Jastrow, were all scientists but (to quote from the book’s introduction) ‘for more than twenty years, these men did almost no original scientific research on any of the issues on which they weighed in. … In fact, on every issue, they were on the wrong side of the scientific consensus. … [They] fought the scientific evidence and spread confusion on many of the most important issues of our time.’

Merchants of Doubt is peculiar in my life in that I commended it to others long before I read it myself. It emerged to great acclaim from people and publications I trusted, reviews showed that it told a very important story and Oreskes’ interviews convinced me it would be well told. It is pleasing to know now that I was right to recommend it and it has been satisfying to read the whole morbidly fascinating story at last.

More information:

Remembering the floods

I wrote about extreme weather events and their connection to global warming two and a half months ago and a small coincidence leads me to revisit the topic. Today has been chosen as the day of remembrance for the disastrous SE Queensland floods a year ago, and a link on RealClimate took me yesterday to a paper by eminent climate scientist James Hansen which touches on something I’ve been thinking about for some  time: the fact that climate change should already be apparent to ordinary people.

First, the floods. Wikipedia has a good overview here with plenty of links to further information and the ABC has put together a terrific gallery of flood photos here. There’s not much point in trying to add to that coverage here. The floods certainly qualify as an ‘extreme weather event’ and were recognised as such in the major global report State of the Climate in 2010 from NOAA and the Bulletin of the American Meteorological Society. 

Hansen’s paper, Climate Variability and Climate Change: The New Climate Dice (November 2011) (pdf here) begins thus:

The “climate dice” describing the chance of an unusually warm or cool season, relative to the climatology of 1951-1980, have progressively become more “loaded” during the past 30 years, coincident with increased global warming. The most dramatic and important change of the climate dice is the appearance of a new category of extreme climate outliers. …

The greatest barrier to public recognition of human-made climate change is the natural variability of climate. How can a person discern long-term climate change, given the notorious variability of local weather and climate from day to day and year to year?

This question assumes great practical importance, because of the need for the public to appreciate the significance of human-made global warming. Actions to stem emissions of the gases that cause global warming, mainly CO2, are unlikely to approach what is needed until the public perceives that human-made climate change is underway and will have disastrous consequences if effective actions are not taken to short-circuit the climate change.

He goes on to show two kinds of systematic change in climate: the averages have shifted and, at the same time, the odds of extreme events occurring have increased dramatically. This, of course, is the significance of his title: the climate dice have been loaded (biased) by global warming. He presents details of the changes which have already occurred and notes that, “The climate dice are now loaded to a degree that the perceptive person (old enough to remember the climate of 1951-1980) should be able to recognize the existence of climate change.” In particular, people should be noticing that extreme weather is far more common than it ever used to be.

He doesn’t quite ask, “Why don’t they notice?” but the question hovers there, waiting for an answer.

I have been trying to answer it myself since a random conversation a year ago. I was chatting to a youngish, intelligent person with a degree in natural sciences and a job in  GBRMPA, which looks after the Great Barrier Reef. I was quite surprised to find that she had not actually observed the effects of climate change. Then I found that she had spent her first ten years on a Pacific island, her next eight in Sydney, and another eight or so here in Townsville, so she hadn’t actually been anywhere long enough to notice a change in that location.

As I thought about that, I realised that she has lots of company. There are far fewer people who might reasonably be expected to notice climate change than we might at first think. A quick estimate goes like this:

  • Age group really has to be 40+, since anyone under ten in the early 1980s won’t remember the old norms. Change has occurred in the last thirty years, but it is the comparison with the pre-1980 baseline which makes it stand out strongly. That rules out more than 50% of the world’s population and perhaps even more than 50% of the world’s voters.
  • But also, those people have to have been living in the same general area for 40+ years, or have returned to it after some time away, because no-one in California will say, “It wasn’t like this when I was a kid,” if they grew up in Normandy, Queensland or even Virginia. How many Westerners are that stable? 50%?
  • Furthermore, the closer we live to nature, the more likely we are to notice its changes – but more and more of us are urbanised. Europe, Australia and the US are all more than 80% urbanised according to UN stats, while China, India and most of the developing nations are less than 40% urbanised. How many of the 50% of 50% are therefore likely to qualify as “perceptive”? Less than 50% in the West, certainly; perhaps more than 50% in less urbanised countries.
  • That leaves less than 10% of the world’s population in a position to recognise climate change from personal observation. And (unfortunately for the debate) most of those 10% are the rural poor of developing nations, the most frequent victims of climate change not the opinion-makers of industrialised nations.

Of course, Hansen’s statistics show that extreme weather events are going to increase very rapidly in number and severity as global warming continues. More and more of us will notice the effects in our daily lives. But that is not really good news.

A carbon tax at last

A message from GetUp! which I am happy to support and pass on:

Today we woke up knowing that the global conversation on climate change has changed. Yesterday’s passage of the Clean Energy Act into law means we’ve finally taken action to secure our clean energy future. To mark the occasion, Al Gore passed on these kind words:

“This is a historic moment. Australia’s Parliament has put the nation’s first carbon price into law. With this vote, the world has turned a pivotal corner in the collective effort to solve the climate crisis. This success is the result of the tireless work of an unprecedented coalition that came together to support the legislation, the leadership of Prime Minister Gillard, and the courage of legislators to take a vote that helps to safeguard the future of all Australians.

I have spent enough time in Australia to know that their spirit of independence as a people cannot be underestimated. As the world’s leading coal exporter, there’s no doubt that opposition to this legislation was fierce. But through determination and commitment, the voice of the people of Australia has rung out loud and clear.

Today, we celebrate. Tomorrow, we do everything we can to ensure that this legislation is successful.”

Al Gore, November 2011

Click here to watch a video that tells the story of how we arrived at this day.

Yesterday’s success is yet more evidence of the fact that coordinated community action has the power to lead our Parliamentarians toward just, environmentally sustainable outcomes. But a wider community movement will be needed to protect these laws and grow further investments in clean energy.

As GetUp! and Al Gore say, there is more to be done – firstly to ensure this step is not allowed to slip away and secondly to build on it – but it’s nice to have got this far at last.