My analysis of Australian climate change beliefs in The Australian

The Australian newspaper has summarised my analysis of variations in belief in climate change in the Australian today (17 May 2019) on page 33. It was written up by Robert Gottliebsen, one of Australia’s most respected and experienced journalists.

There has been a wave of climate change denial by all the usual suspects in the lead-up to the federal election tomorrow. Their arguments are fallacious and misleading, but potentially influential.

I will be updating our survey after the federal election in order to evaluate the extent of any change in beliefs.

Charlie Nelson

The importance of generating renewable energy close to where it is demanded

Our electricity grid was designed for transmitting electricity from huge generators across the country.  Its design is not optimal for transmitting electricity from the distant extremes of the grid back to cities.  It will take some time to re-develop the grid to transmit electricity from remote solar and wind farms to where the greatest demand is.  The grid also needs to become more intelligent so that it can adapt to where the energy is coming from, which can be variable.

Furthermore, up to 10% of generated electricity can be lost in transmission.

For these reasons and others, I was very pleased with the Australian Labor Party’s election promise to spend $1 billion to equip thousands of public schools with solar panels.  Schools are at the centre of communities and so close to demand.

The schools should also be equipped with batteries to store energy and to deliver it at peak times – in the early evening, when schools are mostly empty and households are ramping up demand for heating or cooling, and lighting.  They could also deliver excess electricity during weekends.

Other properties which would also be important generators are suburban railway stations.  Many have large roof areas and the stations are distributed across suburbs and regional towns.

And what about solar panels between the tracks?  There are thousands of kilometres of track in Sydney and Melbourne, with the potential to generate huge amounts of electricity in the suburbs.

With all of this extra generation and storage capacity, we could progressively retire some ancient coal fired power stations.

Charlie Nelson



An inconvenient hot summer in Australia

With record high temperatures across much of the continent, smashing the previous record; with record rainfall in North Queensland and 500,000 cattle lost; with extreme drought in many locations, including the death of millions of fish in the Menindie Lakes; it has been a summer well beyond past experience.  Bushfires have caused loss of property in Tasmania, Victoria, and New South Wales.

With such an extreme summer being closely followed by a federal election, denial of climate change; claiming that Australia should do nothing as we are a small emitter of greenhouse gasses on a global scale; and token policies will not resonate well with the majority of the electorate.  As Australia is being damaged by climate change, and the damage will escalate, it is time to consider what action we can take which is of greater influence on global greenhouse gas emissions than our proportion of emissions.

Australia’s 2018-19 summer was very hot compared with all previous summers, dating back to 2010-11 (Chart 1).

Chart 1

The record mean temperature in 2018-19 was 0.86 degrees C hotter than the previous record set in 2013.  This margin is the greatest on record, exceeding the margin of 0.52 degrees C by which the summer of 1972-73 was hotter than the previous record in 1938-39 and 1925-26.

The only comparable extreme is the very low mean temperature in 1916-17.  That was during an extreme La Nina, but there was no extreme El Nino in 2018-19.

The temperatures shown in Chart 1 are relative to the average of the period 1961 to 1990 (27.5 degrees C).

The upwards trend is 1.3 degrees per century (Chart 2) and has accelerated to 2.2 degrees per century from 1970 (the last seven summers have been hotter than the 109 year trend).  These trends are highly statistically significant.

Chart 2

The trend mean temperature anomaly for 2019-20 is predicted to be 0.64 degrees, with a 95% confidence interval of 0.45 to 0.83.

The mean temperature anomaly relative to 1961 to 1990 across Australia in the summer of 2018-19 is shown in Chart 3.  Much of the continent was more than one degree hotter than the 1961 to 1990 average, many locations had a mean temperature more than 2 degrees hotter, and some places were more than 3 degrees hotter (the average was 2.1 degrees across the continent).

Chart 3

The record rainfall in much of north Queensland was in marked contrast to a dry summer in most of the rest of the continent (Chart 4).  This chart shows rainfall anomalies relative to the 1961 to 1990 average.

Chart 4

The longest continuous tracking of the general public’s level of belief in imminent global warming has been carried out by foreseechange (Chart 5).  The estimated likelihood of clear signs of global warming in the year ahead is a 63% chance, back to the level of 2007 when the electorate last voted the coalition out of office.  The last update of this tracking survey was in November 2018 – since then we have experienced the highly extreme summer of 2018-19, which would have further lifted the level of belief in imminent climate change.

Chart 5

Previous variations in the level of belief in imminent climate change have been caused, in part, by preceding temperatures and rainfall.

When the general public was asked to rate issues on the basis of the level of concern in the foreseeable future, climate change ranked fifth, ahead of traffic congestion, health, and crime (Chart 6).  The scale was from 0 (will not be at all concerned) to 10 (will be extremely concerned).  This survey was conducted in November 2018 and it is likely that the extreme summer of 2018-19 will have lifted the level of future concern about climate change.

Chart 6

In the lead-up to the imminent federal election, the electorate will be looking for a credible, urgent plan to mitigate climate change.

Australia must move on from the seemingly endless debate about whether human activity is causing climate change and whether we should do anything at all because our contribution to greenhouse gas emissions is less than 2% of the global total.

Australia can have an impact beyond our share and it is in our interests to do so given the economic and environmental damage we are experiencing and the economic opportunities we can capitalise on.  That will be the subject of a future article.

Charlie Nelson



Melbourne’s abrupt loss of rainfall

Melbourne’s rainfall has abruptly fallen by an average of 107mm per year from 1997 (Chart 1).

Chart 1

There are still some quite wet years (2010 and 2011) and there have been very few dry years (1997 was the second driest on record.  The average has just suddenly dropped.

A seven year moving average reveals the existence of rainfall cycles over Melbourne (Chart 2).

Chart 2

To some degree, less rainfall is an expected consequence of climate change – the sub-tropical high pressure ridge is expected to move further south towards Melbourne (the deserts extend southwards).  But the change has been a  downwards step change rather than a trend.

There are natural cycles in rainfall in south eastern Australia and these have played a major part in the loss of rainfall from 1996.  The relative contributions of climate change and natural cycles are not clear as yet.  I was able to advise the Victorian Minister for water, in 2011 during the most recent wet period, that there would be another severe drought from 2017 to 2022.  That prediction, so long in advance, looks as though it was accurate.

I will provide an update in early 2020.

Charlie Nelson


The 2019 Australian federal election and climate change


Climate change policy, or the lack of it, has been influential in the demise of several federal political leaders since John Howard lost the 2007 election (and his seat in Parliament).  Malcolm Turnbull lost his leadership of the opposition in 2009 and his prime ministership in 2018 because he proposed policies to reduce greenhouse gas emissions but enough of his Liberal colleagues did not support that.

Three separate prediction methods indicate that the Liberal National Coalition will lose government in the 2019 federal election.

The level of belief in imminent global warming amongst Australian adults is now back to the level of 2007, when Labor last won government from the coalition.  Importantly, the level of belief amongst people aged 65+, the core constituency of the coalition, has recently lifted to the same level as in 2007.

This is documented in my recent article, along with an assessment of the top issues in voters minds.

Of course, it is still up to Labor to propose a credible set of policies which are attractive to voters.

Charlie Nelson


Accurate prediction of Australia’s drought seven years ago

Climate scientists have been criticised for inaccurate decadal forecasts, which may have led to doubts about the accuracy of their longer-term forecasts.

Australia is currently handing out $5 billion in drought relief to farmers.  It would have been better to have planned for this drought, but could it have been predicted?

It was, over seven years ago, by me.  The letter below, from Victoria’s then Minister for Water acknowledges that I predicted another severe drought for Victoria over the period 2017 to 2022.  I made that prediction in July 2011, in the midst of a very wet two year period.  The Minister for Water replied in September 2011, noting that mainstream climate scientists knew of no mechanism for such a prediction.


My prediction was for Victoria and also the Murray Darling Basin.

I have since developed the outlines of that mechanism.  But just the fact that the current drought was predicted so long in advance shows that a mechanism exists!

I can, of course, predict when the next wet period will be.

In early 2010, I accurately predicted that the long millennial drought (1997 to 2009) was about to break – see my March 2010 letter to the Murray Darling Basin Authority predicting that 2010 and 2011 would be wet years.


It is well past time for climate scientists to open their minds to the two decadal cycles I have identified and to gain more credibility as a result of more accurate near term climate predictions.

The benefits for farmers, water supply authorities, emergency management agencies, and insurance companies would be immense.

Charlie Nelson



Climate change is not our highest rating future concern

Most Australian adults believe that the climate is changing and that human activity is at least partially to blame.  Most of us want action to be implemented now to address this pressing problem.

Unfortunately, climate change is not at the top of the list of future concerns that keep us awake at night.

A June 2018 survey by foreseechange has found that climate change is the ninth most highly rated future concern out of 12 rated by over 1,000 adults.

Top of the list is the cost of living, followed by security of personal information.  At least climate change rates ahead of unemployment and interest rates.

Until climate change rates much more highly as a future concern, there will not be enough pressure placed on politicians to act decisively.

In the mean time, a different approach to dealing with climate change is needed, rather than what we have been doing over the past quarter of a century.  This is the subject of a forthcoming report.

Charlie Nelson



Can we suck carbon dioxide out of the air?

Atmospheric carbon dioxide is still rising and looks set to continue rising for decades to come.  This makes a limit of a two degrees Celsius temperature increase, compared with pre-industrial times, rather difficult to achieve.  Accordingly, we need to urgently implement ways of sucking carbon dioxide out of the atmosphere.  This is not the same as carbon capture and storage, which captures carbon dioxide from the chimneys of coal-fired power stations and stores it underground.

There are at least three ways to achieve carbon dioxide removal from ambient air.

One method, described in New Scientist on 21 July 2012, is ocean fertilisation.  This involves tipping iron into the ocean.  Phytoplankton, floating algae, absorb carbon dioxide out of the atmosphere.  When they die, they sink to the seabed taking the carbon with them.  Ocean regions which are iron deficient are not providing the nutrients which plankton need to grow.  In these regions, carbon dioxide is not being absorbed.  Silicon is also needed by the plankton.

A trial reported in the New Scientist article showed that ocean fertilisation can work.  At best, however, a global program could absorb about one gigatonne of carbon per year, about one-tenth of current emissions resulting from human activity.  According to modelling by Ken Caldera, this is “too little to be the solution, but it’s too much to ignore”.

Another method involves channelling air by fans onto a honeycombed plastic slab, where carbon dioxide, which is acidic, reacts with aqueous potassium hydroxide, which is alkaline.  Then the resulting solution of potassium carbonate is filtered before reacting with calcium hydroxide, producing potassium hydroxide along with pellets of calcium carbonate.  Heating this to 900 degrees Celsius releases pure carbon dioxide gas which is captured.  The principles were first established by Klaus S. Lackner 20 years ago but now Carbon Engineering, founded by David Keith with backers including Bill Gates, has established a pilot plant which extracts a tonne of carbon dioxide from the air per day. (The Economist, 9 June 2018).

But what would we do with the captured carbon dioxide and how much would this all cost?  The plan is to turn it back into fuel – which would mean that zero, rather than negative, emissions would be the outcome.  This may be worthwhile if the fuel is produced at a competitive price.  But with a transition to renewable energy, would the fuel produced be actually needed?  And would it be cheap enough to supplant coal, oil, and gas?  If the future of the automobile is electric, does this idea have a long-term benefit?  If not, what would we do with the carbon dioxide sucked out of the air?  The cost of building enough machines to be effective would cost trillions of dollars.

The third way is proven technology and could achieve a significant reduction in atmospheric carbon dioxide, plus it would have many other benefits.

Trees!  We have deforested much of the land and now we need to reforest it.

The Economist article dismissively says that achieving the desired reduction would mean foresting an area the size of India and Canada.  So what?  We don’t have to plant them all in one place!  Trees not only soak up carbon dioxide, they provide cooling shade.  In addition, they provide habitat for animals and insects and food.

The area of Canada is 10 million square km and the area of India is 3.3 million.  The total land area of the world is 149 million.  No doubt some of that would not be suitable for tree planting.

Many countries have large land areas and trees can be planted beneficially in cities, on borders of farming areas as well as large areas of land.

China, the US, Brazil, and Australia all have areas comparable with Canada and Russia has even more (16.4 million).

My priority is to contribute t tree planting and it is easy to do.  Countries that I have contributed to include Brazil, China, Indonesia, and Australia.

It would be good if Bill Gates contributes too – he has much more money that I and could make a huge difference.

Charlie Nelson


Most Australians believe that climate change poses a critical threat

Most Australians believe that climate change poses a critical threat to the vital interests of Australia in the next ten years, according to the 2018 Lowy Institute Poll.

Their survey of 1200 adults asked about the perceived level of threat of 11 possible threats.

Equal number one threats were international terrorism and North Korea’s nuclear program, which were perceived t be a critical threat by 66% of respondents.

Number three was climate change, 58%.

Number four was cyberattacks from other countries, 57%.

Number five was a severe downturn in the global economy, 50%

The other possible threats were perceived as critical by less than 50% of respondents.

Number nine was large numbers of immigrants and refugees coming into Australia, which was perceived to be a critical threat by 40% of respondents.

Discussion and action about the issue of climate change seems to be a lower priority for the federal government than the global economy and immigrants and refugees – at variance with the priorities of the general public.

Charlie Nelson


How accurate are climate change forecasts?


Climate is what you expect, weather is what you get
Attributed to Mark Twain amongst others

Climate refers to the average conditions of the atmosphere, oceans, and land surfaces over a period of time.  Weather is the state of the atmosphere and ocean at a given period of time.

Climate changes over millennia as exhibited by ice ages and interglacial periods.  It also changes over centuries, for example the little ice age in the 17th century in Europe, which has been associated with the Maunder minimum from 1645 to 1715 when the approximately 11 year sun spot cycle disappeared and sunspots were rare.  Over the past 100 years, the climate appears to have changed due to human activity.

The greenhouse effect was first mooted in the 1770’s.  In the 1820’s French physicist Joseph Fourier suggested that the earth was warmer than it was calculated to be because light from the sun penetrated the atmosphere easily and heated the Earth but the heat radiated by the Earth couldn’t pass back through the atmosphere to the same degree.

In 1859, physicist John Tyndall, who was familiar with the theory, decided that experimental proof was needed.  He set about developing the sensitive apparatus needed.  He found that the main gasses in the atmosphere, Nitrogen and oxygen, were virtually transparent to heat radiation – while more complex compound molecules absorbed heat more effectively.  In particular, he found that carbon dioxide and water vapour were particularly effective at blocking heat radiation.  These gasses were clearly responsible for absorbing most of the heat trapped by the atmosphere.  On 10 June, Tyndall demonstrated these experiments before a meeting of the Royal Society with Albert the prince consort in the chair.

In 1894, Swedish chemist Svante Arrhenius decided to calculate the amount of warming for a given increase in atmospheric carbon dioxide.  It took him more than a year but he calculated that a doubling of the carbon dioxide concentration would cause a warming of around 5 to 6 degrees C.

In 1958, daily atmospheric carbon dioxide measurements commenced at Mauna Loa, Hawaii, set up by C. D. Keeling.  In 1975, the first three dimensional global model of carbon dioxide induced climate change was constructed by Suki Manabe.

Like weather models, climate models are based on physical laws such as conservation of energy, mass, and momentum, as well as thermodynamic and radiation laws.

Some of the important drivers of a global climate model relate to:

  • The response to variability of solar irradiance on a range of time scales.
  • Changes to the Earth’s energy balance at the surface and top of atmosphere from volcanic eruptions
  • How radiation is absorbed and reflected on its way through the atmosphere but also at the surface.
  • Atmosphere and ocean dynamics (and how energy and momentum is transported through the different media)
  • How greenhouse gases and aerosols affect the Earth’s climate and climate variability
  • Sea ice and polar ice sheets
  • Various climate ‘feedback’, such as the interaction of clouds and water vapour with the warming climate, and the changing absorption or emission of CO2 from the ocean and land surface.

Climate models simulate historical variations between 1850 and 2005 and then project forward to 2100.  The historical simulations are not designed (or expected) to reproduce the observed sequence of weather and climate events during the 20th century, but they are designed to reproduce observed multi-decadal climate statistics, such as averages.  The 21st century simulations are run from 2006-2100, driven by prescribed anthropogenic forcings.  Owing to uncertainties in the model formulation and the initial state, any individual simulation represents only one of the possible pathways the climate system might follow.  To allow some evaluation of these uncertainties, it is necessary to carry out a number of simulations either with several models or by using an ensemble of simulations with a single model.

Questions about the accuracy of climate change forecasting surfaced in 2006, when climate change deniers started pointing out that the global temperature had not increased since 1998.  This claim was echoed for several years by a number of commentators.

There are many natural factors which influence temperature over a range of timescales, in addition to the increase in greenhouse gasses in the atmosphere.  Still, the claim went largely unanswered by climate scientists for several years.  This contributed to a decrease in the level of belief in the community that human activity was causing the climate to change and provided conservative politicians with a reason to refuse to take any action on emission reduction.

In turn, this was probably a significant reason for the Senates in Australia and the USA refusing to pass legislation to introduce emissions trading schemes in 2009.

The claim that the temperature had not increased since 1998 was a fallacious argument but it was not countered effectively.  There was an extreme el nino event in 1997-98 and this raised the global temperature in 1998 to a then record high.  Temperatures in subsequent years were warmer than 1997 or any earlier year, by a significant margin.  The denial claim cherry picked the single very hot year of 1998.

The subsequent extreme El Nino event, in 2015-16 meant that 2015 was significantly warmer than 1998, so the claim that there has been no warming since 1998 now has even less credibility.  As the next extreme El Nino event may not occur until the early 2030’s, however, there is significant potential for deniers to soon claim that there has been no significant warming since 2016!

Such a claim would again tend to reduce the level of belief in climate change and provide conservative politicians with a further excuse for inaction.

In 2007, Scott Armstrong, who compiled the book “Principles of Forecasting” and who is a business professor at Wharton Business School, challenged Al Gore to a bet on how global average temperature would change.  Gore, former US Vice President, who made the movie “An Inconvenient Truth” and wrote the book “Assault on Reason”, did not take the bet.  In early 2018 Armstrong says he has enough data to claim he would have won the bet.  He has concluded that global temperature deviations since 2007 had easily fallen within the natural level of variation, and “no change” was the most accurate way to describe global weather patterns over the past decade.  This was reported in The Australian newspaper on 1 February 2018.  “When you lack scientific evidence, the primary way to keep ‘global warming’ alive is to avoid having a testable hypothesis,” Professor Armstrong said.

In fact, there has been a statistically significant upwards trend in annual global temperature data between 2007 and 2016, but that was heavily influenced by heat generated by the extreme El Nino event in 2015-16.  It will take several years before we can determine whether Armstrong has won or lost his proposed bet.

Like the earlier claims that there had been no global warming since 1998, ten years is too short a period to separate the long term signal from the short term noise (or natural variation).  Also, like the earlier claim, the ENSO cycle had a role to play.  There was a strong La Nina in 2010-11, which cooled the globe significantly.

Also like the earlier claim, the inability of climate models to accurately predict the near-term climate has the potential to damage the credibility of their models.

Nate Silver, in his 2012 book “The Signal and the Noise” evaluated the 1990 and 1995 IPCC temperature forecasts to 2010.  He found that their 1995 prediction of warming of 1.8 degrees C per century for the business-as-usual scenario was about right over the period 1995 to 2010.

Climate scientists have, belatedly, started to question the accuracy of their models.

Fyfe, Gillett and Zwiers, writing in Nature Climate Change in 2013 found that observed global warming over the period 1993 to 2012 was significantly lower than that simulated by the climate models – specifically Phase 5 of the Coupled Model Intercomparison Project (CMIP5).  These models generally simulate natural variability including that associated with ENSO and explosive volcanic eruptions, as well as estimating the combined response of climate to changes in greenhouse gas concentrations, land use, solar variability, and several other factors.

They ran 117 simulations of the climate by 37 participating models.  The evidence indicated that the then current generation of climate models did not reproduce the observed global warming over the 20 year period, nor did they predict the slowdown over the period 1998 to 2012.  They found that such an inconsistency, if the models were correct, is only expected to occur by chance once in 500 years.

This finding does not confirm the view of deniers that global warming had ceased or that the greenhouse effect is non-existent.  Rather, it means that the models need improving.  This would start by more accurately simulating natural variations – some of which may not be adequately represented in the models.  As the models improve, we will then have a more accurate estimate of the relationship between atmospheric concentrations of greenhouse gasses and temperature.

One of several factors limiting the accuracy of climate forecasting models is clouds.  There are many climate models and they don’t all agree on the effects on clouds.  This is important because some types of clouds enhance the greenhouse effect by trapping heat rising from the earth.  Other types of clouds prevent sunlight from reaching the earth’s surface, so cooling the planet.  Which type of cloud will increase most as the planet warms is uncertain at present.  See “The cloud conundrum” by Kate Marvel in Scientific American, December 2017.

The planetary response to carbon dioxide doubling is called equilibrium climate sensitivity.  The degree of warming the models predict for a doubling of carbon dioxide ranges from 2.0 to 4.4 degrees C – quite a wide range.

This is an extract from my book “Forecasting, the essential skills” which evaluates the performance of forecasting in a range of fields and which contains numerous case studies.

Charlie Nelson