I originally wrote the paper, Issues Arising from the Greenhouse Hypothesis, in 1990 and do not see a need to revise it substantially. Some of the science is better defined and there have been some minor changes in some of the projections; but otherwise little has changed.
In the Introduction to the 2006 update to that paper I wrote:
Climate change has wide ranging implications... ranging from its impacts on agriculture (through drought, floods, water availability, land degradation and carbon credits) mining (by limiting markets for coal and minerals processing) manufacturing and transport (through energy costs) to property damage resulting from storms.
The issues are complex, ranging from disputes about the impact of human activities on global warming, to arguments about what should be done and the consequences of the various actions proposed.
To the conclusion I added:
Australian impact on global climate is insignificant. Our main contribution is likely to be indirect by way of diplomatic efforts to change global behaviour or through research into solutions that can be applied globally. Climate is likely to change no matter what we do. In Australia we are all too familiar with the effects of natural climate fluctuations.
The degree to which human activity changes climate is related to our level of resource utilisation. Although energy consumption is very important in this equation so too are mineral extraction and processing, farming and land clearing, pollution of oceans and lakes and the shear number of humans and their consequent demands for food and shelter. Not only does excessive population lead to stresses on the biosphere of the planet; it makes huge numbers of people highly vulnerable to relatively minor changes in that biosphere.
Sudden climate change is just one of a number of a range of potential catastrophes that might befall the planet. It is important that while doing all possible to mitigate the impacts of increasing resource exploitation we:
1 commit more resources to means to respond flexibly to climate change than to trying to prevent it and;
2 treat the disease (over-population) not just the symptoms (like greenhouse gasses).
We need to focus on the possible. An appropriate response is to ensure that resource and transport efficiency is optimised and energy waste is reduced.
Another is to explore less polluting energy sources. This needs to be explored more critically. Each so-called green power option should be carefully analysed for whole of life energy and greenhouse gas production against the benchmark of present technology before going beyond the demonstration or experimental stage.
Much more important are the cultural and technological changes needed to minimise World overpopulation. We desperately need to remove the socio-economic drivers to larger families, young motherhood and excessive personal consumption (from resource inefficiencies to long journeys to work).
Climate change may be inevitable. We should be working to climate "harden" the production of food, ensure that public infrastructure (roads, bridges, dams, hospitals, utilities and so) on are designed to accommodate change and that the places people live are not excessively vulnerable to drought, flood or storm.
Only by solving these problems will we have any hope of finding solutions to the other pressures human expansion is imposing on the planet.
I have summarised much of this discussion in the Environment chapter within the Meaning of Life essay, also on this website.
Recent extreme weather events appear to confirm the predictions made in my earlier paper. As the energy of the system increases, so this energy is partly dissipated in more violent weather excursions. This upward trend in the severity of weather excursions from the norm, as well as the shift in the norm itself, can be expected to continue.
I am still inclined to believe that human overpopulation will soon have further serious consequences for the climate, in addition to other environmental devastation, and I continue to believe that there are grounds for alarm.
In practical terms the resulting climate impacts may mean that different crops or crop varieties and grazing patterns will be required across arable regions and crop yields may be increasingly affected by extreme events; floods; droughts; fire and so on. Correspondingly some urban and outer urban areas, for example those particularly prone to flooding; fire; or high wind, may need to be relocated. In other areas significant new infrastructure may be necessary to guard against climate related disaster.
And the real and underlying problem, of runaway population, is no nearer to being addressed.
But politically the World is quite different. When I originally wrote the paper on climate change scientists were alarmed but very few politicians had any opinion on the matter. Now it is 'bread and butter'.
The present, increasingly heated, debate seems to be drawing all sorts of red herrings across the path.
For example sea level rise is being promoted as a serious issue and reason for action. But long before this has any real impact there will be a wide range of much worse outcomes of global warming; including crop failures and weather events.
Al Gore's Inconvenient Truth is one such overstatement, wildly quoted by sceptics, as it suggests that Manhattan will be swamped within the lifetime of current buildings (<20 years). Other prominent 'green activists' have claimed that we are facing a five or six meter sea level rise this century. We already have politicians in Western Australia and some Pacific Island nations proclaiming that current coastal inundation is due to sea level rise.
In a runaway feedback loop temperatures could climb higher than expected but if anthropogenic warming is fast enough to cause a rise of 6 metres (or more) this century we will have a lot more to worry about than declining coastal property values; we will have nothing to eat.
Land based ice has been melting for around the past 22,000 years and sea levels have risen about 130 metres over that period as a result. But less than two metres of this rise occurred during the past 5,000 years.
Sea levels have been fairly accurately measured since the 1920's and there have been more accurate satellite data since the late 1990's. Prior to that tidal statistics are less reliable. Back in the 1800's there were some places with good measurement but a whole world view (necessary to measure global sea level) was not available.
Before that, local rises and falls in the earth's crust begin to be significant (where do you measure from). But we can say with some confidence that mean sea levels have risen by around 20 to 30 cm (around a foot) in the past 100 years. More accurate satellite records put this at 6 cm in the past 20 years (3 mm per year) on a linear trend. This is due to land based ice continuing to melt and to ocean expansion due to warming.
Source: Wikipedia, the free encyclopaedia
This effect is considerably less than movements in the earth's crust in many places. The lateral movement of the earth's tectonic plates is typically 50–100 mm per year; in some places much more. Claims that some islands and other places are being inundated by sea level rise are more likely due to tectonics (in the case of coral atolls – as this is how they form) or in places like Venice, due to excessive groundwater use, there may be dozens of other factors before sea level rise becomes an issue. It may even be a positive factor in some locations like the Turkish coast, where once coastal villages are now inland.
I have been catching the ferry in Sydney for various periods spanning 40 years and I see no perceptible change in the sea level in Sydney Harbour (or over harbour side seawalls or pools) but I do accept that I have trouble discerning a 12 cm rise over that period, as the tidal variation is vastly larger. Even the ripples on a calm day would make this difference hard to confirm.
That faster inundation might happen in future relies on the tipping point theory - that at some point soon there will be a cataclysmic climate change due to positive feedback to temperature rise - resulting in the remaining land ice (principally Greenland and Antarctica) melting, together with ocean warming and expansion. This will be troublesome for some cities and very serious for delta dependent countries like Bangladesh.
On the other hand melt water from receding glaciations is an extremely important (if globally short term) resource and is already feeding more people than ever before.
Since I wrote the original paper a credible scientific view has evolved and generally agrees that if global warming accelerates there may be a half metre rise in sea level over the next 50 years. Hardly grounds for selling your harbour frontage just yet.
Ridiculous projections about vastly greater inundation provide succour for those opposed to doing anything; or just tilting at windmills, as in Copenhagen; shades of Don Quixote.
Many, particularly in the media and the green movement, suggest that windmills will save the world from the greenhouse effect.
In the twenty years since I wrote the original paper wind technology has come a long way. Wind turbines are very much larger and more efficient. Larger turbines are higher and have a much greater swept area capturing much more wind. A typical 2MW turbine well located in a good wind province now pays back its whole of life construction, maintenance and removal energy debt in around six months instead of three years.
But wind is limited in the contribution it can make. Wind generates electricity for about a third of the life of a well placed wind turbine; due to the intrinsic variability of wind energy and the fluctuating nature of electricity demand.
Even in windy Denmark: attached to the larger European grid; with a big investment in wind; as well as small cogeneration units (to standby against windless, or overly windy, conditions), wind has trouble supplying more than 20% of total electrical energy.
To match power generated to demand, excess wind turbines have to be turned off during periods of good wind but low consumer demand. A turbine that operates for only half the time takes a year or more to repay its sunken energy and one that is seldom or never used never repays that energy. Thus adding more turbines, once the power generated during optimum wind conditions regularly exceeds minimum consumer demand, is counterproductive.
In other words once this 20% limit is reached every new increment of wind requires four matching new increments of base-load and fill-in energy.
In many places, like much of Australia, good wind provinces are rare or very distant from the main centres of electricity demand. To minimise losses generation should be adjacent to the consumer. In Australia, and particularly in Queensland, grid losses already consume nearly a third of the energy on its way to the consumer, even longer distances to distant wind provinces could mean that half or more of the power produced is lost during transportation.
Wind can and does contribute to the energy mix but as can be seen above it is not a replacement for coal and oil. Once the local practical maximum is reached, each additional increment wind generation requires other (base-load and peak-load combined) generation to expand around four time that amount. At the present time only gas or nuclear power is a practical replacement for base-load coal in Australia but oil and gas can provide peak-load supplementation.
To read a more in-depth discussion of renewable electricity technologies Follow this link...
Anthropogenic climate change is real. Mankind (in our present form) has only been around since the last glaciation. Some Stone Age peoples were geographically isolated by very rapid sea level rise and the climate has been getting hotter throughout our recorded history. Once we developed significant broad-acre agriculture and began mining and smelting metals (over the last 10,000 years) we began to have an increasing and compounding impact on the microclimate in many local areas of the planet. Large cities further compounded this impact.
But for most of this period, human numbers have been under half a billion and our impacts, and even the longer term trends, have been masked by natural fluctuations.
The climate changes naturally and cyclically both in the short medium and longer term. There have been many glacial and interglacial periods in the life of the planet and within these cycles wind and ocean currents, and a naturally chaotic interaction of forces, produce wild variations on an annual, monthly, daily and hourly basis. I outline some of the reasons in the paper.
The underlying problem today is that human numbers have reached such plague proportions that we are now having an impact not just on the micro-climate of say, the Sahara, Oklahoma or Europe but on the whole planet. CO2 is very likely a sideshow in this carnival. The fundamental cause of anthropogenic climate change is just too many people on the planet.
Now, as predicted, we are beginning to see a number of extreme climate events that have already killed many hundreds and cost billions in property damage. The faithful will no doubt find comfort in hearing that the Pope is praying for themin this time of hardship. But they should also consider that it was the Vatican that went on an active campaign to circumvent any attempts to limit world population in 1964 when it may still have been possible to mitigate some of these outcomes.
The International Humanist and Ethical Union from 1974: 'This spring the Vatican has started a campaign to propagate its viewpoint on birth control. Thus it takes an overt stand against the 1974 World Population year, proclaimed by the UN. According to The Times newspaper in London the Vatican resists all efforts to develop a system of world population control. It rejects contraceptives, sterilisation and abortion. In view of this startling campaign I cannot but repeat the statement I gave at the Brussels meeting with the Vatican Secretariat for Unbelievers on October 1,2 and 3, 1970: "The official Catholic policy influences through Catholic political power to a high degree the policy of nations even if the Catholics represent a minority of the population."'
Catholic On Line website hails population growth as a positive outcome as in 'Vatican stats: Catholic Church growing, especially in Asia, Africa'. So keen on eliminating any form of birth control was it that the Vatican persisted in its claims that condoms don't stop Aids until late last year. Since then claims to this effect such as that previously found at http://www.cathnews.com/news/310/53.php (Church in Africa continues AIDS fight without condoms) have miraculously disappeared.
Brazil where over 600 are reported dead in recent flooding has the largest Catholic population in the world; together with Mexico and the Philippines it accounts for a third of all Roman Catholics. Of course this death rate pales into insignificance against the numbers of poor who die each day due to malnutrition and disease as a result of overpopulation.
But it is unfair to put all these miserable deaths at the Vatican's door. Islam is equally to blame; although there is no single organisation heading that religion that forms an easy target; and in the US, fundamentalist Protestants have conspired with Catholics to prevent US Aid being tied to population control programs or incentives. The US has the fourth largest Catholic population in the world but Protestants outnumber Catholics by more than three to one.
According to current UN projections we are already committed to another two, and probably at least four, billon of these before 'something' calls a halt to exponential growth. This 'something' causes the graph to roll over and then fall back to some sustainable number.
Source: Wikipedia, the free encyclopaedia
In a number of developed countries that 'something' is declining fertility; apparently for cultural reasons; in many cases to below replacement levels.
This is extraordinary. Successful species do not normally spontaneously decline in numbers. They do so because of the failure of their food supply; loss of, or dramatic change in, habitat; disease; or competition from a more successful species (or culture).
So what is causing this in humans now? It appears to be the changed habitat or cultural environment due to technological and scientific advance, bringing new options and knowledge.
In population terms, this declining fertility is offset by longer life spans; resulting in the general aging of these populations, further amplifying the trend.
But in places like India, Egypt, most of Africa or parts of South America there is no evidence that things are getting sufficiently better for most women, or in education, for these to have an impact on fertility. The very population growth militates against any improvement in their living standards or education. The populations are typically very young and often getting younger as mortality rates rise. The prevailing religions are antipathetic to a greater role for women (and/or fertility control) and to cultural change in general; and religious adherents are increasing in number and proportion as these classes grow. As a result, there is a rapid growth in 'fundamentalist' religions across the world.
Even in rapidly developing countries like China (and before them Japan) with low or falling fertility, the aging of the existing population means continuing population growth for many decades.
In these places we know that the 'something' mechanism for a stabilising and then reducing population will be much higher death rates occasioned by the depletion of resources, water, food, energy and so on; increasing contamination of food and water; more and more environmental damage; and very likely, significant new climate impacts.
In the worst case (the UN low projection model) world population growth will be its own undoing through total resource collapse and this is going to happen within the next century. This will be managed or un-managed. In the later case many more will die and civilisation itself may well be seriously compromised.
It would be nice to avoid the less unpleasant scenarios. But our politicians continue to fail to do the things they could do to help. They need to work to suppress the factors subjugating women or preventing them their controlling their own fertility. They need to put big resources into the urgent universal and compulsory secular education of depressed minority children.
They need to put more resources into the technology options that have some prospect of delaying the worst case outcome long enough for the above options to take effect. By turning to technology we might come up with a fusion reactor, or some alternative, in time to solve the energy issue. Solving the energy issue may in turn solve the water issue. GM crops and/or algae might help solve some food and transport fuel issues.