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Recently, an increasing number of friends and acquaintances has told me that Climate Change is a myth.
Obviously they are talking about 'Anthropogenic Global Warming', not disclaiming actual changes to the climate.
We don't need climate scientists to tell us that the climate changes. Our own experience is sufficient to be quite sure of that.
During my lifetime the climate has been anything but constant. Else what is drought relief about? And the ski seasons have definitely been variable.
In the longer term we all have to rely on others. For example on scientists who have themselves examined ice cores or tree rings or sea level records or other physical evidence that can be dated.
So I'm prepared to believe the scientists who have determined sea levels showing that fourteen or fifteen thousand years ago a hypothetical Australian could walk from Tasmania to New Guinea or an Irishman all the way to Java.
Changing sea levels during the past 20,000 years
Source Wikipedia: Early Human Migration & Sea Level change
This rise has not stopped. During my lifetime the average sea level in Sydney Harbour has risen by nearly a foot, in keeping with long term trends. More water in the Harbour on average obviously has temperature and therefore microclimate implications. There are thousands of well documented examples of changes that have climate impacts.
But like the tides there is great variability that masks the underlying trends. For example 2014 was a record warm year in Sydney. But in mid 2015 we are going through the longest cold spell in 45 years. It is snowing in Queensland!
Notwithstanding this variability, sea level rise shows that the planet has been getting warmer for at least twenty thousand years and the trend continues.
So there is no doubt that climate changes. The only debate possible concerns the impact mankind is having on this change.
This debate goes to how significant has the impact on the planet of our various activities already been and how significant might our influence be in future. And if we are having an impact is there anything we can do to increase the benefits or mitigate negative impacts?
These are the same issues that I addressed in 1990 in my paper: Issues Arising from the Greenhouse Hypothesis that you can still read on this website.
As I have written and said repeatedly since, although the climate has changed nothing much has changed about the climate debate.
Let's reprise some of the key evidence.
Among the symptoms of mankind's impact on the planet is the extraordinary recent rise in the levels of carbon dioxide (CO2) in the atmosphere.
Source: NOAA - Global Greenhouse Gas Reference Network
This is of concern because over the past four hundred thousand years there has been a close correlation between global atmospheric temperature rise and higher levels of CO2 in the atmosphere.
Graph of CO2 (green), reconstructed temperature (blue) and dust (red)
from the Vostok ice core for the past 420,000 years
Source: NOAA derivative work: Vostok-ice-core-petit; in Wikimedia Commons
Other, shorter term records like tree rings and stalagmites confirm this close correlation between temperature rise and CO2 levels.
But ice cores are one of the best tools for looking back into the past as they contain both dust and air bubbles trapped when the snow fell and in some places, like the Antarctic, the layers of snow have been building up relatively undisturbed for tens of thousands of years.
The above ice core data shows that for half a million years, until the the middle of the last century, CO2 levels fluctuated widely but never exceeded 300 parts per million (ppm). We broke this half million year record in the 1950's. So we have been in unchartered territory since then.
In mid 2015 Atmospheric CO2 went past 400 ppm and if anything its rate of rise is accelerating. Some think that this is approaching the highest level since the Carboniferous Period, over 300 million years ago.
This alarms most observers. Should you be worried?
Maybe there's be some mitigating consideration? A 'get out of jail' card? What's carbon dioxide anyway?
Possibly the data contain a silver lining? The same ice core data shows that higher atmospheric dust correlates to lower temperatures. It has been demonstrated during recent events that dust in the atmosphere, from volcanoes meteor impacts, large fires and so on, reflects sunlight and lowers global temperature. Historically when this happened possibly as a result of fires and volcanoes that release CO2, CO2 levels actually fell, in line with the drop in radiant absorption.
Simplistically this dust correlation might suggest that the correlation of CO2 to temperature is in reverse of that usually assumed. Could atmospheric temperature determine natural CO2 levels? I canvassed this possibility in my 1990 paper but a moment's thought dismisses this possibility. The climate has been hotter several time in the past half million years but CO2 levels have never been as high as they are now.
Maybe CO2 levels have nothing to do with anything? But theory and experiment demonstrate a causal relationship between 'greenhouse gasses' and the rate of temperature rise and the affect of various gasses, CO2 amongst them, has been measured. It is not irrelevant.
Some critics doubt the data altogether and claim that the researchers are seeing what they want to see. But there are now a vast amount of supporting data. So this argument would be difficult to sustain too.
Can we rely on the historical correlation at all? Plausibly both changing temperature and CO2 levels are a response to something else, like the carbon cycle of plants and animals or our orbit relative to the sun and moon or corresponding changes in ocean currents. Again, I canvassed this possibility in the 1990 paper.
Over 400 thousand years the earth's surface has changed significantly. Plants and animals and the area covered by water have been in constant flux. Just 40 thousand years ago there were still mammalian mega-fauna and huge herds of smaller beasts pursued by sometimes frightening predators competing with early modern humans and other hominids. Agriculture where it existed at all was limited to small gardens. The carbon cycle and atmospheric water vapour (clouds) must have varied too.
Critics of the prevailing scientific view argue that if CO2 in excess of 260ppm causes accelerated warming, CO2 levels above 300ppm since the 1950's should have already resulted in much faster warming than we are actually experiencing.
As you can see from the graphs based on ice cores CO2 has shot up steeply in the past ten thousand years and from the Mauna Loa data it has not stopped.
The last ten thousand years correlates with the rise of human civilisations. But in the above dataset temperature change seems to have begun to oscillate at less than plus or minus 2 degrees and this looks to be quite unusual compared to the earlier data.
Other critics suggest that the prevailing climate models are faulty because significant negative feedback effects have not been properly accounted for. For example: water vapour may play a greater part in reflecting sunlight back into space than accounted for. And maybe human activities, like aircraft vapour trails are having much greater than expected cooling effects.
I find this argument quite persuasive. But Science is not a democratic process. You can't determine facts by taking a vote or counting up scientists. The history of science is littered with examples of lone voices who turned out to be correct in the face of accepted orthodoxy.
Today scientific orthodoxy is reinforced by the peer review process; the need to get a higher degree then attract research funding and career support; and a natural tendency to accept the present paradigm in the scientist's field of study.
Rebels who turned out to be right have often been cast out, losing financial support, their job and their livelihood. Having said that, rebels who turn out to be right are generally very well read, carried out novel experiments or observations and were among the most experienced in their field. Galileo is an example and Darwin spent many years of detailed experimental work confirming he was right before he dared publish his theory.
It is extremely unlikely that a journalist, shock-jock, casual observer, businessperson or politician is actually a modern day Galileo, a voice of reason in a sea of conformity. Historically such populists have been at the head of the mob demanding that the malefactor be brought before The Inquisition.
I've spent the past thirty years listening to this debate. One thing I can see for myself is that the harbour is a little deeper. Another is that since 1990 there are another three billion people on the planet, more than were alive when I was born. Otherwise I'm not a lot wiser.
I'm still uncertain if burning fossil fuels is as bad as the greenies say or as harmless as the coalmining, oil and gas companies say.
But I've recently done quite a bit of travel and I am certain that humans are altering the planet in previously unimaginable ways. Changes on this scale have inevitably resulted in a different climate to that which would otherwise have occurred. But is it better or worse?
Today (this day), over fifty thousand people died of poverty related disease; exposure and malnutrition. Over fifty thousand will die tomorrow and a similar number the day after - every day. It's an outcome predicted in the late 1950's. Had it been acted on then a small fraction of this number would be starving. This present and ongoing disaster is a direct outcome of deliberate and active opposition by a number of institutions to efforts to control human fertility during the latter part of the 20th Century. You know who they are*.
At the beginning of the 19th Century there were less than one billion people on the Planet. It took well over a hundred years to add another billion, so that in 1945, the year I was born, the population had reached 2.3 billion. Now, in 2015, we have over seven billion humans competing for resources. We have added a further five billion and the human population has tripled in my lifetime.
As travel or Google Earth quickly reveals, humankind has already transformed vast areas of the planet to meet our many needs - destroying the natural balance everywhere you look. This devastation is set to grow by half as much again by the middle of this century.
It is glaringly obvious that we are now suffering a wide range of impacts on our environment, of which the extraordinarily high level of CO2 in our atmosphere is just one symptom, along with overcrowding, poverty, disease and starvation. Pope Francis has a little list.
We can attack one symptom but the disease is going to get a lot worse before it gets better. Although fertility is now coming under control in much of the developed world, continuing population hot-spots in Africa an the sub-continent together with the aging of those, like me, born during the baby boom and later are almost certain to increase our numbers to around ten billion by 2050.
A majority of climate scientists argue that temperature will indeed rise steeply as a result of high levels of CO2. Many argue that the reason that rapid rise has not been experienced to date is that the impact of high CO2 has a lag of many years before it takes effect. I'm not convinced by this delay and think other factors such as water vapour must be at play. If it's all going to ocean warming Sydney Harbour should be a lot more than a few inches higher. But again, I'm no expert on solar absorption or the radiant quality of clouds.
We may, or may not, suffer catastrophic carbon dioxide induced climate change but it seems we can do little about the real 'elephant in the room', our apparently unstoppable population growth and the vastly increase in resource consumption and depletion that such an increase entails.
Carbon free energy is a trivial problem in comparison to deficiencies in several other recourses, including arable land. Energy is one of the most plentiful resources. There are now many ways of freeing or collecting it available to modern engineering. Wind, solar and hydraulic (dammed or run-of-river) and nuclear energy are already used extensively and tides, wave, and geothermal resources can assist in appropriate locations. It's just a matter of cost.
Like nuclear power, the energy cost of renewables is entirely due to the cost of transforming and delivering the energy to consumers. This is the cost of the equipment required and the salaries of people required to maintain it. As it is entirely a cost issue, provided there is no political interference like restricting nuclear or imposing aesthetic standards on wind farms, the market can be relied upon to determine the best mix of technologies to deliver the least expensive solution.
But as our population increases we become more and more vulnerable to any climate change - like drought - remember.
In the event that the model supported by most climate scientists is right, atmospheric carbon dioxide at over 400ppm is already far too high and going higher. Based on that model a rapid rise in global temperature more than sufficient to devastate presently located agriculture seems inevitable. In this event, the present daily starvation rate will rise to levels that will precipitate economic and social collapse in many countries.
Let's hope my sceptical friends are right and the majority of climate scientists is wrong. In any case the world is in for a bumpy ride over the next few decades.
I commend my 1990 paper: Issues Arising from the Greenhouse Hypothesis to you. Read its conclusions here...
* In 1964 it was already evident that the human population was growing at unsustainable levels. But the Vatican went on an active campaign to circumvent any attempts to limit world population. In interviews with the The London Times (newspaper) in October1970, The Vatican Secretariat for Unbelievers told The Times: "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... "The Vatican resists all efforts to develop a system of world population control. It rejects contraceptives, sterilisation and abortion."
In 1974 United Nations proclaimed World Population Year. As predicted, this was opposed vigorously by the Vatican using every tool and influence at its disposal.
The International Humanist and Ethical Union reported that year: "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...."
In the US, where Protestants outnumber Roman Catholics by more than three to one, fundamentalist Protestants nevertheless conspired with Catholics to prevent US Aid being linked to population control programs or incentives.
As recently as 2010 Catholic On Line website hailed World population growth as a positive outcome: 'Vatican stats: Catholic Church growing, especially in Asia, Africa'.
So keen on eliminating any form of birth control that until late 2009 the Vatican continued to assert that condoms don't protect against Aids. The article 'Church in Africa continues AIDS fight without condoms' could still be found at http://www.cathnews.com/news/310/53.php until that time. But in 2010, in the face of tens of thousands of the faithful dying of aids in Africa these claims disappeared and the policy was miraculously reversed. Now condoms could be used to stop disease but not to prevent conception - an interesting paradox. Do people have sex to risk disease?
But it is unfair to put these thousands of miserable deaths from overpopulation, each hour of every day, entirely at the Vatican's door. Islam (although there is no single organisation heading that religion that forms an easy target) is equally to blame. Its treatment of women as 'baby machines' has resulted in unsustainable population growth in the middle east and Islamic Africa that is a significant factor in current wars and instability in the region. See my travel diary on Egypt Syria and Jordan.
Now Pope Francis' 2015 Encyclical sounds a belated note of alarm at humanity's impact on the Planet that the actions of his church, together with the other institutions actively subverting past efforts at population control, is largely responsible for.