This is a long and detailed post; the quick read version is here
Let's look at some history
. In the 1824 it was discovered that atmospheric CO2 produced an insulating effect, the 'greenhouse effect'. By the end of the 19th century it had been proposed (and scientifically demonstrated), that an increase in atmospheric CO2 would warm the planet. This was recognized as significant, since the Industrial Revolution was in full force and it was well known that atmospheric CO2 levels would increase as a byproduct of human industries. However, back in those days it was considered that this increase in temperature would be slow and gradual, and that it would even have beneficial effects. Now, we know different.
By the 1930s, it was discovered that the US and the North Atlantic had warmed significantly. The significance of this was almost completely overlooked, but Guy Stewart Callendar
(an engineer), interpreted this as the commencement of Anthropogenic Global Warming AGW). Like Arrhenius
before him, Callendar thought that the effects would ultimately be positive.
However, the estimates of Arrhenius and Callendar were considered largely inconsequential. Scientists did not believe that CO2 could be produced by human activity in quantities which would result in significant global climate change, still less widespread negative effects. In any case, there were too many other variables to take into account before accurate predictions could be made. Unfortunately even the estimates of Arrhenius and Callendar underestimated completely the rapacious appetite of human industry and its staggering capacity to produce destructive waste.
We can see therefore that by the 1930s the fundamental science behind AGW had not only been proposed theoretically, but observed objectively. At this point there was genuine scientific skepticism of the ultimate results of the model, though the basic principles were recognized. Still, it was not considered a serious problem nor a completely settled scientific matter.
That changed in the 1950s. Increases in scientific funding, and massive technological advances (especially in computing), suddenly resulted in the ability to collect far more data, assess it far more accurately, and process more of it faster. Significant breakthroughs were made during this time, especially with regard to the question of how much CO2 would be absorbed by the ocean, which had previously been considered a carbon sink large enough to alleviate and offset any anthropogenic CO2 increase. Unfortunately it was discovered that the ocean was not absorbing CO2 at the rate which had been anticipated, and the realization that this massive 'safety valve' was in fact not going to be any such thing, was a cause for concern. However, even at this stage it was generally assumed that the effects would not become problematic for hundreds of years.
The science was good. The theories had been vindicated, and now the scientific community was taking serious notice. At this point it was understood that AGW could be 'a serious problem to future generations' (Gilbert Plass
), and warnings were beginning to filter through to the government and public media (Roger Revelle
, Bert Bolin
). During this time Gilbert Plass made three predictions with regard to climate change due to CO2 increase (global warming, CO2 levels, and the temperature of the planet).Just over fifty years later, all of them were proved true
Throughout the 1960s, independent research was carried out by a range of different groups. Their studies repeatedly converged on the same conclusions, that global warming was taking place, and was the result of human industrial activity. In 1965 it was estimated that by the year 2000 global warming would have discernible and measurable effects on climate. Despite this, the general feeling in the scientific community was still largely complacent with regard to the long term effects of global warming. The science, however, was less debated than in previous decades, although skepticism still remained.
By the 1970s a new shift in scientific research resulted in another dramatic development of knowledge. At this point interdisciplinary studies became involved in the subject of AGW. Now it wasn't simply climatologists who were involved, but a wide range of different scientific disciplines, each of them confirming a small part of a highly complex scientific puzzle. As each new scientific insight was uncovered, the picture became steadily clearer and more difficult to ignore. Economists were able to assess more accurately the annual human production of CO2. Radiologists assessed the relevant issues involved with the insulation of radiation within the earth's atmosphere. Oceanographers addressed the potential of the ocean as a carbon sink. Ice core sampling provided previously inaccessible long term data on global temperatures and atmospheric conditions.
In the 1980s the computer climate models started to produce significant results. A 1981 report on a range of climate change models made a sober pronouncement on the facts of climate change, and the need to reduce anthropogenic CO2 emissions (see here
). There was no denying that the climate model predictions had produced undeniable results. This was confirmed by the latest ice core samples, which 'turned the tide in the greenhouse gas controversy
'. Throughout the 1990s public awareness of the problem grew, as the scientific data was confirmed at every turn
It was in the 1990s that governments started proposing action to reduce the causes of global warming. It was around this time that the industry and its allies started to raise their 'controversy'.
One political party's memo advised staff thus:
* 'Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore you need to continue to make the lack of scientific certainty a primary issue in the debate
Of course there was no lack of scientific certainty, the 'controversy' (as with the cigarette issue), had to be manufactured. Thus the same memo continued:
* 'You need to be even more active in recruiting experts who are sympathetic to your view
, and much more active in making them part of your message'
You may have heard that the term 'climate change' was coined by scientists embarrassed by the lack of evidence for 'global warming', and who had to scrabble to find a new term to maintain their basic position whilst retreating from their previous claims. This isn't true. The term had been in use for a decade before this false claim was first made. In fact when it was coined, the term 'climate change' was seized on by the Republicans, precisely to play down fears of global warming. They were forced to do this when their previous campaign of 'controversy' had failed:
* ''Climate change' is less frightening
than 'global warming''
* 'While global warming has catastrophic connotations attached to it, climate change suggests a more controllable and less emotional challenge
* 'Indeed it can be helpful to think of environmental and other issues in terms of 'story.' A compelling story, even if factually inaccurate, can be more emotionally compelling than a dry recitation of the truth
* 'The facts are beside the point
. It's all in how you frame your argument'
Ironically, years later the author of this very same memo very honestly admitted that he had since changed his views