Nobody can disagree that there is climate change. As geologists, we know about the continual, and even continuous changes, that are the stratigraphic record; none would deny there has been an increase (but of ~1o
C) in average world temperatures since ~1880, nor that CO2
is increasing; but many geologists and other scientists, do not accept that there is a proven, and unique scientific and unbreakable link, between CO2
and catastrophic, anthropogenic climate change. And it is far from clear that this ~1o
C rise is not primarily a product of the repeated fluctuations in temperature recorded over the last 10,000 years - since the ice last retreated.
Climate modellers in the late 1970s changed from prophesying a nuclear winter, which for many years had been the buzz phrase linked to the global cooling that had taken place between ~1943 and ~1973, and particularly so while I was studying geology in the 60s, to warning about anthropogenic global warming. This claim appeared increasingly justifiable as the century aged, for the thirty years of warming showed an increasingly clear trend. Linking this rise to the undeniable rise of CO2 was certainly something to consider, but what was not considered, was that half of the increase in temperature recorded since ~1880, had already happened by 1943, during a period when CO2 increased hardly at all.
More geologically pertinent perhaps, is that the world’s supply of CO2 has declined steadily for the last 150 million years and that, after the last ice sheets withdrew, was lower at 280ppm, than it has ever been in the history of life since the Cambrian explosion. Global warming sceptics noted that during the Pleistocene glaciation, the apparent link between CO2 and temperature was that, as temperature rose or fell, CO2 moved up or down on a similar trajectory, but only after a lag of up to 800 years. This simple observation was denounced by the IPCC and others, as demonstrating the mendacity of ‘global warming deniers’, who did not care about the world’s health. This observation has now been accepted as mainstream climate doctrine, even by anthropogenic CO2 driven climate change proponents. Other inconsistencies suggest that the IPCC hypothesis could be wrong; after the last ice age ended, temperatures rose ~8oC, and CO2 100ppm; since 1880, CO2 has risen by 120ppm, but temperature has barely managed 1oC; how does this fit the IPCC hypothesis of climate change?
As geologists, but not ‘real’ climate scientists perhaps (?), we also know that there is never complete consensus on any hypothesis, and new, initially unpopular ideas – such as plate tectonics, can become mainstream, and increasingly supported by new evidence, or can disappear, like miogeosynclines. Scepticism therefore does seem to have a valued place in science - but not, it seems from your editorial, in the science of anthropogenic climate change?
Looking further at the record of CO2, one third of the total increase since ~1880, has taken place since ~1996, during a time of slow-down, or hiatus in global warming – partially obscured by El Nino warming effects. IPCC’s response to this slowdown, was to drop global warming as a catch phrase, and substitute climate change instead. Is it not reasonable to question why these two examples of CO2 increases not affecting temperature changes, seem to have been studiously ignored in the vast amount of current climate change publications? Put another way, is it not more reasonable to ask, if CO2 does not always result in warming, how does it produce climate change?
Scepticism it seems, is never tolerated by consensus holders, so it is no surprise that a Google Search only produces articles that pay homage to the IPCC position. Popularity however – which is all Google search demonstrates, has, like consensus, never been equated with scientific accuracy or probity. Perhaps President Trump’s new EPA will look more carefully at both sides of the debate before committing the world to a potentially futile but very costly attempt to reduce CO2, which will achieve nothing but a reduction of the recent greening of the planet, and the increased crop yields that are measurable benefits of the increasing CO2 content.
If the sceptics are wrong about everything, let us hear them, so we can put them to shame and get the world’s EPA organisations back on track. I therefore call on the GSL, as representing all of its members, to convene an open climate change conference to hear, without rancour and personal innuendo, the present state of the argument. Failing this, I would like to present you and your colleagues some of the data that concern the many sceptics whose voice is rarely heard. This is not about ‘alternative facts’ but about some unpalatable facts.
Your telling quotation, “In an age of universal deceit, telling the truth is a revolutionary act” is proof of nothing, as it could just as easily be applied to much of what the sceptics say about what IPCC puts forward, and also to the gagging order which prevents sceptical views being expressed in print, even after they have turned out to be correct, as is implied in the article referenced above “On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes.” It seems unreasonable to accept that these paleoclimate effects have been vanquished by humanity’s 125ppm contribution to atmospheric CO2.
And as to whether or not speakers, geologists and other attendees will be suitably ‘qualified’ to speak, it might be useful to remember that the politicians who are going to have to implement whatever changes are called for, and journalists who write about them, are mostly unqualified scientifically, yet their combined voices carry more weight than those of the scientists whose work they rely on.
Howard Dewhirst FGS
 'On the causal structure between CO2 and global temperature'; Adolf Stips, Diego Macias, Clare Coughlan, Elisa Garcia-Gorriz & X. San Liang Scientific Reports 6, Article number: 21691 (2016) doi:10.1038/srep21691: http://www.nature.com/articles/srep21691