There exist several claims in the public domain that the climate is not changing, or the change is part of natural variation, or is not due to human activity:
8.1 Data manipulation?
Remarkably, at least to me, there have been allegations that the Australian Bureau of Meteorology has systematically fabricated the data underlying the climate reports (and I assume by extension, also the American Society of Meteorology, the editors of the Bulletin of the American Society of Meteorology, NASA and many other scientific bodies [site]). I say remarkably, because I see no reason for scientists to fabricate their data and no means for this to be coordinated nationally or internationally. Moreover, data fabrication in science constitutes major misconduct, leading to termination of employment, retraction of papers and even criminal prosecution in the courts [report].
A central claim underlying this allegation is that the official mean data is not the simple average of raw data. But unless temperature recordings are taken on a uniform global grid (i.e. at regular spatial intervals everywhere), which is impossible, and with no historical change in instrumentation– also impossible – then further processing is a mandatory component of time series analysis: This process, which has been peer-reviewed [paper], is performed with slight modifications in many scientific fields, including neuroscience. Moreover, weather records with and without these standard data analysis steps are available for download in the public domain [site] and both show clear warming trends. The Bureau have published a firm rebuttal to these claims [site]
Notably, estimates of global heating are evident when inferring temperature from other meteorological observables including barometric pressure [paper] and from recent satellite estimates of global temperature in the mid- to upper troposphere [paper] making claims regarding data fabrication irrelevant and vexatious.
8.2 Scientists justifying their salary?
On a related note, one sometimes reads allegations that (thousands of) climate scientists have fabricated the data behind global heating in order to justify their own funding. This is extremely implausible for a number of reasons. For a start, salaries in science are substantially below (<50%) those for equivalent expertise in the private sector: A person possessing advanced data analysis skills, report preparation, programming and forecasting can easily obtain employment at much higher salary (and job security) in the finance, insurance, IT or even mining sector: Moving into the private sector to increase income and career security is a common choice among researchers at all levels of seniority and offers a far simpler solution than data manipulation and systematic violation of research integrity. Second, climate science is funded in competition with other areas and assessed by scientists in other fields such as neuroscience. Data manipulation is typically easy to spot and indeed, instances of scientific fraud, when they do occur, have been invariably detected by other scientists. It is not feasible that scientists in other fields, competing for the same pool of money, would be blind to such widespread systematic malpractice and agree to the awarding of competitive funds that might otherwise come to their own field.
It is far more likely and, by Occum’s razor, far simpler that the data analysis is being conducted according to best practice and that scientists are not embroiled in a coordinated collusion of deception but rather accurately documenting the consequences of increased atmospheric CO2.
8.3 Underwater volcanoes and solar radiation?
There also exist sporadic claims that global heating arises from an increase in the activity of deep ocean volcanoes, heating the ocean, causing sea level rises and the release of heat into the atmosphere. This is a highly implausible cause of global heating for a number of reasons: There is no evidence for any increase in volcanic activity; Ocean temperatures at surface (and down to 2000m) have warmed whereas temperatures at deeper levels have not warmed [paper] (contrary to heating from deep ocean volcanoes); and this mechanism does not explain the increase in oceanic carbonic acid (and the reducing ocean pH), nor the clear link between combustion of fossil fuels and increasing atmospheric carbon dioxide.
Likewise, there exist sporadic claims regarding a causal link between solar irradiance and global heating. However, there is no evidence of an upward trend in solar irradiance to substantiate this claim [site]. As with underwater volcanoes, this claim is also inconsistent with many other observations: Global heating of the atmosphere is greatest at surface level, not in the upper atmosphere, and it cannot explain the increase in atmospheric carbon dioxide.
8.4 It’s “just modelling”
The causes and impacts of global heating are occasionally derided because they are “just based on models”. The evidence for global heating and the causative influence of human activity, as reviewed above, constitute strong scientific evidence. Much of the link between heating and harm are based upon surveys of historical associations (such as the impact of WBT on health and death risk), have already been subject to “out of sample” validation [paper] and therefore do not depend upon explicit causative models.
Models play a central role in all branches of scientific enquiry and are core to the endeavour to extract general principles from empirical observations – in fact models (such as the theory of optics) lie at the heart of those observations (such as planetary motion). Newton’s law of motion (F=ma) is a “model”, couched in the same branch of mathematics (calculus) used in weather and climate prediction. Putting “man on the moon” was at its core an exercise in solving the laws of motion and, as such, remained a model prediction until the moment humans actually landed on the moon. Therefore, to critique a branch of science due to its use of mathematical models is a complete misunderstanding of the core principles of scientific enquiry.
Meteorological modelling and model simulations play a core role in climate science, as they should. These models are based on well-established physical principles (such as the flow of atmospheric gases and the separation of time-scales) and subject to state-of-the-art development, empirical validation, refinement and large-scale simulation [paper]. No weight should be given to criticisms about climate science because of its employment of modelling.
8.5 An “Act of God”?
Putting aside the existence of God, there currently exists a compelling scientific account of global heating under the influence of anthropogenic GHG emissions. While the causative link between human activity and global heating may have been unknown historically, it is now well documented, justified and available in the public domain. There are no gaps in physical explanation through which God could impose his will and likewise no means through which “thoughts and prayers” could modify the effects of global heating on human welfare.
Assuming (consistent with major world theologies) that God endowed humans with free will, we now accordingly choose freely (or not) to take action to mitigate future damage to ecological systems and human health through changes in policy and behaviour. Therefore, even if God exists, global heating and the associated damage (e.g. from days of WBT>35°C) are not “Acts of God” but rather “Acts of (hu)man”.
This may seem like an obscure or even facetious point, but it is important because it makes those entities (humans, corporations) who freely choose to increase GHG emissions vulnerable to future class action [site]. To put this in perspective, several thousand residents of Brisbane were recently awarded up to AUD$1billion in a class action for flood damage against the operators of flood mitigation dams, Seqwater and Sunwater [report]. Rough estimates (see above) equate a minimum damage of $1billion for every 0.001°C of additional heating due to GHG emissions every year. Class actions against those who choose to add unnecessary burden to global heating would dwarf short-term profits, particularly to those who enable small but critical infrastructure links to large CO2-emitting projects [site]:-
As time passes, however, and as climate change starts to affect the value of companies, and investors suffer losses, it seems inevitable that plaintiffs will begin to claim damages for these types of breaches by companies and their directors. Those claims might attract the interest of litigation funders, and come in the form of securities class actions.
A further possibility is that claims will be brought connected with misleading conduct in the case of major emitters if they are found to have recognised the risks of climate change (and their contribution to it) some time ago, but have actively taken steps to undermine public recognition of or belief in it, thereby contributing to delay in responding to the risks. Litigation of this type has started to emerge in the US, with local government as the plaintiffs.
Taxpayers should also be mindful that class actions can be mounted against governments, even for historical actions [site]:-
To the extent that governments make decisions (or implement policies) which seem to support ongoing or increasing emissions by industries or entities which contribute meaningfully to Australia’s overall level of emissions, these types of actions may be taken against both governments, and the beneficiaries of those policies,
8.6 A brief reflection on science and public knowledge
In sum, counter-claims to the body of knowledge that links GHG emissions to climate change are spurious and easily rebutted. Nonetheless, they are effective at short-circuiting important strategic decisions to decarbonize the economy, bringing debate back to issues that were essentially resolved in the scientific literature decades ago.
As a scientist, it is disappointing to see the claims outlined above appearing repeatedly in the public domain, often supported by a link to a youtube video or a blog. I find the claims of data manipulation and systematic collusion puzzling and even demoralizing. Where does this derision of scientists derive? The undercurrent of the claims runs completely at odds with my personal experience as a scientist (and medical doctor) that scientists are overwhelmingly open, altruistic, collegial and ethical– often foregoing opportunities in financial sectors that offer greater remuneration and job security for the implicit reward of knowledge discovery. Scientific enquiry is also characterized by a rich tradition of critical enquiry. That is, scientists are trained to critically appraise existing knowledge, using quantitative techniques to improve or refute theory and models. The claims that scientists accept climate science, or worse, fabricate narratives, for reasons of naivety or financial gain are prohibitively unlikely.
Like most contemporary politics, much of the polemics around climate science are currently mediated through the medium of social media. In my experience, it seems that social media can both support the dissemination of science (at least amongst scientists), but also undermine the (apparently) privileged place of science as a source of reputable knowledge. Occasionally this is justified by giving “both sides of the debate” a voice, even when the burden of scientific evidence is overwhelming. Nonetheless, “most” scientific discoveries – new and old – remain widely celebrated across most sectors of society, from Einstein’s work on relativity to the recent detection of gravitational waves. The denigration of science on social media seems confined to the science of climate change.
Climate science, on my reading, sets very high standards of reproducibility, technological excellence, open science (including data availability) and collaboration. For example, the advanced use of data assimilation in weather forecasting (modifying model predictions on-the-fly using real-time data) is far more advanced than its current applications to seizure prediction in neuroscience (an area where I work). Also notable is how climate predictions, through the use of “ensemble models” (vast parallel computer simulations) not only yield expected outcomes but also the uncertainty of those predictions. On paper, climate science is one of the fields that is least vulnerable to issues of reproducibility that have been identified in other fields, such as in small lab driven psychological research – and already employs many of the strategies that have been identified as solutions to these issues (models based on physical principles, data sharing, open collaboration, convergence between different model predictions). In my opinion, the debate surrounding climate science has nothing to do with internal scientific standards within the field and currently nothing to do with existential threats to free market economics. Addressing climate change decarbonization only represents a challenge to the power and wealth of those commercial entities dependent on carbon-based energy production. This selective challenging of a field of science recapitulates the fact that “knowledge” is historically always embedded in social power structures [report].
The disavowal of climate science extends beyond those immediately benefitting from the current reliance on GHG emissions for economic gain to also comprise some sections of the general community, although this number appears to be decreasing [report]. There has been some informative research on the demographics and belief systems of those who disavow the science of climate change,
“Although nearly all domain experts agree that carbon dioxide emissions are altering the world’s climate, segments of the public remain unconvinced by the scientific evidence. Internet blogs have become a platform for denial of climate change, and bloggers have taken a prominent role in questioning climate science. … We show that, above and beyond endorsement of free markets, endorsement of a cluster of conspiracy theories predicted rejection of climate science as well as other scientific findings. Our results provide empirical support for previous suggestions that conspiratorial thinking contributes to the rejection of science. Acceptance of science, by contrast, was strongly associated with the perception of a consensus among scientists” [paper].
In my own experience, scepticism of climate science appears to include those who do not otherwise appear to embrace conspiratorial thinking. However, there are other apparent determinants. In the USA, males who identify as politically conservative are significantly more likely than are other Americans to disavow climate science, even more so for those conservative males who self-report understanding global warming very well [paper]. Gender also has a significant effect in Australia, with women more likely to think that climate change is caused by human activity [report]. Men polled were also less concerned than women about the consequences of climate change. Women (77%) were also more likely than men (66%) to support early action on climate change. And whereas young Australian adults overwhelmingly endorse climate science and the need for action, the level of consensus among older Australians is far more ambivalent [report].