It is welcome that the journalistic ethic has a requirement for “balanced” opinion on topical issues. But, the fact remains that a few climate sceptic pub mates cannot really count as sufficient consensus when weighed against multitudinous real climate scientists whose names you cannot count on your fingertips. The list is too long.

The reality is that there has been a tobacco-company style rear guard action fought to deliberately confuse public opinion, largely funded by vested interests such as the fossil fuel companies. We can refer to the climate science work done by the oil company Exxon in the 1970s, where the oil industry’s own scientists proved that burning fossil fuels leads to greenhouse gas effects. Exxon opted to hide this research from the public and deliberately sow disinformation, according to a recent expose by Inside Climate News.

In learned circles, this turning of science into crafty polemics would be considered intellectual chicanery. The New York Times and the Guardian have deliberate editorial policy to not entertain nonsensical climate change polemics misrepresented as science, since it distorts genuine scientific consensus. It is about time South Africa’s media also take a mature stance while maintaining a lively debate about how to interpret the science in terms of its implications and actions we need to take. The balance precept might be a crowd drawer and entertaining, but putting climate change denial into the mix does not represent the reality on this matter.

While the appeal by Frans Cronje of the Institute for Race Relations (IRR) for transparent and robust debate is commendable, on the face of it, it masks the nature of the “policy paper” written by Andrew Kenny that was published by the institute. As it goes, the paper is largely devoted to rehashing deliberately misleading and poorly-informed pseudo-scientific positions, not policy responses to the science. In other words, this is not so much a policy paper as a paper designed to misrepresent the scientific consensus. Matters of policy should certainly be debated in the public, and in the case of climate change, the policy issues relate to the proposed interventions in and responses to climate change not the science itself. As an illustration of some misrepresentations of scientific evidence to make false points and delay certain policy options we put forward some recurrently recycled evidence denialists used to claim the contrary.

Basic physics

Kenny says that “basic physics” does not support the fact that increased carbon dioxide (CO₂) is resulting in increased temperatures. The veiled assumption here is that a complex dynamic system such as the earth’s climate is readily explained by a simple equation. It is true that CO₂’s absorption does not account for all the heat retention caused by the increased concentration in the atmosphere – there are complex feedback mechanisms that accentuate that impact. For instance, the commonly cited objection that water vapour is a much stronger greenhouse gas than carbon dioxide is valid. However, water vapour has a short residency time and is not directly influenced by humans. On the other hand, increased heat retention in the atmosphere by CO₂ increases the levels of atmospheric water vapour, causing even further heat retention. To integrate the impacts of this feedback and many other forcings is not a simple process, which is why scientists use models to approximate the effects.

20th century warming is not nature at work

When confronted by the vast amounts of direct measurement data showing a significant temperature rise over the period 1880 to the present, doubt is cast on empirical evidence that we are causing it. This doubt is unwarranted. The Inter-governmental Panel on Climate Change (IPCC) which collates the scientific evidence, has said that it is extremely likely (more than 95% certain) that humans are the dominant cause of heating on the basis of such empirical evidence. The logical chain is: 1. The earth has warmed over this period (99% certain – in line with our certainty that gravity exists); 2. We have measured all the things that can feasibly interact with global temperature (CO₂, methane, land cover change, changes in clouds due to dust & smoke, changes in solar irradiance) to determine their impact on the climate – this is empirical data. 3. When we total the effect of all non-human causes of warming (including those often cited by climate deniers), they do not have any significant warming impact. 4. When we total all the forces that are driven by human impacts, it has a much larger effect. Therefore, the predominant driver of climate changes must be the human impacts.

Many of the objections raised by denialists, with respect to this model, deal with small aspects of the science, and have been subsequently analysed, and either integrated into the understanding, or rejected on the basis of empirical data. To put it another way, science has eliminated all the natural drivers, and concluded that their impacts are far too small to be driving the current rapid warming – it can only be the human impacts.

Warming continues

Another common assertion is that warming has stopped (at a year various given as 1995, 1998, 2002, 2007 and 2010 depending on the reference). NASA and climate records still maintain that the years starting in 1998 have been the hottest in recorded human history. These two apparently contradictory statements are based on the fact that climate sceptics “cherry pick” data to demonstrate trends. Real air temperatures vary year on year according to huge numbers of different factors, and it is to be expected that there would be both rising and falling temperatures. The only way to analyse climatic shifts is to look at long term data trends. 1998 was an anomalously high temperature year because of a strong El Nino (much as 2015 is), and so it is no surprise that the following few years were cooler than 1998. If you analyse the trend for just the period from 1998 to 2007, you get a small downwards gradient – effectively choosing your start and end points selectively. However, the average temperature of these years was still much higher than that of the twentieth century, and a long term analysis shows the trend for increasing temperature continues. In addition, oceans absorb the majority of the heat trapped within the atmosphere, and over this same period oceanic temperatures have continued to increase; when this is included in the overall temperature measure, it is clear that there is no pause in the increase, annual variations notwithstanding.

Source: NASA Global Land-Ocean Temperature Index

The link between CO₂ and temperature

Another example of “cherry picking” is the following graph:

Source: Geocraft.

The graph does indeed imply very strongly that there is no connection between levels of atmospheric CO₂ (the black line) and global temperatures (the blue line). However, there are three pertinent facts that are deliberately overlooked here. First, the CO₂ data comes from a model using 10-million year or larger time steps, and it is not able to represent shorter-term variations. The author, Robert Berner, explicitly states in his paper that “CO₂ values… should not be taken literally” and “over the long term there is indeed a correlation between CO₂ and paleotemperature, as manifested by the atmospheric greenhouse effect. Second, the overlaid temperature data is a hand-drawn schematic by Christopher Scotese using a “bistable” model in which the earth is marked either “warm” or “cool”. This model, based on quantitative palæological data, has largely been overtaken by improved qualitative analyses. Again, the time periods are very broad and the temperatures are rough approximations, so it misses out on the short-term variations in temperature that are important for CO₂/temperature correlations. Better measures of palæological CO₂ and temperature have indicated that there is a much stronger link than put forward by this graph.

Finally, the sun has gradually been getting hotter throughout history, increasing the amount of heat available to be trapped by greenhouse gases. This means that 400ppm today will necessarily heat up the earth significantly more than 400ppm of CO₂ 300 million years ago. Thus it is expected that to yield a given palæological temperature, you would require much higher CO₂ levels than today.

The 97% scientific consensus

The assertion that the 97% consensus amongst scientists has been fabricated is another common denialist position. As articulated in Kenny’s report, the assertion is that if “any scientist agreed that CO₂ had increased in the air, or that it was a greenhouse gas, that scientist would be included in the 97%. This summary of mine would be part of the 97%.” The study to which he refers as his evidence selects 11,994 peer-reviewed papers that use the words “global climate change’ and “global warming”, and then digs deeper. The majority of these (66.4%) did not express a position on the cause of climate change, whilst of those that did express a position, 97% directly attributed it to human effects. Moreover, when all the authors were contacted to explicitly state their position, the number who did not express an opinion dropped to 35%, whilst the overall attribution remained just over 97% had the authors’ positions been misread this would have shown a discrepancy. In other words, the principal reason that scientific papers do not state the climate change has a human effect is that the authors are taking it as read that this is the case. Kenny unfortunately misconstrues this as co-option of differing views, or as a conspiracy to prevent alternative voices being heard. Let’s not expend hot air on rearguard debates and in which science, policy, misrepresentations and conjecture now come to claim to truth just on the basis of somebody wearing a label that reads “expert” on something or the other. DM

Saliem Fakir heads up the new think-tank within WWF. It’s main focus is to think about a different type of economy for South Africa.

Louise Naudé works on national and international climate change policy, and leads a programme on mitigation with her own specific focus being on the transport sector

James Reeler has worked in the field of climate change for ten years, as a researcher, adaptation planner, mitigation project developer and consultant. He currently works in WWF South Africa’s Policy and Futures Unit on climate change issues.

Photo: A wave breaks over Kalk Bay harbour wall in False Bay, Cape Town, South Africa 26 October 2009. EPA/NIC BOTHMA

Further Reading:

• Farrell, Justin. 2015. “Network Structure and Influence of the Climate Change Counter-Movement.” Nature Climate Change advance online publication (November)
• Berner, Robert A., and Zavareth Kothavala. 2001. “Geocarb III: A Revised Model of Atmospheric CO₂ over Phanerozoic Time.” American Journal of Science 301 (2): 182–204.
• Scotese, C. R., A. J. Boucot, and W. S. McKerrow. 1999. “Gondwanan Palæogeography and Palæoclimatology.” Journal of African Earth Sciences 28 (1): 99–114.
• Royer, Dana L., Robert A. Berner, Isabel P. Montañez, Neil J. Tabor, and David J. Beerling. 2004. “CO₂ as a Primary Driver of Phanerozoic Climate.” GSA Today 14 (3): 4.