“…here is the geologists’ truth: In the long run, the Earth will be fine. One could make the argument that the climate is always changing, which it technically is. Current atmospheric carbon dioxide levels—though they are at a record high on human time scales, and have been increasing exponentially since we began industrialization—are extremely low compared with most of Earth’s history.” All the Time in the World by Karen L. Vyverberg/University of Florida Dept of Geological Sciences
We say things for a reason and that reason is the use-value of what we say. In other words, communication is a goal-directed behavior: a means to an end. Take the case of the earth’s always-changing climate. Here are a few statements I believe are true based on my reading:
Over geologic time, global temperatures have been much warmer and sea levels much higher than they are now.
Over geologic time, periods of rapid temperature change have been associated with changes in the fortunes of individual species (for better or worse) but not an overall increase in extinctions.
Before a million years ago, atmospheric CO2 levels were not closely coupled with global temperatures or sea levels.
Some people would probably react to the above statements with an urge to argue, along the lines of “yeah, but it’s different this time”. I suspect their reaction would be less about the truth-value of the statements than their perceived use-value: to deny anthropogenic climate change and/or to downplay the potential consequences of climate change and therefore to justify doing little to forestall these consequences. Consider the following:
“… it is true: climate has changed even before humans began to burn fossil fuels. So what can we conclude from that? … (1) that humans cannot change the climate? (2) that we do not know whether humans are to blame for global warming? (3) that global warming will not have any severe consequences? (4) that we cannot stop global warming?” - The climate has always changed. What do you conclude? stefan @ 20 July 2017
The author’s rhetorical question, “what can we conclude from that?” sets-up what he appears to consider the true purpose (read: use-value) of pointing out that climate change is nothing new: to serve as a talking point to further the denier agenda. He then creates a strawman version of common opinions held by climate change skeptics, the better to knock them down as the product of stupid and/or evil minds. But more on that in a later post.
My point here is simply to highlight that disagreements about “facts” are often less about their accuracy than their use-value - that is, what would happen if a lot of people accepted these facts as true. And thus we have a whole industry of scribblers and pundits who provide “context” to uncontested facts. Of course, such context comes with its own truth-value and use-value.
References:
Currano, E. D., P. Wilf, et al. (2008). "Sharply increased insect herbivory during the Paleocene–Eocene Thermal Maximum." Proceedings of the National Academy of Sciences 105(6): 1960-1964. http://www.pnas.org/content/105/6/1960.short
Figueirido, B., Janis, C. M., Pérez-Claros, J. A., De Renzi, M., & Palmqvist, P. (2012). “Cenozoic climate change influences mammalian evolutionary dynamics.” Proceedings of the National Academy of Sciences of the United States of America, 109(3), 722–727. http://doi.org/10.1073/pnas.1110246108
McInerney, F. A. and S. L. Wing (2011). "The Paleocene-Eocene Thermal Maximum: A Perturbation of Carbon Cycle, Climate, and Biosphere with Implications for the Future." Annual Review of Earth and Planetary Sciences 39(1): 489-516. https://www.annualreviews.org/action/showCitFormats?doi=10.1146%2Fannurev-earth-040610-133431
Tripati, A. K., C. D. Roberts, et al. (2009). "Coupling of CO<sub>2</sub> and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years." Science 326(5958): 1394-1397. http://science.sciencemag.org/content/326/5958/1394