A Climate Query for Skeptics

Banner image above: The “Hockey Stick” [Mann, Bradley, & Hughes, 1999]

Global temperature anomalies averaged and adjusted to early industrial baseline (1881-1910) NASA GISS, NOAA NCEL, ESRL

    Above is a combined plot of overall global temperature change and atmospheric CO2 concentration over the past 137 years—since coal and oil burning began.

The temperature scale (left) is the anomaly (the change or difference) from the long term average temperature (1881-1910) in degrees C. [δ1.0C = δ1.8F]

The CO2 scale (right) is the atmospheric concentration in parts-per-million (air), but has been scaled for comparison to plot on the same ordinate as the temperature anomaly.

These plots are referred to as the “hockey stick” owing to the long level “handle” on the left (extending back centuries) and the steep rise on the right which began suddenly around 1950.

    If, as a skeptic, you do not accept that the globe is warming or that CO2 is increasing—the basic science shown by the hockey stick—I do not know what course to offer you.
    If, as a skeptic, you identify with a strong core group of the opposition I fully understand and sympathize—that with a change in your position you could risk the loss of long-time and trusted friends and, perhaps, even of your job.
    But if, while still skeptical, you are free to accept the warming and the CO2 change, I ask:
    Which seems the more likely?

1. An increase in global temperature from some unknown or as yet “unproven” cause somehow—through an unknown or “unproven” mechanism—gradually increases CO2.

    Or that
2. An increase in CO2 from a known cause—fossil fuel burning—increases global temperature through a known mechanism—the greenhouse gas effect [1].

[1] Discovered by the Swedish chemist and Nobel Prize winner Svante Arrehnius in 1896.]

James Hansen, Climate Change in a Nutshell, 2018


One thought on “A Climate Query for Skeptics

  1. Johnathan Swift said (more or less) “you cannot argue a man out of a position he didn’t argue himself into”.
    There seems to be a high correlation between conservatism and climate change denial. To recognise the reality of climate change would threaten their world view. Peter Sandman has some nuanced views about how people deal with an existential threat like climate change. One approach is to be overwhelmed and seek outlets elsewhere. Not denial as such but without guidance a feeling of being powerless that seeks other outlets (save the whales or something).
    Like the pandemic poor or confusing information can lead to counterproductive behaviour. Einstein commented at some stage about a perfection of means and a confusion of aims…
    The aim of humanists is to protect humanity; the aim of conservatives is to protect the economy?
    Trump favours the latter while talking down the risk to life of getting it wrong.


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