When Cassandra is an optimist -- a Carbon Based original

    According to the myth, Cassandra was a royal beauty of Troy.  To woo her, Apollo gave her the gift of prophecy. But she spurned his divine advances, and he cursed her so that everyone would sneer at her predictions and dismiss her as a wafting lunatic. Bad luck for Troy, when she warned of its imminent destruction. Enemies hidden in a wooden horse -- sheer fantasy.

    Modern day Cassandras don't even need the appearance of insanity to be discredited. Their market-besotted critics hurl charges of playing to the media, or simply hating America. Apollo's curse is still working perfectly.

    Cassandra bubbled up in my memory when our corporate masters gathered in Davos recently at the World Economic Forum. Among speakers was Nicholas Stern, the lead author of the 2006 Stern Review of the Economic Effects of Climate Change, a 700-pager on global warming's impact on the world economy. Stern's words at Davos drew some attention because he declared that recent events are worse than the scenarios in his earlier published view.

    In 2006, Stern labeled climate change the largest market failure of all time. According to Stern's first estimate, climate change will cost 5% of global gross domestic product (GDP) every year, if no action is taken. The Review proposed that we invest one percent (later raised to two percent) of global GDP per annum to avoid the worst effects of climate change.  The Stern team concluded that benefits of decisive, early action on climate change surpass the cost of cutting carbon emissions, and far outweigh the costs of inaction.

    In an echo of Apollo's curse, conservatives deemed Stern a Cassandra. After all, his Review accepted the IPCC assessment reports, and a large portion of the commentariat doubted the veracity of this international climate body.  Stern's an eco-fundamentalist, said some.  Bjorn Lomborg, the go-to guy for climate confusion and delay, played his customary tune, exaggerating the expense of cutting emissions and downplaying the impacts of business as usual.  He tut-tutted at Stern for "fear mongering" and described the Stern team's work as "sensationalized."   Surely the market will allow us to innovate our way out of the problem.

    The denialists' fellow travelers among economists also attacked the 2006 Review.  Many pilloried Stern for his supposedly flawed methodology, such as a discount rate that's lower than the financial world would like.  A low discount rate means that present generations are not favored over future generations.  Other scholars disliked Stern's doubts about cost-benefit analysis as a guide to climate action.

    Now, even after all that bluster, Stern has actually reinforced his dire prophetic credentials. In an interview at the World Economic Forum in Davos (as covered by the Guardian), Stern said: "Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then."

    Had he foreseen the situation would evolve, he says, "I think I would have been a bit more blunt. I would have been much more strong about the risks of a four- or five-degree rise. This is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one? These risks for many people are existential."

    Stern isn't the only Cassandra.  Many scientists involved in drafting official climate science publications, such as the IPCC doorstops (next one due out next year) or the Stern Review struggle with the Cassandra accusation.  Even as they write their reports, they take care not to overstate the probabilities lest they alienate their audience, and cringe when people cry "doomsayer!" As a result, they eventually wind up saying something akin to Stern -- the dangers are worse than we thought even a short time ago.

    It's hard to explain the dire facts about climate change to people who object strenuously to anything other than the best-case scenario.  If you believe in only smooth sailing and upbeat projections into the future, climate change threatens your vision of reality.

    Stern as well as the climate consensus actually follows the mainstream scientific view of assessing dangers, in which we revise probabilities in the light of more recent experience. After all, a doctor examines a patient who comes in for an annual check-up by noting what's changed.  If the man has recently gained a lot of weight, has much higher blood pressure than previously and recently started smoking, any sane doctor knows that plenty has changed.   The same sort of steady revision is ongoing in climate research.

    Why doubt Cassandra? Her perfectly sane warnings were true --the Trojan horse really did signal their doom.  But as long as the Koch Brothers have Apollo on their payroll, Cassandra cannot convince her audience.

Evelyn de Morgan's 1898 painting, "Cassandra"