Convincing the climate-change skeptics

A op-ed published in the Boston Globe by Barack Obama’s new science advisor John Holdren:

By John P. Holdren, August 4, 2008

Convincing the climate-change skeptics

THE FEW climate-change “skeptics” with any sort of scientific credentials continue to receive attention in the media out of all proportion to their numbers, their qualifications, or the merit of their arguments. And this muddying of the waters of public discourse is being magnified by the parroting of these arguments by a larger population of amateur skeptics with no scientific credentials at all.

Long-time observers of public debates about environmental threats know that skeptics about such matters tend to move, over time, through three stages. First, they tell you you’re wrong and they can prove it. (In this case, “Climate isn’t changing in unusual ways or, if it is, human activities are not the cause.”)

Then they tell you you’re right but it doesn’t matter. (“OK, it’s changing and humans are playing a role, but it won’t do much harm.”) Finally, they tell you it matters but it’s too late to do anything about it. (“Yes, climate disruption is going to do some real damage, but it’s too late, too difficult, or too costly to avoid that, so we’ll just have to hunker down and suffer.”)

All three positions are represented among the climate-change skeptics who infest talk shows, Internet blogs, letters to the editor, op-ed pieces, and cocktail-party conversations. The few with credentials in climate-change science have nearly all shifted in the past few years from the first category to the second, however, and jumps from the second to the third are becoming more frequent.

All three factions are wrong, but the first is the worst. Their arguments, such as they are, suffer from two huge deficiencies.

First, they have not come up with any plausible alternative culprit for the disruption of global climate that is being observed, for example, a culprit other than the greenhouse-gas buildups in the atmosphere that have been measured and tied beyond doubt to human activities. (The argument that variations in the sun’s output might be responsible fails a number of elementary scientific tests.)

Second, having not succeeded in finding an alternative, they haven’t even tried to do what would be logically necessary if they had one, which is to explain how it can be that everything modern science tells us about the interactions of greenhouse gases with energy flow in the atmosphere is wrong.

Members of the public who are tempted to be swayed by the denier fringe should ask themselves how it is possible, if human-caused climate change is just a hoax, that:

The leaderships of the national academies of sciences of the United States, United Kingdom, France, Italy, Germany, Japan, Russia, China, and India, among others, are on record saying that global climate change is real, caused mainly by humans, and reason for early, concerted action.
This is also the overwhelming majority view among the faculty members of the earth sciences departments at every first-rank university in the world.
All three of holders of the one Nobel prize in science that has been awarded for studies of the atmosphere (the 1995 chemistry prize to Paul Crutzen, Sherwood Rowland, and Mario Molina, for figuring out what was happening to stratospheric ozone) are leaders in the climate-change scientific mainstream.
US polls indicate that most of the amateur skeptics are Republicans. These Republican skeptics should wonder how presidential candidate John McCain could have been taken in. He has castigated the Bush administration for wasting eight years in inaction on climate change, and the policies he says he would implement as president include early and deep cuts in US greenhouse-gas emissions. (Senator Barack Obama’s position is similar.)

The extent of unfounded skepticism about the disruption of global climate by human-produced greenhouse gases is not just regrettable, it is dangerous. It has delayed – and continues to delay – the development of the political consensus that will be needed if society is to embrace remedies commensurate with the challenge. The science of climate change is telling us that we need to get going. Those who still think this is all a mistake or a hoax need to think again.

John P. Holdren is a professor in the Kennedy School of Government and the Department of Earth and Planetary Sciences at Harvard and the director of the Woods Hole Research Center.

Update:  You can download a nice lecture with lots of great graphics that Dr. Holdren gave at the John F. Kennedy School of Government, Harvard University
November 6, 2007 here

6 thoughts on “Convincing the climate-change skeptics

  1. Satellite Aqua has shown no increase in global temps since 1998 and a cooling of the north Atlantic decadal oscillation and Pacific decadal oscillation, with a background of increased CO2.
    Cause and effect? I think not. The evidence suggests a negative feedback scenario, due to increased albedo associated with more clouds (atmosheric water vapour is 90% of ‘greenhouse gases’), rather than the positive feedback of increasing temperature. Aside from this evidence, those of the GW church would do well to remember that their’s is a hypothesis that remains to be falsified. Their dependence on linear, deterministic mathematical models to ‘prove’ a chaotic, non-linear stochastic system is ridiculous, unscientific and implausible. However, when this dreadful myth is linked to ‘feel-good’ save the world balderdash the mix is compelling to most invertebrates and non-believers alike; it furnishes a ready made religion with St AL leading the way. Fortunately, like most cults, intelligence and science eventually prevails, although I fear it will be at the cost of impoverishment and destitution to those least able to afford it.

  2. John, do you have a graph or raw data from the aqua satellite to hand? I searched google and couldnt find “no increase in global temps since 1998 and a cooling of the north Atlantic decadal oscillation and Pacific decadal oscillation”. The Spencer paper published here is only 20 degrees either side of the equator, not global temps. Luke.

  3. Desmond is copypasting from the stories about Spencer, exaggerating that very limited report to claim it’s a “global” finding — illustrating Holdren’s point quite well. This is how confusion spreads.


    When you don’t find where the guy got his notion by searching on that kind of long quoted string from the claim, break it into pieces and eventually you’ll find the source. It’s almost always — as with this one — some blog PR site misstating the result of a scientific paper the person clearly hasn’t read.

    Then someone sees that, generalizes from it, and posts it like was done here. Easy beginner error.

  4. Thanks for the comments. This type of respectful, science-based debate is exactly what we’d love to foster here. This is what I think:

    “Satellite Aqua has shown no increase in global temps since 1998”

    This is one of the most common memes of climate change deniers. The argument is based on the fact that global mean temps. have indeed been lower in the years since 1998 (scroll down to the temp. fig in the post below that combines data from GISS, HadCRU, RSS, and UAH). This short term blip is inaccurately depicted as a “global cooling”. To repeat what I said in a previous post:

    This graph essentially represents the state of our knowledge about recent anthropogenic climate change. The world is clearly warming, not cooling. Unless you spuriously compare the last 8 years with 1998. The first half of 2008 was relatively cool (but as noted by Andrew Revkin, 2008 was between the 7th and 12th warmest since meteorological record keeping began in 1880 and the 9 warmest years in the record have occurred since 1998). Nobody said that EVERY year is going to be progressively warmer. The argument is that over the next several decades and centuries we will see a general warming trend (but certainly not ever year or everywhere).

    Yes, 2000-2008 were not as warm as 1998 but they were a lot warmer than the 100+ previous years.

    “and a cooling of the north Atlantic decadal oscillation and Pacific decadal oscillation, with a background of increased CO2. Cause and effect? I think not.”

    I know of no climatologist that have made such a cause and effect link. The cause of this pattern was simple: the extremely intense El Nino of 98/99 (which many believe was a consequence of climate change). In the years following we went into a La Nina phase. Again, you can’t look at the year-to-year variability as a signal of any type of long-term climate change. The scale is simply wrong. When climatologist point out that the 9 warmest years in the record have occurred since 1998, the record goes back to the 1880s, not just back a decade or two.

    “The evidence suggests a negative feedback scenario, due to increased albedo associated with more clouds (atmosheric water vapour is 90% of ‘greenhouse gases’)”

    The evidence, sadly, does not support this. But I’d be thrilled if we did begin to see a negative feedback. However, my understanding of this hypothesis is that the proposed feedback mechanism would take decades or centuries to kick in and reverse the warming seen over the last decade. Also note that regardless, we are already committed to further ocean acidification, no matter what happens with air temperature. Moreover, the hypothesized feedback mechanisms ONLY APPLY TO TEMPERATURE (at least in the short term, in the really long term, one could envision increased CO2 stimulating greater C4 plant biomass which could begin to suck some of the CO2 out of the atmosphere). Moreover, what many of us are realizing is that temperature may have smaller impacts than decreased ocean pH.

  5. A good summary from Hank Roberts above of how the denialists seize on small mercies to overstae cases. I have had a go at a more general version of this here

    By the way, great site, which I was unaware of. I heard Ove speak at the RZSNSW conference recently (I was also a speaker) and was impressed by his analysis of what we need to do to communicate. Some of you might find my approaches here over a number of years, on various international blogs and in various newspapers of interest. it seems to me that turning the denialists into figures of fun may be the only way to counteract them.

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