The Draft Climate Science Report

The draft multi-agency US government report on climate change is available in draft form, after it was apparently leaked to mainstream news organizations including the New York Times.

The Draft Report is a virtual clinic on how to explain a complex topic. It’s not perfect, and occasionally downshifts into government-report formatting and prose, but it is very good.

It’s also rational and prudent, and therefore convincing in its conclusions, which are labeled as to their certainty.  The Report is a credit the participating authors and agencies.

Which is not to say anyone should take the report conclusions at face value. I offer a few comments on that below.

One of our greatest problems with climate change is a dismal level of public dialogue.  Sure, it’s a complicated topic, but we have allowed public debate to be dominated by alarmists and denialists, both of which tend to be uninformed.

To arrive at sensible dialogue people actually need to understand what the issues are!  The executive summary on pages 12-37 of the Report is a good place to start, and requires only about 30 minutes to read.

Ironically, I felt that even the Report’s executive summary jumps into the middle of things, without framing the key questions in summary form.  Those questions (with the Report’s conclusions and indicators of likelihood) are:

  • Q: Are temperatures rising in the Earth’s biosphere (land, sea, atmosphere)?
    • A: To a very high certainty, they’re going up, particularly in the last century and last forty years.
  • Q: Then, what are the likely consequences of increased temperatures?
    • A: Increased sea levels (very likely); other climate changes (ranging from possible to likely); social consequences (also possibly to likely).
  • Q: Then, are temperature increases the result of external energy (i.e. the Sun and Volcanoes), or changes within the biosphere?
    • A: Internal energy transfer within the biosphere.  Increased temperatures cannot be blamed on solar fluctuations (likely).
  • Q: Then, what are the primary causes of temperature increases within the biosphere?
    • A: The primary culprit is increasing levels of atmospheric carbon dioxide (likely) – energy that would be returned to space is absorbed by carbon dioxide and partially re-emitted into the biosphere.
  • Q: are these biosphere causes man-made or natural?
    • A: Primarily man-made (extremely likely).


My pitch is simply: check it out – you’ll be glad you did.  And don’t feel intimidated! You’ll be surprised at what you pick up.   Reading the Report and accepting its value is not the same as accepting its dictates wholesale.  Here are a few of my takeaways:


It’s a challenge to evaluate climate change information independently, and news outlets like the New York Times shriek that humanity has caused climate change with extreme likelihood, and that sea levels will rise.

Ever unctuous, is the Times. But they are just aping the Report, on the basis that many smart people contributed to its conclusions.

It’s true: many smart people have contributed to the Report’s conclusions, but this is also a very bad reason to accept a scientific conclusion.  As for the argument that climate change is too complicated to understand, and we therefore should accept its findings on faith, I say a) nonsense, and b) that’s the fault of the scientific community.  As the saying goes, those who cannot explain do not truly understand.

As for the word “extreme,” I think that’s a mistake on two levels.  First, it’s inflammatory. Second, the basis for assigning a very high likelihood to man’s role in global warming is essentially that there are multiple “lines of evidence,” which point to this assertion.  But that idea only holds if the lines of evidence are really independent, which is questionable, and if no single argument, should it be proven false, might call everything else into question – that’s also suspect.


Is action prudent? I think the short answer is hell yes, even if the climate change community is sometimes over-optimistic with their uncertainty estimates, as I believe they might be.

We should stop asking whether these conclusions are entirely right, and instead consider the chances they are entirely wrong – for those are really the only conditions in which we can justify inaction.   And there is simply too much solid science for climate science to be largely invalid.

If there were even a 25 percent chance that a meteor would hit my house today, you can bet I’d be taking evasive action. That would be, well, the conservative thing to do.  Unfortunately, conservatives don’t act like conservatives anymore.   The perception of climate change consequences is somehow different from other potential catastrophes, because it’s not happening instantly, and is not a well-defined event like blowing up my house.  But that does not mean there is no potential calamity.


There are serious thinkers – not uninformed denialists – who suggest that some aspects of climate change thinking is flawed. These people have sometimes been shouted down, which is both an embarrassment to the scientific community, and terrible science. Challenging consensus views is how science progresses – and it’s a win regardless of the outcome.

If the challengers fall short, we’re even more sure of being on the right track. If the challengers find a serious flaw, that could be good or bad news – it might suggest we have less leverage over climate change than we think.  While it’s probable the consensus view is largely valid, it’s always worth the trouble to see if somehow, we’ve missed something.


The origins and consequences of climate change, as the Report’s authors remark, are not entirely certain, but there is  more than enough certainty to warrant action, and definitely enough to warrant informed dialogue.


If you haven’t checked it out already, I think the Report is a great place to start, with summaries and individual chapter introductions that are surprisingly accessible.

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