[Offtopic] Line fitting [was Re: Numpy outlier removal]

[Robert Kern]

On 08/01/2013 06:35, Chris Angelico wrote:
> On Tue, Jan 8, 2013 at 1:06 PM, Steven D'Aprano
> <steve+comp.lang.python at pearwood.info> wrote:
>>> given that weather patterns have been known to follow cycles at least
>>> that long.
>>
>> That is not a given. "Weather patterns" don't last for thirty years.
>> Perhaps you are talking about climate patterns?
>
> Yes, that's what I meant. In any case, debate about global warming is
> quite tangential to the point about statistical validity; it looks
> quite significant to show a line going from the bottom of the graph to
> the top, but sounds a lot less noteworthy when you see it as a
> half-degree increase on about (I think?) 30 degrees, and even less
> when you measure temperatures in absolute scale (Kelvin) and it's half
> a degree in three hundred.

Why on Earth do you think that the distance from nominal surface temperatures to 
freezing much less absolute 0 is the right scale to compare global warming 
changes against? You need to compare against the size of global mean temperature 
changes that would cause large amounts of human suffering, and that scale is on 
the order of a *few* degrees, not hundreds. A change of half a degree over a few 
decades with no signs of slowing down *should* be alarming.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco