Tuesday, January 20, 2015

Visualizing 2014's Record Warmth and Its Heat Gain

Perhaps here's a way of capturing how slight 2014's record warmth was.

<grain of salt>
<turn envelope over>

Assume the surface temperature stations are measuring the first 2 meters of the atmosphere(* but see below). The density of air at the surface is 1.2 kg/m3. So the total mass of the 2-meter sliver is ~ 1015 kg.

It has a heat capacity of about 1000 J/kgK, so it takes ~ 1016 Joules to create a 0.02°C temperature rise in this 2-meter sliver of the atmosphere, which is ~50 J/m2 over the Earth's surface.

50 Joules isn't much. It's ~ 10-5 kilowatt-hours -- about how much electricity the average American uses (12,900 kWh/yr) in 30 milliseconds.

If that 0.02°C of warming happens over 4 years, and if I've not made any mistakes, the average heating rate is 0.4 microwatts per square meter. By contrast, the average surface heat flux from the Earth's interior heat is 86 milliwatts per square meter -- 200,000 times higher.

(But the average heat flux from the Earth's interior is essentially constant, so it doesn't create global warming or global cooling.)

(*) OK, in reality the sensors that measure temperature are very small -- this one (page 18) is about 5 mm x 4 mm. So it's only measuring a 0.5 cm-thick slice of the atmosphere. That would require only 0.1 J/m2, or, over four years about 1 nanowatt per square meter.

So crowing over these types of records -- 0.02°C -- just opens up a world of "yeah, but"'s. It would be more scientific to say, as Roger Pielke Sr tweeted today (and has emphasized for years):

As he wrote in Physics Today in 2008:

How much heat can a 2-dimensional surface hold? Zero. Not much lower than can a 2-dimensional surface with a 5 mm-thick layer of air on top of it.

Of course, all NOAA and NASA (and all other) climate scientists know all of this. But try explaining this to the public -- or even to a teleconference full of journalists. And good luck explaining that you really haven't measured the temperature change of the Earth's surface, but the temperature change of your model of the Earth's surface. The public would never get it, and the usual suspects would certainly take it as an opening for all kinds of purposeful confusion and dissembling denialism.

Last word? It's the trend, stupid.

</turn envelope over>
</grain of salt>


John Fleck said...

I think you're probably right here, but let me try out a devil's advocate argument:

Whatever the daily newspaper reporter writes *must* be a narrow abstraction of some much larger thing, delivered to a naive audience that starts with little or no background on the issues. This is a general point, applies to any work like this on any complex topic.

Maybe the abstraction everyone uses here is sufficient? If it's not, what might a similarly constrained abstraction look like? I honestly don't know. I've been banging my head against this wall for 30 years. Makes me wanna just quit the thing and write a book. :-)

tonylearns said...

to me the issue is all about the public and media and the climate deniers.
It seems to me their last effective argument is the pause. they have been harping on it for several years and using that to show Global warming is not happening and therefore we don't need to do ANYTHING about it.
The media and public, not really interested in the idea of trends,can easily understand that if it is the hottest year ever recorded then the idea that there is no global warming does not make sense.
it's a field goal in the 4rth quarter when the opposition says their defense is impenetrable.
Makes you seriously question how good their defense is.