Monday, March 28, 2011

Barrister fails to recognise temperature contradiction

Always super-keen to fault Andrew Bolt, PP boy Jeremy Sear today again accuses Bolt of ignorance:
Andrew Bolt apparently thinks that the following two quotes are incongruent – “Twenty years or 1000? One of these “experts” is hopelessly wrong”:

Andy Pitman: If we could stop emissions tomorrow we would still have 20 to 30 years of warming ahead of us because of inertia of the system.

Tim Flannery: If the world as a whole cut all emissions tomorrow the average temperature of the planet is not going to drop in several hundred years, perhaps as much as a thousand years.

Does Andrew not understand what “inertia” means? Those two statements are in no way contradictory.
Bolt is right, of course: the statements are contradictory.

Pitman says that even if all emissions cease, inertia will cause temperatures to increase for 20 to 30 years before they stabilize. The unstated assumption is that temperatures would at some point in the not too distant future begin to drop.

Flannery, on the other hand, states that temperatures would not drop for up to a thousand years.

Given that the longevity of carbon dioxide in the atmosphere is poorly understood, Flannery's 1,000 year figure is pure speculation. Thus for all practical purposes Bolt is right.

Update A Pure Poison readers challenges Jeremy:
Perhaps you should explain why they are not contradictory, Jeremy.
Actually they are two different statements. The first says it will take 30 years to reach equilibrium (radiation leaving earth same as that entering). The second says that it will take hundreds to thousands of years for the carbon cycle to reabsorb a significant amount of CO2 for a measurable fall in temperature.
Jeremy goes on the defensive:
“Thousands of years” is of course again exaggerating the worst case scenario Flannery there describes – “perhaps as much as a thousand years”.

Secondly, it depends whether you’re referring to temperature dropping from NOW, or dropping from the high point. It could be that in Pitman’s scenario the world warms for 20 to 30 years before reaching an equilibrium, and then takes another century or more to drop back below the present figure.

Thirdly, any figure that varies from “hundreds” to “perhaps as much as a thousand” is clearly a figure being given with a big margin of error. The climate is a complex system that changes over a long period of time, and only an idiot would try to declare dates of change with any precision. Or demand such figures.

Finally, we’re talking about a scenario that won’t happen, and it’s a bit pointless to be demanding the scientists waste time answering it. The entire world is not going to cease emissions tomorrow. The point is to get to that situation, or minimise the emissions, as quickly as possible to minimise the destructive change.

Flannery is indeed an idiot for predicting up to a 1,000 year time lag for a drop in temperature.

Update II Mr Lefty provides his typically persuasive "Bolt is an idiot" argument.

Labels: , , , ,


Anonymous Anonymous said...

I wouldn't call "several hundred years" to "a thousand years", precise.

I guess that Tim Flannery meant to say that it will take hundreds of years for the temperature to drop below where it is now.

This is not an 'admission'. This is what it says in the IPCC.

So there is warming for 20 to 30 years.

Then the temperature very very gradually drops over hundreds of years.

This is not contradictory.

The purpose of cutting emissions is to prevent the temperature rising, not to make the world colder.

7:17 AM  
Anonymous Anonymous said...

Thanks Jezza.

However, if Tim Flannery really meant that, don't you think he would have said it?

6:36 PM  

Post a Comment

<< Home