"How would you like that snowball in your pants?
Posted on 8/4/2008, 1:33:19 AM by Delacon
This is absolutely amazing. I was checking out this article in the Ithaca Journal called "Climate Change 101: Positive Feedback Cycles" based on a pointer from Tom Nelson.
The Journal is right to focus on feedback. As I have written on numerous occasions, the base effects of CO2 even in the IPCC projections is minimal. Only by assuming unbelievably high positive feedback numbers does the IPCC and other climate modelers get catastrophic warming forecasts. Such an assumption is hard to swallow - very few (like, zero) long-term stable natural processes (like climate) are dominated by high positive feedbacks (the IPCC forecasts assume 67-80% feedback factors, leading to forecasts 3x to 5x higher).
So I guess I have to give kudos to an alarmist article that actually attempts to take on the feedback issue, the most critical, and shakiest, of the climate model assumptions.
But all their credibility falls apart from the first paragraph. They begin:
Our world is full of positive feedback cycles, and so is our society. Popular children's books like “If You Give a Mouse a Cookie” by Laura Numeroff are excellent examples. In Numeroff's tale, a mouse asks for a cookie, leading it to ask for a glass of milk, and so on, till finally it asks for another cookie.
Oh my God, they go to a children's book to prove positive feedback? If I had gone this route, I probably would have played the "sorcerer's apprentice" card from Fantasia. Anyway, they do soon get into real physics in the next paragraph. Sort of.
Here's an example everyone in Ithaca can relate to: the snowball. If you make a small snowball and set it on the top of a hill, what happens? 1) It begins rolling, and 2) it collects snow as it rolls. When it collects snow, the snowball becomes heavier, which causes gravity to pull on it with more force, making the snowball roll faster down the hill. This causes more snow to collect on the snowball faster, etc., etc. Get the picture? That is a positive feedback cycle.
OMG, my head is hurting. Is there a single entry-level physics student who doesn't know this is wrong? The speed of a ball rolling downhill (wind resistance ignored) is absolutely unaffected by its weight. A 10 pound ball would reach the bottom at the same moment as a 100 pound ball. Do I really need to be lectured by someone who does not understand even the most basic of Newtonian physics. (I would have to think about what increasing diameter would do to a ball rolling downhill and its speed -- but the author's argument is about weight, not size, so this is irrelevant."
Do you really need any more? This guy has already disqualified himself from lecturing to us about physical processes. But lets get a bit more:
And what happens to the snowball? Eventually the hill flattens and the ball comes to a stop. But if the hill continued forever, the snowball would reach some critical threshold. It would become too big to hold itself together at the raging speed it was traveling down the hill and it would fall apart. Before the snowball formed, it was at equilibrium with its surroundings, and after it falls apart, it may again reach an equilibrium, but the journey is fast-paced and unpredictable.
Two problems: 1) In nature, "hills" are never infinitely long. And any hills that are infinitely long with minimal starting energy would find everything at the bottom of the hill long before we came into being 12 billion years or so into the history of the universe. 2) Climate is a long-term quite stable process. It oscillates some, but never runs away. Temperatures in the past have already been many degrees higher and lower than they are today. If a degree or so is all it takes to start the climate snowball running down the infinite hill, then the climate should have already run down this hill in the past, but it never has. That is because long-term stable natural processes are generally dominated by negative, not positive, feedback. [ed: fixed this, had it backwards]
The author goes on to discuss a couple of well-known possible positive feedback factors - increases in water vapor and ice albedo. But it completely fails to mention well-understood negative feedback factors, including cloud formation. In fact, though most climate models assume positive feedback from the net of water processes (water vapor increase and cloud formation), in fact the IPCC admits we don't even know the net sign of these factors. And most recent published work on feedback factors have demonstrated that climate does not seem to be dominated by positive feedback factors.
It hardly goes without saying that an author who begins with a children's book and a flawed physics example can't take credit for being very scientific. But perhaps his worst failing of all is discussing a process that has counter-veiling forces butfails to even mention half of these forces that don't support his case. It's not science, it's propaganda.
Robt beats GW to the camel..... (But remembers not to gloat about it.)
“an author who begins with a children’s book and a flawed physics example...”
This is the Democrat’s version of “settled science”.
Gannett is totally agenda driven, nationwide.
This is so funny my eyes shut tight with laughter.
Only last night on Oz tv Prime Minister Rudd mentioned "climate change deniers".Considering the usual care politicians (particularly prime ministers)take when choosing words it sent a chill up my spine.
Some of this stuff is hilarious and some of it is not funny at all.
In the presence of significant friction, the above is not true. Try rolling a marble and a bowling ball down a grassy hill and see which goes faster.
Cheers!
Cheers!
“In the presence of significant friction, the above is not true. Try rolling a marble and a bowling ball down a grassy hill and see which goes faster.”
In the presence of my significant foot stepping on the marble, the above is also not true. What’s your point? The Ithaca writer’s point was invalid because it was based on an increased mass causing increased speed. What you are talking about is momentum. Btw if you applied equal amounts of force on the marble and the bowling ball to get them rolling down that grassy hill, your bowling ball wouldnt move at all, while the marble would move quite a bit.
Even citing Wikipedia would be better.
LOL. Saving that link to my favs.
Gore used footage from a Futurama episode. How much more proof does anyone need?
A small snowball will have a certain amount of friction acting against it as it rolls down a hill (or doesn't). A larger snowball will not have a proportionately larger amount of friction. On a moderate incline, it's possible for larger snowballs to roll whereas smaller ones will not (since only in the former case will gravity overpower friction).
Btw if you applied equal amounts of force on the marble and the bowling ball to get them rolling down that grassy hill, your bowling ball wouldnt move at all, while the marble would move quite a bit.
Place a marble and a bowling ball both on a grassy hill with a 30 degree slope. The bowling ball will roll just fine even without anyone pushing it. The marble won't (at least not if the hill is ordinary grass, as opposed to e.g. a putting green).
In Al Gore’s film he refers to a pool of “melting water” on the Larsen B ice shelf. Since when does water melt?
Also, when talking about polar bears not being able to have solid ground to stay on due to melting ice, he shows a computer-generated image, not actual footage.
Noticed how you left out the momentum part of my post which you have to consider in both your examples. Force needed to start things rolling(or keep them from rolling before you want them to) and such. But come supercat, we digress. The writer was wrong. A snowball doesn’t gain speed strictly due to an increase in mass.
Re-read the article. The author addressed your comment with the following parenthetical statement.
(I would have to think about what increasing diameter would do to a ball rolling downhill and its speed -- but the author's argument is about weight, not size, so this is irrelevant."
The idiot who made the original argument must have never hear of Galileo and the wood ball and the iron ball --- in other words, 7th grade science. But of course Galileo got in trouble for being a 'denier' too.
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