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.