So do you think, to quote, " the Earth has net positive feedback's to an increase in radiative forcing."?

Yes. And to a decrease in radiative forcing, obviously.

But I hope you don't think that the existence of positive feedbacks in the climate system means that there is no mechanism that limits the magnitude of the temperature excursion (in either direction) to be expected from any such change. Because that's where I suspect you are trying to take us.

Dear, dear, you are a suspicious person. I wasn't trying to take us anywhere, I was simply trying to clarify your position since you appear to have a habit telling people they are wrong without providing any explanation as to why. For example you claim climate models are accurate but have yet to provide any evidence that they are.

But back to your reply, what are these limiting mechanisms?

They can be, sort of. So there are model reanalysis projects that compare climate models to the real-world, and training where they can be fed data to try and train them. So rather than forecast, they hindcast and results compared to observations. Problem with that is they often only hindcast accurately if they're tweaked to use more aerosols or black carbon.. Which basically helps with the lack of warming in observations.

Problem with that is they still don't match observations for aerosols or black carbon (aka soot). Then again, the introduction of clean air acts around the world and shift from domestic coal burning may also explain temperature rises, especially in urban areas.

I apologise for that, but what you have to understand is that most of the people I argue with on here about climate science are people I have argued with many times before. So they have been told repeatedly what mainstream science says, but they refuse to learn anything, and will usually just rehash the same incorrect arguments over and over again. Providing detailed responses to their vague and incorrect assertions each time they make them is something of an exercise in futility.

Positive feedbacks in the climate system are often objected to by people claiming to have an engineering background. They think that they imply an unstable system. So your question was something of a red flag.


For some values of "accurate". My objection was to your implied claim that they were badly flawed, rather than merely imperfect, with deficiencies acknowledged by mainstream science.

I rather lost interest when your claim turned out to be based on some things you had read in the media, but weren't sure what, or where. I am often prepared to do more work in refuting an argument than the person put into making it, but not always. If you are genuinely interested, you could start by looking at how climate models are evaluated in the IPCC assessments, or at a number of papers published since.


The over-arching negative feedback is of course the Planck response, whereby the thermal radiation from a body (in this case, the Earth) increases in proportion to the fourth power of its temperature.

But there are other limiting mechanisms. Clearly the ice-albedo feedback (for example) is limited by the presence of ice. Once it's all gone, further warming won't make it any worse!

Glad you mentioned that one. So how does that fit with, say, andykn's suggestion that 0-275ppmv CO2 lead to >20C warming?

That sounds about right, unless you are positing some other greenhouse gas to stand in. Without CO2, there would be almost no water vapour, so the entire greenhouse effect would collapse. And without a greenhouse effect, we would expect the Earth's mean temperature to be about -18C. It's currently about 15C, and that's somewhat higher than the pre-industrial average.

Is this your enduring problem with logarithms again, or something else?

Fair enough.
BiB

An overall positive feedback would imply an unstable system but thanks to the Planck response that isn't what we have got.
So it comes dow to the relative magnitudes of the feedbacks (positive and negative) within the system.

Yes, that's true. So the slightly more sophisticated denier will seize on any area where there is legitimate uncertainty (clouds, aerosols, black carbon), and claim that because it isn't fully understood (and hence cannot be perfectly characterised in climate models), we should simply ignore all the copious scientific evidence we have amassed and believe whatever the denier has made up in their head that morning.

The question is, when they find, in hindsight, that the original model gave the wrong results, do they headline publish it, sneak a little note in somewhere or let it fade into obscurity? I need the answer for my new project. shhhhhhh

You do know that there isn't just one climate model, don't you?

You seem even more than usually perplexed.

Of course I know there's more than one. I'm asking in respect of any or all of them.

Perhaps if you named one of them, we could look at its history for you.

Therein lies the problem. If climate scientists understood the climate, why then is there more than one model? And thus a wide range of possible outcomes.

And any idea if any managed to predict the sudden fall in temperatures?

So I thought of an analogy. Suppose you were the proud owner of a clipper ship and had been making nice money on the tea or banana runs. Then along came steam and unwelcome competition.

The 'renewables' response would be to fit a steam engine or perhaps paddle wheels to your ship, then compress air and store it. When the wind's not blowing, release the air into the sails and off you go again.

Or you could just give in to progress and efficiency, and trade your clipper for a steam ship. They did manage to last quite a while, but we're building ever better steam ships today, ie most Navy ships.

You're hedging.

I knew you were anti-science, but I hadn't realised you wanted most of it suppressed.


Climate models don't usually address annual variations, oddly enough.

Presumably you are referring to the latest claim by the usual assortment of idiots - such as the serial liar and worthless Daily Mail hack David Rose - that because temperatures fall immediately following an El Nino peak, that means global warming has ended, just as they previously claimed about 1998?

When can we expect the "There has been no warming since 2016" bleating to start?

You don't actually know the names of any climate models, do you? But you know you don't like them.

And now you're guessing.