Are you the publisher? Claim or contact us about this channel


Embed this content in your HTML

Search

Report adult content:

click to rate:

Account: (login)

More Channels


Showcase


Channel Catalog


older | 1 | .... | 4077 | 4078 | (Page 4079) | 4080 | 4081 | .... | 4134 | newer

    0 0

    This is a better link, just to get you on the same page with those who read this site. https://judithcurry.com/2010/12/11/co2-no-feedback-sensitivity/

    0 0

    Well no - the Planck response to doubling of CO2 (1.2 K) is calculated - in the EBM - in terms of the Planck feedback (λ = -3.1 W m^-2 K^-1). λ can be relatively accurately determined which allows calculation of ΔTs. Where R is 4 W/m2. ΔTs=−(R/λ) Plugging in the sum of very uncertain IPCC estimates of feedbacks gives ECS. So I am of course Monktonian, the IPCC is sloppy and the post graduate climate modelling course notes are muddled? Is that about right?

    0 0

    If you're defining the Planck response as a negative feedback, so is a conventional positive feedback because λ is still negative for that.

    0 0

    Huh? The Planck response (1.2K) is calculated from the Planck feedback (-3.2 W m^2 K^-1). . They are related but different. Stop mangling the ideas.

    0 0

    The Planck feedback is given by the IPCC as -3.2 W m^-2 K^-1. The Planck response based on the Planck feedback is 1.2 K. You are mangling these different but related ideas.

    0 0

    Conventionally a positive feedback amplifies a response and a negative feedback mutes it. This is how it is defined in climate and other fields. https://upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Ideal_feedback_model.svg/280px-Ideal_feedback_model.svg.png

    0 0

    The Planck feedback is negative because a warmer planet emits more IR. The Planck response is the equilibrium warming without other feedbacks. So no I am not defining the Planck response as negative.

    0 0

    Almost. The Planck response is the warming without feedbacks.

    0 0

    The Planck response is based on forcing and the Planck feedback. I showed you the formula whose derivation involves differentiation of the Steffan-Boltzman equation. We have a forcing calculated at some 4 W/m2 - and the temperature increase - the Planck response - needed to cancel out that forcing is determined by the Planck feedback. That is and must be negative and is the most fundamental feedback. How do you imagine that a tendency to maximum entropy and a transient energy equilibrium works?

    0 0

    By your definition all feedbacks are negative including what everyone else calls positive ones.

    0 0

    B is less than A - but additive - or the system is unstable. These are the IPCC feedbacks. Nor am I guaranteeing their veracity - as Judith suggests in the link you attempted to divert with. But the Planck negative feedback exponentially increases with temperature and tends to drive the world towards transient energy balances. https://www.ipcc.ch/site/assets/uploads/2018/03/Fig7-09-1024x584.jpg https://www.ipcc.ch/site/assets/uploads/2018/03/Fig7-10-1024x621.jpg It is as simple as it gets. No wonder you don't get the harder and more interesting stkuff.

    0 0

    By the IPCC graphics - that I have just posted yet again - some feedbacks are positive and some negative. The clue is the sign of the feedback on the left hanf axis.

    0 0

    Do you agree that an amplified response is a sign of a net positive feedback or not? It's not a trick question.

    0 0

    What do you consider a net positive feedback to look like? Check your Albany reference if you're not sure. Clue: it still has a negative lambda.

    0 0

    No - the IPCC feedbacks can be summed - it's not a trick answer. It is about forcing and response. The greater the negative net feedback the smaller the response. And the less negative the greater the response. But net feedback is negative - primarily because of the Planck feedback.

    0 0

    You say a net amplified response is not a positive feedback.

    0 0

    Water vapor is positive - clouds are presumptively positive. You can tell because they are above the zero. "We have defined things here such that λ>0 for a positive feedback, λ<0 for a negative feedback. That’s convenient!"

    0 0

    Less negative feedback leads to a larger response to the forcing. Simples to some but not to you.

    0 0

    Most people call an amplified response a positive feedback. That will help you to understand climate papers about sensitivity where you get 3 C per doubling instead of 1.2 C because of a net positive feedback. Your Albany reference explains this terminology towards the end there.

    0 0

    They calculate net feedbacks using the central model estimate of 4K as -1.3 W m^2 K^-1. If you sum the IPCC feedbacks it is -1.5 W m^-2 K^-1 for 2.6 K ECS with wide uncertainties. So all the world's best climate scientists and their sloppy thinking v little #jiminy and his habitual prevarications?

older | 1 | .... | 4077 | 4078 | (Page 4079) | 4080 | 4081 | .... | 4134 | newer