Sentences with phrase «not runaway feedbacks»

Not exact matches

The Arrhenius rate laws do not show runaway positive feedback with increases in temperature.

There's also a number of interesting applications in the evolution of Earth's atmosphere that branch off from the runaway greenhouse physics, for example how fast a magma - ocean covered early Earth ends up cooling — you can't lose heat to space of more than about 310 W / m2 or so for an Earth - sized planet with an efficient water vapor feedback, so it takes much longer for an atmosphere - cloaked Earth to cool off from impact events than a body just radiating at sigmaT ^ 4.

See here for an overview of positive feedbacks and how this doesn't imply a runaway scenario.

I would love to be convinced that this graph, when added to what we know about other carbon feedbacks, does not mean that we are now in a «Chuvian» runaway.

What I meant (what I thought you meant) by Chuvian runaway was a runaway of an extent more limited (covering a smaller range of temperatures that can't be at equilibrium) than the big ice - albedo and H2O - vapor greenhouse runaway feedbacks of snowball and «steamball» conditions.

CH4 — yes, the rate at which, as a feedback, a C reservoir is depleted with some fraction going into the atmosphere would be relatively more impotant if more of it is as CH4; if Chuvian runaway (thanks, wili) can be achieved, to the point of exhausting some (designated portion of a) surface C reservoir, with a CH4 flux, then there would be a cooling period afterword (setting aside other slow feedbacks), and if the CH4 feedback were slowed down, then the feedback wouldn't be as strong, and perhaps the C reservoir wouldn't be exhausted unless the external forcing were larger (this being a hypothetical discussion; no assertion that it will happen).

Maybe inclusion of CH4 and a sufficient climate sensitivity from the other feedbacks would make it runaway for some part (maybe not all) of the process.

So feedbacks can be slow or fast, lead to runaway (via total effect) or not; they can also lead to hysteresis or be immediately reversable.

I can't understand why that is a sensible definition of a runaway feedback effect, or why that ends up «putting things completely out of our control» (as if once the methane starts going up, let's just give up and burn all the coal because it won't matter anyway).

When their is enough CO2 to start thawing near the equator, a runaway positive feedback would tend to ensue, not stopping until the climate is much warmer.

Once the ice reaches the equator, the equilibrium climate is significantly colder than what would initiate melting at the equator, but if CO2 from geologic emissions build up (they would, but very slowly — geochemical processes provide a negative feedback by changing atmospheric CO2 in response to climate changes, but this is generally very slow, and thus can not prevent faster changes from faster external forcings) enough, it can initiate melting — what happens then is a runaway in the opposite direction (until the ice is completely gone — the extreme warmth and CO2 amount at that point, combined with left - over glacial debris available for chemical weathering, will draw CO2 out of the atmosphere, possibly allowing some ice to return).

On Venus, the feedback was of a different magnitude and there is, if not a catastrophic runaway, a feedback that has expanded beyond the ability of life as we know it to exist.

We don't know that anthropogenic global warming will be limited before the system goes into runaway positive feedback driven by melting methane hydrates we can't control.

So, for that case with rapid northern temperature change and other rapid changes in the climate system, the methane acted as a feedback, fast enough to be considered in economic planning, but not so fast that most people would consider it a runaway.

Isn't «runaway» usually used to describe when feedbacks and forcings are no longer controllable by reducing emissions: the handbrake no longer works, so to speak?

A «runaway greenhouse effect» occurs when something warms the planet, triggering positive feedbacks which warm it further; however, even this does not mean the planet continues warming infinitely, forever.

In fact, positive feedbacks do not necessarily lead to «runaway warming».

So your scientific intuition rebels at the thought of runaway positive feedback (like that which causes the rapid transition from ice age to interglacial which is so well established), but it doesn't rebel at the thought that somehow, every scientist since 1922 has failed to notice an allegedly major flaw in our understanding of the greenhouse effect?

Choose constants appropriately such that the feedback is not a runaway.

An effective linear feedback greater than one implies a runaway process, yet GCMs are always run for finite time, so there can not be divergence to infinity.

Positive feedback will always cause some kind of runaway, and is always stopped by some non-linearity (for instance Stefan Boltzmans law decides that the earth will not melt due to runaway CO2).

The CO2 is a feedback to ocean warming, but not strong enough for a runaway effect.

Runaway ice sheet feedbacks seem not to require much in the way of CO2 increase.

There is a class of positive feedback that is amplification and not runaway, which is f between 0 and 1.

Furthermore, the existence of some feedbacks leading to new states — classically the deglaciation / albedo runaway at the end of glaciations — can not be disputed, but is also accounted for with traditional approaches.

Since we are not living on a burning globe after billions of years of possibility of the runaway happening, I suggest the feedback of CO2 on temperature is more the product of too many fevered imaginations rather than a real physical effect with any real consequence.

Of course Ferdinand is right not to project catastrophism onto anthropogenic CO2 levels for as you likely know there is a inverse logarithmic relationship between changes in temperature and CO2 levels such that without the assumed positive feedback from water vapour there is no chance of runaway global warming, tipping points or whatever.

They don't explain at all why the data shows a feedback effect, or what the mechanism is that stops the positive feedback from being a runaway process (a frequent question by skeptics).

I think you have it basically right, but at the beginning of your post you came up with and discarded the reason it is not a runaway effect: I am assuming of course that positive feedback is linear Wrong assumption!

If the typical explanation that rising then creates a feedback loop that increases temperatures, and so on, why doesn't this cause a runaway greenhouse effect?

Per the IPCC's global warming hypothesis, at the very top of the troposphere, above the equator region, is the location (12 km, 200hPa @ 20 ° N - 20 ° S) that triggers a positive climate feedback, which produces the mythical runaway, tipping point of accelerated, dangerous global warming, which of course is unequivocal and irrefutable, except when it isn't.

Feedbacks don't runaway to a collapse in Climate Science as far as I know, like when that guy back in elementary school put a gum foil wrapper into an electrical outlet and shorted it out.

In the case of glacials (note — not ice ages to distinguish the quaternary cycles from other periods) signals perhaps from orbital eccentricities triggering runaway snow and ice feedbacks.

Some skeptics ask, «If global warming has a positive feedback effect, then why don't we have runaway warming?

Positive feedback won't lead to runaway warming; diminishing returns on feedback cycles limit the amplification.

Actually I think the claim is that CO2 warming (but mysteriously not «natural» warming) triggers other positive feedbacks causing a runaway effect (I won't call it «greenhouse» because that's a misnomer).

Long - term stable systems do not demonstrate this kind of radically positive feedback - driven runaway behavior (much longer post on climate and positive feedbacks here).

I don't believe we're going to have any runaway feedback, at worse it almost neutral, but I think we'll find it (melting polar ice) net cools the Oceans.

Note that a self - sustaining feedback is not the same thing as a runaway greenhouse effect.

point 4: There is not the slightest reason why a moderate positive feedback (feedback factor smaller than 1) would lead to instability (a runaway reaction).

With Hansen talking about «tipping points» in the climatic energy - budget, high priests of AGW raising the specter of «runaway greenhouse,» and modelers resorting to a fictitious positive water - vapor feedback in their calculations, energetics (power fluxes) in the geosystem is not only relevant, but the central issue.

Climate scientists like James E. Hansen predict that methane clathrates in the permafrost regions will be released because of global warming, unleashing powerful feedback forces which may cause runaway climate change that can not be halted.

-- so it may be that the threshold forcing for releasing all permafrost C is not a threshold for permafrost C runaway but simply the point at which the source of the feedback has been exhausted.

Eventually, we're going to have to do what works scientifically, that keeps methane out of the atmosphere, and takes CO2 back out of it — if it is not already too late to stop positive feedback generated low level runaway global heating.

For some reason that I don't totally fathom, some people on the skeptic side (like martin mason above or Smokey in other threads) seem to like to group together this prediction of feedbacks amplifying things and producing an actual «runaway» instability, perhaps because it makes a better «strawman» argument to attack.

# 422 wili: «Does anyone else reading the article — looking at the flat dashed line in figure three and putting that together with the fact that we know there will be other carbon feedbacks — come to my conclusion that this means we are now in a kind of runaway (not the Venusian kind, though)?

A positive cloud feedback does not imply a runaway greenhouse effect.

So, I was simply saying that the generally - accepted projections for AGW are that positive feedbacks amplify the radiative effects due to greenhouse gases alone but do not lead to an actual «runaway» instability.

Many people think the unrealistic, high end forecasts are due to runaway positive feedbacks, in the models not in reality.

Since no such effect has been observed or inferred in more than half a billion years of climate, since the concentration of CO2 in the Cambrian atmosphere approached 20 times today's concentration, with an inferred mean global surface temperature no more than 7 ° K higher than today's (Figure 7), and since a feedback - induced runaway greenhouse effect would occur even in today's climate where b > = 3.2 W m — 2 K — 1 but has not occurred, the IPCC's high - end estimates of the magnitude of individual temperature feedbacks are very likely to be excessive, implying that its central estimates are also likely to be excessive.