Sentences with phrase «temperature feedback would»

The findings reinforce suggestions that strong positive ice — temperature feedbacks have emerged in the Arctic15, increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice - sheet mass balance and human activities in the Arctic...» *** This is the heart of polar amplification and has very little to do with your stated defintion of amplifying the effects of warming going on at lower latitudes.

An important one is additional poleward energy transport, but contributions from local high - latitude water vapour, cloud and temperature feedbacks have also been found.

If so, then the instability inherent in the IPCC's high - end values for the principal temperature feedbacks has not occurred in reality, implying that the high - end estimates, and by implication the central estimates, for the magnitude of individual temperature feedbacks may be substantial exaggerations.

Some 20 temperature feedbacks have been described, though none can be directly measured.

Not exact matches

If the exercise work rate is free to vary, then experimental interventions such as changes in ambient temperature, oxygen content of the inspired air, energy substrate availability or the provision of incorrect distance feedback all alter the power output (pacing strategy), whereas the rate of increase in RPE has been found to be similar between conditions.13 20 21 24 — 26

The real learning comes in once you have returned to work or school and you get feedback from your caregivers about how your baby is doing with the bottle, the volume, the temperature, etc..

«Our results show that Earth has had a moderate temperature through virtually all of its history, and that is attributable to weathering feedbacks — they do a good job at maintaining a habitable climate,» said first author Joshua Krissansen - Totton, a UW doctoral student in Earth and space sciences.

The climate sensitivity classically defined is the response of global mean temperature to a forcing once all the «fast feedbacks» have occurred (atmospheric temperatures, clouds, water vapour, winds, snow, sea ice etc.), but before any of the «slow» feedbacks have kicked in (ice sheets, vegetation, carbon cycle etc.).

The corresponding first order fractional change in temperature (neglecting any feedbacks) would be about 0.01 %, or about 0.03 K at Earth.

The change in temperature you'd need to balance a forcing of 4 W / m2 with no feedbacks is around 1.2 ºC and the difference between that and the real sensitivity (around 3 ºC) is a measure of how strong the net feedbacks are.

When the CLIMAP data proved to be wrong, and was replaced by more reliable estimates showing a substantial tropical surface temperature drop, Lindzen had to abandon his then - current model and move on to other forms of mischief (first the «cumulus drying» negative water vapor feedback mechanism, since abandoned, and now the «Iris» effect cloud feedback mechanism).

If you have a normal thermostat, for example, the heater goes on when the temperature falls and turns off as it rises («negative feedback», a feature which tends to keep things stable.)

i.e. water vapour would have to go down as temperature rises, low clouds would have to be incredibly sensitive, high clouds not sensitive at all — and forget the ice - albedo feedback!

In the other direction, at higher temperatures there is expected to be carbon - cycle feedbacks, that will amplify the warming, so then the climate sensitivty would be higher.

If there were a bad design flaw in a thermostat, such that temperatures over 100 F turned the furnace on, that room's climate would have a tipping point ~ 100 F and the room would get hard to cool whenever temperatures rose over that («positive feedback,» at least for awhile.)

So here's an attempt: When temperatures change because of an orbital forcing, you've got a strong CO2 feedback because the CO2 in the atmosphere was in equilibrium with the CO2 in the oceans before temperatures changed.

Spencer and Braswell (2010) used middle tropospheric temperature anomalies and although they did not consider any time lag they may have observed some feedback processes with negligible time lag considering that the tropospheric temperature is better correlated to the radiative flux than the surface air 15 temperature.

And that additional water vapour would in turn cause further warming - this being a positive feedback, in which carbon dioxide acts as a direct regulator of temperature, and is then joined in that role by more water vapour as temperatures increase.

You have to look at how the added ghgs — both CO2 and H2O respond to the altered IR spectrum and how all of the feedbacks and temperature evolve as the system moves again toward equilibrium.

[Response: The concept of water vapor feedback (which goes back to Arrhenius, and was fully consolidated in the 1960's by Manabe and co-workers) has always stated that the water vapor was determined by temperature.

Slow feedbacks have little effect on the immediate planetary energy balance, instead coming into play in response to temperature change.

The video links also offer some useful links to science and temperature measurement, Please let me have feedback.

Some buttons have detents to give feedback, and there are mechanical controls for temperature, volume and tuning, yet problems persist — some inherent, some solvable.

[15] Through study of Pacific Ocean sediments, other researchers have shown that the transition from warm Eocene ocean temperatures to cool Oligocene ocean temperatures took only 300,000 years, [11] which strongly implies that feedbacks and factors other than the ACC were integral to the rapid cooling.

This suggest to me that the stable / cooling temperatures of the 1950s to 70s could have been a bow wave of resistance (negative feedbacks) and we are now on a stable warming ramp.

[1] CO2 absorbs IR, is the main GHG, human emissions are increasing its concentration in the atmosphere, raising temperatures globally; the second GHG, water vapor, exists in equilibrium with water / ice, would precipitate out if not for the CO2, so acts as a feedback; since the oceans cover so much of the planet, water is a large positive feedback; melting snow and ice as the atmosphere warms decreases albedo, another positive feedback, biased toward the poles, which gives larger polar warming than the global average; decreasing the temperature gradient from the equator to the poles is reducing the driving forces for the jetstream; the jetstream's meanders are increasing in amplitude and slowing, just like the lower Missippi River where its driving gradient decreases; the larger slower meanders increase the amplitude and duration of blocking highs, increasing drought and extreme temperatures — and 30,000 + Europeans and 5,000 plus Russians die, and the US corn crop, Russian wheat crop, and Aussie wildland fire protection fails — or extreme rainfall floods the US, France, Pakistan, Thailand (driving up prices for disk drives — hows that for unexpected adverse impacts from AGW?)

The climate sensitivity classically defined is the response of global mean temperature to a forcing once all the «fast feedbacks» have occurred (atmospheric temperatures, clouds, water vapour, winds, snow, sea ice etc.), but before any of the «slow» feedbacks have kicked in (ice sheets, vegetation, carbon cycle etc.).

I wonder what would happen if the same approach was applied to other climate metrics, like sea surface temperature, water vapor feedback strength, and precipitation - evaporation changes.

The latter paper involves an unwarranted extrapolation of the IRIS hypothesis to early Earth (i.e., a negative feedback between temperatures and high clouds), a hypothesis which is highly controversial even in the modern day and has convincingly been shown to be highly exaggerated.

Your comment also deals with another question I have for a long time (not completly on topic I am afraid): If a CO2 - doubling provokes 3.7 W / m ^ 2 additional forcing and that leads (with feedbacks and so on) to about 3K temperature increase, how much temperature increase from the beginning of the instrumental record till now should we expect?

Olympus Mons, What it would take is a new model that explained climate better than the current one and a) had a CO2 sensitivity lower than 1 degree per doubling; or b) had a large negative feedback that somehow kicked in right at the current terrestrial temperature range; or c) had a mechanism whereby CO2 suddenly stopped being a greenhouse gas at 280 ppmv

You are welcome to try something similar with global radiative forcing fluctuation, but if you do it will be rather tricky to isolate the cloud effect, since you have the snow and ice albedo effect to deal with then, which are largely temperature - related feedbacks.

On the possibility of a changing cloud cover «forcing» global warming in recent times (assuming we can just ignore the CO2 physics and current literature on feedbacks, since I don't see a contradiction between an internal radiative forcing and positive feedbacks), one would have to explain a few things, like why the diurnal temperature gradient would decrease with a planet being warmed by decreased albedo... why the stratosphere should cool... why winters should warm faster than summers... essentially the same questions that come with the cosmic ray hypothesis.

If one takes the simple view that deglaciation is forced by only global ice volume change and greenhouse feedbacks, then one would be forced to conclude that Antarctic temperature change led all of its forcings!

What really concerns me is that I've read a lot about climate models not being able to replicate the magnitude of abrupt regional temperature changes in the past, and Raypierre has said here that he fears that past climate records point towards some yet unknown positive feedback which might amplify warming at the northern latitudes.

I can understand how the feedback of CO2 release with temperature increase is weak and self - limiting but it has to play at least a part of the process.

Seeing this as a baseline, positive CO2 feedback from temperature changes, or a running out of capacity for greater uptake from CO2 accumulation, would be seen as adding more CO2 to the air in addition to anthropogenic releases, but it would have to surpass some level before it would result in a total atmospheric accumulation of CO2 greater than anthropogenic emissions (first, as a rate, and later, cummulative change).

One other point on cloud feedbacks from a paleoclimate perspective — if a strong negative cloud feedback begins at modern earth temperatures, it would be unlikely for past temperatures to have exceeded modern ones.

Well, that seems to have worked for a while, but as temperatures rise due to higher CO2 concentrations plants become subject to both heat and drought stress, and so we have that sink working less well than it has in the past — which is a feedback.

Including a temperature feedback on would change the climate sensitivity, but doesn't much change the impact of a small offset in.

At some temperature (s), carbonate rocks themselves will decompose — the negative chemical weathering feedback has limits (http://www.pnas.org/content/98/7/3666.full, fig. 1)-RRB-

(PS regarding Venus — as I have understood it, a runaway water vapor feedback would have occured when solar heating increasing to become greater than a limiting OLR value (Simpson - Kombayashi - Ingersoll limit — see http://chriscolose.wordpress.com/2010/08/23/climate-feedbacks-part-1/ — although I should add that at more «moderate» temperatures (warmer than today), stratospheric H2O increases to a point where H escape to space becomes a significant H2O sink — if that stage worked fast enough relative to solar brightening, a runaway H2O case could be prevented, and it would be a dry (er) heat.

Finally, because of the posited strong water vapor feedback, which depends on absolute, not anomaly, temperatures, one would expect that the relationship should be positive, not negative due to the greater rate of accumulation of water vapor at higher absolute temperatures.

However both do in fact force global temperature, therefore both could be called forcings and the greenhouse effect of water vapour would then be a positive feedback forcing.

David Benson, Based solely on the fact that Earth was 33 degrees warmer than its blackbody temperature, on what was known of the absorption spectrum of CO2 and on the fact that Earth's climate did not exhibit exceptional stability characteristic of systems with negative feedback, I'd probably still go with restricting CO2 sensitivity to 0 to + infinity.

We also know that there must be positive feedbacks in order for Earth to be at its current temperature — you wouldn't get 33 degrees of warming from just the intrinsic radiative properties of the greenhouse gasses.

Such an issue provides a positive feedback and also underlies the amplification of temperature in the Arctic, which has recently clearly emerged in observations.

I have a question for the ice scientists: If an ice free Arctic summer becomes routine, say in 2013, how much will the absorption feedback vs. normal albedo raise global temperature?

Climate models, on the other hand, have a successful track record — look at the melting Arctic, warming around Antarctica, the surface temperature, the water feedback effect, the reduction in mountain glaciers... etc..

In other words, after the immediate increase in temperature caused by a doubling of CO ₂ over 70 years, would the temperature necessarily continue to increase a certain (large or small) amount or could the more slowly acting feedbacks cause it to drop back in the longer term?