Sentences with phrase «feedback than in water»

Therefore, the current evidence suggests that permafrost thaw in dry soils will cause a stronger permafrost carbon — climate feedback than in water - saturated soils 1,7.

Not exact matches

While the ECS factors in such «fast» feedback effects as changes in water vapor — water itself is a greenhouse gas, and saturates warm air better than cold — they argued that slow feedbacks, such as changes in ice sheets and vegetation, should also be considered.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

Anyone who accepts that sunlight falling on ice free waters which has less reflectivity than sunlight falling on a large ice mass covering those waters and also accepts that this reduction in albedo has a positive feedback effect, leading to further warming, can't help but opt for A or B, it seems to me.

The water vapor just makes the Planck response less effective, so you need a higher temperature change for the same perturbation than in a no feedback case.

There was more ice around in the LGM and that changes the weighting of ice - albedo feedback, but also the operation of the cloud feedback since clouds over ice have different effects than clouds over water.

[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?)

Yes, overall change in clouds may be a positive feedback, rather than a negative feedback assumed from simple ideas like more water - > more clouds - > cooling.

Specific humidity content of the air has increased, as expected as part of the conventional water vapor feedback, but in fact relative humidity also increased between 1950 and 1990, indicating a stronger water vapor feedback than given by the conventional assumption of fixed relative humidity.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

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.

I think what Alastair is alluding to is the fact that, say by 2050 when the arctic ocean will conceivably be ice - free in the summer, the atmosphere will have a much higher relative humidity than it has currently because of the open air = water interface, so this will have a magnifying effect beyond just the feedback from increased CO2.

In the case of a failure of the surface to warm due to a La Nina - like process, the OLR reduction (and hence the energy gain) will be lessened by the reduction in water vapor and other feedback moieties, but it will still be greater than occurs with a warmed surfacIn the case of a failure of the surface to warm due to a La Nina - like process, the OLR reduction (and hence the energy gain) will be lessened by the reduction in water vapor and other feedback moieties, but it will still be greater than occurs with a warmed surfacin water vapor and other feedback moieties, but it will still be greater than occurs with a warmed surface.

Now adding back the CO2 will have a larger magnitude of forcing than the initial removal because there is much less water vapor, and the water vapor feedback in terms of W / m2 will be smaller in magnitude because of the overlap with CO2.

Warming must occur below the tropopause to increase the net LW flux out of the tropopause to balance the tropopause - level forcing; there is some feedback at that point as the stratosphere is «forced» by the fraction of that increase which it absorbs, and a fraction of that is transfered back to the tropopause level — for an optically thick stratosphere that could be significant, but I think it may be minor for the Earth as it is (while CO2 optical thickness of the stratosphere alone is large near the center of the band, most of the wavelengths in which the stratosphere is not transparent have a more moderate optical thickness on the order of 1 (mainly from stratospheric water vapor; stratospheric ozone makes a contribution over a narrow wavelength band, reaching somewhat larger optical thickness than stratospheric water vapor)(in the limit of an optically thin stratosphere at most wavelengths where the stratosphere is not transparent, changes in the net flux out of the stratosphere caused by stratospheric warming or cooling will tend to be evenly split between upward at TOA and downward at the tropopause; with greater optically thickness over a larger fraction of optically - significant wavelengths, the distribution of warming or cooling within the stratosphere will affect how such a change is distributed, and it would even be possible for stratospheric adjustment to have opposite effects on the downward flux at the tropopause and the upward flux at TOA).

If a doubling of CO2 resulted in a temperature increase of approximately 1 K before any non-Planck feedbacks (before water vapor, etc.), then assuming the same climate sensitivity to the total GHE, removing the whole GHE would result in about a (setting the TOA / tropopause distinction aside, as it is relatively small relative to the 155 W / m2 value) 155/3.7 * 1 K ~ = 42 K. Which is a bit more than 32 or 33 K, though I'm not surprised by the difference.

If CO2 in the Anthropocene atmosphere contributes to re-vegetating currently arid areas as it did post-LGM, we should expect an even greater warming feedback from CO2 than is assumed from water vapor and albedo feedbacks, due to decreased global dust - induced albedo and increased water vapor from transpiration over increased vegetated area.

Is less poleward transport of heat by the Gulf Stream as the AMOC weakens a positive feedback for global warming, since that energy will escape more slowly in the humid (higher water vapor GHG effect) tropics than near the poles?

But in the end, all of the water vapor adds somewhat less than 1.8 C to the original 1.2 C for a CO2 doubling in the fast feedbacks.

Assuming that scientists haven't left out anything vital, this suggests that the net effect of water - based feedbacks is positive and would amplify GHG - induced warming by more than a factor of two.Many assumptions have been made, but the historical evidence increases our confidence in model results.

July 17, 2013 at 1:39 pm The lapse rate feedback is only a negative feedback (in the general circulation model) if the long wave radiation that is released when the water vapour condenses is emitted to space rather than trapped by increased water vapour.

In addition, it now appears that water vapor feedback, while still positive and robust, is likely to be weaker than previously estimated by the models.

Niche Modelling concludes from the Leviticus data that net total global radiative feedback from water vapor, etc. is negative, rather than strongly positive, as estimated by the models cited in IPCC AR4.

Your thermostat proposition means that the water vapour feedback in particular will be less than assumed and will operate at a faster rate than assumed (I might even convert it into a lapse rate discussion).

To point out just a couple of things: — oceans warming slower (or cooling slower) than lands on long - time trends is absolutely normal, because water is more difficult both to warm or to cool (I mean, we require both a bigger heat flow and more time); at the contrary, I see as a non-sense theory (made by some serrist, but don't know who) that oceans are storing up heat, and that suddenly they will release such heat as a positive feedback: or the water warms than no heat can be considered ad «stored» (we have no phase change inside oceans, so no latent heat) or oceans begin to release heat but in the same time they have to cool (because they are losing heat); so, I don't feel strange that in last years land temperatures for some series (NCDC and GISS) can be heating up while oceans are slightly cooling, but I feel strange that they are heating up so much to reverse global trend from slightly negative / stable to slightly positive; but, in the end, all this is not an evidence that lands» warming is led by UHI (but, this effect, I would not exclude it from having a small part in temperature trends for some regional area, but just small); both because, as writtend, it is normal to have waters warming slower than lands, and because lands» temperatures are often measured in a not so precise way (despite they continue to give us a global uncertainity in TT values which is barely the instrumental's one)-- but, to point out, HadCRU and MSU of last years (I mean always 2002 - 2006) follow much better waters» temperatures trend; — metropolis and larger cities temperature trends actually show an increase in UHI effect, but I think the sites are few, and the covered area is very small worldwide, so the global effect is very poor (but it still can be sensible for regional effects); but I would not run out a small warming trend for airport measurements due mainly to three things: increasing jet planes traffic, enlarging airports (then more buildings and more asphalt — if you follow motor sports, or simply live in a town / city, you will know how easy they get very warmer than air during day, and how much it can slow night - time cooling) and overall having airports nearer to cities (if not becoming an area inside the city after some decade of hurban growth, e.g. Milan - Linate); — I found no point about UHI in towns and villages; you will tell me they are not large cities; but, in comparison with 20-40-60 years ago when they were «countryside», many small towns and villages have become part of larger hurban areas (at least in Europe and Asia) so examining just larger cities would not be enough in my opinion to get a full view of UHI effect (still remembering that it has a small global effect: we can say many matters are due to UHI instead of GW, maybe even that a small part of measured GW is due to UHI, and that GW measurements are not so precise to make us able to make good analisyses and predictions, but not that GW is due to UHI).

The theory is that increasing CO2 will cause a small bit of warming and this will increase evaporation rates (which occur fastest in the tropics) and dumps more water vapour in the atmosphere (water vapour is by far a more potent greenhouse gas than CO2) and this feedback amplification is meant to continue until Earth settles down and finds a new equilibrium temperature.

The fact that the actual measured planetary warming is less than the lowest IPCC model prediction warming and is found only at high latitudes (which is not predicted by the IPCC models) logically supports the assertion that the planet's response to a change in forcing is to resist the change (negative feedback, planetary clouds in the tropics increase reflecting more sunlight in to space) rather than to amplify the change (positive feedback) due increased water vapour in the atmosphere.

dude I don't think the observed reduction in relative humidity with rising temperature implies a negative water vapor feedback, just a less strongly positive water vapor feedback than has been otherwise postulated.

I find looking at available data that since the increase in absolute humidity is larger than the increase in precipitation, with cloudiness pretty much a wash, that the evidence supports the existence of a water vapor feedback that is positive.

The IPCC, its models, and the climate establishment insist warming will be more than this because the warming will cause an increase in atmospheric water vapor (the major greenhouse gas) which will amplify the CO2 - caused warming, a net positive feedback.

That is, while the roles of water vapour and cloud effects are very important in the net greenhouse effect, they function as feedbacks rather than primary drivers of change.

Since the less than positive feedback of clouds in the tropics appears to be the reason that the tropical troposphere hot spot signature of WMGHG warming is missing which implies that the water vapor and cloud feedbacks that are supposed to produce 2/3 of the GHG effect warming are not following the game plan, Spencer et al., by averaging ever damn thing they would find that might possibly show the tropical troposphere hot spot, are basically telling Trenberth and Dessler, «told ya so!»

Negative trends in q as found in the NCEP data would imply that long - term water vapor feedback is negative — that it would reduce rather than amplify the response of the climate system to external forcing such as that from increasing atmospheric CO2.

And if the pattern were to continue into the future, one would expect water vapour feedback in the climate system to halve rather than double the temperature rise due to increasing CO2.

His more recent argument (back in 2001 I think) is the IRIS hypothesis which had more to do with cloud feedbacks than water vapor.

A substantial spread is apparent in the strength of water vapour feedback that is smaller in Soden and Held (2006) than in Colman (2003a).

It's apparent that the negative feedbacks from water in all its phases are much stronger than the positive feedback from water vapor as a GHG.

Water vapor is the most important greenhouse gas, but it's an educated guess that the change in water vapor has been more important than the change in carbon dioxide, but since, as I wrote, «That's a feedback, and I can't count it», it doesn't really maWater vapor is the most important greenhouse gas, but it's an educated guess that the change in water vapor has been more important than the change in carbon dioxide, but since, as I wrote, «That's a feedback, and I can't count it», it doesn't really mawater vapor has been more important than the change in carbon dioxide, but since, as I wrote, «That's a feedback, and I can't count it», it doesn't really matter.

Much of the time these «outsider» critiques are not based on anything other than a desire to confuse (claims that IPCC doesn't mention water vapour feedbacks for instance, or that there is a deliberate attempt to downplay solar effects on climate or that the number of vineyards in England a thousand years ago implies that CO2 has no radiative effect) and have no traction in the scientific community.

Notable among these are Wentz et al. (2007), who suggest that the IPCC has failed to allow for two - thirds of the cooling effect of evaporation in its evaluation of the water vapor - feedback; and Spencer (2007), who points out that the cloud - albedo feedback, regarded by the IPCC as second in magnitude only to the water - vapor feedback, should in fact be negative rather than strongly positive.

Regardless, climate models are made interesting by the inclusion of «positive feedbacks» (multiplier effects) so that a small temperature increment expected from increasing atmospheric carbon dioxide invokes large increases in water vapor, which seem to produce exponential rather than logarithmic temperature response in the models.

«Interestingly, the true feedback is consistently weaker than the constant relative humidity value, implying a small but robust reduction in relative humidity in all models on average, as weighted by the water vapor kernel.»

The implied positive feedback is smaller than indicated by our model (8.5 — 9.5 ppmv K - 1), but as with the case of MLS, the HALOE water vapor data show that the UT humidity — SST relationship in the present climate regime lies between the cases of constant mixing ratio and constant relative humidity.