Sentences with phrase «radiative forcing which»

But in fact Chap.9 of WG1 where the «most» claim originates leaves out atmospheric water vapor -LRB-[H2O]-RRB- from its «non-human» or «natural» prime movers of radiative forcing which would have surprised Arrhenius and Tyndall; what it asks us to believe is that [H2O] ONLY originates from rising temperature caused by CO2, and that the role of the sun in producing 99 % of atmospheric water vapor is irrelevant and not a natural forcing.

For «skeptics» to make a convincing argument that humans are not causing global warming, they must both explain where this large greenhouse gas radiative forcing has gone, and find an even larger «natural» radiative forcing which nobody has yet identified.

In brief, the temperature profile of the atmosphere is set by convection & latent - heat considerations (= > adiabatic lapse rate); based upon that temperature profile, the radiative transfer processes give rise to the radiative forcing which is the GHE.

Absorption in the atmosphere of solar radiation by CO2 doesn't buy you any reduction in the radiative forcing which is conventionally applied to the whole atmosphere and surface.

The model is parameterized and then optimized to produce the most likely values for the climate parameters and radiative forcings which reproduce the 20th century global warming.

An example is in the radiative forcings which change from report to report.

Not exact matches

«We estimate that their total radiative forcing is around -1.3 [watts / meter2],» which is a cooling effect, he says.

A study released last month in the Journal of Geophysical Research: Atmospheres used three different models to run the same SSCE scenario in which sea - salt engineering was used in the low - latitude oceans to keep top - of - atmosphere radiative forcing at the 2020 level for 50 years and was then abruptly turned off for 20 years.

The reduced DMS emissions induce a significant positive radiative forcing of which 83 % (0.4 W / m2) can, in the model, be attributed to the impact of ocean acidification alone.

[Response: A similar conclusion to the one cited by Gavin above was reached independently by a panel of scientists (of which I was a member) convened to report on these issues by the National Academy of Sciences last year, resulting in the NAS report «Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties (2005)».

Much more careful studies, in which the actual radiative forcing can be quantified, pretty much show that the paleoclimate record is compatible with the full IPCC range, with both the higher and lower ends appearing less probable.

Changes in TSI can be converted into a radiative forcing, which tells us the energy imbalance it causes on Earth.

The mechanism for reducing anthropogenic global warming, initiated through radiative forcing of greenhouse gases, is to stop emissions and reduce their concentration in the atmosphere to levels which do not stimulate carbon feedbacks.

... The Earth's atmospheric methane concentration has increased by about 150 % since 1750, and it accounts for 20 % of the total radiative forcing from all of the long - lived and globally mixed greenhouse gases (these gases don't include water vapor which is by far the largest component of the greenhouse effect).

He then uses what information is available to quantify (in Watts per square meter) what radiative terms drive that temperature change (for the LGM this is primarily increased surface albedo from more ice / snow cover, and also changes in greenhouse gases... the former is treated as a forcing, not a feedback; also, the orbital variations which technically drive the process are rather small in the global mean).

Where «dT» is the change in the Earth's average surface temperature, «λ» is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C / [W m - 2]-RRB-, and «dF» is the radiative forcing, which is discussed in further detail in the Advanced rebuttal to the «CO2 effect is weak» argument.

Similarly, many studies that attempt to examine the co-variability between Earth's energy budget and temperature (such as in many of the pieces here at RC concerning the Spencer and Lindzen literature) are only as good as the assumptions made about base state of the atmosphere relative to which changes are measured, the «forcing» that is supposedly driving the changes (which are often just things like ENSO, and are irrelevant to radiative - induced changes that will be important for the future), and are limited by short and discontinuous data records.

Indeed, most of the response is probably due to obliquity, which has close to zero radiative forcing all said and done.

M2009 use a simplified carbon cycle and climate model to make a large ensemble of simulations in which principal uncertainties in the carbon cycle, radiative forcings, and climate response are allowed to vary, thus yielding a probability distribution for global warming as a function of time throughout the 21st century.

The estimated difference between the present - day solar irradiance cycle mean and the Maunder Minimum is 0.08 % (see Section 2.7.1.2.2), which corresponds to a radiative forcing of about 0.2 W m — 2, which is substantially lower than estimates used in the TAR (Chapter 2).

Numerous climate modeling experiments which have included the role of natural (both solar and volcanic) radiative forcing have concluded that natural forcing can not explain 20th century warming.

I also note that if Asia (particularly China) converts its many existing coal - fired power plants to methane (from hydrofracking) over the next few decades, then the air pollution in this part of the world will likely be reduced, which would further increase radiative forcing on the Earth.

The model results (which are based on driving various climate models with estimated solar, volcanic, and anthropogenic radiative forcing changes over this timeframe) are, by in large, remarkably consistent with the reconstructions, taking into account the statistical uncertainties.

If it happens for CO2 radiative forcing, it will also happen for Solar activity - related (or any other) forcing, which thus would be equally ineffective to explain late 20th century warming.

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.

And yet, Simon, you were responding to a set of comments which were about climate sensitivity, for which radiative forcing would be a much more relevant metric — and you responded in a fashion which gave no suggestion that you were changing the topic.

There is no set number of years automatically «falsifying the theory» — after all, the laundry list of radiative forcings has about a dozen terms, so the hypothetical lack of warming you propose would raise the question of just which factors were involved.

Gavin disputes that the main driver of the sea ice retreat is the albedo flip, but we are seeing not only polar amplification of global warming but positive feedback, which would not be explained simply by radiative forces and ocean currents.

Calculations of «Cloud radiative forcing» (which is a specific kind of diagnostic — Cess et al definition) are not the same as the «radiative forcing» in the sense of CO2.

Some of the problems are the same which Gavin mentioned in his reply to 46 above (Mixing of Cloud Radiative Forcing and TOA radiative forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the resulRadiative Forcing and TOA radiative forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the result,Forcing and TOA radiative forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the resulradiative forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the result,forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the result, etc.).

As for Wielecki, I'm not sure which red graph you are referring to, but if you mean the one at the top of the three - panel graph from the corrected version of the Science article, that is labeled «LW,» which, as I said in my response to Spencer Weart that is the TOA longwave radiative forcing.

This mostly reflects the response to global radiative forcings, which are dominated by anthropogenic forcing over the 20th Century.

Conclusion: Or result show indelibly that the pdf and cdf for Î?T2x very strongly depend on which radiative forcing factors have actually been at work during the period of instrumental temperature measurements»

Given the economic tenor of many news stories, an analogy to inflation may be useful in clarifying the idea of slow but steady radiative bracket creep, as the CO2 forcing can be outlined in terms of its effect on the radiative balance, which reduces to watts / M2 and their rate of change.

But models based on physical principles also reproduce the response to seasonal and spatial changes in radiative forcing fairly well, which is one of the many lines of evidence that supports their use in their prediction of the response to anthropogenic forcing.

As an aside, the radiative forcing by aerosols (in both long wave and solar radiation at the tropopause) is not the same as global dimming (which is a solar radiation effect at the surface) though they are related.

Given those assumptions, looking at the forcing over a long - enough multi-decadal period and seeing the temperature response gives an estimate of the transient climate response (TCR) and, additionally if an estimate of the ocean heat content change is incorporated (which is a measure of the unrealised radiative imbalance), the ECS can be estimated too.

The main changes in radiative forcing from the precessional cycle are in the latitudinal and seasonal distribution, not in the global mean, which is why the nature of the response can be expected to be different from doubling CO2.

Reminds me of the UK met Office annual predictions, which forecast annual global temperatures based on atlantic multidecadal oscillation, ENSO, solar, recent volcanic activity and, crucially, radiative forcing due to GHG.

Given the much more rapid respons time of the stratosphere to radiative forcings, there is (can be) some initial stratospheric cooling (or at least some cooling somewhere in the stratosphere), which consists of a transient component, and a component that remains at full equilibrium.

Climate models may therefore lack — or incorrectly parameterize — fundamental processes by which surface temperatures respond to radiative forcings... In contrast with climate model simulations, the zonal surface temperature changes... do not increase rapidly from mid to high latitudes.»

Different climates have different vertical temperature profiles (aside from horizontal and temporal temperature variations), which affects the radiative forcing that an amount and arrangement of greenhouse agents (CO2, CH4, etc, also, water vapor and clouds) will have.

The magnitude of the radiative forcing per doubling is equal to the effect of band widenning, which is (BW1 + BW2) * depth of valley or height of hill, plus some additional effect in the center of the band, which is on the order of 1/2 * (BW1 + BW2) * increase in height or depth of hill or valley; the central contribution could be more or less than that, but it will be less than double (because the shape of the absorption spectrum won't allow a square shape in the graph of the spectral flux).

Secondly, unlike the global average surface temperature trend, which has a lag with respect to radiative forcing, there is no such lag when heat content is measured in Joules (see http://blue.atmos.colostate.edu/publications/pdf/R-247.pdf).

Starting from an old equilbrium, a change in radiative forcing results in a radiative imbalance, which results in energy accumulation or depletion, which causes a temperature response that approahes equilibrium when the remaining imbalance approaches zero — thus the equilibrium climatic response, in the global - time average (for a time period long enough to characterize the climatic state, including externally imposed cycles (day, year) and internal variability), causes an opposite change in radiative fluxes (via Planck function)(plus convective fluxes, etc, where they occur) equal in magnitude to the sum of the (externally) imposed forcing plus any «forcings» caused by non-Planck feedbacks (in particular, climate - dependent changes in optical properties, + etc.).)

the problem is that this definition implicitly assumes that the global, time average surface temperature is a definite single valued function of the radiative average forcing, which is far from being true since there are considerable horizontal heat transfer modifying the latitudinal repartition of temperature: the local vertical radiative budget is NOT verified.

You said — «Anything which turns carbon dioxide into methane will increase the radiative forcing of the carbon atom considerably.»

The overall human - caused radiative forcing, which is given here as 1.6 watts per square meter, had already risen to 2.3 watts per square meter by the year 2011 according to the 5th IPCC report.

which clearly show the radiative forcing resulting from volcanism since 1880.

The effect of band widenning is a reduction in net upward LW flux (this is called the radiative forcing), which is proportional to a change in area under the curve (a graph of flux over the spectrum); the contribution from band widenning is equal to the amount by which the band widens (in units ν) multiplied by - Fνup (CO2).