Sentences with phrase «given radiative forcing»

The sources of uncertainty are many, including the trajectory of greenhouse gas emissions in the future, their conversion into atmospheric concentrations, the range of responses of various climate models to a given radiative forcing and the method of constructing high resolution information from global climate model outputs (Pittock, 1995; see Figure 13.2).

For example, scenarios that rely on the results from GCM experiments alone may be able to represent some of the uncertainties that relate to the modelling of the climate response to a given radiative forcing, but might not embrace uncertainties caused by the modelling of atmospheric composition for a given emissions scenario, or those related to future land - use change.

The climate sensitivity value tells us how much the planet will warm or cool in response to a given radiative forcing change.

However, they illustrate an important point; namely, there are numerous ways that a given radiative forcing goal can be achieved.

Not exact matches

For one thing, the energy balance between radiative forcing and temperature response gives a non-linear relation between the forcing, F, and temperature to the fourth power, T4 (the Stefan - Boltzmann law).

As we explain in our glossary item, climatologists use the concept of radiative forcing and climate sensitivity because it provides a very robust predictive tool for knowing what model results will be, given a change of forcing.

That is, a change in radiative forcing of about 4 W / m2 would give around 1 °C warming.

Suppose also that — DESPITE THIS STABILIZING MECHANISM some as - yet unknown ocean circulation cycle operates that is the sole cause of the Holocene centennial scale fluctuations, and that this cycle has reversed and is operating today, yielding a temperature change that happens to mimic what models give in response to radiative forcing changes.

Given that there is continual heating of the planet, referred to as radiative forcing, by accelerating increases of carbon dioxide (Figure 1) and other greenhouses due to human activities, why is the temperature not continuing to go up?

You are arguing that 100ppm change in radiative forcing for CO2, amounting to 0.6 deg C change, multiplied by a wv feedback giving 1.8 deg C change, plays an important part in raising the sea level by 100 meters.

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.

As an example of the possible extreme change in radiative forcing in a 50 - year time horizon for Isaken et al (2011)'s 4 x CH4 (i.e. quadrupling the current atmospheric methane burden) case of additional emission of 0.80 GtCH4 / yr is 2.2 Wm - 2, and as the radiative forcing for the current methane emissions of 0.54 GtCH4 / yr is 0.48 Wm - 2, this give an updated GWP for methane, assuming the occurrence of Isaksen et al's 4 x CH4 case in 2040, would be: 33 (per Shindell et al 2009, note that AR5 gives a value of 34) times (2.2 / [0.8 + 0.48]-RRB- divided by (0.54 / 0.48) = 50.

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.

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.

Suppose also that — DESPITE THIS STABILIZING MECHANISM some as - yet unknown ocean circulation cycle operates that is the sole cause of the Holocene centennial scale fluctuations, and that this cycle has reversed and is operating today, yielding a temperature change that happens to mimic what models give in response to radiative forcing changes.

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.

That is, a change in radiative forcing of about 4 W / m2 would give around 1 °C warming.

[Response: I wouldn't want to criticize my colleagues without adequate space to give the scientific justification, but aside from that you need to remember what I said about the contribution from non-CO2 radiative forcing to date (and unlike CO2, the methane radiative forcing is largely reversible, so I myself don't count that the same way as CO2 radiative forcing).

As we explain in our glossary item, climatologists use the concept of radiative forcing and climate sensitivity because it provides a very robust predictive tool for knowing what model results will be, given a change of forcing.

Radiative forcing RF at a level is equal to a decrease in net upward flux (either SW, LW, or both; the greenhouse effect refers to LW forcing) at that given level, due to a change in (optical) properties, while holding temperatures constant.

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.

While the definition of a forcing may appear a little arbitrary, the reason why radiative forcing is used is because it (conveniently) gives quite good predictions of what happens in models to the global mean temperature once the climate system has fully responded to the change.

The effect is a continuum of different absorption spectra that all have the same band - widenning per doubling and same effects at the center at various stages between no effect and saturation, though they are at different stages in that process for any given amount of CO2; the radiative forcing is a weighted average of the effects of each of those absorption spectra; once the center of the band is saturated for all of the spectra, the band widenning effect is the same for each and thus the forcing from the band widenning is the same as it is in the original simplified picture.

Even if it could be shown that climate is more sensitive to solar variability than the strict radiative forcing would suggest (along the lines of Shindell et al) one would still have to contend with the fact that we know the solar variability for the past fifty years quite well, and it does not do the kind of things necessary to give the present warming pattern.

The radiative forcing for CFCs is given as a linear relation for low concentrations see http://www.esrl.noaa.gov/gmd/aggi/ Does this hold for the much (ten times or more) larger concentrations we would expect without the Montreal Protocol?

Using the known amplification of the solar cycle (and presumably the long term trend) in the UV band, allowing stratospheric temperatures and circulation patterns to adjust and including the direct radiative forcings from the sun and volcanoes, we found that it gave temperature anomalies and spatial patterns that were in fair agreement with the observations (Shindell et al, 2003).

Would such radiative forcing be evident given what we know about planet Earth?

Both give a sensitivity to solar - cycle forcing of about 0.1 K / (W / m ^ 2)(about twice what would be expected from radiative calculations alone).

The term «climate sensitivity» refers to the steady - state increase in the global annual mean surface air temperature associated with a given global mean radiative forcing.

Using the TAR estimates of radiative forcing gives 2.7 Watts / m2.

By using dual radioactive tracers with differing lifetimes, Wilson et al. [2017] found short term increases in CH4 and CO2 release during periods of thaw in a discontinuous permafrost were generally offset by long - term accumulation of peat in the ensuing millennia, leading the regions to continue to be net carbon sinks with negative atmospheric radiative forcing, given the long life - time of atmospheric CO2.

The climate sensitivity is defined as the equilibrated change in global mean surface air temperature (SAT) for a given change in radiative forcing and has been a major focus of climate research over the last three decades.

Nowhere in the paper is any justification given as to why radiative transfer models give values for radiative forcing as defined in Chaper 6 of the TAR.

The imbalance between the absorbed and emitted radiation that results from these changes will be referred to here as «climate forcing» (sometimes known as «radiative forcing») and given in units of Wm - 2.

Given our very short and spotty data on the relative abundance (or importance) of the majority of these aerosols, and given our very poor understanding of the direct, indirect, and side effects of the majority of these aerosols, any numbers that anyone generates about their abundance, importance, or total radiative forcing are going to be a Given our very short and spotty data on the relative abundance (or importance) of the majority of these aerosols, and given our very poor understanding of the direct, indirect, and side effects of the majority of these aerosols, any numbers that anyone generates about their abundance, importance, or total radiative forcing are going to be a given our very poor understanding of the direct, indirect, and side effects of the majority of these aerosols, any numbers that anyone generates about their abundance, importance, or total radiative forcing are going to be a SWAG.

The increased water vapor roughly doubles the direct radiative forcing, giving the 1 — 2 % value, although this will vary from day to day.

Fortunately, the negative and positive forcings are roughly equal and cancel each other out, and the natural forcings over the past half century have also been approximately zero (Meehl 2004), so the radiative forcing from CO2 alone gives us a good estimate as to how much we expect to see the Earth's surface temperature change.

The authors give some hint when they write:» This suggests that estimates of the net negative radiative forcing due to the total ACI can also be significantly reduced and its uncertainty range could even include positive values.».

Using a global energy budget approach, this paper seeks to understand the implications for climate sensitivity (both ECS and TCR) of the new estimates of radiative forcing and uncertainty therein given in AR5.

Equivalent carbon dioxide (CO2) emission - The amount of carbon dioxide emission that would cause the same integrated radiative forcing, over a given time horizon, as an emitted amount of a well mixed heat - trapping gas (greenhouse gas) or a mixture of well mixed greenhouse gases.

E.g. I would argue that even amidst the very large uncertainty, some trajectories are more likely than others (e.g. given a continued positive radiative forcing, warming is more likely than cooling).

You can use df = 5.35 * ln (C / C0) to find the radiative forcing, and use e.g. the figure above to find the expected warming for a given ECS value.

The figure can be used if you know the radiative forcing, and is handy in light of e.g. the RCP scenarios which are given in terms of expected radiative forcing.

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.

I find the lack of evidence for such simple things as CO2 radiative «forcing» in the temperature record to be apalling, considering how much undue weight it is given.

[Equilibrium] climate sensitivity is defined as the increase in global mean surface temperature (GMST), once the ocean has reached equilibrium, resulting from a doubling of the equivalent atmospheric CO2 concentration, being the concentration of CO2 that would cause the same radiative forcing as the given mixture of CO2 and other forcing components.

The second point means that it may be more difficult to distinguish between the response to different factors than one might expect, given the differences in radiative forcing.»

To describe the relative contribution of various GHG emissions to global warming, emissions were converted to CO2 equivalents, a metric that relates the radiative forcing caused by 1 mass unit of trace GHG to that caused by the emission of 1 mass unit of CO2 over a given time span.

from the pdf: Using a global energy budget approach, this paper seeks to understand the implications for climate sensitivity (both ECS and TCR) of the new estimates of radiative forcing and uncertainty therein given in AR5.

The radiative transfer formula for doubling of CO2 gives forcing in W / M2... F = 5.35 xLN (2) = 3.7 W / M2.