Sentences with phrase «then climate sensitivity»

If the cooling from 1940 - 1970 was from aerosols then climate sensitivity to CO2 might be high enough to be worried about.

If the period prior to 1940 was mostly due to «natural variation» then climate sensitivity to forcings must be higher than expected and CO2 warming will actually be worse than expected.

Wigley states, «If one accounts for the ocean damping effect using either a PD or UD model, and, if one assumes that greenhouse gas forcing is dominant on the century time scale, then the climate sensitivity required to match model predictions is only about 0.4 deg C / wm -2.

In a lengthy article this week, The Economist magazine said if climate scientists were credit - rating agencies, then climate sensitivity — the way climate reacts to changes in carbon - dioxide levels [continue reading...]

If my best guesses are indeed better than those of the IPCC, then climate sensitivity to a doubling of CO2 concentration is 0.8 K before feedbacks are taken into account and 0.7 K after feedbacks, very much in line with the results of Lindzen & Choi and Spencer & Braswell.

If the damage function is small, then the climate sensitivity can be high and the consequences of warming are small or even beneficial.

He had already been warned on this thread that when I had earlier answered a legitimate question from a commenter far more polite and sensible than he, I had replied with a straightforward account of how Professor Lindzen, in a talk that he had given under my chairmanship at the Houses of Parliament, had calculated that if the increase in evaporation from the Earth's surface with warming was thrice that which the models predicted then climate sensitivity was one - third of that which the models predicted.

And if there is no CO2 signal, then the climate sensitivity of CO2 is indistinguishable from zero.

If someone could measure the increase in CO2 from current levels, and prove that an observed rise in temperature was caused by this increase in CO2, then climate sensitivity can be measured, and CAGW could be proven or falsified.

then climate sensitivity (TCR) for CO2 works out to be 1.4 C.

If the influence of solar variability has been greatly underestimated, and the greater century - scale climate variability shown in some reconstructions is a) correct and b) due to that solar variability, then the climate sensitivity could be the same (or less) then indicated by other reconstructions.

Not exact matches

«If we are lucky and the climate sensitivity is at the low end, and we have a strong agreement in 2015, then I think we stand a chance to limit climate change to 2 °C,» says Corinne Le Quéré of the Tyndall Centre for Climate Change Research in Norwiclimate sensitivity is at the low end, and we have a strong agreement in 2015, then I think we stand a chance to limit climate change to 2 °C,» says Corinne Le Quéré of the Tyndall Centre for Climate Change Research in Norwiclimate change to 2 °C,» says Corinne Le Quéré of the Tyndall Centre for Climate Change Research in NorwiClimate Change Research in Norwich, UK.

If that is so, then the future rise (on a climate sensitivity figure of 2degC) would be a further 1.2 degC.

The data is only 33 years in length, but based on that data, there is no first order correlation between temperature and CO2 during its 33 year period and this suggests that then signal to CO2 (ie., Climate Sensitivity) is so low that it can not be measured within the sensitivity, resolution and errors of our best current temperature meSensitivity) is so low that it can not be measured within the sensitivity, resolution and errors of our best current temperature mesensitivity, resolution and errors of our best current temperature measurements.

If no warming between now and then, what will the IPCC be forced to concede with respect to Climate Sensitivity.

If the high climate sensitivity effect of the ice ages is a result of the hysteresis effect as proposed by Oerlemans and Van den Dool (1978), then the present observed sensitivity of 1K / 2xCO2 can not be much higher.

Where (equilibrium / effective) climate sensitivity (S) is the only parameter being estimated, and the estimation method works directly from the observed variables (e.g., by regression, as in Forster and Gregory, 2006, or mean estimation, as in Gregory et al, 2002) over the instrumental period, then the JP for S will be almost of the form 1 / S ^ 2.

I'm not even an amateur climate scientist, but my logic tells me that if clouds have a stronger negative feedback in the Arctic, and I know (from news) the Arctic is warming faster than other areas, then it seems «forcing GHGs» (CO2, etc) may have a strong sensitivity than suggested, but this is suppressed by the cloud effect.

The bottom line is that if the radiative forcing of the cosmic - ray flux / climate link is valid, then a sensitivity of Tx2 ~ 1 - 1.5 ° is obtained (and about 2 °C if there is no cosmic ray flux climate link, i.e., still relatively low — this is all explained in the linked paper I sent above: [abstract][pdf]-RRB-.

On the other hand, they do claim the greater changes were perhaps due to forcings & factors (solar radiation & volcanos), so would this then show greater climate sensitivity both to nature & us?

But then Archibald multiplies the radiative forcing by an absurdly low value of the climate sensitivity parameter.

If you set the aerosol forcing to zero you don't get the mid-century interruption of warming, and if the aerosol forcing were allowed to get as big as, say, 10 W / m ** 2 you would get excessive cooling unless you imposed a very low climate sensitivity — which would then make it impossible to reproduce the post-1970's warming.

S&W presumes a desired conclusion when arguing that if the TSI variations are small but the temperature variations are pronounced, then this suggests greater climate sensitivity and vice versa.

If the climate sensitivity is low, for example due to increasing low - lying cloud cover reflecting more sunlight as a response to global warming, then how can these large past climate changes be explained?

Rather, their analysis shows that if you compare the LGM land cooling with the model land cooling, then the model that fits the land best has much higher GLOBAL climate sensitivity than you get for best fit if you use ocean data.

So, the key thing in evaluating climate sensitivity is to use the LGM as a test of how well the models are doing clouds, using the LGM, and then see what happens in the same model when you project to the future.

I am also interested in how long is required for the surface temp to «achieve» 95 % of the ECS change: e.g. if climate sensitivity is 2K, how much time is required for the surface temp to increase by 1.9 K; and then how much longer for the deep oceans to increase by 1.9 K (or whatever 95 % of the projected increase in deep ocean temperature works out to.)

Indeed, if one accepts a very liberal risk level of 50 % for mean global warming of 2 °C (the guiderail widely adopted) since the start of the industrial age, then under midrange IPCC climate sensitivity estimates, then we have around 30 years before the risk level is exceeded.

Since warming is proportional to cumulative carbon, if the climate sensitivity were really as low as Schmittner et al. estimate, then another 500 GT would take us to the same risk level, some 11 years later.

Then, if you scale the Antarctic temperature change to a global temperature change, then the global climate sensitivity to a doubling of CO2 becomes 2 - 3 degrees C, perfectly in line with the climate sensitivity given by IPCC (and known from Arrhenius's calculations more than 100 years aThen, if you scale the Antarctic temperature change to a global temperature change, then the global climate sensitivity to a doubling of CO2 becomes 2 - 3 degrees C, perfectly in line with the climate sensitivity given by IPCC (and known from Arrhenius's calculations more than 100 years athen the global climate sensitivity to a doubling of CO2 becomes 2 - 3 degrees C, perfectly in line with the climate sensitivity given by IPCC (and known from Arrhenius's calculations more than 100 years ago).

Then on page 9.5 we read «There is very high confidence that the primary factor contributing to the spread in equilibrium climate sensitivity continues to be the cloud feedback.

«Of course, if the natural trend was greater than zero — if the natural climate was warming even a little bit — then the models have the atmospheric sensitivity to CO2 even further out of whack than that.»

Another way to estimate climate sensitivity from both models AND observations is to calculate the ratio of observed warming to forecast warming... then multiply that by the ECS value used in the model.

M2009 use a range of climate sensitivities to compute a probability distribution function for expected warming, and then McKibben [255] selects the carbon emission limit that keeps 80 % of the probability distribution below 2 °C.

If true climate sensitivity is only 50 - 65 % of the magnitude that is being simulated by climate models, then it is not unreasonable to infer that attribution of late 20th century warming is not 100 % caused by anthropogenic factors, and attribution to anthropogenic forcing is in the middle tercile (50 - 50).

If the high climate sensitivity effect of the ice ages is a result of the hysteresis effect as proposed by Oerlemans and Van den Dool (1978), then the present observed sensitivity of 1K / 2xCO2 can not be much higher.

If climate sensitivity and thermal inertia are strongly connected, then that implies two extreme possibilities since the recent rate of warming is currently near the middle of the range:

If climate sensitivity was much lower than most models predict then adaptation would be a logical political response.

Other readers here know better than I, but if we presume that a 3 ˚C per doubling of CO2 is correct for climate sensitivity then the current level of 395 ppm translates into an actual temperature commitment right now of 1.41 ˚C.

(but quickly: On the point of paleoclimatic evidence: if there is a threshold below (or above) which a feedback is not activitated, then climate variations staying below (or above) that threshold would not bear on the sensitivity with that feedback.)

I thought the basic idea was that, if sulphate cooling is greater than we thought, then GHG warming must be greater than we thought, and therefore climate sensitivity must be greater than previously thought.

Just to follow - up on John Finn's question (# 10), if one puts in a rough value for the emissivity of the earth (whatever that might be), so one is no longer assuming it is a perfect blackbody, then does the resulting estimate for climate sensitivity correspond to what one would expect in the absence of any feedback effects?

But if the aerosols are contributing a net reduction of just -1.7 W / m2 (a value entirely consistent with the evidence of solar dimming), then that implies a climate sensitivity of 10K.

If indeed climate sensitivity is a significantly non-linear function of the base climate (as suggested above), then the whole concept is probably flawed.

What I mean by this is: When you plot ocean heat uptake against climate sensitivity, I get the impression that the distribution of good models will be a large clump around a climate sensitivity of 3 but then there is a long tail out towards higher sensitivities.

If aerosol forcing is high, then reconciling with recent warming demands very high climate sensitivity (which you see realized after the aerosols go away)-- and that would indeed mean we may have already passed the threshold for 2C warming.

If the other feedbacks combine to be a net positive feedback as expected, then the (Charney **) climate sensitivity for a doubling of CO2 would be around 3 K, give or take 1 K.

If climate senstivity to CO2 is eventually shown (rather than just assumed) to be close to the sensitivity to solar, I think a case can then be made that the GHG attribution should be equal or higher than the solar attribution, despite the large uncertainty in our knowledge of the increase in solar forcing.

If it is correct, then the term Equilibrium Climate Sensitivity would surely be a misnomer, in that no predictable equilibrium is achieved.

An important takeaway point from this is that with a low climate sensitivity (i.e. one with limited positive feedbacks, or counterbalancing negative feedbacks), then the ice ages can't happen.