Sentences with phrase «best estimate of climate sensitivity»

This new study found that accounting for the efficacy of historical forcings changes the best estimate of climate sensitivity from analysis of the instrumental period.

Did you notice how everyone wrote a lot of meaningless words, but no one actually challenged your work that concluded that the best estimate of climate sensitivity (ECS) of only 1.6 C using IPCC data?

A best estimate of climate sensitivity close to 3 °C for doubled CO2 has been inferred from paleoclimate data [51]--[52].

If the climate sensitivity is a function of temperature, then the current discussion about the best estimate of climate sensitivity is misdirected.

I tend to believe that including the recent years will, indeed, lower the best estimate of climate sensitivity and, hopefully, allow for a more reliable upper limit.

In the final report from CLIMSENS Berntsen et al has calculated their best estimate of climate sensitivity to be 1.9 °C.

while the «best estimate of climate sensitivity is 3.3 K».

A best estimate of climate sensitivity close to 3 °C for doubled CO2 has been inferred from paleoclimate data [51]--[52].

This is of first importance for better estimates of the climate sensitivity.

The best estimates of climate sensitivity (around 3 deg.C per doubling of CO2) indicate that that's too much — in agreement with the conclusion from the model - data comparison.

Comparing the trend in global temperature over the past 100 - 150 years with the change in «radiative forcing» (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.

Not exact matches

When Otto calculated the climate sensitivity from his data, he found it was about 2 °C — with a range of 0.9 to 5 °C — well below the IPCC's best estimate of 3 °C.

«Our estimates of climate sensitivity lie well within the range of 1.5 to 4.5 ºC increase per CO2 doubling summarised in the latest IPCC report.

«My view on this is that the research needs to broaden out to have more of a focus on variability more generally so that a) we can predict the next few years better b) we can refine our estimates of the sensitivity of the climate system to increases in greenhouse gas concentrations.»

Well while they are «dialing back» their estimate of «Climate Sensitivity», that legacy of presumably the late Dr Stephen Schneider, they might also consider the claim that: -

The NGN article itself gives a good explanation of climate sensitivity and the various studies and estimates of it, and does quote Michael Schlesinger of the University of Illinois saying that Hegerl's result «means climate sensitivity is larger than we thought for 30 years, so the problem is worse than we thought.

Note that the old GISS model had a climate sensitivity that was a little higher (4.2 ºC for a doubling of CO2) than the best estimate (~ 3ºC) and as stated in previous years, the actual forcings that occurred are not the same as those used in the different scenarios.

«the long fat tail that is characteristic of all recent estimates of climate sensitivity simply disappears, with an upper 95 % probability limit... easily shown to lie close to 4 °C, and certainly well below 6 °C.»

A combination of circumstances makes model - based sensitivity estimates of distant times and different climates hard to do, but at least we are getting a good education about it.

It bears noting that even if the SEA mean estimate were correct, it still lies well above the ever - more implausible estimates of those that wish the climate sensitivity were negligible.

There are two recent papers on paleo constraints: the already mentioned PALAEOSENS (2012) paper which gives a good survey of existing estimates from paleo - climate and the hierarchy of different definitions of sensitivity.

The Schmittner et al. analysis marks the insensitive end of the spectrum of climate sensitivity estimates based on LGM data, in large measure because it used a data set and a weighting that may well be biased toward insufficient cooling.

The NGN article itself gives a good explanation of climate sensitivity and the various studies and estimates of it, and does quote Michael Schlesinger of the University of Illinois saying that Hegerl's result «means climate sensitivity is larger than we thought for 30 years, so the problem is worse than we thought.

Dan has yet to acknowledged is that the fossil record clearly shows that the best value of the known feedbacks, whatever their «exact» values may be, are included in the IPCC's approximate estimate of the climate sensitivity, and that this is strongly supported by the GCMs.

This is also a good recent presentation of the various estimates of climate sensitivity and of the amount of uncertainty associated with them — found by doing a Google image search on the terms:

The obvious answer (from someone who is indeed receptive to arguments for lower - than - consensus climate sensitivities) is that it was on a par with recent hot years because temperatures at US latitudes of the globe really weren't as much cooler in the 1930s / 1940s (compared to the present) than GISS / Hadley's best estimates (from often sketchy global coverage) suggest.

Temperature and CO2 are scaled relative to each other according to the physically expected CO2 effect on climate (i.e. the best estimate of transient climate sensitivity).

Your attempt to estimate equilibrium climate sensitivity from the 20th C won't work because a) the forcings are not that well known (so the error in your estimate is large), b) the climate is not in equilibrium — you need to account for the uptake of heat in the ocean at least.

Do you think that in the same way that the Solanki et al paper on solar sunspot reconstructions had a specific statement that their results did not contradict ideas of strong greenhouse warming in recent decades, this (the fact that climate sensitivity projections are not best estimates of possible future actual temperature increases) should be clearly noted in media releases put out by scientists when reporting climate sensitivity studies?

I think that the vast majority of lay readers who read the headlines and the text of stories on climate sensitivity do not know this and they simply presume that the scientists concerned are talking about their absolute best estimates of the possible temperature increases which may be faced.

As stated last year, the Scenario B in that paper is running a little high compared with the actual forcings growth (by about 10 %)(and high compared to A1B), and the old GISS model had a climate sensitivity that was a little higher (4.2 ºC for a doubling of CO2) than the best estimate (~ 3ºC).

In particular, Annan and Hargreaves (2006) used a Bayesian statistical approach that combines information from both 20th century observations and from last glacial maximum data to produce an estimate of climate sensitivity that is much better constrained than by either set of observations alone (see our post on this, here).

The IPCC range, on the other hand, encompasses the overall uncertainty across a very large number of studies, using different methods all with their own potential biases and problems (e.g., resulting from biases in proxy data used as constraints on past temperature changes, etc.) There is a number of single studies on climate sensitivity that have statistical uncertainties as small as Cox et al., yet different best estimates — some higher than the classic 3 °C, some lower.

What's new is that several recent papers have offered best estimates for climate sensitivity that are below four degrees Fahrenheit, rather than the previous best estimate of just above five degrees, and they have also suggested that the highest estimates are pretty implausible.

But 3,2 °C is the best estimate for equilibrium climate sensitivity (that is when the runs of models consider all the feedbacks).

What I still miss is, for climate sensitivity at 2xCO2 (540 ppm) we're discussing here, how you «jump» from a best estimate of 3 °C to 6 °C.

But they don't seem to provide informative enough data to enable a well constrained estimate of climate sensitivity to be obtained.

(ppm) Year of Peak Emissions Percent Change in global emissions Global average temperature increase above pre-industrial at equilibrium, using «best estimate» climate sensitivity CO 2 concentration at stabilization (2010 = 388 ppm) CO 2 - eq.

These values have been estimated using relatively simple climate models (one low - resolution AOGCM and several EMICs based on the best estimate of 3 °C climate sensitivity) and do not include contributions from melting ice sheets, glaciers and ice caps.

The right - hand panel shows ranges of global average temperature change above pre-industrial, using (i) «best estimate» climate sensitivity of 3 °C (black line in middle of shaded area), (ii) upper bound of likely range of climate sensitivity of 4.5 °C (red line at top of shaded area)(iii) lower bound of likely range of climate sensitivity of 2 °C (blue line at bottom of shaded area).

My estimate that, since there is no CO2 signal in any modern temperature / time graph, the value of climate sensitivity is probably indistinguishable from zero, is a much simpler way of doing the estimations, and is probably as good as any other guess.

However as we document in the Lewis / Crok report, the IPCC was well aware of these recently published lower estimates of climate sensitivity.

What would happen if an unbiased assessment of climate sensitivity were 1.5 - 3.0 degK with a best estimate of 2.0 degK?

However, because climate scientists at the time believed a doubling of atmospheric CO2 would cause a larger global heat imbalance than today's estimates, the actual climate sensitivities were approximatly 18 % lower (for example, the «Best» model sensitivity was actually closer to 2.1 °C for doubled CO2).

However, as in the FAR, because climate scientists at the time believed a doubling of atmospheric CO2 would cause a larger global heat imbalance than current estimates, the actual «best estimate» model sensitivity was closer to 2.1 °C for doubled CO2.

Assuming the same climate sensitivity, Lindzen's estimate of a 2.5 °C drop for a -30 W / m2 forcing would imply that currently doubling CO2 would warm the planet by only a third of a degree at equilibrium, which is well outside the bounds of IPCC estimates and even very low by most skeptical standards.

It appears that the Hansen Scenario B performed fairly well, with an overestimated trend consistent with its estimate of climate sensitivity at what is now considered to be toward the high end of the likely range (although of course, Hansen continues to estimate climate sensitivity at higher levels than most other observers).

It also states, «No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.»

Note 16 «No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.»

Spectral radiance emitted to space consistent with Tyndall gas concentrations (confirms ability to calculate radiative forcing); magnitude of Tyndall gas radiative forcing larger than that of all other known forcing agents; observed temperature changes similar in magnitude to those estimated from forcings (confirms ballpark estimates of climate sensitivity); observed pattern of temperature changes match Tyndall gas pattern better than that of all other known forcing agents.