Sentences with phrase «sensitivity uncertainty range»

Not exact matches

«This is one of several recent studies that provide sobering evidence that earth's climate sensitivity may lie in the upper end of the current uncertainty range,» Mann said in an email.

The study provides sensitivity analyses of key model assumptions and starting data uncertainty, indicating that the UN projections may have too small a range of uncertainty.

Climatologists would have dearly loved to narrow the uncertainty range of climate sensitivity, but until recently there has been not enough solid evidence to justify this.

I agree (as does IPCC) that there is uncertainty, as stated, in the climate sensitivity, but you are completely unjustified in your claim that the cosmic - ray correlation (for which there is still no sound physical basis or quantified mechanism) supports the lower end of the sensitivity range.

Therefore, I wouldn't attach much credence, if any, to a modelling study that didn't explore the range of possibilities arising from such uncertainty in parameter values, and particularly in the value of something as crucial as the climate sensitivity parameter, as in this example.

For example, we know the past CO2 radiative forcing to very high accuracy, but there are more uncertainties in the aerosol forcing; applying a consistent climate sensitivity to both CO2 and aerosols, you can get a match to the observed record for a range of different supposed aerosol forcings, but you can't take it too far.

This paper suggests that models with sensitivity around 4ºC did the best, though they didn't give a formal estimation of the range of uncertainty.

It is not all that earthshaking that the numbers in Schmittner et al come in a little low: the 2.3 ºC is well within previously accepted uncertainty, and three of the IPCC AR4 models used for future projections have a climate sensitivity of 2.3 ºC or lower, so that the range of IPCC projections already encompasses this possibility.

Climatologists would have dearly loved to narrow the uncertainty range of climate sensitivity, but until recently there has been not enough solid evidence to justify this.

Cloud responses are more uncertain and that feeds in to the uncertainty in overall climate sensitivity — but the range in the AR4 models (2.1 to 4.5 deg C for 2xCO2) can't yet be constrained by paleo - climate results which have their own uncertainties.

There are reasons why the AR4 runs did not span the whole possible space of aerosol forcings & sensitivity (e.g., Kiehl, 2007, GRL) and thus do not sample the full range of uncertainty.

The uncertainty due purely to the climate sensitivity for any one scenario is around half that range.)

This paper suggests that models with sensitivity around 4ºC did the best, though they didn't give a formal estimation of the range of uncertainty.

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.

The current batch of models have a mean climate sensitivity of about 3 C to doubled CO2 (and range between 2.5 and 4.0 degrees)(Paris meeting of IPCC, July 2004), i.e an uncertainty of about 30 %.

What is clear is that uncontrolled emissions will very soon put us in range of temperatures that have been unseen since the Eemian / Stage 5e period (about 120,000 years ago) when temperatures may have been a degree or so warmer than now but where sea level was 4 to 6m higher (see this recent discussion the possible sensitivities of the ice sheets to warming and the large uncertainties involved).

Unfortunately, there are many factors that preclude an effective bound on the risks — ranging from uncertainties in downscaling to more fundamental issues such as the uncertainty of climate sensitivity.

There's no real progress in our evaluation of climate sensitivity, rather the demonstration that real progress will be very difficut to reach (worse even, the range should enlarge as we include more and more parameters for evaluation of f, so more and more uncertainty because each new parameter will have its own distribution of probability).

If you pick a modern ear baseline where you have more data and a better handle on forcings you end up with about 0.8 C — 2.0 C «sensitivity» and an uncertainty range of about + / -0.3 C degrees.

A main focus for climate science in the coming years should be to use whatever methods are available to try to limit the range of uncertainties in key climate variables like the climate sensitivity and transient climate response.

Steven, it is kinda funny that since aerosols and ocean circulation are so poorly understood, the no feedback CO2 forcing is the best understood tracer we have:) So Vaughan could reset his CO2 sensitivity to 1.0 and produce a pretty accurate range of uncertainty.

If you set goals in terms of global average temperature, then you need to feed that through the uncertainty of climate sensitivity to get the concentration of greenhouse gases — not just carbon dioxide, but the whole range of greenhouse gases.

Because of the many uncertainties involved, any estimate of climate sensitivity comes with a range, a lower and upper limit within which the real value could reasonably lie.

The reason for the «wild range» of model predictions has much more to do with the uncertainty in how emissions will play out in the coming century than it does in the climate sensitivity to CO2 forcing.

I ask that because I haven't seen evidence one way or the other that I think convincing — because I think that the uncertainties are too large in a number of ways (w / r / t to the range of sensitivity, w / r / t the massive unknowns about positive and negative externalities, w / r / t modeling future economies, etc..)

4) The spread (the range) of sensitivity, is a constraint on future uncertainty being reduced, and even if there is increased information it will increase.

In most cases, these range from about 2 to 4.5 C per doubled CO2 within the context of our current climate — with a most likely value between 2 and 3 C. On the other hand, chapter 9 describes attempts ranging far back into paleoclimatology to relate forcings to temperature change, sometimes directly (with all the attendant uncertainties), and more often by adjusting model parameters to determine the climate sensitivity ranges that allow the models to best simulate data from the past — e.g., the Last Glacial Maximum (LGM).

In summary, given the large uncertainties, I am unconvinced by Annan and Hargreave's analysis in terms of providing limits to the range of expected climate sensitivity values.

In fairness, there remains considerable uncertainty in aerosol effects, but if there will be real progress in narrowing the credible range for climate sensitivity, it has to come from reducing the still too wide uncertainty in aerosol effects, not from flogging climate models which assume aerosol offsets inconsistent with the best available measured effects.

Our method for understanding this uncertainty was to test the sensitivity of the analysis to a range of different assumptions.

You also might be interested to know that the IPCC range of uncertainty is not stratified by sensitivity across this short period.

And the range of the IPCC climate sensitivities reflects to some degree those uncertainties.

«Reducing the wide range of uncertainty inherent in current model predictions of global climate change will require major advances in understanding and modeling of both (1) the factors that determine atmospheric concentrations of greenhouse gases and aerosols, and (2) the so - called «feedbacks» that determine the sensitivity of the climate system to a prescribed increase in greenhouse gases.»

and «no data or computer code appears to be archived in relation to the paper» and «the sensitivity of Shindell's TCR estimate to the aerosol forcing bias adjustment is such that the true uncertainty of Shindell's TCR range must be huge — so large as to make his estimate worthless» and the seemingly arbitrary to cherry picked climate models used in Shindell's analysis.

The dynamic content presented here illustrates that point by showing separately the projected temperature ranges for a given choice of climate sensitivity (with uncertainty due solely to radiative forcing).

Thus the uncertainty in sensitivity itself argues for insurance against high sensitivity, and narrowing down the range (and particularly excluding the higher end) could significantly change our optimal policy response.»

Large uncertainties remain, but that's exactly the reason for the wide uncertainty range of climate sensitivity acknowledged by IPCC.

Energy budget estimates of equilibrium climate sensitivity (ECS) and transient climate response (TCR) are derived based on the best estimates and uncertainty ranges for forcing provided in the IPCC Fifth Assessment Scientific Report (AR5).

The wide range of estimates of climate sensitivity is attributable to uncertainties about the magnitude of climate feedbacks (e.g., water vapor, clouds, and albedo).

Energy budget estimates of equilibrium climate sensitivity (ECS) and transient climate response (TCR) are derived using the comprehensive 1750 — 2011 time series and the uncertainty ranges for forcing components provided in the Intergovernmental Panel on Climate Change Fifth Assessment Working Group I Report, along with its estimates of heat accumulation in the climate system.

Also, it is very clear (from the SOD) that there is little dispute about the range of the TCR, but there is still uncertainty about the long tail of the Equilibrium Climate Sensitivity, which (according to the SOD) is still kind of determined by an «expert consensus».

I strongly suggest you read the articles that are referred to in chapter 9 to understand how they calculate climate sensitivity and the uncertainty ranges therein.

Each effect is given in terms of its impact on the mean airborne fraction over the simulation period (typically 1860 to 2100), with bars showing the uncertainty range based on the ranges of effective sensitivity parameters given in Tables 7.4 and 7.5.

Knutti and Hegerl in the November, 2008 Natural Geoscience paper, The equilibrium sensitivity of the Earth's temperature to radiation changes, says various observations favor a climate sensitivity value of about 3 degrees C, with a likely range of about 2 — 4.5 degrees C per the following graphic whereas the current IPCC uncertainty is range is between 1.5 - 4.5 degrees C.

Barring a dramatic breakthrough in reconciliation of some long - standing differences in the magnitude of paleotemperature estimates for different proxies, the range of paleo - sensitivities will continue to have this uncertainty.

I think there is likewise no consensus on the studies that have recently argued for a lower climate sensitivity, yet the IPCC has widened the uncertainty range to encompass them.

We investigate the sensitivity of our results to uncertainties in the prescribed CO2 and orographic changes, to derive uncertainty ranges for the various contributing processes.

They use a group of climate models — characterized as «an ensemble of opportunity» in AR4 — that don't reflect the full range of uncertainty in our knowledge of climate sensitivity.

It is clear you do not like statements like «the current AOGCMs may not cover the full range of uncertainty for climate sensitivity».

climate sensitivity is provided as a range of estimates due to underlying uncertainty in the behaviour of some aspects of the climate system as the planet warms.