Why Is Climate Sensitivity So Unpredictable?

@article{Roe2007WhyIC,
  title={Why Is Climate Sensitivity So Unpredictable?},
  author={G. Roe and M. Baker},
  journal={Science},
  year={2007},
  volume={318},
  pages={629 - 632}
}
Uncertainties in projections of future climate change have not lessened substantially in past decades. Both models and observations yield broad probability distributions for long-term increases in global mean temperature expected from the doubling of atmospheric carbon dioxide, with small but finite probabilities of very large increases. We show that the shape of these probability distributions is an inevitable and general consequence of the nature of the climate system, and we derive a simple… Expand
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References

SHOWING 1-10 OF 60 REFERENCES
Uncertainty in predictions of the climate response to rising levels of greenhouse gases
TLDR
Results from the ‘climateprediction.net’ experiment are presented, the first multi-thousand-member grand ensemble of simulations using a general circulation model and thereby explicitly resolving regional details, finding model versions as realistic as other state-of-the-art climate models but with climate sensitivities ranging from less than 2 K to more than 11’K. Expand
Climate sensitivity constrained by temperature reconstructions over the past seven centuries
TLDR
An independent estimate of climate sensitivity is found that is very similar to those from instrumental data, and if the latter are combined with the result from all proxy reconstructions, then the 5–95 per cent range shrinks, thus substantially reducing the probability of very high climate sensitivity. Expand
Quantifying Uncertainties in Climate System Properties with the Use of Recent Climate Observations
We derive joint probability density distributions for three key uncertain properties of the climate system, using an optimal fingerprinting approach to compare simulations of an intermediateExpand
Climate sensitivity constrained by CO2 concentrations over the past 420 million years
TLDR
Long-term equilibrium climate sensitivity is estimated by modelling carbon dioxide concentrations over the past 420 million years and comparing the calculations with a proxy record to indicate that a weak radiative forcing by carbon dioxide is highly unlikely on multi-million-year timescales. Expand
An Observationally Based Estimate of the Climate Sensitivity
Abstract A probability distribution for values of the effective climate sensitivity, with a lower bound of 1.6 K (5th percentile), is obtained on the basis of the increase in ocean heat content inExpand
Quantification of modelling uncertainties in a large ensemble of climate change simulations
TLDR
A systematic attempt to determine the range of climate changes consistent with these uncertainties, based on a 53-member ensemble of model versions constructed by varying model parameters, which produces a range of regional changes much wider than indicated by traditional methods based on scaling the response patterns of an individual simulation. Expand
Constraining climate forecasts: The role of prior assumptions
[1] Any attempt to estimate climate sensitivity using observations requires a set of models or model-versions that simultaneously predict both climate sensitivity and some observable quantity(-ies)Expand
How Well Do We Understand and Evaluate Climate Change Feedback Processes
Processes in the climate system that can either amplify or dampen the climate response to an external perturbation are referred to as climate feedbacks. Climate sensitivity estimates dependExpand
Constraints on climate change from a multi‐thousand member ensemble of simulations
[1] The first multi thousand member “perturbed physics” ensemble simulation of present and future climate, completed by the distributed computing project climateprediction.net, is used to search forExpand
Objective estimation of the probability density function for climate sensitivity
The size and impacts of anthropogenically induced climate change (AICC) strongly depend on the climate sensitivity, ΔT2x. If ΔT2x is less than the lower bound given by the Intergovernmental Panel onExpand
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