Home
| | Home | | My BADC | | Data | | Search | | Community | | Help | |
 | Get Data | Access Rules | Submit Data | Dataset Index |  |
Introduction
The IPCC estimates of climate sensitivity to a doubling of CO2 ranged from ~1.5 to 4.5 deg.C, a range that creates difficulty in defining and tackling "dangerous" climate change. The DEFRA-funded project QUMP (Quantifying Uncertainties in Model Prediction) investigated the effects of parametrization on sensitivity by running a series of simulations of the modern climate, systematically altering parameter values and comparing them with observations. QUMP found that the constraints supplied by recent observations of climate did not reduce uncertainties in prediction.
PalaeoQUMP aims to constrain climate sensitivity better, by using a wider range of derived climate observations from the geological past (reconstructions from sediments and geomorphological changes for the Last Glacial Maximum and the mid-Holocene period), to evaluate climate model predictions generated using the same series of simulations as QUMP produced for the modern climate.
Scientific issues and rational Estimates of the climate sensitivity to a doubling of CO2, based on multiple climate models, are in the range of 1.5-4.5 deg.C (Houghton et al., 2001). One source of uncertainty in these estimates comes from uncertainties in the values assigned to key processes that are parameterised in current models.
The DEFRA-funded Quantifying Uncertainties in Model Predictions (QUMP) project has perturbed parameters in the HadSM3 model to determine the range of climate changes consistent with the uncertainties in modelling key processes. The resulting probability density function for the sensitivity of the climate to a doubling of CO2 has been constrained by weighting different model versions using estimates of reliability from a climate prediction index (CPI) based on a broad range of observed modern climate variables. On the basis of a 53-member ensemble of perturbed-physics model versions, the 5-95% probability range for climate sensitivity is 2.4-5.4 deg.C (Murphy et al., 2004). This means that the constraints supplied by recent observations of mean climate are insufficient to limit uncertainties in prediction.
A similar study in which many more ensemble experiments were made has shown the possibility of very high climate sensitivities (Stainforth et al., 2005: climateprediction.net). Stronger constraints may be derived from records of different climatic conditions in the past.
Our aim is to derive further constraints based on the existence of robust, quality-controlled global palaeoenvironmental datasets for the mid-Holocene (MH: 6000 yr B.P.) and Last Glacial Maximum (LGM: 21,000 yr B.P.), which show strong, regionally-coherent signals in response to large and well-known changes in climate forcing, specifically changes in the latitudinal and seasonal distribution of insolation during the MH and the existence of large ice sheets, cold oceans and lowered greenhouse gases at the LGM. The signals of regional climate change are sufficiently robust to provide ideal sources of additional constraints on model uncertainties.
Availability of data and file format
The data filenames should follow the BADC File Name convention and the data file format should be NetCDF or NASA-Ames.
Access to data and information
Please refer to the QUEST Conditions of Access page for details on access restrictions.
Links and References
References:
Tamsin L. Edwards, Michel Crucifix, and Sandy P. Harrison. (2007). Using the past to constrain the future: how the palaeorecord can improve estimates of global warming. Progress in Physical Geography, 31:5, 481-500
Citation
Who to contact
Each QUEST project will have a designated "data co-ordinator" to ensure good communication with the QUEST core team/BADC regarding data issues, and to ensure that each project meets its data provision obligations. The data co-ordinator for the PalaeoQUMP project is to be determined.
 | Home | Contact | Disclaimer | Last Modified:
|  |
Back to QUEST Home page