Details of Award
NERC Reference : NER/B/S/2003/00884
Impact of soil carbon decomposition on future global climate.
Grant Award
- Principal Investigator:
- Professor D Powlson, BBSRC Institute of Arable Crops Research, UNLISTED
- Co-Investigator:
- Dr T Falloon, BBSRC Institute of Arable Crops Research, UNLISTED
- Co-Investigator:
- Professor AP Whitmore, Rothamsted Research, Net Zero and Resilient Farming
- Grant held at:
- BBSRC Institute of Arable Crops Research, UNLISTED
- Science Area:
- Terrestrial
- Atmospheric
- Overall Classification:
- Atmospheric
- ENRIs:
- Global Change
- Science Topics:
- Land - Atmosphere Interactions
- Biogeochemical Cycles
- Soil science
- Climate & Climate Change
- Abstract:
- Climate-carbon cycle feedbacks over the next century could have significant impacts on future CO2 levels and climate . The magnitude of this feedback and whether or not it drives the terrestrial C cycle to become a net source of CO2 during the next century depends critically on the response of soil respiration to temperature, and, to a lesser extent, to moisture. HADCM3LC is one of the foremost global circulation models (GCMs) in use at the current time, and predictions of future climate from HADCM3 (the parent model) have been included in the Intergovernmental Panel for Climate Change (IPCCs) assessments. HADCM3LC incorporates a simple, single pool model for soil carbon decomposition (HADCM3LC-DM), and its coupling with the dynamic global vegetation model TRIFFID enables soil-climate-vegetation feedbacks to be simulated. The RothC-26.3 model is one of the most widely used multi-pool soil carbon models worldwide, and recent model evaluations have shown the model to be able to accurately reproduce observed long-term trends in soil C stocks for different climates, soil types and land uses. Thus RothC should be able to more accurately predict soil carbon fluxes than HADCM3LC. Previous climate change studies using RothC at the global scale for Holdridge life zones, and driven by GCM output data from HADCM3LC at 1km level in the UK have shown there could be significant increases in releases from soils due to changes in temperature. However, neither of these studies accounted for feedback mechanisms, such as the enhanced temperature rise as a result of additional CO2 derived from the decomposition of soil C, or for changes in net primary production (NPP), which would absorb atmospheric CO2. Failure to accurately represent these processes within a GCM could lead to significant errors in the predicted future climate. A fully integrated modelling approach must be taken to fully capture the feedbacks in the soil-plant-atmosphere system and to understand important controls of climate change. Former studies with HADCM3LC have shown that the terrestrial vegetation also has a key role to play in climate feedbacks. Since changes in NPP will affect changes in soil C via litter fall and C input, linking RothC to HADCM3LC will be a crucial step in improving prediction of soil-vegetation-climate feedbacks. We propose to conduct investigative work towards incorporating the RothC model into the HADCM3LC framework, in order to improve predictions of future climate from HADCM3LC. We will use HADCM3LC-DM and RothC offline from the climate model, driven by averaged monthly forcings (temperature, rainfall and evaporation) from several climate scenarios. Recent work has shown that HADCM3LC-DM run in this way reproduces its behaviour when fully integrated into the climate model. This will enable some of the forcing data to be held constant in order to examine which are most important in determining soil C changes. Full analysis of feedbacks will only be possible through formally linking RothC and HADCM3LC, which will be conducted by the Hadley Centre following successful model testing. Since HADCM3LC also predicts soil moisture and soil temperature, whilst RothC simply assumes soil temperature to equal air temperature and has a simple soil water module, RothC will also be tested using soil temperature and moisture outputs from HADCM3LC. The project will be undertaken in the Agriculture and Environment Division at Rothamsted Research, which has a long history of carbon cycle modelling research, in collaboration with the Hadley Centre. The total costs will be #27,380. This work relates directly to the fundamental research questions outlined in NERC's strategic plan Science for a Sustainable Future 2002-2007, under the theme Climate Change - Predicting and Mitigating the Impacts ('What are the biological and geological feedbacks on the climate system in response to climate change?', and 'When do current terrestrial C sinks .....etc (too many words)
- NERC Reference:
- NER/B/S/2003/00884
- Grant Stage:
- Completed
- Scheme:
- Small Grants Pre FEC
- Grant Status:
- Closed
- Programme:
- Small Grants
This grant award has a total value of £28,104
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs | Total - Equipment | Total - Indirect Costs |
|---|---|---|---|---|
| £15,133 | £308 | £4,203 | £1,500 | £6,961 |
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