Climate system modeling in the framework of the tolerable windows approach: The ICLIPS climate model

The computational burden associated with applications of theTolerable Windows Approach (TWA) considerably exceeds that oftraditional integrated assessments of global climate change. Aspart of the ICLIPS (Integrated Assessment of Climate ProtectionStrategies) project, a computationally efficient climate model hasbeen developed that can be included in integrated assessmentmodels of any kind. The ICLIPS climate model (ICM) is implementedin GAMS. It is driven by anthropogenic emissions of CO2,CH4, N2O, halocarbons, SF6, andSO2. Theoutput includes transient patterns of near-surface airtemperature, total column-integrated cloud cover fraction,precipitation, humidity, and global mean sea-level rise. Thecarbon cycle module explicitly treats the nonlinear sea watercarbon chemistry and the nonlinear CO2 fertilized biosphereuptake. Patterns of the impact-relevant climate variables arederived form empirical orthogonal function (EOF) analysis andscaled by the principal component of temperature change. Theevolution of the latter is derived from a box-model-typedifferential analogue to its impulse response function convolutionintegral. We present a description of the ICM components and someresults to demonstrate the model's applicability in the TWA setting

WIATEC: A World Integrated Assessment Model of Global Trade Environment and Climate Change

This paper describes the structure of the World Integrated Assessment model of global Trade, Environmental, and Climate change (WIATEC).The model consists of a multi-regional multi-sectoral core CGE model linked to a climate model. The core CGE is based on an existing global trade and environment model called GTAP-E (Truong, 1999; Burniaux and Truong, 2002). A suite of different and interchangeable 'modules' are then built around this 'core' to enable the model to be able to handle a range of different policy issues such as CO2 emissions, abatement, trading, non-CO2 (CH4 and N2O) emissions, land use land use change and forestry (LULUCF) activities, and changing technologies in the electricity generation sector. The approach which uses a core model structure with different additional modules built around this core structure allows the overall model to be flexible and can be adapted to a range of different policy issues. We illustrate the usefulness of this approach in a policy experiment which looks at the interaction between emissions trading scheme and the promotion of renewable energy targets in the European Union climate policy

The substitution of high-resolution terrestrial biosphere models and carbon sequestration in response to changing CO₂ and climate

Strategies are developed to analyze and represent spatially resolved biosphere models for carbon sequestration in response to changes in atmospheric CO2 and climate by reduced-form, substitute models. We explore the High-Resolution Terrestrial Biosphere Model as implemented in the Community Terrestrial Biosphere Model (HRBM/CTBM), the Frankfurt Biosphere Model (FBM), and the box-type biosphere of the Bern model. Storage by CO2 fertilization is described by combining analytical representations of (1) net primary productivity (NPP) as a function of atmospheric CO2 and (2) a decay impulse response function to characterize the timescales of biospheric carbon turnover. Storage in response to global warming is investigated for the HRBM/CTBM. The relation between the evolution of radiative forcing and climate change is expressed by a combination of impulse response functions and empirical orthogonal functions extracted from results of the European Center/Hamburg (ECHAM3) coupled atmosphere-ocean general circulation model. A box-type, differential-analogue substitute model is developed to represent global carbon storage of the HRBM/CTBM in response to regional changes in Temperature, Precipitation and cloud cover. The substitute models represent the spatially resolved models accurately and cost-efficiently for carbon sequestration in response to changes in CO2 or in CO2 and climate and for simulations of the global isotopic signals. Deviations in carbon uptake simulated by the spatially resolved models and their substitutes are less than a few percent. [References: 65

The substitution of high-resolution terrestrial biosphere models and carbon sequestration in response to changing CO2 and climate

Strategies are developed to analyze and represent spatially resolved biosphere models for carbon sequestration in response to changes in atmospheric CO2 and climate by reduced-form, substitute models. We explore the High-Resolution Terrestrial Biosphere Model as implemented in the Community Terrestrial Biosphere Model (HRBM/CTBM), the Frankfurt Biosphere Model (FBM), and the box-type biosphere of the Bern model. Storage by CO2 fertilization is described by combining analytical representations of (1) net primary productivity (NPP) as a function of atmospheric CO2 and (2) a decay impulse response function to characterize the timescales of biospheric carbon turnover. Storage in response to global warming is investigated for the HRBM/CTBM. The relation between the evolution of radiative forcing and climate change is expressed by a combination of impulse response functions and empirical orthogonal functions extracted from results of the European Center/Hamburg (ECHAM3) coupled atmosphere-ocean general circulation model. A box-type, differential-analogue substitute model is developed to represent global carbon storage of the HRBM/CTBM in response to regional changes in Temperature, Precepitation and cloud cover. The substitute models represent the spatially resolved models accurately and cost-efficiently for carbon sequestration in response to changes in CO2 or in CO2 and climate and for simulations of the global isotopic signals. Deviations in carbon uptake simulated by the spatially resolved models and their substitutes are less than a few percent