INSTRUCTIONS
The WITCH Policy Simulator is an online tool for exploring the effects on the environment, on the energy and on the economy of different mitigation policy scenarios . In this page, you can learn how to use the interface and read a general description of available scenarios.
Using the Policy simulator
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You can start your analysis by choosing one of the four dimensions represented in the right-hand side bar: Energy, Economy, Climate, or Policy Cost. Upon pressing one of these large coloured buttons, you will land on a web page composed of two modules with:
Each of these modules allows the exploration of variables under different scenarios. The layout of the modules is explained below: simply pass your mouse over the figure to read the instructions. |
Scenarios description
The WITCH Policy simulator incorporates three different GHG stabilisation targets:
- 535 ppm CO2 equivalent, corresponding to a 2.41 °C increase above pre-industrial levels at 2100
- 640 ppm CO2 equivalent corresponding to a 2.61 °C increase above pre-industrial levels at 2100
- None (Business as Usual), corresponding to a 3.79 °C increase above pre-industrial levels of at 2100
Once you have chosen a stabilisation target, different options may be available such as avoiding certain technological and policy options or limiting the participation of some countries within a climate agreement.
The WITCH model features a series of mitigation options in the power generation sector and within other usages of energy. Mitigation options in the power sector include nuclear, hydroelectric, IGCC-CCS, renewables and a backstop option that can substitute nuclear. Nuclear power is an interesting option for decarbonised economies,however, fission still faces controversial difficulties such as long-term waste disposal and proliferation risks. The limited deployment of controversial technologies, such as nuclear options, calls for other alternative mitigation options. One technology that has received particular attention in the recent past is carbon capture and sequestration (CCS), even if a viable technology is still far from large-scale deployment. Electricity from wind and solar is another important carbon-free technology. Less flexiblity is seen within the non electric sector due to the prevalence of oil based energy. There are two major mitigation options: biomass and the deployment of a breakthrough technology. This breakthrough technology can substitute oil use and is often thought to include next generation biofuels or carbon-free hydrogen to be used in the transport sector. Finally, two important mitigation options are the endogenous improvement of overall energy efficiency with dedicated energy R&D and reducing emissions from deforestation and degradation (REDD).
The relative importance of different policy options is quantified by considering scenarios in which their deployment is restricted to the baseline level or excluded.
- LIMITED TRADING: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with limitations on the use of international offsets at most 10% of overall abatement.
- LIMITED WIND AND SOLAR: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with limitations only on the deployment of wind and solar which has been restricted to the baseline level.
- LIMITED R&D for ENERGY EFFICIENCY INNOVATION: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with limitations only on the deployment of Energy Efficiency Innovation which has been restricted to the baseline level.
- LIMITED DEPLOYMENT OF NUCLEAR: a scenario withimmediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with limitations only on the deployment of nuclear power which has been restricted to the baseline level.
- NO CCS: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with the exclusion of Carbon Capture and Sequestration (CCS) deployment.
- NO REDD: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with the exclusion of Reducing Emissions from Deforestation and Forest Degradation (REDD).
- NO BACKSTOP TECHNOLOGIES: a scenario with immediate and global collaborative action on climate change. The policies implemented in this scenario include a broad portfolio of mitigation options, with the exclusion of Innovation in Breakthrough Technologies deployment, in both the electricity and the non electricity sector.
In a realistic future there may neither be immediate action nor full participation of all countries in an international climate agreement. The relative importance of an immediate and global collaborative action on climate change is quantified by considering scenarios including either a global delay or a progressive participation. For example, reaching 535 ppm CO2-eq stabilization by 2100 remains feasible if mitigation actions at global level are postponed until 2020, even if the delay will boost global mitigation costs. With a greater proportion of regions taking early action by 2010, the global costs of stabilization decrease. The participation of large Annex I countries, such as China and India, is particularly relevant for the magnitude of mitigation costs. The WITCH model shows that early participation of Annex-I countries is particularly important, with global consumption losses in the Annex-I only scenario lower than in the Global Delay 2020 scenario.
The relative importance of different participating countries to climate agreements can be quantified by comparing scenarios with different delays in the formation of a World coalition to tackle climate change.
- ALL TECHNOLOGIES AND POLICIES AVAILABLE - NO CHINA AND INDIA: under this scenario OECD-only immediate and collaborative action on climate change begins in 2012 while China and India follow their Business as Usual emission path until 2020 whilst the Rest of Non-Annex I (RNAI) do so until 2030. The policies implemented in this scenario include a broad portfolio of mitigation options, but the delay till 2030 in the global climate agreement leads to free riding by non participating countries and to a more stringent climate stabilisation target (coupled with an increase in global mitigation costs).
- ALL TECHNOLOGIES AND POLICIES AVAILABLE - START 2020: all regions follow their Business as Usual emission path until 2020, when global collaborative action on climate change starts.The policies implemented in this scenario include a broad portfolio of mitigation options but are delayeduntil 2020 when the climate agreement leads to a stringent climate stabilisation target (coupled with an increase in global mitigation costs).