Climate Change Mitigation Scenarios Research Articles

Hedging the climate sensitivity risks of a temperature target

This paper addresses the problem of meeting a predetermined temperature target cost-effectively under uncertainty and gradual learning on climate sensitivity. The firstorder optimality conditions to a stochastic cost-minimization problem with a temperature constraint are first provided, portraying how marginal costs evolve with an optimal hedging strategy. Then, numerical stochastic scenarios with cost curves fitted to recent climate changemitigation scenarios are presented, illustrating both the range of possible future pathways and the effect of uncertainty to the solution. Last, the effect of several different sets of assumptions on the optimal hedging strategy are analyzed. The results highlight that the hedging of climate sensitivity risk calls for deeper early reductions, although the possibility of different assumptions prevents providing accurate policy guidance.

Water Distribution System Rehabilitation under Climate Change Mitigation Scenarios in Canada

Many countries are considering policy instruments such as a carbon tax and economic discounting to reduce greenhouse gas (GHG) emissions in key sectors like the water sector. This paper examines the impact of economic discounting and a carbon tax on the optimization of water main rehabilitation. A new pipe rehabilitation optimization algorithm that accounts for GHGs was developed and applied to the Fairfield water distribution system in Amherstview, Ontario, Canada. GHG intensity factors for the provinces of Ontario (low-carbon) and Alberta (high-carbon) were applied to the Fairfield network. In both cases, adopting a low discount rate and levying a carbon tax had a weak effect in reducing energy use, GHG emissions, pipe breaks, and leakage. Further, a low discount rate and a carbon tax encouraged the search process to invest in rehabilitation early in the planning period to reduce continuing leakage, pipe repair, energy, and GHG costs.

The role of renewable energy in climate stabilization: results from the EMF27 scenarios

This paper uses the EMF27 scenarios to explore the role of renewable energy (RE) in climate change mitigation. Currently RE supplies almost 20 % of global electricity demand. Almost all EMF27 mitigation scenarios show a strong increase in renewable power production, with a substantial ramp-up of wind and solar power deployment. In many scenarios, renewables are the most important long-term mitigation option for power supply. Wind energy is competitive even without climate policy, whereas the prospects of solar photovoltaics (PV) are highly contingent on the ambitiousness of climate policy. Bioenergy is an important and versatile energy carrier; however—with the exception of low temperature heat—there is less scope for renewables other than biomass for non-electric energy supply. Despite the important role of wind and solar power in climate change mitigation scenarios with full technology availability, limiting their deployment has a relatively small effect on mitigation costs, if nuclear and carbon capture and storage (CCS)—which can serve as substitutes in low-carbon power supply—are available. Limited bioenergy availability in combination with limited wind and solar power by contrast, results in a more substantial increase in mitigation costs. While a number of robust insights emerge, the results on renewable energy deployment levels vary considerably across the models. An in-depth analysis of a subset of EMF27 reveals substantial differences in modeling approaches and parameter assumptions. To a certain degree, differences in model results can be attributed to different assumptions about technology costs, resource potentials and systems integration.

Impacts of different diffusion scenarios for mitigation technology options and of model representations regarding renewables intermittency on evaluations of CO2 emissions reductions

This paper evaluated the impacts of climate change mitigation technology options on CO2 emission reductions and the effects of model representations regarding renewable intermittency on the assessment of reduction by using a world energy systems model. First, different diffusion scenarios for carbon dioxide capture and storage (CCS), nuclear power, and wind power and solar PV are selected from EMF27 scenarios to analyze their impacts on CO2 emission reductions. These technologies are important for reducing CO2 intensity of electricity, and the impacts of their diffusion levels on mitigation costs are significant, according to the analyses. Availability of CCS in particular, among the three kinds of technologies, has a large impact on the marginal CO2 abatement cost. In order to analyze effects of model representations regarding renewables intermittency, four different representations are assumed within the model. A simplistic model representation that does not take into consideration the intermittency of wind power and solar PV evaluates larger contributions of the energy sources than those evaluated by a model representation that takes intermittency into consideration. Appropriate consideration of renewables intermittency within global energy systems models will be important for realistic evaluations of climate change mitigation scenarios.

Future nuclear perspectives based on MESSAGE integrated assessment modeling

Nuclear energy has the potential to be a vital component toward a clean energy strategy – but future energy systems may or may not include nuclear power. This study explores a range of future nuclear pathways consistent with different levels of energy demand, and explicitly assesses the implications of a potential global nuclear energy phase-out. In our scenarios the mitigation of climate change is one of the main factors driving a much needed transformation of the global energy system. A range of climate change mitigation scenarios is outlined and compared to a business-as-usual case. The scenarios are characteristic of different approaches to climate mitigation, including alternative combinations of supply and demand-side changes. Our analysis indicates that under a comprehensive and global mitigation effort, the stabilization of GHG concentrations at low levels (450 ppm CO2) would be technically achievable even at high energy demand and with a nuclear phase-out. We identify that significant investments in energy efficiency improvements and demand reduction offer the most flexibility in energy supply options and may or may not include nuclear power.

Comparing the impacts of mitigation versus non‐intervention scenarios on future temperature and precipitation extremes in the HadGEM2 climate model

Although international climate change negotiations focus on global mean temperature targets, it is also important to assess the impact of emission scenarios on climate extremes at the global and regional scale. This paper examines how temperature and precipitation extremes indices are projected to change around the globe during the 21st Century under an aggressive climate change mitigation scenario in the United Kingdom Met Office Hadley Centre HadGEM2‐AO coupled climate model, and how these changes might differ from a mid‐range non‐intervention scenario. Even under an aggressive mitigation strategy there are projected increases in warm temperature extremes on a global and regional scale up to the mid‐21st Century, and temperature extremes tend to follow a similar trajectory to the projected global mean temperature change associated with each scenario. Changes in precipitation‐related extremes are projected to be more variable. There are regional differences in the direction of changes and it appears that the aerosol forcing associated with the scenarios could have an important influence. The regions which are projected to benefit most from mitigation vary depending on the index being considered, but in general absolute increases in temperature extremes are reduced in the northern midlatitudes, whereas for frequency based indices it is northern South America, parts of the USA, Africa and Asia which see the largest avoided increases. For precipitation indices, northern South America sees the most consistent signal toward avoided drying conditions, along with the Mediterranean and parts of Russia and central Asia.

Green occupants for green buildings: The missing link?

Green buildings, often defined as those featuring natural ventilation capabilities, i.e. low-energy or free-running buildings, are now at the forefront of building research and climate change mitigation scenarios. This paper follows the results of recent post-occupancy evaluation (POE) surveys within two academic office buildings located in sub-tropical Sydney, Australia. Supplemented with an environmental attitudes questionnaire, based upon the New Ecological Paradigm [1]), it was found that occupant satisfaction levels on the POE were positively associated with environmental beliefs. Occupants with higher levels of environmental concern were more forgiving of their building, particularly those featuring aspects of green design, such as natural ventilation through operable windows. Despite their criticisms of the building’s indoor environmental quality, the ‘green’ occupants were prepared to overlook and forgive less-than-ideal conditions more so than their ‘brown’ (non-green) counterparts. These results support the hypothesis that pro-environmental attitudes are closely associated with the stronger ‘forgiveness factor’ often observed in green buildings, but the question of causality remains moot.

A Scenario Evaluation Model for the Application of CO2 and Air Pollutant Reduction Policies

In this work, the authors present a mathematical model capable of calculating CO2, NOx and PM emissions, based on statistical data for emission sources at country level. The underlying methodology has been based on both the IPCC guidelines and the EMEP/CORINAIR air pollutant emission inventory guidebook. The case study focuses on Cyprus and investigates the application of specific climate change mitigation scenarios. The key results of the study show that an increased use of biomass and diesel can promote decarbonisation, but fail to reduce air pollution, while hybrid technologies and natural gas offer significant improvements for both goals.

Managing carbon emissions: A discursive presentation of ‘market-driven sustainability’ in the British media

The article studies discursive (re)construction of market-based solutions to climate change through the use of so-called ‘carbon compounds’-lexical combinations of at least two roots such as carbon footprint – in the UK national newspapers between 1990 and 2009. Applying techniques of corpus-assisted discourse analysis, compounds are identified and grouped according to their frequency and chronological appearance. The analysis then focuses on (1) finance compounds used between 1990 and 2005 and (2) compounds modified by low-, zero- carbon and carbon neutral which became popular after 2005. It is argued that the representation of market-based initiatives with the help of carbon compounds has restricted the debate on climate change mitigation scenarios by relying on calculation and monetization of emissions as the starting point.

A review of recent developments in climate change science. Part II: The global-scale impacts of climate change

This article presents a review of recent developments in studies assessing the global-scale impacts of climate change published since the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Literature covering six main impact sectors is reviewed: sea-level rise (SLR) and coastal impacts, ocean acidification, ecosystems and biodiversity, water resources and desertification, agriculture and food security, and human health. The review focuses on studies with a global perspective to climate change impacts assessment, although in the absence of global studies for some sectors or aspects of impacts, national and regional studies are cited. The review highlights three major emerging themes which are of importance for the policy- and decision-making process: (1) a movement towards probabilistic methods of impacts assessment and/or the consideration of climate modelling uncertainty; (2) a move towards assessing potential impacts that could be avoided under different climate change mitigation scenarios relative to a business-as-usual reference scenario; and (3) uncertainties that remain in understanding the relationship between climate and natural or human systems. Whether recent impact assessments show a changed risk of damage to human or natural systems since the AR4 depends upon the impact sector; whether the assessments are robust or not (i.e. will stand the test of time) requires additional expert judgement. However, using this judgement, overall we find an increased risk to natural systems, and in some components of human systems.

Bio-IGCC with CCS as a long-term mitigation option in a coupled energy-system and land-use model

Abstract This study analyses the impact of techno-economic performance of the BIGCC process and the effect of different biomass feedstocks on the technology’s long term deployment in climate change mitigation scenarios. As the BIGCC technology demands high amounts of biomass raw material it also affects the land-use sector and is dependent on conditions and constraints on the land-use side. To represent the interaction of biomass demand and supply side the global energy-economy-climate model ReMIND is linked to the global land-use model MAgPIE. The link integrates biomass demand and price as well as emission prices and land-use emissions. Results indicate that BIGCC with CCS could serve as an important mitigation option and that it could even be the main bioenergy conversion technology sharing 33% of overall mitigation in 2100. The contribution of BIGCC technology to long-term climate change mitigation is much higher if grass is used as fuel instead of wood, provided that the grass-based process is highly efficient. The capture rate has to significantly exceed 60% otherwise the technology is not applied. The overall primary energy consumption of biomass reacts much more sensitive to price changes of the biomass than to techno-economic performance of the BIGCC process. As biomass is mainly used with CCS technologies high amounts of carbon are captured ranging from 130 GtC to 240 GtC (cumulated from 2005–2100) in different scenarios.

Effort sharing in ambitious, global climate change mitigation scenarios

The post-2012 climate policy framework needs a global commitment to deep greenhouse gas emission cuts. This paper analyzes reaching ambitious emission targets up to 2050, either ‐ 10 % or ‐ 50 % from 1990 levels, and how the economic burden from mitigation efforts could be equitably shared between countries. The scenarios indicate a large low-cost mitigation potential in electricity and industry, while reaching low emission levels in international transportation and agricultural emissions might prove difficult. The two effort sharing approaches, Triptych and Multistage, were compared in terms of equitability and coherence. Both approaches produced an equitable cost distribution between countries, with least developed countries having negative or low costs and more developed countries having higher costs. There is, however, no definitive solution on how the costs should be balanced equitably between countries. Triptych seems to be yet more coherent than other approaches, as it can better accommodate national circumstances. Last, challenges and possible hindrances to effective mitigation and equitable effort sharing are presented. The findings underline the significance of assumptions behind effort sharing on mitigation potentials and current emissions, the challenge of sharing the effort with uncertain future allowance prices and how inefficient markets might undermine the efficiency of a cap-and-trade system.

International climate regimes: Effects of delayed participation

This paper analyses how delayed participation by regions can affect international climate regimes in terms of the feasibility, costs, timing, magnitude and nature of the long-term mitigation response. We use the energy-systems optimization model MESSAGE to construct several climate change mitigation scenarios with various levels of regional participation in short-to-mid term. By comparing these with a global scenario that assumes full spatial and temporal flexibility throughout the century, we are able to evaluate how participatory decisions affect the mitigation response as well as the costs and technology choices. We find that short-term postponement of participation from some regions can often lead to a delay of mitigation measures on the global level. However, if the regional delay lasts until mid-century, participants of the regime are likely to increase their efforts in the short term. Mitigation costs are found to substantially increase as a result of delayed participation—the extent of the increase depends on the relative importance of the region that postpones its participation, the stringency of the climate target and the ability to reorganize mitigation measures. Our analysis also shows that a region's decision to delay its participation in an international climate regime can lead to accumulated inertia in its energy system and thus to a delayed ‘technological transition’ toward a low-carbon future.