A Time Dependent Zonally Averaged Energy Balance Model to be Incorporated into IMAGE (Integrated Model to Assess the Greenhouse Effect)

This paper is the first report of a collaborative effort between IIASA and The Netherlands' National Institute of Public Health and Environmental Protection (RTVM), Bilthoven, on developing an integrated model for assessing, in a time-dependent manner, the socio-economic and ecological effects of a given greenhouse gas scenario. This involves linking greenhouse gas emission accounting frameworks, models for calculating changes with time of greenhouse gas concentrations and climatic change, and ecological changes such as shifts in growing zones for natural vegetation and agricultural crops, and effects on forest growth, water supply and sea level rise. This paper reports on one of the first steps in this linkage: modifying the climate module of RTVM's Integrated Model to Assess the Greenhouse Effect (IMAGE) to provide appropriate temperature and precipitation scenarios for the ecological models. The work follows in the tradition of both institutions in developing science-based tools for policy analysis

Post-2012 climate policy scenarios

The cost and effectiveness of climate policy in Europe depend on the international post-2012 climate regime. Crucial are the stringency of the policy and the size of the climate coalition, e.g. the willingness of regions outside Europe to implement a climate policy. This report analyzes four alternative policy scenarios. These four scenarios are characterised along two dimensions: the sense of urgency expressed by the policy goal, and the willingness to resolve the climate problem through concerted action. This analysis provides a background for identifying the best mitigation options, both in the Netherlands and the EU. Only if all major countries become actively involved in emissions abatement before 2020, the EU 2 degrees climate target is feasible. In smaller coalitions the costs to coalition members and the environmental ineffectiveness tend to increase.

Предисловие

This study provides a conceptual framework for exploring the bargaining space within international climate negotiations based on important economic, political and environmental considerations. Based on it, we analyse combinations of the proposed emission reduction ranges for Annex I countries as a group (25–40% below 1990 levels) and non-Annex I as a group (15–30% below baseline) by 2020 to limit global warming to 2 °C. We use results of the FAIR model with costs estimates based on two energy system models. We conclude that the range of targets that comply with a set of criteria for economic, political and environmental considerations is smaller than that by environmental considerations alone. More specifically, we find that according to our criteria, a 30% Annex I reduction target below 1990 levels, combined with a 20% non-Annex I reduction target below baseline emission levels (i.e. 20 to 30% above 2005 levels), is the only combination of targets fulfilling all our criteria for both energy system models. Otherwise, reaching the 2 °C target becomes less likely, technically infeasible, or non-Annex I abatement costs are likely to exceed those of Annex I, a result, which we consider less plausible from a political viewpoint in our conceptual framework

IMAGE and MESSAGE Scenarios Limiting GHG Concentration to Low Levels

This report discusses the attainability of low greenhouse gas concentrations levels based on an analysis using two integrated assessment models (MESSAGE and IMAGE). Model runs were preformed which explored the feasibility of reaching radiative forcing levels in 2100 between 2.6 to 2.9 W/m2 above pre-industrial levels. Such low targets are necessary to limit global mean temperature increase to below 2oC compared to pre-industrial levels with high probability. The analysis examines the attainability of low targets systematically with respect to key uncertainties, including alternative baseline development pathways, availability of different technologies, emissions of bio-energy, and impacts of forestry and land use assumptions. A number of sensitivity tests were carried out to test the robustness of achieving low GHG concentration targets. The results from the two models are discussed in detail comprising energy profiles and emission pathways consistent with such low stabilization targets

Vleesconsumptie en klimaatbeleid

In deze studie wordt de mogelijke invloed van dieetveranderingen op de kosten van ambitieuze klimaatdoelstellingen verkend. Doel van de studie is uitsluitend om in te schatten wat de wereldwijde bijdrage van dieetverandering kan zijn. De vleesconsumptie wordt aangepast in vier varianten van dieetverandering: GeenHerkauwers (geen vlees van herkauwers), GeenVlees (geheel geen vlees), GeenDierproducten (geen enkel dierlijk product) en WilettDieet (een 'gezond' dieet). Hiervoor wordt het geïntegreerde model IMAGE (Integrated Model to Assess the Global Environment) gebruikt. Ook worden resultaten voor landgebruik en biodiversiteit gegeve

Early action on Paris Agreement allows for more time to change energy systems

The IMAGE integrated assessment model was used to develop a set of scenarios to evaluate the Nationally Determined Contributions (NDCs) submitted by Parties under the Paris Agreement. The scenarios project emissions and energy system changes under (i) current policies, (ii) implementation of the NDCs, and (iii) various trajectories to a radiative forcing level of 2.8 W/m2 in 2100, which gives a probability of about two thirds to limit warming to below 2 °C. The scenarios show that a cost-optimal pathway from 2020 onwards towards 2.8 W/m2 leads to a global greenhouse gas emission level of 38 gigatonne CO2 equivalent (GtCO2eq) by 2030, equal to a reduction of 20% compared to the 2010 level. The NDCs are projected to lead to 2030 emission levels of 50 GtCO2eq, which is still an increase compared to the 2010 level. A scenario that achieves the 2.8 W/m2 forcing level in 2100 from the 2030 NDC level requires more rapid transitions after 2030 to meet the forcing target. It shows an annual reduction rate in greenhouse gas emissions of 4.7% between 2030 and 2050, rapidly phasing out unabated coal-fired power plant capacity, more rapid scale-up of low-carbon energy, and higher mitigation costs. A bridge scenario shows that enhancing the ambition level of NDCs before 2030 allows for a smoother energy system transition, with average annual emission reduction rates of 4.5% between 2030 and 2050, and more time to phase out coal capacity

Credibility gap in net-zero climate targets leaves world at high risk

Global climate policy is undergoing a rite of passage. What used to be a conversation about ambitious target setting now focuses increasingly on implementation and interventions to achieve these targets. This liminal transition from ambition to implementation is complex and presents deep ambiguities that are challenging for scientists to communicate and decision-makers to fathom. A critical question is whether we can believe that countries will deliver on the commitments they have made. By evaluating policy characteristics of countries’ net-zero targets, we can assign the targets credibility ratings, then estimate how greenhouse gas (GHG) emissions and temperature are differentiated by our confidence in the targets. When we consider the credibility of current climate pledges, our assessment shows that the world remains far from delivering a safe climate future

Updated nationally determined contributions collectively raise ambition levels but need strengthening further to keep Paris goals within reach

By January 2022, 156 countries had submitted new or updated nationally determined contributions (NDCs) under the Paris Agreement. This study analyses the greenhouse gas (GHG) emissions and macroeconomic impacts of the new NDCs. The total impact of the updated unconditional and conditional NDCs of these countries on global emission levels by 2030 is an additional reduction of about 3.8 and 3.9 GtCO2eq, respectively, compared to the previously submitted NDCs as of October 2020. However, this total reduction must be about three times greater to be consistent with keeping global temperature increase to well below 2 °C, and even seven times greater for 1.5 °C. Nine G20 economies have pledged stronger emission reduction targets for 2030 in their updated NDCs, leading to additional aggregated GHG emission reductions of about 3.3 GtCO2eq, compared to those in the previous NDCs. The socio-economic impacts of the updated NDCs are limited in major economies and largely depend on the emission reduction effort included in the NDCs. However, two G20 economies have submitted new targets that will lead to an increase in emissions of about 0.3 GtCO2eq, compared to their previous NDCs. The updated NDCs of non-G20 economies contain further net reductions. We conclude that countries should strongly increase the ambition levels of their updated NDC submissions to keep the climate goals of the Paris Agreement within reach