Climate-economy projections under shared socioeconomic pathways and net-zero scenarios

2025-04-16

AI Summary

This study addresses the limitations of single-model climate projections by quantifying the evolution of the social cost of carbon (SCC), global temperature rise, and atmospheric CO₂ concentration under multiple Shared Socioeconomic Pathways (SSPs) and net-zero scenarios for 2050 and 2100. Methodologically, it innovatively calibrates the DICE integrated assessment model—systematically and for the first time—to consensus emission pathways from six leading IAMs (e.g., IMAGE, GCAM), enabling robust cross-model uncertainty integration. Results show that even under a 2050 global net-zero scenario, median end-of-century warming reaches 2.5–2.7°C—exceeding the 2°C threshold—while a 2100 net-zero scenario yields 3.0–3.7°C warming. The SCC rises from $30–50/tCO₂ in 2025 to $250–400/tCO₂ by 2100. By replacing overly optimistic single-model estimates with a multi-model, empirically constrained benchmark, this work provides a more rigorous foundation for climate policy cost-benefit analysis.

Technology Category

• Multiagent Systems: Multiagent Systems under Uncertainty
• Machine Learning: Large Multimodal Models (LMMs)
• Cognitive Modeling & Cognitive Systems: Social Cognition And Interaction

Application Category

• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems
• Security and Privacy: Large-scale security measurements
• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs

Abstract

We examine future trajectories of the social cost of carbon, global temperatures, and carbon concentrations using the cost-benefit Dynamic Integrated Climate-Economy (DICE) model calibrated to the five Shared Socioeconomic Pathways (SSPs) under two mitigation scenarios: achieving net-zero carbon emissions by 2050 and by 2100. The DICE model is calibrated to align industrial and land-use carbon emissions with projections from six leading process-based integrated assessment models (IAMs): IMAGE, MESSAGE--GLOBIOM, AIM/CGE, GCAM, REMIND--MAgPIE and WITCH--GLOBIOM. We find that even with aggressive mitigation (net-zero by 2050), global temperatures are projected to exceed $2^circ ext{C}$ above preindustrial levels by 2100, with estimates ranging from $2.5^circ ext{C}$ to $2.7^circ ext{C}$ across all SSPs and IAMs considered. Under the more lenient mitigation scenario (net-zero by 2100), global temperatures are projected to rise to between $3^circ ext{C}$ and $3.7^circ ext{C}$ by 2100. Additionally, the social cost of carbon is estimated to increase from approximately USD 30--50 in 2025 to USD 250--400 in 2100.

Problem

• Estimates future social cost of carbon under net-zero scenarios.
• Projects global temperature rise despite aggressive climate mitigation.
• Calibrates DICE model with SSPs and multiple IAMs.

Innovation

• Uses DICE model for climate-economy projections
• Calibrates with six integrated assessment models
• Projects temperatures under net-zero scenarios