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CO2 Pathways and IPCC Carbon Budgets
     
     

The Impact of CO2 Emissions on the Global Temperature Increase in 2100
This Web site has been designed to allow users to explore the impact of CO2 emissions on the global temperature increase in 2100. It does this by providing two simplified ways for users to specify CO2 emission pathways:
     1. By percent decline per year
     2. By a specific year for annual CO2 emissions to reach three GTCO2 or less.
The model also allows the user to specify carbon feedback emission and carbon capture and storage (CCS) trajectories.
Based on a user-specified desired temperature increase, the model calculates a range of carbon dioxide removal (CDR) trajectories that will result in the desired temperature increase.
The model uses a revised version of the “Post 2019 IPCC Carbon Budget” (see Figures 1 and 2) to determine the expected temperature increase in 2100 based on cumulative CO2 emissions and CCS removals. For example, if post-2019 cumulative net CO2 emissions were 400 GTCO2 through 2100, there would be a 67 percent chance that the global temperature increase would not exceed 1.5⁰C in 2100. But there is no remaining post-2025 budget carbon budget for the same percent chance. (Refer to the article at https://essd.copernicus.org/articles/17/2641/2025/essd-17-2641-2025.pdf for a descrption of the process used to revise the post 2019 IPCC carbon budget to a post 2023 carbon budget.)
Figure 1. Post 2019 IPCC Carbon BudgetFigure 2. Post 2025 IPCC Carbon Budget
Based on data from the En-ROADS global climate simulator  the model calculates reasonable values for the yearly temperature increase.
To explore CO2pathways, click on one the “PATHWAYS” links above or on one of these links: CO2 Pathways - Percent       CO2 Pathways - S-Curve
Note that each “explorer” has multiple tabs that can be clicked-on to provide additional information (note many of these are “under development”):
1 CO2 Pathways Allows user input and runs the model
2 Carbon Budgets Describes how the post-2025 carbon budget was derived
3 Pathways Discusses reasonable values for CO2 emission pathways
4 Feedbacks Discusses reasonable values for carbon feedbacks, etc.
5 CCS Discusses reasonable values for CCS, etc.; calculations for costs from CCS
6 CDR Discusses reasonable values for CDR, etc.; calculations for costs from CDR
7 SRM Discusses SRM
8 SLR Calculations for costs from SLR
9 Disasters Calculations for costs from natural disasters
10 Costs Displays expected costs
11 Impacts Discusses various impacts from global warming
12 Calculations Displays the detailed calculations
A PowerPoint presentation on how to use the model can be downloaded from http://www.co2pathways.org/Downloads/CO2PathwaysModel.pptx.
A PowerPoint presentation that shows how the model can be use to analyze CO2 pathways can be downloaded from
    http://www.co2pathways.org/Downloads/CarbonBudgetsandCO2EmissionPathways.pptx.