The Climate Mitigation Challenge-Where Do We Stand?

Greenhouse gas emissions, driven by population growth and an increasing demand for resource-intensive goods, foods and services, are altering the planet's climate in ways that threaten the habitability of the planet. Transparent modeling tools and recent literature are used to quantify the mitigation challenge and assess potential remedies. Model results identify mitigation actions needed to have a chance of limiting global warming to 2 C, and how difficult it will be to limit warming to 1.5 C. Since a recent study concluded that there could be "runaway," irreversible warming when global temperatures reach 2 C or higher, this would argue for the importance of limiting warming to 1.5 C, despite the difficulty in meeting such a target. Serious emission reductions must start as soon as possible, involve all countries, include emission reductions in all sectors and for all the greenhouse gases. For achieving the 1.5 C target, and probably to meet the 2 C target, Carbon Dioxide removal (CDR) technologies/practices will need to be operational at large scale. Unfortunately, given their early stage of development, and high projected costs, there is no guarantee that removing CO2 from the air will be practical at the scale needed. For the U.S., a unique model examines key impactful mitigation actions and quantifies the monumental challenge of achieving net zero emissions by 2050. Also examined are the different mitigation trajectories needed for developed versus developing countries, how different emission trajectories would affect warming this century, and a summary of the status of R, D&D needs for key technologies. The two most impactful global mitigative actions, are to implement a strong, escalating price on carbon and greatly expanding R, D&D on promising clean energy and CDR technologies.Implications: Humanity continues on its unsustainable trajectory. Greenhouse gas emissions, driven by population growth and an increasing demand for resource-intensive goods, foods and services are altering the planet's climate in ways that threaten the habitability of the planet. Transparent modeling tools and recent literature are used to quantify the mitigation challenge and assess potential remedies. Model results identify mitigation actions needed to have a chance of limiting global warming to 2 C, and how difficult it will be to limit warming to 1.5 C. Since a recent study, concluded there could be "runaway," irreversible warming when global temperatures reach 2 C or higher, this would argue for the importance limiting warming to 1.5 C, despite the difficulty in meeting such a target. Serious emission reductions must start as soon as possible, involve all countries, include emission reductions in all sectors and for all the greenhouse gases. For achieving the 1.5 C target, and probably to meet the 2 C target, Carbon Dioxide removal (CDR) technologies/practices will need to be operational at large scale. Unfortunately, given their early stage of development, and high projected costs, there is no guarantee that removing CO2 from the air will be practical at the scale needed. For the U.S., a unique model examines key impactful mitigation actions and quantifies the monumental challenge of achieving net zero emissions by 2050. Also examined are the different mitigation trajectories needed for developed versus developing countries, how different emission trajectories would affect warming this century, and a summary of the status of R, D&D needs for key technologies. It was concluded that the two most important global mitigative actions are to implement a strong, escalating price on carbon and greatly expanding R, D&D on promising clean energy and CDR technologies.