If Emissions of Greenhouse Gases are Reduced, How Quickly do Their Concentrations in the Atmosphere Decrease?

Please note that this material is from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published in 2007. The latest climate science can be found in the IPCC’s 6th Assessment Report, published in August 2021. For other reports and further updates, please refer to the IPCC website.

This material is extracted from the Frequently Asked Questions (FAQs) section of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), Working Group 1 (see full reference below).  

The adjustment of greenhouse gas concentrations in the atmosphere to reductions in emissions depends on the chemical and physical processes that remove each gas from the atmosphere. Concentrations of some greenhouse gases decrease almost immediately in response to emission reduction, while others can actually continue to increase for centuries even with reduced emissions.

FAQ 10.3, Figure 1. (a) Simulated changes in atmospheric CO2 concentration relative to the present-day for emissions stabilised at the current level (black), or at 10% (red), 30% (green), 50% (dark blue) and 100% (light blue) lower than the current level; (b) as in (a) for a trace gas with a lifetime of 120 years, driven by natural and anthropogenic fluxes; and (c) as in (a) for a trace gas with a lifetime of 12 years, driven by only anthropogenic fluxes.

Reference

IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment, Report of the Intergovernment Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Thumbnail image credit: Onnola (Flickr) 

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