Introduction to Modern Climate Change

Chapter 06  ·  Resources

Forcing, Feedbacks, and Climate Sensitivity

Radiative forcing, feedbacks, the relative strength of the greenhouse gases, and how the consensus range for climate sensitivity was reached.

Running the models

EdGCM The ambitious among you can download and run a full-blown research-grade climate model.
columbia.edu ↗
Simple climate models to play with in the classroom There are a lot of simple on-line climate models that you can play around with. Steve Easterbrook has compiled a very useful list of them on his blog.
easterbrook.ca ↗

The control knob

One question that frequently comes up is to quantify the relative strengths of the various greenhouse gases. Here’s the answer: water vapor is the most important (responsible for 50% of the greenhouse effect), followed by clouds (25%) and carbon dioxide (20%). It also explains why carbon dioxide is the "control knob" for the climate — without the warming from carbon dioxide, water vapor would condense out of the atmosphere and the greenhouse effect would disappear.

The role of long-lived greenhouse gases as principal LW control knob Lacis, A. A. et al., Tellus B, v. 65, Nov. 2013.
tellusjournals.se ↗
Richard Alley on the control knob This fantastic video explains why CO2 is the control knob of our climate.
youtube.com ↗

Forcing and feedbacks

The history of radiative forcing If you want to read an advanced description of the historical evolution of the conceptualization, formulation, quantification, application, and utilization of “radiative forcing” of Earth’s climate, you’re in luck!
ametsoc.org ↗
How carbon-cycle feedbacks could make global warming worse Some of the most scary climate scenarios involve carbon-cycle feedbacks; i.e., a warming climate melts permafrost, which releases methane or more carbon dioxide. This article is an accessible discussion of the issue.
carbonbrief.org ↗
The Tambora eruption For more about the climate effects of volcanic eruptions, read this great NYT article.
nytimes.com ↗
The consensus climate sensitivity range To understand how the scientific community arrived at the range discussed in the chapter, see this (quite technical) paper.
wiley.com ↗

Errata for second edition

On page 103, there is a reference to "Equation 6.4" in the second full paragraph. This should be equation 6.3.