This is the seventh of nine lessons in the 'Visualizing and Understanding the Science of Climate Change' website. This lesson addresses climate feedback loops and how these loops help drive and regulate Earth's unique climate system.

In this audio slideshow, an ecologist from the University of Florida describes the radiocarbon dating technique that scientists use to determine the amount of carbon within the permafrost of the Arctic tundra. Understanding the rate of carbon released as permafrost thaws is necessary to understand how this positive feedback mechanism is contributing to climate change that may further increase global surface temperatures.

In this activity, students gain experience using a spreadsheet and working with others to decide how to conduct their model 'experiments' with the NASA GEEBITT (Global Equilibrium Energy Balance Interactive Tinker Toy). While becoming more familiar with the physical processes that made Earth's early climate so different from that of today, they also acquire first-hand experience with a limitation in modeling, specifically, parameterization of critical processes.

In this activity for undergraduate students, learners build a highly simplified computer model of thermohaline circulation (THC) in the North Atlantic Ocean and conduct a set of simulation experiments to understand the complex dynamics inherent in this simple model.

The purpose of this activity is to identify global patterns and connections in environmental data contained in the GLOBE Earth Systems Poster, to connect observations made within the Earth Systems Poster to data and information at the National Snow and Ice Data Center, and to understand the connections between solar energy and changes at the poles, including feedback related to albedo.

This interactive visualization from the NASA Earth Observatory website compares Arctic sea ice minimum extent from 1984 to that of 2012.

This lesson covers different aspects of the major greenhouse gases - water vapor, carbon dioxide, methane, nitrous oxides and CFCs - including some of the ways in which human activities are affecting the atmospheric concentrations of these key greenhouse gases. This is lesson six in a nine-lesson module about climate change.