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 series of activities students investigate the effects of black carbon on snow and ice melt in the Arctic. The lesson begins with an activity that introduces students to the concept of thermal energy and how light and dark surfaces reflect and absorb radiant energy differently. To help quantify the relationship between carbon
and ice melt, the wet lab activity has students create ice samples both with and without black carbon and then compare how they respond to radiant energy while considering implications for the Arctic.

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 analyze data maps of sea surface temperature anomalies for a 14-year interval and create an ENSO time line in a case study format. Based on their findings, students determine the recurrence interval of the ENSO system.

In this activity, students work in groups, plotting carbon dioxide concentrations over time on overheads and estimating the rate of change over five years. Stacked together, the overheads for the whole class show an increase on carbon dioxide over five years and annual variation driven by photosynthesis. This exercise enables students to practice basic quantitative skills and understand how important sampling intervals can be when studying changes over time. A goal is to see how small sample size may give incomplete picture of data.

This article and slide show from the New York Times, features several scientists from the University of Alaska, Fairbanks, who study the effects of thawing permafrost in Alaska.

In this role-playing activity, learners are presented with a scenario in which they determine whether the Gulf Stream is responsible for keeping northern Europe warm. They must also address the potential future of the Gulf Stream if polar ice were to continue melting. The students work in small groups to identify the issue, discuss the problem, and develop a problem statement. They are then asked what they need to know to solve the problem.

In this activity, students examine the effects of hurricanes on sea surface temperature using NASA data. They examine authentic sea surface temperature data to explore how hurricanes extract heat energy from the ocean surface.

In this jigsaw activity, students explore meteorological data collected from Eureka, Canada to try to decide when would be the best time for an Arctic visit.

This video describes how the normal thousands-of-years-long balance of new ice creation and melting due to ocean currents has been disrupted recently by warmer ocean currents. As a result, glacier tongues that overhang the interface between ice and ocean are breaking off and falling into the ocean.