In the 2011 Arctic Report Card, scientists report that the bright white surface of the Greenland Ice Sheet has grown less reflective. The darker surface absorbs more sunlight, accelerating melting.

Arctic sea ice extent for the month of March was the second lowest in the satellite record. Ice cover at winter maximum continues to be dominated by young, thin ice.

 The Sun is the main source of power for the Earth's climate machine. Space-based measurements, begun in 1978, indicate Earth receives an average of 1,361 W/m<sup>2</sup> of incoming sunlight, and the amount varies by about one-tenth of a percent over the course of the 11-year solar cycle. 

This animated video outlines Earth's energy. The video presents a progression from identifying the different energy systems to the differences between external and internal energy sources and how that energy is cycled and used.

This NASA video discusses the impacts of the sun's energy, Earth's reflectance and greenhouse gases on the Earth System.

In this worksheet-based activity, students review global visualizations of incoming sunlight and surface temperature and discuss seasonal change. Students use the visualizations to support inquiry on the differences in seasonal change in the Northern and Southern Hemispheres and how land and water absorb and release heat differently. The activity culminates in an argument about why one hemisphere experiences warmer summers although it receives less total solar energy.

In this activity students learn how Earth's energy balance is regulating climate. This activity is lesson 4 in the nine-lesson module Visualizing and Understanding the Science of Climate Change.

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