Unit D: Energy Flow in Global Systems

10 images of some snowflake crystals and some winter scenes with snow

5 images of stratus clouds that cover a wide horizontal layer in the sky at low level and are often associated with rain or drizzle

Can carbon offsets help you reduce your environmental footprint, practice sustainable living and fight climate change?

This backgrounder explains what greenhouse gases are and how they contribute to climate change.

Biofuels like ethanol might help fight climate change. But they can contribute to food insecurity and greenhouse gases in ways that might surprise you.

These two “point-counterpoint” videos provide arguments for and against using nuclear energy to generate electricity.

5 images of cumulus clouds that are white, puffy clouds with a flat base at mid level and are often associated with fair weather

15 images of various instruments such as rain gauges, wind vanes and weather satellites used to inform us about the weather

What is the nitrogen cycle? How do human activities such as using fertilizer affect the nitrogen cycle? How can this cause greenhouse gases?

5 images of cirrus clouds that are wispy or feather-like clouds at high level, made of ice crystals and may indicate an approaching storm

11 images that illustrate some daily weather conditions such as cold, hot and windy

Temperature is an important part of life on Earth and life in space. This backgrounder explains what temperature is, how it affects people and how it is controlled on the International Space Station.

One-third of all food produced is wasted. Learn about the environmental consequences of food waste, and what you can do about it.

1 diagram illustrating the water cycle

One of the greatest hazards that humans in space face is cosmic radiation. Learn what cosmic radiation is, why it's dangerous, and ways that we are looking at protecting humans in deep space.