Introduction: Earth Emergency (02:48)

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This segment orients viewers to the topic of global climate change and taking action. Scientists have identified many feedback loops that amplify warming.

Climate Crisis (04:48)

Greenhouse gases increase global warming. Experts discuss feedback loops. As temperatures rise, forests release carbon, frozen ground releases CO2 and methane, ice caps melt, drought and forest fires increase, organic matter decays, and jet stream and weather disruptions occur.

Climate Change (05:43)

Heat trapping greenhouse gasses comprise less than 1% of Earth's atmosphere but are essential to temperature regulation. The geological record reveals abrupt changes in Earth's past. Human activity has disrupted Earth's cooling trend.

Earth's Trees (02:42)

Trees are vital to the planet's health. Terrestrial ecosystems remove approximately 30% of CO2 emissions every year. Forests are suffering and as they die, they become part of the feedback loop.

Net Sink to Net Source? (07:52)

Three forests have the most important roles related to global warming. Experts discuss the Amazon and transpiration, the boreal forests and wildfires, old and young growth temperate forests, and forest management.

Permafrost (07:32)

The icy expanse that covers nearly 25% of the land in the northern hemisphere is thawing and emitting heat-trapping gases that amplify warming. Experts discuss microbes, greenhouse gases, ground collapse, and lake regions.

Albedo Effect (08:59)

Global warming threatens the Earth's reflectivity; breakdown triggers a dangerous feedback loop. In the Arctic, sea ice and snow cover are rapidly disappearing. Experts discuss climate models, ice sheets in the Antarctic, and sea level rise.

Clouds and Weather (06:06)

Clouds play an important role in Earth's climate. The atmosphere absorbs more water vapor as temperatures rise, amplifying a feedback loop. Experts discuss the effects of greenhouse gases, cloud feedbacks, storms, and the jet stream.

Human Responsibility (06:02)

Current weather patterns may continue for a long time to come. We can reverse the feedback loops and begin cooling the Earth; every country needs to be part of the solution. (Credits)