Earth's Changing Climate [repost]

In 2007 the Intergovernmental Panel on Climate Change concluded that "warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level." Representing a consensus of hundreds of scientists, the report went on to note that human activity is "very likely" the cause.

This course of 12 half-hour lectures reviews the most up-to-date research on climate change, explaining the concepts, tools, data, and analysis that have led an overwhelming number of climate scientists to conclude that Earth is warming and that we humans are in great part responsible.

Behind the Consensus

Whatever your views on climate change, it's important to understand how the current scientific consensus on global warming evolved out of basic physical principles and a broad range of observations. In a lucid presentation designed for nonscientists, you will learn about:

The difference between climate and weather
The concept of energy balance, which governs the natural warming of the planet by the Sun and is the key to a stable climate
The greenhouse effect, which makes Earth warmer and more hospitable than it would otherwise be due to naturally occurring gases in the atmosphere, such as carbon dioxide and water vapor
The carbon cycle, which controls the rate at which carbon dioxide released by fossil-fuel combustion accumulates in the atmosphere, and how long it remains to enhance the natural greenhouse effect.

Along with these and other concepts, you will investigate the "fingerprints" of global climate change, ranging from borehole temperatures to melting glaciers to the altered behavior of plant and animal species. These and other indicators show that Earth has been warming at an unprecedented rate in recent decades.

You will also explore the physical mechanisms behind these changes and their connections to the increasing concentration of greenhouse gases in the atmosphere since the start of the Industrial Revolution. And you will look at the techniques for projecting future climates, along with the options for switching to alternative energy technologies to avoid the most disruptive scenarios that now seem possible.

Look also:

Black Holes Explained

The Inexplicable Universe: Unsolved Mysteries

My Favorite Universe

Physics and Our Universe: How It All Works

Cosmology: The History and Nature of Our Universe