A few years ago Paul Crutzen, a Nobel Prize winner for work on the ozone layer, proposed a new name for the geological epoch based on the effects of human civilization on the earth. He proposed that the new epoch began in the early 1800 and should be named the Anthropocene Epoch. You can read a good pro/con on the proposal at Andrew Alden’s geology site. As Alden points out the present geological epoch is the Holocene, which began about 12,000 years ago, about the time when the most recent glacial ice began to retreat from North America and Europe. It also coincides with the rise of human civilization.

Crutzen and Eugene Stoermer, in their announcement to emphasize the central role of humankind in geology and ecology, proposed the term anthropocene for the current geological epoch. They said:

“To assign a more specific date to the onset of the ‘anthropocene” seems somewhat arbitrary, but we propose the latter part of the 18th century, although we are aware that alternative proposals can be made (some may even want to include the entire holocene). However, we choose this date because, during the past two centuries, the global effects of human activities have become clearly noticeable. This is the period when data retrieved from glacial ice cores show the beginning of a growth in the atmospheric concentrations of several ‘greenhouse gases”, in particular CO2 and CH4. Such a starting date also coincides with James Watt’s invention of the steam engine in 1784. ”

There are others that believe that the effects of human activity on global warming started earlier than the 18th century, and that human farming might have started the warming trend. William Ruddiman proposes that this warming may have started as early as 8,000 years ago (Known as the Early Anthropogenic Hypothesis).

John Baez’s Zooming Out in Time is a powerful slide show of a talk he gave at the Long Now Foundation about climate change. Zooming out is a way of changing perspective and helps us understand why a few degrees of warming can be troublesome to us when compared with other climate change episodes in the past. The Long Now Foundation supports Seminars About Long-term Thinking which “promote ‘slower/better’ thinking as opposed to today’s ‘faster/cheaper’ mind set.

The changes we observe going on in terms of temperature increase, rising sea level, species migration north, climate zones moving north, all are related to human activity, and most scientists point to our emitting greenhouse gases into the ocean of air. The graph below shows the reconstructed temperature of earth back to A.D. 1000. Note that the Earth was relatively cold until the 18th Century.

Source: globalwarmingart.com
The following graph shows temperature changes since 1860. In both of these graphs, the one above and one below, the big problem is how fast the temperature is changing since about 1860.

Source: globalwarmingart.com

This proposal, and the observations surrounding the impact of humanity on the earth’s atmosphere is a powerful topic for science teachers. There are a number of resources that I would recommend.

Firstly, I would start with Tim Flannery’s book, The Weather Makers: How Man is Changing the Climate and What It Means for Life on Earth. The book is extremely readable, and there is a wonderful supporting website that also includes activities for students.

Another resource is the EPA website on climate change. It is extensive, and includes resources and activities for students.

You should also check the United Nation’s website on climate change, where you will have links to global initiatives, including the Kyoto Protocol, and the Intergovernmental Panel on Climate Change.

Here are some others:
The Exploratorium’s Global Climate Change Research Explorer
The Pew Center’s Climate Change Resource