Cities deep underwater, frozen continents, the collapse of global agriculture: so far, much of the discussion about climate change has focused on these distant, catastrophic effects of a superheated world. What's less talked about is how global warming is making itself felt already. Even the modest temperature rise we've already experienced has set in motion fundamental shifts—and the further warming we can expect in the next few decades has the potential to set off dramatic changes.

View Slideshow: Top 10 Places Affected by Climate Change



It's still difficult to confidently trace any given phenomenon directly to greenhouse gas emissions from our cars, factories and power plants. The computer models used by climate scientists lack resolution and certainty. Yet they do provide an idea of what we can anticipate, and there are places in the world where impacts of the type we can expect have already hit. We don't have to guess at what it will be like to live in a warming world. As the following examples show, the future of our planet can be found now, on the frontiers of climate change.

Stephan Faris's Forecast: The Consequences of Climate Change, from the Amazon to the Arctic, from Darfur to Napa Valley, from which this article is adapted, will be published by Henry Holt in January 2009.