Don't you love people who think that global warming is a political agenda? You might let her know that it's ONLY in the U.S. that global warming is seen as political. Here are a few sites that I know of:
BBC News In Depth
There are links to lots of environmental problems including these on climate change:
Intergovernmental Panel on Climate Change (IPCC)
A group of hundreds of scientists from all over the world, their latest report comes out this Friday
Union of Concerned Scientists
"... the leading science-based nonprofit working for a healthy environment and a safer world."
Climate Hot Map
Early signs of global warming
2100: A World of Wild Weather
Recent article in New Scientist.
"Climate Science from Climate Scientists" (science blog)
The HBO documentary "Too Hot Not To Handle " is also excellent- I show it in class. Have you seen it? They interview climate scientists and talk about impacts of climate change on the U.S., specifically. Here is their list of links (some may be too political for your friend).
Those are the main ones I know- there is plenty of information out there. I don't get people who think it's all a liberal hoax- to what end? Good luck convincing her!