According to an extremely poorly researched and presented article in Nature magazine, man-caused global warming will cause Earth's sixth great mass extinction. I won't go into the weaknesses of the article in a deep scientific manner, because I'm not a scientist. I'll leave that sort of thing to Al Gore.
But for the science, or lack of it, please go here.
I'll continue with observations of a more general nature which I have gleaned from reading and listening to experts, and briefly describe below.
In the Galapagos we watched finches adapting rapidly to natural cycles of change in their food stocks. In my brief (by geological measurement) lifetime thousands of previously unknown species have been identified, many of apparently recent vintage. An astute observer of Greenland would note dramatic natural changes in just the past 1,000 years involving fish, birds, mammals, and plants adapting to the cold and ice of the Little Ice Age following the much-warmer-than-today Medieval Warm Period. Through all the natural changes, nature has produced winners and losers, and then reversed the game. Now we are in a brief interglacial period characterised by unusal warmth, compared to the glacial periods just preceding and, most assuredly, soon following.
Button up your overcoats. We're going to be one of the challenged species when it gets cold.