Tiny metal nanoparticles can damage DNA, essentially by triggering toxic gossip.

There are 33 days until the opening of formal negotiations in Copenhagen on the next global climate-protection treaty. The hoped-for accord would take up where the current treaty leaves off. But to get some perspective on just where that is, a new United Nations report describes for negotiators and the public just how much the Kyoto Protocol has achieved. And real strides have been made in slowing the growth of greenhouse-gas emissions, thanks to many European nations (albeit with little help from North American ones or Japan).

Some were pets whose bodies and appetites apparently got too big for their owners to support. Most are probably descendants of released pets. Today, thousands of really big non-native snakes — we’re talking boa constrictors, anacondas and pythons — slither wild in southern Florida. And there’s nothing holding them in the Sunshine State. Which is why a report that was released today contends they pose moderate to high ecological threats to states on three U.S. coasts. Indeed, the homelands of these snakes share climatic features with large portions of the United States — territory currently inhabited by some 120 million Americans. Based on comparisons of the temperatures, rainfall and land cover found in the snakes’ native range, it’s possible that these slithering behemoths could stake claims to territory as far north as coastal Delaware and Oregon.