Some 500 people drive or fly to the Pop!Tech conference on Maine's scenic midcoast from all over the US, and a few from overseas. They burn a lot of fossil fuels to get here. To make up for that, the conference is sponsoring solar power projects by the Solar Electric Light Fund that it says will save twice the amount of carbon emissions that will be expended by the conference and its attendees.

Climate change and where tomorrow's energy will come from after fossil fuels are spent has to be on any agenda grappling with the great issues. No exception here. As one speaker put it: Al Gore was wrong about climate change and clean energy: It's much more serious a problem than he says.

Tom Friedman, the New York Times columnist and author of "The World Is Flat," used his 20 minutes to basically sound out the themes in his book and columns. They're powerful themes. We have to redefine what we mean by "green," he says. It's not all granola crunching and "girly men," he says, it's not something "vaguely French." Green, Friedman says, is the new "red, white, and blue," patriotic and capitalistic. If we don't solve our oil addiction, he says, we're going to "heat up, choke up, burn up" this planet. The Chinese are already recognizing they can't follow the US model. A Green China, he says, is going to pose a greater challenge than Red China ever did.

Friedman knows how to create memorable images with words, giving his ideas intellectual muscle and mindshare. So do nearly all the presenters, which make them not only thinkers but impressive communicators as well.

Stewart Brand continued the green theme later Thursday by outlining where the environmental movement may be headed. Those with a romantic attachment to Mother Earth will still be on the front lines, but increasingly they're being joined by hard-headed scientists and engineers. New and better data is pushing everything. The scientists and engineers, many of whom still feel uncomfortable being ID'd as "green," are more likely to recognize that humans are already "Terra forming," or changing the natural world using science and technology, to meet their demands. (So we better do it right, he adds.) They're going to be more open to nuclear power if the alternatives are really worse. (Maybe we don't need a 10,000 year solution for nuclear waste, but a few-hundred year solution will do. Presumably the world and scientific knowledge will be much more prepared to deal with it by then.)

One billion people now live in squatter cities, the vast slums that surround cities, especially in the developing world. Two billion more are expected. That's trouble in some obvious ways, but surprisingly, perhaps, there's another side. In the slums, everything is recycled, much less fossil fuel is consumed per person, and underneath the chaos, entrepreneurs come up with innovative ideas to make it all work.

Seeing what's happening clearly is always the first step. But follow-up sessions from people sharing innovative ideas, like environmental journalist Alex Steffen, show there's no excuse not to go beyond hand-wringing. "Junk tagging," for example, is just one idea for an Internet-connected world. Why not point out online the location of one person's junk to everyone? It might be someone else's treasure, he says. Technology can "dematerialize" some of the damage done by an industrialized society. Netflix, the mail-based video company, not only has a profitable business plan: It also eliminates car trips to the video store and the video store itself, along with all the energy and materials that are needed to build and maintain it.

We gain status and identity from possessing objects, but services like car sharing programs in big cities show that the need is really something else, he says. We need to get someplace. Could dishwashers be shared too? Power drills? "We want the hole, not the drill," Steffen says.

Better product design can play a part, too. What if old cellphones could be put in a 350-degree oven for a few minutes and simply pop apart into their constituent parts for easy recycling? With the one billion cell phones expected to be sold worldwide next year, that's a compelling idea. (Get used to recycling going mainstream. "Virgin" raw materials will be used up in the next 30 to 70 years, says materials researcher Blaine Brownell.)

Sometimes no new technology is needed at all, only a better understanding of human nature. Homes use less energy when the electric or gas meter is put INSIDE the house where residents see what's happening. Same thing for cars: Drivers whose cars show how many miles per gallon the car is achieving actually drive in a more fuel-efficient way.

Apparently, knowledge IS power.

Toads are exploding in Hamburg, Germany, and scientists can't figure out why.

No, it's not a joke.  Toads really have been exploding in Hamburg.

It's like "a science fiction film," said  Werner Smolnik, a member of a Hamburg nature protection society, in an AFP story. "You see the animals crawling on the ground, swelling, and then exploding."

Over the last few weeks, some thousand toads have come to an explosive end in one particular pond in Hamburg, now known as "the pond of death."  And while it seems like tabloid-fodder (the Daily Mirror and Daily Mail did indeed cover it), the story of the bursting batrachians has caught the attention of serious newspapers like the Sunday Telegraph too.

"I could hardly believe what I saw," Smolnik told the Telegraph.  "Dozens of toads were crawling out of the water.  They were puffed up to almost three times their normal size and making strange screeching noises.  Then they just started popping.  Some just went 'phut!'... but others literally exploded."

The circumstances of the toads' excessive inflation were just as strange as the phenomenon itself.  Toad casualties only began appearing with the start of their mating season, and most of the toads seemed to burst between 2:00 a.m. and 3:00 a.m.  Also, though the pond is host to frogs as well as toads, only the toads met grisly ends; the frogs remain hale and whole.

The city of Hamburg, fearing a chemical spill into the pond, quickly launched an investigation, but the emergency team turned up no toxins, nor any thing else that would explain the toad phenomena.  Viruses, bacteria, and fungal infection theories were put forward, inspired by the presence of South American horses at a nearby race track.  Investigators found no evidence of any disease or infection, however.

There was one theory that was supported, though: bird attacks.  The veterinarians who examined the toads' remains found that all bore incision marks. 

"We think that birds may have attacked the toads and eaten much of their entrails,'' Anke Himmelreich told the Telegraph. "It is possible that the toads survived the attacks and then filled up with water through the incision made in their bodies. After that they simply burst open.''

German amphibian expert Frank Mutschmann, quoted in the Independent, agrees.  He found that all the toads' livers were missing - evidence that crows were to blame.

Although the bird attack theory may seem dubious (as it does to Smolnik - "If birds were responsible we would have seen them attacking the toads en masse, but we saw nothing of the kind," he told the Telegraph), it would take only a few crows to do the damage, according to Mutschmann.  Three to five crows could kill around 100 toads by themselves, he told AFP.

The fact that it was mating season was likely a contributing factor in the toads' deaths.  With their attentions elsewhere, the toads were easy pickings for the crows.  "They would have noticed something as the crow pecked at them, but it wouldn't have been particularly painful," Mutschmann told the Independent.

In fact, the Independent reports that exploding toads are not a new phenomenon: they've apparently been reported as early as 1968, in Germany, Denmark, Belgium, and even America.  And though it may seem a particularly unpleasant way for the toads to go, it's a perfectly normal occurrence, really.

"I've had several angry emails," Mutschmann told the Independent. "But there's no reason to worry. It's just a part of nature."