Former U.S. President Bill Clinton is starting an investment fund for renewable energy with an expected $1 billion. It ain’t all altruism: renewable energy may not be the highest return investment at the moment, but it’s a safe bet there’s money to be made there.

Predicting the future is still more art than science, but science is making inroads. The concept of a critical threshold, beyond which a system’s characteristics change significantly (and possibly irreversibly) is both applicable across physical and social phenomena, and approachable through mathematics.

SizeEasy is a site with a simple mission, to help people compare the size of two items. That’s a step closer to bricks and mortar online.

I’ve heard the arguments from both sides, but I’ve always sided with the science mainstream in believing that climate change is not only human-linked but a serious short- to medium-term risk. If it isn’t, then I’m not entirely sure what to make of the idea of a Texas-sized chunk of Arctic perennial sea ice disappearing within the space of a year – historical cycles left aside for a moment, that’s surely going to cause some serious human problems if it continues for a decade or two, whatever may be causing it.

METI (Messaging to Extraterrestrial Intelligence) isn’t a new idea, but is getting increasing backing from sections of the SETI community. Centauri Dreams wonders whether broadcasting the interstellar equivalent of a cheery “hey, you guys!” is a wise move – shouldn’t there at least be some reasoned debate before calling open house? Meanwhile, Sentient Developments discusses a new paper that proposes we shouldn’t be looking for signals but for artificial objects (like Dyson Spheres) around stars as indicators of the presence of alien civilisations.