The first in a series that explores a big unknown variable for modeling future global warming: human action.

“What will the humans do?”

Climate scientists have told me this is now “the biggest unknown,” as they try to create computer models to project how fast global temperature will rise.

They report a general consensus (with a few caveats) on the other factors leading to the roughly estimated overall trend in global warming: how seawater, sunlight, oxygen, natural methane deposits, and so on may interact as we put more excess heat-trapping greenhouse gas in the borderless swirling air.

Seven days; lots of science in the news. Here’s our roundup of this week’s most notable and quotable items: Chimpanzees seem to have a natural inclination for murder. The tiny, dense galaxy M60-UCD1 was found to have a humongous black hole that accounts for 15 percent of its mass. T. Rex died for your fall leafpeeping excursion: Scientists now believe the meteorite that wiped out the dinosaurs also remade Earth’s landscape, favoring deciduous flowering plants over the once-dominant evergreens. An ancient Egyptian woman was buried 3,300 years ago wearing a complex hairstyle involving 70 separate hair extensions. In mice, artificial sweeteners seem to encourage glucose intolerance, which leads to higher-than-normal blood sugar levels and is a known precursor to diabetes. Scientists discovered the modernEuropean gene pool is a mixture of three distinct types of ancestors that combined within the last 7,000 years: blue-eyed, darker-skinned hunters and fairer, brown-eyed farmers from the Near East, plus a third population from Siberia. A new analysis of King Richard III’s skeleton (discovered underneath a parking lot in 2012) shows he died after suffering 11 stab wounds, nine of them to his head. Syphilis cases are spiking in Australia. Genetically engineered tobacco plants contain enzymes from blue-green algae that allow them to perform photosynthesis faster than normal plants. Earth’s population could hit …

For molecular biologist Liz Heinecke, one of the perks of having a physicist father was getting to try out some of the cool physics apparatus at Kansas State University, like a big rotating table that provided hands-on demonstrations of centripetal force. Not every family has a physics lab handy for inspiration, though, so Heinecke made it her mission to highlight how parents can teach science with everyday household ingredients. We talked to her about her plan for putting science in action on the home front.

Colin Pitchfork might not be as recognizable a name as Ted Bundy or Jeffrey Dahmer, but he does occupy a certain significance in the annals of crime: He is the first person to be convicted based on DNA fingerprinting, apprehended for the rape and murder of two young girls in 1986 after being betrayed by the bodily fluids he had left at the scene. DNA fingerprinting not only led to Pitchfork’s arrest, but also exonerated a young teenage boy who had initially confessed to the murders. Since 1989, 317 people have been exonerated by DNA evidence after being convicted of crimes, according to the Innocence Project; of those reopened cases, 154 have led to the identification of the true perpetrator (or at least a more likely suspect). Current Practice: Telltale Little Pieces As laboratory techniques advance, investigators are finding new ways to use DNA evidence. The initial technique used for DNA fingerprinting, developed by British geneticist Alec Jeffreys in the late 1970s (and initially primarily used for paternity testing), was called restriction fragment length polymorphisms (RFLP) analysis. In this technique, an investigator uses an enzyme to break the DNA sample at certain specific points in the genetic code. The lengths …

Cartoonist Peter Bagge’s Woman Rebel: The Margaret Sanger Story is not just a biography of Planned Parenthood’s founder; it’s also a dynamic graphic novel, combining Bagge’s frenetic style with a portrait of a powerful woman who altered American society in deep ways. We had a chance to catch up with Peter Bagge and discuss some of the more interesting and controversial aspects of Sanger’s social and scientific crusade.