Phasing Out “Problematic” Plastics

Plastic packaging is just about impossible to avoid. Getting takeout? You’ll likely wind up with a plastic container, or cutlery. Grabbing a coffee? Plastic stirrers and straws are hard to evade. These items are tough to recycle, and most sanitation systems aren’t equipped to process them. That means they go into the trash, or worse, waterways.

Last week, the U.S. Plastics Pact released a much-anticipated list of “Problematic and Unnecessary Materials” that pact members should phase out by 2025. These items include cutlery, straws, and stirrers, as well as materials that include certain chemicals and pigments. The impact could be large: Pact members make up about third of America’s plastic packaging producers. Members include companies that use a lot of packing, like Target, Walmart and Aldi, as well as those that make raw plastic materials.

The goal of the U.S. Plastics Pact is to help make America’s recycling system more circular, where materials in theory could be recycled in perpetuity. But some in the plastics industry say the timeline for phasing out these materials are too fast, or may cause a reliance on more carbon-intensive materials. Joining Ira to break down the potential impact of phasing out these materials is Emily Tipaldo, executive director of the U.S. Plastics Pact, based in Mount Pleasant, South Carolina.

The Science Of Slip Versus Stick

We’ve all had the experience of that uncomfortably sticky feeling of syrup or jam residue on the breakfast table. Or a wad of chewing gum binding our shoe to the sidewalk. But what’s the science behind why some things stick, while other things slip?

Many of the reasons come down to friction, says Laurie Winkless, a physicist and science writer based in New Zealand. Her new book, Sticky: The Secret Science of Surfaces, explores how different materials interact—from the toes of an acrobatic gecko scaling a sheer wall to the molecular magic inside the rapid fusion of super glue.

Winkless joins SciFri’s Charles Bergquist to talk about surface science, and what makes something slippery, including the question of how the famously non-stick Teflon manages to stick to your kitchen frying pan.

How Long Will California’s Butterfly Boom Last?

Like their brethren east of the Rocky Mountains, the western population of monarch butterflies has been declining steeply since the mid-1990s. Every November, volunteers set out through the mountains of California with one goal in mind: Count those western monarchs as they gather for winter hibernation. Unfortunately, the recent numbers have been bad news. Back in the 1990s, the western population numbered more than a million. But in 2018 and 2019, volunteers only counted about 20,000 and 30,000, respectively. In 2020, the count turned up a mere 2,000 butterflies.

This year, though, the news was good: The 2021 Thanksgiving Count found nearly 250,000 butterflies in winter enclaves throughout California.

How did the population bounce back so dramatically? And is this number a blip on the radar, or the start of better times for the beleaguered butterfly? Ira talks to UC-Davis entomologist Louie Yang about the intricate timing of milkweed and monarchs, and why ecologists remain uncertain about the fate of this charismatic insect.