As Harvard University’s Arnold Arboretum prepares for its annual Lilac Sunday, senior scientist Dr. Peter Del Tredici takes Living on Earth host Steve Curwood on a tour to demonstrate how acid rain and climate change are affecting the arboretums’s plants and trees.

A new study from the National Snow and Ice Data Center in Boulder, Colorado shows that scientists grossly underestimated the rate of ice loss due to warming from greenhouse gas emissions. The study claims that if current trends continue, we could be facing an ice-free Arctic summer within the next 50 years.

Living on Earth host Steve Curwood talks with Tom Philps, an editorial writer for the Sacramento Bee, about a court battle that pits environmentalists and sports fishermen against the California Department of Water Resources. The dispute is over how to save struggling smelt and Chinook salmon populations while meeting massive human demands on the drinking water from the San Joaquin River.

Tidal currents from New York City’s East River are being used for electrical power. The energy is generated by underwater turbines as part of a demonstration project by Verdant Power. The company must show that the turbines won’t hurt migrating fish. As WNYC’s Beth Fertig reports, Verdant is one of several companies experimenting with tidal power in coastal regions of the country.

Where are the hoverboards, jetpacks, underwater cities and flying cars that Hollywood promised us decades ago? Author Daniel Wilson tells host Steve Curwood what he learned while writing his new book "Where's My Jetpack: A Guide to the Amazing Science Fiction Future that Never Arrived."

Wind energy is clean, but is it green if windmills chop up birds and bats? The country's top science panel says government agencies should take the environmental impacts of wind power more seriously. Living on Earth's Jeff Young reports that some in Congress are ready to tilt at the windmills.