Happy Earth Day!  On April 22, 1970, 20 million Americans thronged the streets and public places across the country to demonstrate their concern about the degradation of the environment around them.  Their protest was fueled by widespread publicity about the Cuyahoga River in Ohio catching fire and by a massive oil spill off the California coast.  In Baltimore, as pictured above, Patterson High School students picketed garbage dumps on Kane Street and North Point Boulevard.

The state of the environment has changed since then - much of the more visible pollution has been cleaned up.  Concerns have shifted now to less obvious and more difficult issues like climate change, declining diversity of plants and animals and our exposure to the residues of thousands of chemicals used in making our food and consumer products.

Earth Day has shifted, too.  For many marketing folks, this is a perfect opportunity to try to sell green, greenish or green-looking products.  My inbox has been peppered in the past few weeks with pitches for various types of water bottles, clothing, motor vehicles and green travel, if there is such a thing.

But others are marking the day in a spirit more akin to the original Earth Day.  The city is putting recycling bins in the Inner Harbor for tourists to use, and kicking off the production of energy from methane generated by all the refuse disposed of in the city's landfill.   In schools, students are studying environmental issues or planting trees. 

And some activists are demonstrating their concern in an old-fashioned way, vowing to eat no solid food until Congress acts on legislation to reduce the nation's output of climate-warming greenhouse gases.  Hearings started on the topic this week, and House leaders have pledged to send a bill to the floor by Memorial Day.  That could be a long fast.

How are you marking Earth Day?  I'm speaking at an environmental symposium shortly at St. Paul's School for Girls in Brooklandville.  Then it's back to the business of covering the bay and environment.

(Photo by William H. Mortimer of The Baltimore Sun).

UPDATE:  I spoke to group of students at St. Paul's School for Girls as part of the school's inaugural Earth Day symposium - quite an undertaking.  Besides the 462 students in grades 5 through 12 at the school, there were about 181 students and faculty from about 10 other private schools in the area.  They heard from 40 speakers and had more than 70 hands-on presentations, including recyclable art and "mad science."

"Our goal is to get students excited about the environment and conserving resources," said Janet Wolfe, academic dean for the school.  Students were asked to sign Earth Day pledges listing three things they personally would work on in the coming year.  The school hopes to produce a YouTube video of the symposium highlights, but until then you can see the program here.