Sometimes I think that our planet Earth, named for the Old English word for “dry land” (eorthe), should get a new name. Despite our knowledge that more than 70 percent of the planet’s surface is ocean—definitely not “dry land”—we still refer to our home by an 8th century description.

The same goes for Earth Day. Since 1970, people around the world have set aside April 22nd of each year to think about protecting the environment. This includes the ocean, as it’s a huge part of Earth’s environment. But the sea often seems to play a background role compared to more terrestrial causes.

What many people forget is that the inspiration for Earth Day came from the ocean. In 1969, a pipe carrying oil from 3,500 feet below the seafloor split off the coast of Santa Barbara, California, spilling some 3 million gallons of oil into the ocean over the course of 10 days—the biggest spill in U.S. history at that point, and still the third-largest. Then, as with the Gulf oil spill, the oil company responsible flubbed its initial attempts to plug up the leak, showing that they had no viable back-up plan in case of an accident, while volunteers led beach cleanups. The thick oil killed thousands of seabirds, along with dolphins, California’s iconic sea lions and elephant seals, and countless fish and invertebrates.



The whole thing was broadcast to the nation’s people, who watched in horror at the harm to the ocean and the shoreline. And thus Earth Day was born. On April 22 of the following year, 20 million Americans focused on environmental issues for a single day, inspired by the devastation off the coast of Santa Barbara. Now more than 1 billion people participate from countries around the world.

This year’s Earth Day theme is “Green Cities.” The sustainability of cities might seem completely unrelated to the ocean—but that is not so. Many of the world’s largest cities are located on or close to the coast, so it is no accident that many ocean “dead zones” are city harbors. Even inland cities are connected to the ocean via rivers. And as sea level rises over the coming centuries, it's coastal cities that will need to be best prepared or be hit the hardest.

Cities have the potential to be the most sustainable way for people to live together. By living close together, people in cities can share resources like transportation, roads, and infrastructure, reducing the costs of building and fuel. But as they are now, they use a lot of energy and release carbon dioxide into the atmosphere, adding to the problems of ocean acidification and warming ocean water.

By reducing the energy and pollution costs of cities, we can help develop ways of living that do less harm to the environment—including the ocean. Some ways are:

We must also try to reduce our own impacts on the ocean and the atmosphere any small way we can. It will mean learning new personal habits, such as using less plastic and cutting down on energy use, and working collectively as nations and as a species to keep our spaceship Earth clean and healthy.

What are you going to change about your life to help the ocean? For ideas, see our long list of ways you can help the ocean or our short list: five simple ways you can help the ocean.

And don’t forget to talk about the ocean today, and tell your friends the origin story of Earth Day: just like life, it came from the sea.