An oceanographer who studied under a pioneer in the discovery of global warming will speak about what’s happening locally and around the globe at Southwestern Oregon Community College tonight.

As part of his discussion, he is going to point out something that he says local fishermen have been noticing for some time — a decrease in the number of fish. Many fishermen disagree, but he says scientists are noticing it, too.

“This used to be a very famous fishing port,” said John McGowan, a research professor at the Scripps Institution of Oceanography at the University of California in San Diego and a leading international authority on the relationship between climate change and the sea. “That’s changed. All these towns up and down the coast have changed.”

McGowan is coming to Coos Bay to give a free talk on “The State of the Oceans” in hopes of raising awareness on what effects global warming will have, not just here, but around the world.

“The general public has heard about global warming, but I don’t think they know the facts very well,” McGowan said on the phone from his second home in Bandon. “We are seeing the effects of large scale changes here. It isn’t just local, it’s global.”

McGowan said he will go into detail about how biological production has decreased on a large scale.

“A lot of our protein comes from the ocean on a global basis,” McGowan said. “It’s very important economically. It’s going to affect everyone.”

Changes are already happening in agriculture, forestry and rainfall patterns, McGowan said.

“They’ll be felt gradually and over time, but there will be effects,” he said.

People will have to switch to alternative energy sources, such as nuclear, wind and solar energy and biofuels. But this change will not come without growing pains, he said.

“I have the impression the auto industry is doing research into other fuels,” he said. “First of all, if we have to change our usage of fossil fuel, it’s going to be very disruptive, I think, especially economically.”

As a graduate student, McGowan met oceanographer Roger Revelle, a scientist and McGowan’s professor at the Scripps Institution.

Revelle was one of the first who talked publicly about the effects of carbon dioxide on the oceans in the 1950s. Inspired by Revelle, McGowan also became a professor of oceanography at the Scripps Institution, serving in that capacity for 40 years before becoming a research professor.

McGowan said he is going to quote Ohio State University Geologist Lonnie Thompson, who gave a talk at the community college in December. McGowan said Thompson’s research of glaciers is “really phenomenal.”

During McGowan’s discussion, he will acknowledge that the ocean has warmed, then ask the audience, “so what?” His lecture will be followed by a question-and-answer period.

“We know that has happened,” McGowan said. “We want to know, can we detect any change due to the warming? And the answer is, ‘Yes, we can.’”

Satellites are helpful in gathering data about oceans, but they only show what’s on the surface, he said.

“The ocean is so large that measuring such a huge area is difficult,” McGowan said.

Phillip Johnson, director of CoastWatch and Oregon Shores Conservation Coalition staff member, asked McGowan to give his presentation. McGowan is one of 1,300 CoastWatch volunteers who keep watch over Oregon’s coastline, and report abnormalities back to agencies like Oregon Shores, State Parks and the Department of Environmental Quality. Each volunteer chooses one mile to watch, shared with other volunteers. McGowan’s is mile 113, near his Bandon home.

“I discovered he’s really an international oceanographer — respected in his field,” Johnson said of McGowan.

Johnson said changes due to global warming are evident on the Oregon Coast.

“We all notice it when we have terrible salmon years — salmon crashes due to poor productivity.”

Farther north along the coast, scientists have discovered “dead pools,” areas of the ocean that contain very little oxygen, he said.

“This is something new and scary that is happening,” Johnson said. “Let Dr. McGowan walk you through the pattern. You’ll get a whole sense the ocean is inexorably changing.”