WASHINGTON (AP) - Greenhouse gases are making the world’s oceans hot, sour
and breathless, and the way those changes work together is creating a
grimmer outlook for global waters, according to a new report Wednesday from
540 international scientists.
The world’s oceans are getting more acidic at an unprecedented rate, faster
than at any time in the past 300 million years, the report said. But it’s
how this interacts with other global warming impacts to waters that
scientists say is getting them even more worried.
Scientists already had calculated how the oceans had become 26 percent more
acidic since the 1880s because of the increased carbon in the water. They
also previously had measured how the world’s oceans had warmed because of
carbon dioxide from the burning of coal, oil and gas. And they’ve observed
that at different depths the oceans were moving less oxygen around because
of the increased heat.
But together “they actually amplify each other,” said report co-author Ulf
Riebesell, a biochemist at the Geomar Helmholtz Center for Ocean Research in
Germany. He said scientists are increasingly referring to the ocean’s future
prospects as “hot, sour and breathless.”
The 26-page report released by the United Nations and several scientific
research organizations brings together the latest ocean science on climate
change, stemming from a major conference of ocean scientists last year.
For example off the U.S. Pacific coast, the way the ocean is becoming
stratified and less mixed means lower oxygen in the water, and the latest
studies show that means “80 percent more acidification than what was
originally predicted,” said study co-author Richard Feely of the National
Oceanic and Atmospheric Administration’s Pacific Marine Environmental Lab in
And computer models predict that the American northwest coast will be hit
harder because of the combined change than other places, Feely said.
The theory is that species like squid can only live in waters at certain
temperature, acidity and oxygen levels, and the sweet spots where the
factors combine are getting harder to find, Feely and Riebesell said.
The world ocean pH already has gone from 8.1 to 8.0 - it’s considered a 26
percent increase in acidity because scientists measure hydrogen ions for
this. But computer models predict the world will hit 8.0 in the next 20
years to 30 years and 7.9 in about 50 years, Riebesell said. At those levels
shells of some mollusks, like clams and mussels, start corroding, he said.
“This is another loss that we’re facing,” Riebesell said. “It’s going to
affect human society.”