Just about 5 million tons of carbon dioxide (CO2) is dumped into the atmosphere every hour from the burning of fossil fuels mostly for transportation, electrical generation, industry and heating.
This is the fastest rate of CO2 generation that the earth has experienced in millions of years. It’s been estimated that about a quarter of the man-made carbon dioxide from the burning of fossil fuels has been absorbed by the oceans, one quarter by the land, and the rest has accumulated in the atmosphere. All told, around 600 billion tons of CO2 gas since the Industrial Revolution has been absorbed by the ocean.
The absorption of all this CO2 by the world’s oceans has certainly benefited us by reducing the amount of this greenhouse gases in the atmosphere. However, the introduction of massive amounts of CO2 in the world’s oceans is changing the sea’s water chemistry.
Let me explain. When CO2 is absorbed at the ocean’s surface, carbonic acid is formed. This leads to lower pH levels. The pH level is a measure of acidity in an aqueous solution, like seawater. Solutions with a pH level greater than 7 are basic or alkaline like our oceans at around 8.2, while solutions less than 7 are said to be acidic.
Years ago at Diablo Canyon Power Plant, I recorded pH levels with a Seabird CTD instrument from one of our research vessels along the Pecho Coast that stretches from the Point San Luis Lighthouse to Point Buchon. This instrument recorded pH and dissolved oxygen levels.
With the exception of estuaries with an inflow of fresh water from creeks like Morro Bay and periods of strong upwelling when the winds blow strong out of northwest, pH levels remain relatively stable along our shoreline. In fact, until recently, the ocean’s average pH levels have remained stable for thousands and thousands of years.
This condition has allowed a diversified and ridiculously huge web of life to flourish that we all enjoy and depend upon. But the latest pH level readings from the world’s oceans indicate that these ancient pH levels have recently dropped to an average of 8.1. As the ocean becomes more acidic, the life cycles of marine organisms, especially zooplankton primarily found in surface waters and at the lower end of the food chain, could be affected.
Crustaceans such as copepods and krill make up a large portion of zooplankton. Marine biologists often refer to these crustaceans as “potato chips of the sea” that are fed upon by numerous larger animals in the oceanic food web. These creatures form their shells from calcium. Unfortunately, increasing levels of carbonic acid could gravely affect the development of their protective shells, which could drastically reduce the number of these creatures with ominous consequences for the marine ecosystem.
There still is uncertainty as to total effects, as scientific awareness of ocean acidification is relatively recent. But we do know that unless we are able to reduce our emissions from burning fossil fuels, these marine organisms will find themselves in a less life-sustaining environment, which could significantly affect the rest of the food chain.
Oceanographer and climate scientist Josh Willis of NASA’s Jet Propulsion Laboratory in Pasadena told me, “We often forget that it's the oceans getting the brunt of climate change. They take up heat and carbon dioxide. The oceans are really taking a beating."
In the United States, the generation of electricity is one of the largest contributors of carbon dioxide. However, in PG&E’s service territory the generation of electricity utilizing nuclear, hydroelectric, solar, wind, geothermal and biomass has contributed to making our state one of the cleanest in the country. In fact, more than 50 percent of the electricity that PG&E delivers to its customers is carbon free. With each passing year, it’s expected to become cleaner.