Most people view climate change simply as a warming of the atmosphere, the effects of which are felt primarily on land. However, this is an anthropocentric perspective and does not go far enough. This view ignores the fact that climate change also greatly affects the oceans. Not only do they absorb much of the additional heat produced in the atmosphere due to increasing greenhouse gas concentrations, they also absorb approximately one-third of human-caused CO2 emissions from the atmosphere. This CO2 absorption causes ocean acidification, which has significant consequences for marine life.

“Despite these profound changes, many people are unaware of what is happening to our oceans,” says Nicolas Gruber, professor of environmental physics at ETH Zurich. A marine explorer and his team want to change that. So how can people understand such an abstract concept of a complex process in an unfamiliar environment?

Make environmental changes visible

The researchers’ answer: “Ocean Acidification Bands” is a web-based graphical tool that intuitively shows ocean acidification over time in different ocean regions using colored bands. The format and appearance of the “acidification bands” were deliberately inspired by the famous “temperature bands” or “climate bands” of British climatologist Ed Hawkins.

“We want to make ocean acidification more visible and raise awareness that this environmental change is another serious consequence of anthropogenic CO2 emissions ₂ with atmospheric warming,” explains Gruber.

Stressful environment for marine inhabitants

CO when ₂ It dissolves in water, forming carbonic acid. This process acidifies the sea; pH value decreases. Some of the carbonic acid reacts with carbonate ions dissolved in seawater, causing a decrease in the saturation level of seawater with carbonate minerals such as aragonite (the building material of corals).

Both chemical processes are particularly harmful to marine organisms that depend on calcareous shells composed of carbonate minerals, including various species of plankton, mussels, and coral.

“Since these organisms are often at the base of the food chain, they are critically important to many marine ecosystems and therefore important to us humans as well,” says Gruber.

The new ETH band generator is available for free and allows users to visualize the change in aragonite acidity (pH) or saturation in more than 60 regions. For example, anyone interested in the degree of ocean acidification at a resort can select the appropriate area of ​​the ocean and create the acidification bands themselves.

Acidification trends and factors confirmed

The scientific basis for the visualization is a dataset based on observations of ocean acidification called OceanSODA-ETHZ. It has covered almost all oceanic regions for the last four decades (1982 to 2021). OceanSODA-ETHZ was created in 2021 by Gruber PhD student Luke Gregor, who combines ship measurements and satellite data using machine learning.

Thanks to this observational data set, Gruber’s team was now able to investigate the trends and drivers of acidification. In research published in the journal Global Biogeochemical CyclesResearchers used these data to show for the first time how ocean acidification has developed worldwide in recent decades.

“Oceans are good at absorbing CO2,” says first author Dunling Ma.₂ Remove from atmosphere and acidify. “But global growth cannot currently be adequately confirmed by observations alone,” explains Usta from Gruber’s team. Now researchers have eliminated this gap.

“Our results confirm that pH and aragonite saturation are decreasing in the world’s oceans, and that these trends are mainly driven by increased dissolved inorganic carbon absorbed from the atmosphere,” Ma said.

Thus, researchers can clearly prove that anthropogenic CO2 emissions occur.₂ causing continued ocean acidification. Source