Ocean surface climates may disappear by 2100, says study

Published August 27, 2021
Ocean surface climates support the vast majority of sea life. — AFP
Ocean surface climates support the vast majority of sea life. — AFP

PARIS: Up to 95 percent of Earth’s ocean surface will have changed by the end of the century unless humanity reins in its carbon emissions, according to research published on Thursday.

Ocean surface climates, defined by surface water temperature, acidity and the concentration of the mineral aragonite — which many marine animals use to form bones and shell — support the vast majority of sea life.

The world’s seas have absorbed around a third of all carbon pollution produced since the Industrial Revolution.

But with atmospheric CO2 levels increasing at a rate unprecedented in at least three million years, there are fears that ocean surface climates may become less hospitable to the species it hosts. US-based researchers wanted to see what effect carbon pollution has already had on ocean surface since the mid-18th century. They also projected the impact of emissions through to 2100.

To do so, they modelled global ocean climates across three time periods: the early 19th century (1795-1834); the late 20th century (1965-2004); and the late 21st century (2065-2014).

They then ran the models through two emissions scenarios. The first — known as RCP4.5 — envisions a peak in greenhouse gas emissions by 2050 followed by a slow decrease across the rest of the century.

The second scenario — RCP8.5 — is a “business as usual” approach, where emissions continue to rise throughout the next 80 years.

Writing in the journal Nature Scientific Reports, the researchers found that under the RCP4.5 scenario, 36 percent of the ocean surface conditions present throughout the 20th century are likely to disappear by 2100. Under the high emissions scenario, that figure rises to 95 percent.

The team also found that while ocean surface climates showed little sign of change during the 20th century, by 2100, up to 82 percent of ocean surface may experience climates not seen in recent history.

These include seas that are hotter, more acidic and that contain fewer minerals vital for sea life to grow.

Lead study author Katie Lotterhos, from Northeastern University’s Marine Science Center, said the ocean’s changing composition due to carbon pollution would likely impact all surface species.

“Species that are narrowly adapted to a climate that is disappearing will have to adapt to different conditions,” she said.

“A climate in which the temperature and chemistry of the water is common today will be rare or absent in the future.”

While surface species have so far been able to move around in order to avoid anomalously warm or acidic areas of ocean, Thursday’s study suggests that in the future their options may be limited due to near-uniform warming and acidification.

“Already, many marine species have shifted their ranges in response to warmer waters,” said Lotterhos.

“The communities of species that are found in one area will continue to shift and change rapidly over the coming decades.” She said that governments needed to monitor future shifting habits in marine surface species.

But, ultimately, the world’s oceans need the emissions driving their heating and acidification to cease.

“Without (emissions) mitigation, novel and disappearing climates in the sea surface will be widespread around the globe by 2100,” said Lotterhos.

Published in Dawn, August 27th, 2021

Opinion

Editorial

‘Source of terror’
Updated 29 Mar, 2024

‘Source of terror’

It is clear that going after militant groups inside Afghanistan unilaterally presents its own set of difficulties.
Chipping in
29 Mar, 2024

Chipping in

FEDERAL infrastructure development schemes are located in the provinces. Most such projects — for instance,...
Toxic emitters
29 Mar, 2024

Toxic emitters

IT is concerning to note that dozens of industries have been violating environmental laws in and around Islamabad....
Judiciary’s SOS
Updated 28 Mar, 2024

Judiciary’s SOS

The ball is now in CJP Isa’s court, and he will feel pressure to take action.
Data protection
28 Mar, 2024

Data protection

WHAT do we want? Data protection laws. When do we want them? Immediately. Without delay, if we are to prevent ...
Selling humans
28 Mar, 2024

Selling humans

HUMAN traders feed off economic distress; they peddle promises of a better life to the impoverished who, mired in...