PARIS: Up to 95 per cent of Earth’s ocean surface will have changed by the end of the century unless humanity reins in its carbon emissions, according to a research.
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 per cent 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 per cent.
— AFP
