Oceans will transition to unprecedented conditions soon, flags IPCC in report

In a wake-up call for world leaders, the Intergovernmental Panel on Climate Change (IPCC) has warned that oceans are projected to transition to “unprecedented” conditions, marked by an increase in temperatures, higher acidification and a decline in oxygen levels over the rest of the 21st century.

Marine heatwaves and extreme El Nino and La Nina phenomena will become frequent, IPCC said in a report released on Wednesday.

Extreme sea level events that are historically rare, occurring once per century, are projected to occur at least once a year in many locations, particularly the tropical region, by 2050.

In India, parts of the West Bengal and Odisha coasts are likely to experience such events annually by 2075, according to a map referred to by the IPCC, while the Americas will experience such events even earlier - by 2040.

The report states that the global mean surface temperature is projected to rise by around 1.6 degrees over pre-industrial levels by as early as 2031-2050.

Underlining the urgency for action, the Special Report on the Ocean and Cryosphere in a Changing Climate by the IPCC, which has assessed research on the state of glaciers, oceans and marine ecosystems, has projected that global glacier mass loss in the next few decades till 2050 will increase river run-off and related hazards like landslides, avalanches and floods, which will have serious consequences for India’s Himalayan region, according to experts.

The IPCC report also sums up how climate change impact has intensified to dangerous proportions. Since 1993, the rate of ocean warming has more than doubled, intense marine heatwaves have doubled in frequency since 1982, and receding glaciers and ice sheets have increased the rate of sea-level increase.

“The sea level is rising in the Indian Ocean also. In north Tamil Nadu, Puducherry and Vishakapatnam, coastal erosion is taking place - one of the reasons for the sea-level rise,” said M Rajeevan, secretary at the ministry of earth sciences.

“Our studies show that in the 2030-2050 period, glacier mass loss in the Himalayas will be accelerated and become even more serious after that. This will mean higher discharge in rivers, which will also be accentuated by extreme precipitation events,” said AL Ramanathan, glaciologist from Jawaharlal Nehru University.