With representatives from nearly 200 countries at the United Nations Climate Summit underway in the United States, the Intergovernmental Panel on Climate Change (IPCC) – the apex referee for scientific evidence on the impact of global warming – made public a special report on 25, September 2019, that underlined the dire changes taking place in oceans, glaciers and ice-deposits on land and sea.
“Over the 21st century, the oceans is projected to transition to unprecedented conditions with increased temperatures, further ocean acidification, marine heat-waves and more frequent extreme El Nino and La Nina events”, according to a summary of the report.
The report updates scientific literature available since 2015-when the IPCC released its comprehensive 5th Assessment report – and summarises the disastrous impacts of warming based on current projections of global greenhouse gas emissions.
The global ocean has warmed unabated since 1970 and has taken up more than 90% of the excess gear in the climate system.
Since 1993, the rate of ocean warming has more than doubled. Marine heat waves have very likely doubled in frequency since 1982 and are increasing in intensity”, the report notes.
The Southern Ocean accounted for 35%-43% of the total heat gain in the upper 2,000 m of global ocean between 1970 and 2017, and its share increased to 45%-62% between 2005 and 2017.
“Floods will become more frequent and severe in the mountainous and downstream areas of the Indus, Ganges and Brahmaputra river basins, because of an increase in extreme precipitation events. The severity of flood events is expected to more than double towards the end of the century,” the report quoted.