Climate stakes are high for ice and oceans, IPCC report explains

Enlarge (credit: NASA Earth Observatory)

"Over the 21st century, the ocean is projected to transition to unprecedented conditions with increased temperatures, greater upper-ocean stratification, further acidification, oxygen decline, and altered net primary production." That's one of the top-line conclusions detailed in a new IPCC report released Wednesday. This latest report-the volunteer work of over 100 scientists summarizing almost 7,000 published studies-focuses on our planet's ocean and cryosphere, describing the changes we've measured, projected future changes, and the choices before us.

The report follows on others covering the potential benefits of limiting warming (which has already reached 1C) from exceeding 1.5 C, the role of land use in climate change, and impacts on global biodiversity.

The observed changes in oceans and ice run the gamut from physical changes to chemistry to living things. Sea levels are rising at increasing rates, of course, but it's also true that marine heatwaves (the kind of event that can bleach coral reefs) have doubled in frequency over the last few decades, and oxygen availability has slightly declined in the surface ocean as circulation changes. Marine species have shifted their geographic ranges to track changing conditions, and sea-level rise combined with coastal habitat loss have boosted flooding events and the inland intrusion of saltwater.

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