Oceans need big reduction in greenhouse gases

Our oceans need an immediate and substantial reduction of greenhouse gas emissions. Otherwise, there will be far-reaching and irreversible impacts on marine ecosystems, says a study.

And such impact will be more pressing in developing countries. The research team from the Ocean 2015 initiative assesses the latest findings on the risks that climate change poses for our oceans and demonstrates how fundamentally marine ecosystems are likely to change if human beings continue to produce just as much greenhouse gases as before.

"To date, the oceans have essentially been the planet's refrigerator and carbon dioxide storage locker. For instance, since the 1970s they've absorbed roughly 93 percent of the additional heat produced by the greenhouse effect, greatly helping to slow the warming of our planet," said co-author Hans-Otto Portner, researcher at Alfred Wegener Institute, at Potsdam in Germany.

"If we can successfully limit the rise in air temperature to two degrees Celsius through the year 2100, the risks, especially for warm-water corals and bivalves in low to middle latitudes, will become critical. However, the remaining risks will remain fairly moderate," said lead author Jean-Pierre Gattuso.

"If instead carbon dioxide emissions remain at their current level of 36 billion tonnes per year (the 2013 level), the situation will escalate dramatically," Gattuso said.

"If we just go on with business as usual, by the end of this century the changes will hit nearly every ecosystem in the oceans and cause irreparable harm for marine life," Partner added.

This would in turn have massive impacts on all areas in which human beings use the oceans -- whether in capture fisheries, tourism or in coastal protection.

"The ocean provides compelling arguments for rapid reductions in CO2 emissions and eventually atmospheric CO2 drawdown. Hence, any new global climate agreement that does not minimize the impacts on the ocean will be inadequate," Partner said.

The study was published in the journal Science.