UN warns on ocean acidification as GHG levels soar

Carbon dioxide emissions in 2013 were largest on record since 1984, says World Meteorological Organization 

Shellfish are vulnerable to acidification, as acid in waters prevents species developing calcium shells  (Pic: NOAA)

Shellfish are vulnerable to acidification, as acid in waters prevents species developing calcium shells (Pic: NOAA)

By Ed King

Current levels of ocean acidification are “unprecedented” and directly linked to rising emissions of carbon dioxide, according to the UN’s World Meteorological Organization (WMO). 

In a greenhouse gas analysis of 2013, released on Tuesday, it said concentrations of CO2 in the air had risen more than any other year since 1984. Methane and nitrous oxide levels also rose.

Carbon dioxide levels in the atmosphere are now 142% higher than 1750, before the industrial revolution.

And the WMO said data showed the warming effect on the world’s climate due to greenhouse gases, known as radiative forcing, had risen 34% between 1990 and 2013.

“Carbon dioxide remains in the atmosphere for many hundreds of years and in the ocean for even longer,” said WMO secretary general Michel Jarraud.

“Past, present and future CO2 emissions will have a cumulative impact on both global warming and ocean acidification. The laws of physics are non-negotiable.”

Jarraud added the latest data should be used as a “scientific base for decision-making”.

World leaders are primed to meet in New York in two weeks for a UN summit to discuss options to reduce emissions of climate warming gases.

This report is the latest evidence of the levels of atmospheric gases burning fossil fuels has released.

A leaked draft of the UN’s IPCC climate science panel syntheses report, due out in November, stressed that “human influence on the climate system is clear”.

Earlier this year the Mauna Loa observatory in Hawaii recorded for the first time in recorded history that concentrations of carbon dioxide in the atmosphere had passed 400 parts per million (ppm).

Report: Alaska fisheries hit by rising acidifiction levels

Equally concerning, WMO scientists said the ability of the biosphere to absorb rising carbon levels had diminished, leaving the oceans to compensate.

“The ocean cushions the increase in CO2 that would otherwise occur in the atmosphere, but with far-reaching impacts,” it said in a press release.

“The current rate of ocean acidification appears unprecedented at least over the last 300 million years, according to an analysis in the report.”

Caused when the oceans suck in CO2, acidification is likely to lead to the decline of corals, algae, molluscs and some plankton, say scientists.

The ocean currently absorbs around a fourth of manmade CO2 emissions. The WMO said if emissions continue to rise, acidification is likely to accelerate until the 2050s.

Earlier this year the IPCC said ocean warming and acidification linked to rising CO2 levels would undermine food production and threaten the world’s poorest people.

Wendy Watson-Wright, executive secretary of the Intergovernmental Oceanographic Commission of UNESCO welcomed the WMO’s focus on oceans in its report.

“The inclusion of a section on ocean acidification in this issue of WMO’s greenhouse gas bulletin is appropriate and needed,” she said.

“It is high time the ocean, as the primary driver of the planet’s climate and attenuator of climate change, becomes a central part of climate change discussions.”

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