Greenhouse gas emissions could double the acidity of New Zealand’s oceans within 80 years, damaging sea life and the fishing industry, says a new report by Forest & Bird.
The report states that the acidity of the seas around Aotearoa has increased by 26 percent since pre-industrial times and could increase by 116 percent by the end of the century.
Forest & Bird is calling on government, councils and the fishing industry to urgently take up the report’s 16 key recommendations to limit the impacts of climate change on our seas.
The report offers a troubling view of the risks to all sea life as our oceans become more acidic and warmer, says Forest & Bird chief conservation advisor Kevin Hackwell.
“Increasing acidity in the sea poses a huge risk to New Zealand’s shellfish, corals and fish and to the seabirds, dolphins, seals, and whales that need healthy oceans to survive,” says Mr Hackwell.
“So far, we have not seen the urgency from the fishing or aquaculture industries that would suggest they fully understand the scale and speed of the climate crisis, or how it will devastate the ecosystems they depend on.
“Marine industries are hugely exposed to climate change effects, which are already being felt with reduced hoki numbers and shifting of tuna stocks.
“This report must be a wake-up call for New Zealand’s marine based economies and government regulators. The fishing and aquaculture industries must add their influential voices to demanding New Zealand dramatically reduces greenhouse emissions,” says Mr Hackwell.
The Ocean Acidification – Implications for New Zealand report, draws on insights and research from 10 New Zealand scientists on how climate change will impact on our seas.
Globally, oceans absorb 30 percent of carbon dioxide in the atmosphere, so the greenhouse gases that cause climate change and sea temperature increases also cause ocean acidity to rise, the report says.
New Zealand research has found that the diversity of phytoplankton species was reduced in more acidic and warmer waters. Zooplankton also fed less efficiently.
“Less plankton will have a massive impact on aquatic life, because plankton are the foundation of the ocean’s food chain, eaten by everything from fish to giant whales,” says Mr Hackwell.
More acidic seawater is associated with less calcium carbonate being available for shellfish and corals to form and maintain their shells. Some coral skeletons, shellfish and sea snail shells could start to dissolve.
The report makes 16 recommendations to industry, government Ministers, and regional councils, including:
- To protect at least 30 percent of New Zealand’s seas in marine reserves, to increase the resilience of our oceans in the face of climate change
- To reform the Resource Management Act to include provisions to protect oceans from acidification and require that greenhouse gas emissions are considered in decision making
- To fix the Fisheries Act, so it includes ecosystem-based fisheries management that takes ocean acidification into account
- To amend the Zero Carbon Bill to include ocean acidification in all government risk assessment and planning for climate change adaptation
- To reform the Exclusive Economic Zone Act to allow for direct and indirect CO2 emissions to be taken into account when assessing an activity.
- Ocean acidification disrupts the sensory systems of some fish, changing their behaviour.
- A study of yellowtail kingfish in New Zealand showed elevated levels of dissolved carbon dioxide in the water caused larvae to swim slower and a shorter distance when startled.
- Studies of paua and mussels have shown more acidic seas lead to smaller shellfish and pitting of their shells. However, research from the Nelson-based Cawthron Institute suggests green lipped mussels might be able to be selectively bred to increase their resilience to climate change impacts.
- Rising ocean acidity is compounded by higher sea temperatures. The surface waters around New Zealand have already warmed by 0.4 to 1.2 degrees Celsius since 1981 and the southwest Pacific is expected to be 2.5 degrees warmer by the end of the century.
See the full Ocean Acidification – Implications for New Zealand report here.