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Source: Department of Conservation

Climate change effects are considered the top threats to marine ecosystems according to a 2012 study. These effects will disrupt ocean currents, food webs, species distribution, and intertidal habitats.

The likely impacts from climate change on some of our marine species and ecosystems are relatively easy to predict and understand, but others require a bit more investigation. Some of the processes that will change the ocean dynamics include: increased sea-surface temperature, sea level rise, ocean acidification, and extreme weather events (heat waves, storms etc).

Marine Climate Change Project Team

Our Marine Climate Change Project Team was formed in early 2019, with staff from our Mountains to Sea, Marine Species, and Marine Ecosystems teams. The purpose of the team is to prioritise work, support action and report on work relating to marine climate change mitigation and adaptation.

The team is working to increase the resilience of native species and ecosystems so they have a better chance to adapt to climate change. As well as working on adaptation solutions we are focusing effort on marine mitigation opportunities.

Mangroves (and other coastal plants) are important to protect our shorelines from extreme tides, sea level rise, and tsunamis. They are a form of coastal adaptation and protection.

The team is also helping with DOC’s Climate Change Adaptation Action Plan which will set out actions we can take to reduce the impacts of climate change across all aspects of our business.

The Marine Climate Change Project Team are focussing on five specific areas: coastal wetlands and blue carbon, marine protected areas, seabirds, marine mammals, and coastal adaptation for nature .

Coastal wetlands and blue carbon

There is a lot of focus on ‘One Billion Trees’, but we are keen to add marine opportunities into the toolbox. Marine ecosystems are a great opportunity for mitigation! This so called “blue carbon” may be a new idea for New Zealand but the concept already has much traction overseas and in some countries people are getting paid to grow coastal wetlands! Salty wetlands can store 10-40 times more carbon, per unit area, compared with terrestrial forests. 

Mangroves store more carbon than terrestrial forests, and most if it is stored underground. Blue carbon might be more effective than traditional foliage at sequestering and storing carbon (Conservation International Global Mangroves Project).

This project supports the restoration of coastal wetlands (one rich form of blue carbon) as a tool for carbon sequestration to help mitigate climate change.

A coastal wetlands and blue carbon central government hui was held in November to start an ongoing programme, throughout the country, to get timely action on healthy estuaries to restore carbon.

Coastal adaptation for nature

Many of our coastal marine ecosystems – shallow surf zones, dunes, intertidal areas of open beaches and estuaries, coastal wetlands, coastal sequences – are at risk from sea level rise induced “coastal squeeze”.

How should we be managing our coasts against sea level rise and increased storm events? Seawalls and hard structures, or a managed retreat? What can we do to help our coastal species adapt – particularly those that rely on our shorelines for rest, reproduction, and feeding, e.g. NZ sea lions, yellow-eyed penguins.  


Seabirds are a key indicator of the impact of climate change, as they are an apex predator that traverse the world’s oceans.

Seabirds rely on both the land and the sea throughout their lives and will therefore be affected by both land-based and sea-based risks. There will be some direct measures we can take to help seabirds at their breeding colonies adapt to increased storm frequency, sea level rise, and predator eruptions. Indirect effects on food webs at sea will be harder to manage.

The challenge will be prioritising the species or populations most at risk.

Some adaptation projects have been identified that we could focus on e.g. coastal nesting gulls and terns, protection of surface nesting seabirds from extreme heat events, and identification of future risks to seabirds from climate change.

Marine mammals

Did you know a single great whale is worth at least 2 million dollars? Each great whale (baleen whales and sperm whales) is equivalent to a forest with 400,000 trees when it comes to carbon storage! Worldwide, this “whale pump” transfers about 10 gigatonnes of carbon from the atmosphere to the deep ocean each year. Even more reason why we should protect our whales – they can help us fight climate change (see this podcast for more info on the value of whales).

The “whale pump” describes the feedback loop whereby whales excrete nutrient rich faecal plumes fertilising surface waters and stimulating growth of phytoplankton which feeds the zooplankton (e.g. krill) and hence the whales. Credit: University of Tasmania

A focus of our action to help make dolphins and whales, and seabirds, resilient to climate change will be reducing other stressors that we have control over. Seals will also face similar land-based threats as nesting seabirds and could benefit from more direct action.

It is going to be important to review current knowledge, and to learn from other countries, on the possible impacts of climate change on New Zealand’s threated, and protected marine species. In particular, when it comes to distribution and migration patterns so we know where to focus our management for future scenarios.

Marine protected areas (MPAs)

Establishing MPA networks is critical to maintaining the resilience of our marine ecosystems to climate change and other pressures. MPAs can be used to protect climate change refugia and critical habitats for climate change affected species. We can also use MPAs as monitoring and research sites to help track the effects of climate change and distinguish climate change or environmental variability from the effects of human activities. As part of DOC’s Biodiversity 2018 Programme, we are increasing funding for monitoring climate change (temperature and ocean acidification) at 13 marine reserves over the next two years.

Additionally, the MPA Research workstream of Biodiversity 2018 Programme includes a project on MPAs and climate change. As part of this, DOC staff and WWF-NZ are intending to co-host a workshop this financial year to discuss state of knowledge and information gaps, specific to MPAs and climate change, and make recommendations on how climate change can be better incorporated into MPA planning and management in Aotearoa New Zealand.

Happy Seaweek! If you would like to participate in some of the activities happening across the country – check out what’s on in your region.