Source: Department of Conservation
Climate change effects are considered the top threats to marine ecosystems according to a 2012 study. 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). These effects will disrupt ocean currents, food webs, species distribution, and intertidal habitats.
The Ministry for the Environment is the central government lead for climate change mitigation and adaptation but we (DOC) have an important role to play for our protected and threatened species and marine protected areas.
DOC Marine Climate Change Project Team
Our marine climate change project team (MCCT) was formed in early 2019, with staff from the Mountains to Sea, Marine Species, and Marine Ecosystems teams. The purpose of the team is to enable the Aquatic Unit to prioritise, support action and report on work relating to marine climate change mitigation and adaptation.
We are working to increase the resilience of native species & 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.
We are also contributing to the creation of a DOC 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.
Below are some examples of areas of work we are focusing on.
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.
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.
Coastal adaptation for nature
Many of our coastal marine ecosystems are at risk from sea level rise induced “coastal squeeze”: shallow surf zones, dunes, intertidal areas of open beaches and estuaries, coastal wetlands, coastal sequences.
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. New Zealand sea lions, yellow-eyed penguins/hoiho.
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.
Seabirds
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.