The ocean plays a fundamental role in regulating global temperatures. Not only does the ocean absorb 93 percent of the heat trapped by rising anthropogenic carbon dioxide (CO2), but it also absorbs approximately 25 to 30 percent of anthropogenic CO2 emissions that would otherwise remain in the atmosphere and increase global warming. The ocean also produces around 50 percent of the oxygen on the planet through the photosynthetic activity of marine plants and algae. The ocean’s ability to contribute to these fundamentally important services, however, is at risk (IPCC 2019). Ocean warming and acidification (a direct result of the extra CO2 dissolving into the ocean) are damaging marine ecosystems and compromising the ability of the ocean to provide food, livelihoods, and safe coastal living on which billions of people depend (IPCC 2014, 2018, 2019).
The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate was issued September 25. Important findings are:
- By 2100, the ocean will take up 2 to 4 times more heat than between 1970 and the present if global warming is limited to 2°C, and up to 5 to 7 times more at higher emissions.
- Marine heatwaves have doubled in frequency since 1982 and are increasing in intensity. They are projected to further increase in frequency, duration, extent and intensity. Their frequency will be 20 times higher at 2°C warming, compared to pre-industrial levels.
- Glaciers will lose more than a third of their mass on average with high emissions, cutting water supplies for people who depend on them.
- Ocean warming and acidification, loss of oxygen and changes in nutrient supplies, are already affecting the distribution and abundance of marine life in coastal areas, in the open ocean and at the sea floor.
- Strongly reducing greenhouse gas emissions, protecting and restoring ecosystems, and carefully managing the use of natural resources would make it possible to preserve the ocean and cryosphere as a source of opportunities that support adaptation to future changes, limit risks to livelihoods and offer multiple additional societal benefits.
- The report reveals the benefits of ambitious and effective adaptation for sustainable development and, conversely, the escalating costs and risks of delayed action.
Ocean Panel Paper
Parallel to this, the High Level Panel for a Sustainable Ocean Economy has released a report that specifically looks into ocean-based mitigation options to reduce or sequester and store emissions which offer significant potential to contribute to global efforts. However, ocean-based mitigation options do not feature prominently in countries’ nationally determined contributions (NDCs) or long-term low greenhouse gas emission development strategies under the Paris Agreement. Among the report’s key conclusions:
- When wider impacts on the environment and social well-being are considered, nature-based interventions—especially protection and restoration of mangroves, seagrass and salt marshes—offer the best combination of carbon mitigation and broader co-benefits.
- Offshore wind generation and other forms of ocean-based renewable energy such as wave and tidal power are estimated in the range of 500 to over 5,000 TWh/year.
- Ocean-based transportation has the potential for a roughly 100 percent reduction in operational net GHG emissions.
- The combined emissions reduction potential of global fisheries is 137.1 MtCO2e.
The IPCC report on ocean and cryosphere describes in stark terms the devastating impact of the climate emergency on the critical marine ecosystems. In order to urgently address these issues, policy action that includes comprehensive governance and finance measures is required.
International cooperation is vital if these challenges are to be tackled successfully. The Marine Regions Forum 2019 aims to develop clear recommendations, catalyze actionable outputs and build partnerships for stronger regional ocean governance, making a timely contribution to the United Nation’s 2030 Agenda for Sustainable Development. The outcomes of the Marine Regions Forum 2019 will feed into key ocean governance policy processes both regionally and globally, in particular the 2020 UN Ocean Conference.