Climate and Ocean
Our ocean plays a key role in regulating the Earth’s weather and climate.
The ocean has absorbed about 30% of carbon dioxide released into the atmosphere since the beginning of the industrial revolution. This has helped limit global climate change, but at a high price – ocean waters are 26% more acidic than in pre-industrial times. This increased acidity weakens the shells of sea creatures and the skeletons of coral reefs.
The ocean has also absorbed over 90 % of the additional heat in the Earth system since the 1970s. This has helped limit global average temperature rise, but again at a high price. Ocean waters are warmer, which affects the distribution of marine species and the health of marine ecosystems, while also contributing to sea level rise. Sea ice and glaciers are melting around the world, exacerbating sea level rise. By the end of the 21st century, sea levels are on track to rise at least another 1 to 4 feet, affecting the lives and livelihoods of coastal communities.
The pace of these changes is quickening, making it difficult for marine life and coastal communities to adapt. Coral reefs and polar ecosystems are especially vulnerable. We already see differences in the ranges, activities, and populations of many marine species in response to climate change.
The impacts of these changes are already clear – fishermen working harder in search of a catch, coastal communities awash at high tide, coral bleaching around the world. Ocean acidification, ocean warming, and sea-level rise threaten economic livelihoods, food sources, the biodiversity of the ocean, the integrity of coastal areas, tourism, and recreation.
There is much we can do – and are doing – to minimize the impacts of climate change on our ocean and to adapt to those effects that are unavoidable. Reducing greenhouse gas emissions globally will be critical to this effort, and the commitments countries have made in the Paris Agreement are a step in the right direction, but much more needs to be done.
The protection and restoration of marine ecosystems and coastal habitats, such as mangroves and wetlands, can both sequester additional CO2 and increase the resilience of these areas to rising temperatures and extreme weather events. Coastal zone planning can help reduce the expected effects of sea level rise, while careful fisheries management can help adapt to shifts in species populations and ranges. To be effective, these responses require coordinated action and commitments from governments and individuals around the globe.