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Oceans

Oceans will likely experience a decrease in marine productivity, an increase in ocean acidification, and an increase in the number of oxygen dead zones.


Decreased Sea Ice Habitat

The average thickness of Arctic sea ice has declined markedly over the past few decades. It is estimated that the thickness will further decrease by approximately 15% for every 1.8°F (1°C) of global warming. Arctic sea ice is vital for seals, polar bears, and walruses to hunt and rest.

Adaptation
It is uncertain whether animals that are dependent on sea ice habitats could adapt to a significant loss of sea ice.

Locations
Arctic

 

Increased Dead Zones

As ocean water warms, ocean oxygen levels are likely to decline, exacerbating low-oxygen zones in coastal areas and deeper waters.  These dead zones degrade habitat and can lead to extensive fish and invertebrate mortality. 

Adaptation
Implement early warning and notification systems for events of coastal oxygen deprivation.

Locations
Brazil, India, Gulf Coast, Western Europe, China

 

Decreased Catch Potential of Fisheries

With global average warming of 3.6°F (2°C), catch potential could decrease by up to 40% in the tropics, as commercial species shift away from the warming waters there. Many of the complexities of marine ecosystems that affect fisheries are not well understood.

Adaptation
Put practices into place to sustain fisheries in a changing climate. Use adaptive management principles in natural resource management plans to reduce ecosystem vulnerabilities. Encourage alternative vocations in traditional fishing communities.

Locations
Tropics

 

Increased Catch Potential of Fisheries

With global average warming of 3.6°F (2°C), catch potential could increase by 30–70% in high latitudes as commercial species shift away from the tropics due to ocean warming. Many of the complexities of marine ecosystems that affect fisheries are not well understood.

Adaptation
Put practices into place to sustain fisheries in a changing climate. Incorporate adaptive management principles in natural resource management plans to take advantage of fishery changes, while reducing ecosystem vulnerabilities.

Locations
High latitudes

 

Coral Reef Decline

Rising CO2 concentrations and ocean acidification reduce shell and skeleton growth in marine species such as corals and mollusks. Coral reefs will tend to erode rather than grow, harming the diverse forms of life that are reef-dependent.

Adaptation
Implement systems to evaluate and manage ecosystem impacts.

Locations
Global

 

Affected Polar Marine Species

Due to invasion of warm water species and high local extinction rates, marine species in the Arctic and Southern Ocean will continue to shift geographic ranges and many will die off.

Adaptation
Marine species are generally adapting by migrating down to deeper, cooler waters.

Locations
Arctic and Southern Oceans

 

Decreased Ocean Productivity

Warming of the ocean surface is projected to decrease production of organic compounds in the oceans of the tropics and subtropics. This decreased production will reduce nutrient availability in surface waters.

Adaptation
Conduct evaluations and put systems into place to manage ecosystem impacts.

Locations
Western Atlantic Ocean off the coast of Great Britain, Black Sea

Next: Impacts on Coasts & Wetlands