Human-induced climate change has led to a significant increase in the oceans’ temperatures. As a result of this, species and ecosystems are under threat of extinction. This article dives into ocean warming and explains some of the ways we can avoid the worst possible effects of anthropogenic climate change.
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Climate Change and Ocean Warming
Higher concentrations of greenhouse gases in the atmosphere cause the planet’s temperature to rise, but 93% of the heat increase caused by greenhouse gases since the 1970s has been absorbed in the oceans. As a result, the oceans have been warming up quickly.
The global average temperature of the first few meters of the sea below the surface has increased by approximately 0.13 °C every decade in the last century. Further down, approximately a third of all the excess heat absorbed by the oceans was absorbed 700 m below the surface.
This widespread warming is impacting marine species and ecosystems. Many animals have moved to new areas due to too much heat, and their predators have been forced to follow them.
Case Study: North Atlantic Right Whales
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Oceanographers have recently reported on a concerning example of this phenomenon. The North Atlantic right whale population’s habitat in the Gulf of Maine was warmed in 2010 when warm slope waters entered the region, caused by climate-driven changes to the Gulf Stream.
The endangered right whales shifted their late spring and summer foraging grounds because of this and started to exhibit high rates of mortality in 2017. Only 15% of adult female right whales gave birth in the 2010s, compared to 47% in the 2000s.
Unfortunately, this is one case among many in which anthropogenic climate change has put marine species and ecosystems at risk.
Fish, seabirds, and marine mammals alike all face these risks from high ocean temperatures. Mortalities increase, breeding grounds are threatened and lost, and species make mass migrations in search of better conditions.
Coral reefs are also bleached by ocean warming, another loss of life and biodiversity in the oceans. Warming oceans also make human diseases more prevalent, leading to more extreme weather events, and harm coastal protection for human populations.
Save the Seas: Keep Global Warming Below 2 °C
Much of the harm caused by global warming has already been done and may be irreversible. However, many species and ecosystems can be saved if ambitious global targets are met.
Keeping global warming below 2 °C above pre-industrial levels is essential. Without this limitation, massive, irreversible impacts on marine ecosystems cannot be avoided.
This means decarbonizing our economies. Large-scale investment in renewables and nuclear power and regulation such as carbon taxes are needed to end our dependence on the fossil fuels that destroy the planet.
What Can We Do? IUCN Suggestions
The International Union for Conservation of Nature (IUCN) is a membership organization comprising government agencies, corporate businesses, and other stakeholders. Its funding comes mostly from governments and foundations, with some funding from multinational energy corporations such as Total Se.
The IUCC makes suggestions and policy recommendations to protect the natural environment worldwide. Focussing on ocean warming, the organization makes the following practical suggestions.
Limit Greenhouse Gas Emissions
The Paris Agreement set out targets to drastically reduce greenhouse gas emissions to limit global warming to below 2 °C above pre-industrial temperatures. Keeping global warming in check will protect the oceans as well.
Protect Marine and Coastal Ecosystems
Conservation in well-managed protection areas is an effective way to protect marine ecosystems. Regulating human activities such as trawling, shipping, and tourism in these areas can help protect the animals that live there.
Restore Marine and Coastal Ecosystems
The IUCN recommends restoring damaged ecosystems by building artificial structures and adjusting species to warmer temperatures with assisted breeding.
Improve Human Adaptation
The IUCN suggests using catch limits and reduced subsidies to prevent overfishing, which damages marine ecosystems as well as ocean warming caused by CO2 emissions. Regulation can also ensure development in coastal areas is as ecologically sound as possible.
Strengthen Scientific Research
More data on the scale, nature, and impacts of ocean warming can contribute to better decision-making and planning to protect the seas.
The North Atlantic right whale’s plight is a warning for us. Without immediate and large-scale action, many more marine species and ecosystems will be under threat from ocean warming.
References and Further Reading
Frölicher, T.L., E.M. Fischer, and N. Gruber (2018) Marine Heatwaves Under Global Warming. Nature. https://doi.org/10.1038/s41586-018-0383-9
Greene, C.H. (2016) North America’s Iconic Marine Species at Risk Due to Unprecedented Ocean Warming. Oceanography. https://doi.org/10.5670/oceanog.2016.67
IUCN. Ocean Warming. IUCN. [Online] Available at: https://www.iucn.org/resources/issues-briefs/ocean-warming
Meyer-Gutbrod, M.L., et al. (2021). Ocean Regime Shift is Driving Collapse of the North Atlantic Right Whale Population. Oceanography. https://doi.org/10.5670/oceanog.2021.308.
Scannell, H.A., et al. (2016) Frequency of Marine Heatwaves in the North Atlantic and North Pacific Since 1950. Geophysical Research Letters. https://doi.org/10.1002/2015GL067308.