Effects of global warming on marine mammals

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The effects of global warming on marine mammals are of growing concern. The effects can be both direct; like loss of habitat, temperature stress, and exposure to severe weather, and indirect; like changes in host pathogen associations, changes in body condition because of predator prey interaction, changed in exposure to toxins, and increased human interactions. All of these are effects that are predicted that the marine mammals are living with because of the rapid climate change.[1]The increase of carbon dioxide and other greenhouse gases into the atmosphere is thought to be the main cause of climate change or global warming. Exactly how this will affect the ocean, which is home to marine mammals, is hard to predict since there are many factors, such as weather events and salinity that affect ocean ecosystems. How all these will interact is highly unpredictable. Using global climate models (GCM)s, scientists can get a general idea of how climate change will impact the ocean environment in the future.


Marine mammals have evolved to live in the ocean, but the effects of climate change are rapidly altering their habitat.[2][3][4][5] The climate change for arctic marine mammals by studying the difference in their habitat, distribution, abundance, movement and migration, body conditions, behavior, and their sensitivity. The climate change is drastically changing, so it is hard for some arctic marine mammals to adapt to the new conditions as quickly as needed, so the arctic marine mammals are being studied to see what happens to them due to the high stress they are put in due to the rapidly changing climate change. These climate changes put the arctic marine mammals in immense pressure and stress, due to this many species who cannot adapt begin to slowly die off due to the extra stress.[6] As levels of greenhouse gases in the atmosphere increase they trap heat which causes an overall warming of the planet. During the last century, the global average land and sea surface temperature has increased dramatically.[7] Warming has reached down to about 700 meters[8] and more (per a study which finds that 30% of the ocean warming, over the past decade, has occurred in the deeper oceans below 700 meters).[9][10] Many marine mammal species require specific temperature ranges in which they must live. The warming of the ocean will cause changes in the species migration or area that they inhibit. The species that cannot relocate due to some type of barrier will be forced to adapt to the increasingly warming sea waters or they will face extinction. Many of the species ranges are being pushed further and further north as water temperatures increase and they will soon have nowhere else to go.

The rise in sea level affect the coastal habitat and the species that rely on it.[11]T he rising sea levels are causing erosion of the beaches, so this then causes the turtles to have a hard time finding a spot to lay their eggs. The rising temperature are also causing problems for the turtles because the temperature of the sand determines the sex of the eggs, so many places are having a 90% production of females and if the temperature rises by just one degree, there could potentially be no more male turtles. The right whales have been on the endangered species list since the 1970s and the population keep declining because of the decline of zooplankton. Because of the climate change, the population of zooplankton is decreasing and since this is the right whale’s main food source, the female whales are not able to bulk up for the calving process. The seals are effected by the climate change because of the rapid increase of the melting ice. The seals use the ice to rest between their searches for food. With the increase of melting ice, the seals could be in trouble.[12] This habitat is often used by pinnipeds as haul out sites. In order to combat rising sea levels in areas inhabited by humans, the construction of sea walls has been proposed, however, these walls may interfere with the migration routes of several marine mammal species. These routes can be very important to some marine mammal species for reaching feeding and breeding grounds.

Changes in the temperature ranges will also change the location of areas with high primary productivity. These areas are important to marine mammals because primary producers are the food source of marine mammal prey or the marine mammals prey themselves. Marine mammal distribution and abundance will be determined by the distribution and abundance of its prey. Migration of marine mammals may also be affected by the changes in primary productivity.

Increased glacier ice melt also impacts ocean circulation because due to the increase of freshwater in the ocean, salinity concentrations in the ocean are changing. Thermohaline circulation may be altered by increasing amounts of freshwater in the ocean. Thermohaline circulation is responsible for bringing up cold, nutrient rich water from the depths of the ocean, a process known as upwelling. This may affect regional temperatures and primary productivity.

Susceptibility to disease is also thought to increase while reproductive success may decrease with increasing ocean temperatures.

The world's oceans absorb a large amount of carbon dioxide from the atmosphere and causes an increase in carbon dioxide concentrations and decreases its overall pH, increasing ocean acidification.

See also


  1. Burek, Kathy. "Effects of Climate Change on Arctic Marine Mammal Health". Ecological Society of America.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. Hardwood, 2001
  3. Simmonds and Isaac, 2007
  4. Tynan and DeMaster, 1997
  5. Learmonth et al, 2006
  6. Laidre, Kristin L.; Stirling, Ian; Lowry, Lloyd F.; Wiig, Øystein; Heide-Jørgensen, Mads Peter; Ferguson, Steven H. (2008-01-01). "Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change". Ecological Applications. 18 (2): S97–S125.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  7. Map Shows Vast Regions of Ocean Are Warmer March 30, 2013 Scientific American
  8. Warming Ocean Threatens Sea Life; Warming down to 700 meters could also affect currents, weather March 30, 2013 Scientific American
  9. New Research Confirms Global Warming Has Accelerated March 25, 2013 Skeptical Science
  10. doi:10.1002/grl.50382
  11. Glick, Patrick; Clough, Jonathan; Nunley, Brad. "Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region" (PDF). National Wildlife Federation. Retrieved 8 November 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  12. "Endangered Species and Habitats". Climate Change: The Effects on Ocean Animals.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>


  • Poloczanska, E. S., Babcock, R. C., Butler, A., Hobday, A. J., Hoegh-Guldberg, O., Kunz, T. J., Matear, R., Milton, D. A., Okey, T. A., & Richardson, A. J. 2007. "Climate change and Australian marine life". Oceanography and Marine Biology: An Annual Review, 45, 407-478.
  • Hardwood, J.. 2001. "Marine mammals and their environment in the twenty-first century". Journal of Mammalogy, 82(3), 630-640.
  • Learmonth, J.A., Macleod, C.D., Santos, M.B., Pierce, J.G., Crick, H.Q.P. & Robinson, R.A. 2006. "Potential effects of climate change on marine mammals". Oceanography and Marine Biology: An Annual Review, 2006, 44, 431-464.
  • Marine Climate Change Impacts Partnership. 2006. "Marine Climate Change Impacts Annual Report Card 2006". (Eds. Buckley, P.J., Dye, S.R., & Baxter, J.M..), Summary Report, MCCIP, Lowestoft, 8pp.
  • Simmonds, M.P. & Isaac, S.J. 2007. "The impacts of climate change on marine mammals: Early Signs of Significant Problems". Oryx, 41(1), 19-26.
  • Tynan, C.T. & DeMaster, D.P.. 1997. "Observations and predictions of Arctic climate change: potential effects on marine mammals". Arctic, 50(4), 308-422.

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