How are whales affected by global warming?

Global warming was fist noticed in the 19th century when there were suspected changes in the ice layer and the earth’s climate. 100 years ago, the Swedish scientist, Svante Arrhenius predicted negative changes taking place to the world’s temperature caused by carbon dioxide. Today, the land, the oceans and man are at increasing risk. The oceans are rich in marine life including 13 species of the largest mammals of all – whales. Their future hangs in the balance.

Put simply, global warming has been caused by the steady increase in the amount of carbon dioxide that is being produced. Global warming is creating changes in the overall temperatures of the world’s atmosphere and the earth surface and is the major aspect that is causing climate change which is having a devastating effect on the oceans.

The ocean are rising

Scientists have recorded that the levels of the oceans are rising. This is being caused by thermal expansion and also by the melting of the ice sheets and glaciers. The temperature of the oceans is also rising and these factors are having a huge impact on the whale population. The increased volume of water means that the saline levels are dropping in places and this affects the krill, fish and other small marine animals that whales feed on. Importantly, the location of the feeding grounds for the krill and marina animals is changing. This in turn impacts the whales as they are now travelling to new areas in search of food and their food supply is also diminishing.

Affecting the whales’ migration patterns…

Migration is an important part of a whale’s life, but their migration patterns are being affected by global warming and the whales are no longer able to determine when they should be migrating or where is their destination. As the water temperature is now often warmer, the whales are no longer eating well to build up layers of blubber. Whales are mammals with warm blood so it is essential that they have adequate protection (provided by the blubber) when swimming in colder water. Scientists have found that many whales are confused and swimming into colder waters but do not have adequate layers of protective blubber and this causes strain on their heart as they try to keep warm. Studies have also shown that many whales are now only swimming half the distance for their migration as they find the water warmer and think that they have arrived at their destination. Sadly, many of these areas do not have adequate supplies of food for the arrival of a school of whales.

….and reproduction.

Whales do not mature until they are 7-10 years old and even then, the female will only have a calf every 2-4 years. When they are preparing to breed, they like to be in a part of the ocean with abundant food supplies, otherwise breeding does not take place. The female whale needs plenty of food following the birth of her calf as she needs to produce about 12 litres of milk a day to feed her baby for the first year of its life. When the calf starts to feed for himself, he needs plentiful supplies of small fish, but sadly, these are often in short supply and the calf fails to thrive.

Whales help combat global warming.

Whales play a crucial role role in preserving the oceans’ ecosystems as they provide up to 50% of the oxygen in the oceans and help combat the effects of increased C02 levels. The daily life of the whale includes feeding, excreting and swimming close to the surface and diving to the greatest depths of the ocean. These activities all help to maintain a healthy ecosystem in the ocean. When the whales dive down deep into the ocean, they push nutrients up to the surface which help feed the phytoplankton and other marine plants and fish. The whales also excrete a faecal plume near the surface of the water and this is rich in iron and nitrogen which helps to fertilise the plankton and other marine plants – encouraging their growth. The more whales there are, the more plankton and other plant life there is. Phytoplankton and marine plants float on the surface of the ocean and using photosynthesis to feed, they absorbs large amounts of carbon dioxide from the atmosphere. The phytoplankton eventually sinks down to the ocean floor where it remains- with its trapped carbon dioxide- for thousands of years. https://www.scientificamerican com/article/whales-keep-carbon-out-of-the-atmosphere/

Interestingly, it has been argued that the diminishing number of whales is good as this will ensure a greater abundance of small fish and plankton in the oceans. Scientists have found that as whale numbers have fallen, so have the levels of their food stocks.

A stark warning for the future…

The 21st century could see the extinction of many animals and whales, dolphins and porpoises are amongst those facing the greatest threat. The earth is changing at an astonishing speed which is faster than many animals can adapt to. Changing marine habitats and increased competition for ever-diminishing food stocks poses a huge threat to our whales.

Some scientists believe that commercial whaling in the 19th and 20th centuries led to such a huge slaughter of whales that this alone accelerated climate change. In the time when there were many more whales in the oceans, than there are today, they were responsible for removing several million tons of carbon dioxide from the atmosphere every year which had a huge and positive impact on the earth. Whales have always played a fundamental role in balancing and maintaining the oceans’ ecosystems and because of this, it is now imperative that the number of whales remains static or starts to increase so that they can once again play their role in combating global warming…