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Light and warmth on planet Earth comes almost exclusively from the sun. What happens to this arriving solar radiation - including how much of it is bounced back into space - depends on a number of things, including the composition of gases in the atmosphere and how reflective the Earth’s surface is (for example, polar ice is more reflective than ploughed fields).
Most importantly it is planet Earth’s atmosphere that has moderated the effects of solar radiation to maintain the conditions that we now enjoy, and which has also allowed life on earth to evolve and be maintained here for many millions of years. The greenhouse effect is in fact a natural phenomenon caused by the atmosphere and which helps to keep the Earth warm (you might like to think of the atmosphere as a blanket around the Earth, keeping a lot of the heat in). However, in the last centuries we have significantly changed the atmosphere, putting extra amounts of what have become known as ‘greenhouse gases’ into it (the blanket has become thicker and the temperature underneath is becoming dangerously hot).
The main greenhouse gas being pumped out by humankind is carbon dioxide and it comes from the burning of fossil fuels (coal, oil and gas) which we use to power our factories, warm and light our homes and run our cars. The increasing amounts of greenhouse gases mean the atmosphere is retaining more heat and so it is that the planet is warming up. At the same time this increased warmth is melting the polar ice cover - so there is less shiny ice to reflect light away and this too is increasing the warming effect. In addition vast areas of rainforest are being destroyed and this too is releasing carbon dioxide into the atmosphere.
Climate change, driven by the greenhouse effect, is a fundamental threat to whales, dolphins and porpoises. There is unequivocal evidence that climate change is happening and that human activities are contributing to it and the climate is changing fast: so fast that some whale and dolphin populations may be unable to adapt. Yet at the same time, whales themselves play a key part in helping to combat this threat through their role in the marine ecosystem.
Climate change is expected to affect whales, dolphins and porpoises mainly through the loss of habitat (given the distinct temperature-linked ranges of most species), changes in prey availability, potential increased competition from range expansions of other species. The potential impacts include changes in abundance, distribution, timing and range of migration, prey abundance and distribution, and reproductive success and ultimately survival.
It is unclear to what extent whales, dolphins and porpoises will be able to adapt to the rate of climate change predicted, in some cases such range shifts will not be possible. For example, the northern Indian Ocean is fringed by land, limiting the ability of species to move northwards into cooler habitat as waters warm.
There are some indications that some cetaceans are already being significantly affected by climate change and to protect them and indeed to protect all other living things, including ourselves, we need to act now.
The extent and the duration of temperature increases and the associated effects of climate change around the world will depend on how swiftly and effectively emissions of greenhouse gases can be restricted and reduced.
WDC facilitates research on the impacts of climate change, leading work to raise awareness of the impacts on whales and dolphins. Working with other groups, we campaign for international action to find solutions and reduce the impacts of threats.
Find out more about how the continued recovery of whale populations can play a major role in combating climate change in our new report: Whales - their future is our future.