Global warming and wildlife

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Even small changes in temperature are enough to send hundreds if not thousands of already struggling wildlife species into extinction. Habitat displacement is one of the key impacts of global warming. Animals are forced to abandon ecosystems where they have spent millions of years. Ice giving way to water in polar bear habitat is just one such example.

Why should I be aware of this?

  • In just 40 years' time one in four of all animals and plants could be extinct due to global warming, according to a new WWF report. [1]
  • While climate change continues to be a contentious issue, changes in animal behavior are providing enough clues about the reality of global warming.
  • Many scientists believe that the number of changes occurring among plants and animals are because of unnatural climate change. Some significant changes are: [1]
  • Marmots end their hibernations about three weeks earlier now compared to 30 years ago.
  • Polar bears today are thinner and less healthy than those of 20 years ago.
  • Many fish species are moving northward in search of cooler waters.
  • A fruitfly gene normally associated with hot, dry conditions has spread to populations living in traditionally cooler southern regions.

All about global warming and wildlife

Beyond habitat displacement, many scientists agree that global warming is causing a shift in the timing of various natural cyclical events in the lives of animals. Many birds have altered the timing of long-held migratory and reproductive routines to better sync up with a warming climate. And some hibernating animals are ending their slumbers earlier each year, perhaps due to warmer spring temperatures.

Earlier biologists believed that species responded to temperature changes as a group, thus preserving their relationships to one another. But today scientists feel this is not often the case and different species respond to environmental stressors in different ways.

It was also predicted that timing of natural events like flowering, migration, and egg-laying could shift. Ecosystems are intricately connected webs, and even if a species doesn't rely on temperature and daylight cues to trigger certain behaviors, it may interact with other species that do.

Effects on animals

Land animals

  • Reindeer are expected to disappear from large portions of their current range by the end of the century.
  • Canadian red squirrels are breeding about 18 days earlier.
  • Red foxes are spreading northward, encroaching on territory normally occupied by their artic cousins.
  • North American Fowler's toads are breeding six days later than they did a decade ago.

Marine life

  • Coral reefs around the world are predicted to increase by up to a third in size.
  • Elephant seal pups are leaner because their prey is migrating to cooler waters.
  • Loggerhead sea turtles are laying their eggs about 10 days earlier than they did 15 years ago.
  • Rising temperatures are influencing the sex of Hawkbill turtle hatchlings, with more females than males being born.
  • Tidal organisms like rock barnacles, mollusks, and tidal snails commonly found in warm southern waters are moving northward.
  • Many fish species are moving northward in search of cooler waters.

Birds

  • The diet of some songbirds are changing, with some avoiding insects that consume leaves exposed to high levels of carbon dioxide.
  • North American tree swallows are laying their eggs about nine days earlier than they did 40 years ago.
  • Common murres are breeding 24 days earlier than they did a decade ago.

Threat to polar bears

The primary observation is that as the sea ice shrinks away, the polar bears are not growing as big as they used to.

In some places such as Canada's Hudson Bay, home to a large polar bear population, the ice season is now three weeks shorter than it was 30 years ago. As a result bears have reduced opportunities to hunt seals, their primary source of food and an essential source of fat needed for their long summer fast.

Females today weigh around 230 kilos (500 pounds), some 65 kilos less than in 1980, and measure about 185 centimetres (6.07 feet) on average, compared to around 220 centimetres a few decades ago.

The melting ice means not only shorter hunting seasons, but it also means the bears, who number some 20,000 to 25,000 worldwide, have to cross greater distances to reach their icy hunting grounds. This has led to a deterioration of health, impacting their reproductive capacities and the cubs' chances of survival. [1]

Salamanders facing extinction

A new study speaks of Salamanders endangered by global warming. It is feared that salamanders may soon become extinct, because of a sharp decline in the number of species worldwide. [1]

Two common species surveyed in the 1970s in cloud forests of southern Mexico and Guatemala are extinct, and the numbers of several others have gone down considerably.

Sea turtles threatened

Sea turtles lay their eggs on Brazilian beaches, many of which are threatened by rising sea levels. Climate change also threatens the offspring of sea turtles, as nest temperature strongly determines the sex: the coldest sites produce male offspring, while the warmer sites produce female offspring. This nest-warming trend is reducing the number of male offspring and seriously threatens turtle populations.

Australian frogs

Climate change is affecting home range, abundance and breeding cycles of many of Australia’s frog species. Since frogs rely on water to breed, any reduction or change in rainfall could reduce frog reproduction. Higher temperatures contribute to the drying out of breeding pools, and as a result, to the deaths of tadpoles and eggs. Drier conditions also cause adult frogs to die, due to increased rates of internal water loss through their permeable skin.

90 degrees

As average temperature increases, optimum habitat for many species will move higher up mountains or further towards the Poles. Where there is no higher ground or where changes are taking place too quickly for ecosystems and species to adjust, local losses or even global extinctions will occur.

Glaciers

Some of the most intense climate change-related habitat alterations are those that affect glaciers and ice-fields. Glaciers are retreating at an unprecedented rate, changing the entire ecology of mountain habitats. [1]

References:

  • How is Wildlife Affected by Global Warming?
  • How Global Warming is Changing the Wild Kingdom
  • If you can't bear to lose them...

Source