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THE EFFECTS OF HUMAN INDUCED GLOBAL WARMING ON POLAR BEARS

This map shows how much the polar bears habitat has diminished.The dark outlines show where the ice used to be

The red on this map indicates how much ice will melt in the next few decades. The sea ice on which the polar bears depend for hunting is virtually gone

Two-thirds of all polar bears are at risk of extinction by 2050

Polar Bears are the world’s largest terrestrial carnivores.Although they look innocent, Polar Bears are known as the most ferocious of all bears.They live in the arctic and spend most of their time roaming the frozen arctic waters.But what if they fall through the ice?Don’t worry, polar bears are excellent swimmers.They use their large paws to propel them through the water at speeds upwards of 10 kilometers per hour (6.2 miles) Polar bears enjoy feasting on sea creatures such as seal, walrus, beluga whale and fish to fulfill their daily requirement of 4.4-5lbs of fat per day .Polar Bears migrate throughout the year based on mating, food and housing. From season to season the polar bears pack their belongings (even that expensive fur coat) and migrate towards icier regions.A migration range can approach 350,000 sq/km .Polar Bears breed during April and May .Mating takes place in seal rich areas.Food intake and mating are directly correlated as will be explained in greater detail later. The greenhouse effect on climate alters migration, feeding, and reproduction patterns in polar bears.

The word is out!Rumor has it human activities are responsible for the increase in arctic temperature, according to the International Panel on Climate Change .The Arctic ecosystem relies on the cold climate to maintain stability.As monthly temperature averages slowly increase, summers become warmer and the ice covered waters are breaking up prematurely. Average air temperatures in the arctic have increased 5 degrees Celsius over the past 100 years .To top that off, as a result, the ice extent, or length of time before ice melts has decreased 14% since the 1970’s .Many authorities on the topic predict that by the year 2080 arctic summers will be ice free !The world of the polar bear revolves around the presence of ice.It is the ground they walk on, the basis of their homes, and the platforms they feed from.Increasing climate spells extinction for polar bears!
                                                                                                                                  
In 1999, Ian Sirling, Nicholas J. Lunn and John Iacozza conducted a study in Hudson Bay.Their results indicated that ringed seals, polar bears primary food source were becoming less available due to the shortened ice season .Bears require a high fat diet to survive.Seals are becoming a rare commodity and low-fat fish are becoming their staple .The ice is melting in early spring and forming during late autumn, which results in a shorter feeding period.Bears camouflage with the ice.They lay on their stomachs while covering their black noses to remain completely hidden.As seals unknowingly approach the bears, they are pounced upon and killed .This surprise element of attack is impossible without the presence of ice.Each week earlier the ice breaks apart, bears return ashore approximately 22lbs lighter. As the living range decreases there is a population surplus for the given amount of land.Competition for the limited food supply increases.As is common with many animals the fittest survive.Bears endure physical battle which results in wounds, but rarely death.Often, the larger and more dominant males maintain their intake leaving the remaining bears to starve.As the ice caps continue to recede, bears will be stranded ashore and ultimately intake no food.To compensate for their lack of consumption, bears are forced to use their fat stores for energy and survival (4).If this continues over and extended period of time, the final effect will be death in the form of starvation.

In order to relieve their hunger, bears scavenge new grounds to find food.Imagine opening your front door to retrieve the morning paper only to find a polar bear lounging on your steps.Human bear altercations are a growing trend .Involuntarily, the food deficit in polar bears natural setting is forcing these animals to find alternate feeding grounds.As the Polar Bears recede northward they begin to encounter food in populated villages.Despite various tactics to rid their presence including firecracker use and attack dogs, if the bear deems a community dumpster its food source, little can be done to stop its wandering.

Pack your things kids we’re going on vacation.The Polar Bears of the arctic are doing just that.The amount of ice in the polar region can be compared to the size of the United States.With that in mind imagine each year an area twice the size of New Jersey vanishes. The ice in the polar region is performing a disappearing act right before our very eyes.As the ice season shortens and its volume decreases, polar bears are changing their migration patterns. Bears tend to migrate towards ice. The ice aids the bears in hunting.An ideal range of migration for the average polar bear is 50,000 to 60,000 square kilometers .Due to human induced climate changes, migration ranges are increasing upwards to 350,000 square kilometers. Experts indicate that as the southern ice formations melt, bears will slowly progress northward .

In another scenario, ice recession has limited migration.The bears are forced to “stay home.”Often, leads (cracks between ice panels) are melting and drifting farther apart.Leads that used to be close in proximity spread so far apart that the bears become stranded .The bears migration capabilities are then limited.The end result is an overpopulation for a given area causing increased feeding competition.

So you see, migration, feeding and reproduction are all related and affect one another.Bears are being forced to migrate from their prime feeding areas; as a result they are malnourished and weigh less.Lower weights in polar bears are directly correlated with a decrease in reproduction. Also the shortened feeding results in cubs with smaller birth weights and higher mortality rates.

In fact, recently there are 10% fewer cubs than there were 20 years ago!If this trend continues polar bears could become extinct.In Hudson Bay, scientists found the main cause of newborn deaths to be lack of food.A two week decline in the ice free season results in an 8% weight loss for mothers which inhibits their ability to lactate and feed their newborns .Cubs follow their mothers for approximately two and a half years .The mother has difficulty supporting her own nutritional needs, let alone a den of cubs as well.In another fatal situation, glacial pieces are warming and cracking into multiple pieces.These subdivisions unrecognizable drift farther apart.Newborn cubs that are unprepared for long distance swims are in danger of drowning .

As we have learned, the climate changes are correlated with human activities which result in greenhouse emissions.Although no one person can turn the effect around single handedly, every effort counts.Here are ten things you can do at your household to help control the greenhouse effect.

• Take shorter showers and use a water efficient shower head.
• Turn off your computer screen if you are away longer than 10 minutes.
• Turn off you televisions!
• Wash your clothes with cold water and air dry ( if possible) as opposed to electrical drying.
• Use compact fluorescent lights
• Plant you own vegetable gardens.
• Wear a sweater when you house is cold instead of turning on the heater
• Use solar or high efficiency gas
• Insulate your home well
• Use a lid when cooking food instead of cooking with the lid off.