Planet Earth Weekly

Climate Change and Renewable Energy: Saving Our Planet for Future Generations

Tag Archives: Disappearing Ice Shelves


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Record Heat Waves Plague the Planet

There will be more severe heat waves. They will become hotter, more frequent, last longer and occur in more varied places.

By Dr. John J. Hidore
February 12, 2019——Heat wave is a general term. When it seems unusually warm someplace there is often a tendency to describe the weather as a heat wave. As it turns out it is very hard to define a heat wave. The reason is simple. Normal summer high temperatures vary greatly from place to place. What would be defined as a heat wave in one location would not be appropriate for another location, perhaps not even too far away. An adequate definition might be, “A heat wave is an unusually warm or hot period lasting for days or perhaps weeks.” We associate them with summer but by this definition they can actually occur at any season.

climate change

The exchange of energy is causing rapid arctic melting.

At least one country makes a clear definition of a heat wave and that is Pakistan. India also defines heat waves and uses different temperatures in different parts of the country to establish what constitutes a heat wave. In the plains regions of the Unites States, temperatures above 40degreesC (104 degreesF) constitute a heat wave. They also define a severe heat wave for this region as experiencing temperatures over 46 degreesC (114.8 degreesF).

Distribution of the 2018 Heat Waves

In 2018 the northern hemisphere experienced major heat waves. Heat waves occurred over most of the northern hemisphere as well as Australia. Europe experienced a major heat wave in the spring and summer. These extreme heat waves were largely a function of climate change, particularly of global warming.

Indian drought

Millions effected by the drought

Global warming also increases the probability of higher extreme temperatures during a heat wave. Such was the case in 2018. All-time highs were recorded in North America and Europe. At one location in Finland that is north of the Arctic circle, a temperature of 33.3°C (92°F) was recorded. Undoubtedly extreme highs were recorded in many other areas as well. Qurayyat, in Oman, experienced a 24 hour period when the temperature did not drop below 42.6°C. This was the highest minimum daily temperature ever recorded.

The Impact of the Heat Waves

The impacts of the heat waves were many and varied. They included:
A. Increased mortality: Japan, Algeria, and Canada recorded fatalities attributed to the heat.
B. Droughts and agricultural losses. In parts of Europe precipitation amounts fell to as little as 20% of normal.
C. The closing of nuclear power plants due to a shortage of water for cooling.
D. Frequent and severe wild fires. Severe wild fires occurred on every continent except Antarctica.
E. In 2016 and 2017 there was major bleaching of the Great Barrier Reef. In all probability 2018 will turn out to be the same
F. In the summer at one point the combined concentration of greenhouse gasses reached 500 ppm, approximately 100 ppm above the average for this time.

The Deadly Heat Wave of Europe in 2003

Some heat waves have become deadly. Perhaps the most deadly heat wave of the 21st Century was that which occurred in Europe in August of 2003. Temperatures in France reached as much as 40°C (104 DegreesF) and remained exceptionally high for two weeks resulting in nearly 15,000 deaths in that country alone. The death toll over Europe reached approximately 35,000 and may have been as high as 50,000.

Climate Change

The earth’s overall temperatures are increasing every year.

A large contributing factor in the high death toll was warmer than normal nighttime temperatures. As a result people without air conditioning could not cool down during the night. The heat stress accumulated over time. Extreme heat waves also can devastate agriculture. In Europe, in the heat wave of 2003, temperatures averaged 5.5°C (10°F) above normal. In Italy corn yields dropped 36% below average. In France fruit yields fell 25% and wine production 10%. Heat also affects the rate of plant pollination.

Asian heat waves of 2015

That year a May heat wave in India claimed at least 2,500 lives. Heat waves are fairly frequent in India but this was the greatest loss of life from a heat wave in over 30 years. Extremely high temperatures were reached in cities scattered over the country. Power outages were wide spread as a result of high demand for air conditioning. The city of Khammam recorded the highest temperature ever recorded there at 48 degrees C (118.4 degreesF). Other high temperatures that were recorded were:

Allahabad 47.8 degrees C (118.0 degrees F)
Delhi 45.5 degrees C (113.9 degrees F)
Hyderabad 46 degrees C (115 degrees F)
Jharsuguda 45.4 degrees C (113.7 degrees F)

In June the deadliest heat wave known to have occurred in Pakistan took place in the southern part of the country near Karachi. The death toll is unknown for certain but may have reached more than 1000. The heat wave struck during the month of Ramadan which made the impact of the event more severe than it might have been. Unfortunately, city services were not in condition to cope with the heat.

As the planet warms it can be expected that: (1) there will be more severe heat waves. They will become hotter, more frequent, last longer and occur in more varied places. As cities grow larger in area and population they will experience increasing heat waves. (2) new record high temperatures will be set more frequently on the planet.

Heat Wave

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Climate Change over the last Millennium: The Medieval Warm Period

Global warming

Climate Change in the last 1000 years.

“A great variety of information and data indicate there were major fluctuations in the global climate during the last 1000 years.”

By Dr. John J. Hidore

September 3, 2018—-A great variety of information and data indicate there were major fluctuations in the global climate during the last 1000 years. There were periods when it was warmer than now and others when it was colder. Fluctuating temperatures brought significant changes in the global environment.

The Medieval Warm Period or Little Climatic Optimum

One distinctive climatic period during this time is what is known as the Medieval Warm period or Little Climatic Optimum. The period extended from about 950 to 1250 AD. This time was unusually warm for the millennium and was warmer even by present global temperatures. With the increase in temperature came increased precipitation in many areas. This increased lake levels. The Caspian Sea rose by some 18 meters (59 feet).

The medieval warm period was a global phenomenon. Perhaps the best evidence of this was that sea level rose. This had a widespread impact on the human population at the time. The rise in sea level forced the migration of large numbers of people away from the coast and into areas already occupied. This resulted in clashes between different groups and cultures. There was an expansion of Eskimo cultures around the arctic. Central Asian cultures also expanded into areas they had not previously occupied.

Climate Change

Global Warming over time.

Climate of the Western Arctic Basin

Contemporary literature from Iceland has aided in reconstructing of one of the most complete sequences of the Arctic Basin climate over the last thousand years. There is much data for Iceland from the following sources:

900-1590: information from Icelandic sagas about times of severe weather and related famine.
1591-1780: historical records combined with incomplete drift ice data.
1781-1845: a reconstruction of weather conditions as derived from the relative severity and frequency of drift ice near Iceland.
1846 to present: actual meteorological instruments.

Climate Change

The earth’s overall temperatures are increasing every year.

Iceland and Greenland’s Changing Climate

The Vikings settled Iceland in the ninth century. Evidence of agriculture and other activities indicate the climate that existed at the time. When the Vikings settled Greenland, it was quite warm, as Eric the Red discovered in Greenland in 982 A.D. In 984 A.D. the Norse founded the colony of Osterbygd on Greenland. While an icy land, it supported enough vegetation (dwarf willow, birch, bush berries, pasture land) for settlement.

The settlers brought cattle and sheep that not only survived but thrived for a considerable period. They established two colonies and began to farm. The outposts thrived and regular communications existed with Iceland. Between 1250 and 1450 AD climate deteriorated over wide areas. Iceland’s population declined. Grains that grew there in the tenth century would no longer grow. Greenland became isolated from outside contact. Extensive drift ice prevented ships from reaching the settlements.

Global Greenhouse Gases

Climate Change

Europe’s Changing Climate

In Europe storminess resulted in the formation of the Zuider Zee and the excessively wet, damp conditions led to a high incidence of the disease St. Anthony’s Fire (ergotism.). Chronicles contain many references to weather conditions of the time, including the Arctic Basin. William of Malmsbury, writing in 1125 about the Gloucester region of England stated “the area exhibits a greater number of vineyards than any other county in England, yielding abundant crops of superior quality….they may also bear comparison with the growths of France.” What is significant about this statement is that by the fifteenth century there was no wine industry in England. The most probable reason is a cooling of the climate since the twelfth century.

Climate Changed in the Interior of North America

There is ample evidence that the warmer conditions affected continental areas as well. Research shows that Indians in the Great Plains of the United States migrated as a result of changes in precipitation. A study by archaeologists and climatologists show for example, that Indians of the Mill Creek culture of Iowa deserted a thriving community about 1200 A.D. Precipitation declined rapidly at the time.

The abandonment of settlements in the southwest United States probably was due to drought. The historic settlements of Chaco Canyon and Mesa Verde indicate that they supported large and prosperous communities. By 1300 A.D., these settlements were deserted.

Reasons other than drought certainly may account for the abandonment. However, tree-ring analysis shows that between 1276 A.D. and 1299 A.D, practically no rain fell in these areas.

Climate Change


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The Warming of Planet Earth Varies from Place to Place

Melting of the Arctic

The Arctic sea ice is melting at a record rate.

“The Arctic Region is the Most Rapidly Warming Region in the Northern Hemisphere.”

By Dr. John J. Hidore

April 10, 2018—–There is no doubt that Planet Earth is warming relatively fast! Data supports this allegation. The data supporting global warming include biological, geological, hydrological and climatological. 

The year 1880 has been established as the beginning of a period of accelerated warming due to the increased use of fossil fuels and a growing population. From 1880 to 1979, the global temperature increased 0.1°F (0.05ºC) above the pre-industrial average. By 2016 the global temperature had climbed 1.4°F(0.6ºC).

Land and Sea Warm at Different Rates

The warming of our planet is not the same from place to place over the surface. With the possible exception of Antarctica, the continents are warming faster than the oceans. The main reason is the difference in specific heat between land and ocean. The specific heat of a substance is the amount of energy it takes to raise the temperature of one gram of the substance 1°C (1.8ºF). The specific heat of water is used as the base for measuring specific heat and has a value of 1.0. The specific heat for some other substances are ice=0.5, air=0.24, and sand=0.19.

The significance in the difference in specific heat is that a given unit of energy will raise the temperature of earth materials about five times as much as a unit of water. Thus, land surfaces warm faster than water when an equal amount of energy is added.

Glacier National Park

Global warming is causing disappearing glaciers.

Northern Hemisphere is Warming Faster Than the Southern

Climate normals are periods of 30 years that move forward every 10 years. The current normal being used is that of the period 1980-2010.When compared to the 30 year global average for the period 1980-2010, the northern hemisphere is warming faster than the average for the earth as a whole. It is also warming faster than the southern hemisphere. The Northern Hemisphere temperature increased more than two degrees Fahrenheit. The reason the Northern Hemisphere is warming faster than the southern Hemisphere is due to the fact that most of the earth’s land mass is in the Northern Hemisphere.

Disease and melting ice caps

Consequences of Global Warming

The Arctic Region is Rapidly Warming

The Arctic is the coldest region in the Northern Hemisphere. The region consists of the sea surrounding the North Pole and land that rings the sea. The arctic is warming faster than mid-latitude or tropical regions. It is warming more than twice as fast as the average for the earth. The reason for this is that as ice and snow melt on the fringes of the arctic the ratio between reflection and absorption of solar energy changes drastically.

In the winter the sea is covered by a veneer of ice and the surrounding land is generally covered by snow. With the onset of summer, the increased solar radiation results in the melting of ice and snow melting off the land. The more snow and ice that melts, the faster the arctic warms. This change results in what is known as a positive feedback mechanism. More and more energy is absorbed rather than reflected or used to melt the ice. As the melting season lengthens the land and atmosphere above it warm faster than areas further south.

While the Arctic is still the coldest region in the Northern Hemisphere, it is warming more rapidly than other areas!

Global Warming

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Global Warming is Changing Glacier National Park

Glacier National Park

Global warming is causing disappearing glaciers.

“With the rapid rise in temperatures it is probable that most national parks will see substantial changes.”

By Dr. John J. Hidore

June 24, 2016—June 30 is the 100th anniversary of the establishment of the National Park Service in the United States. This year attendance in the parks is expected to be the largest ever. Many of the parks are now quite different from what they were when they were established on August 25, 1916. Perhaps none has changed more than Glacier National Park in Montana.

Glacier National Park and Waterton National Park

Extending from interior Canada south through the United States is a great range of mountains. The mountains were thrust upward 65 million years ago. The rugged mountains and deep canyons that now exist have been created over the long period of time since the mountains were uplifted. The Continental Divide runs along the crest of the mountain chain. From the crest eastward rainfall and snow melt end up in the Atlantic ocean and, west of the crest, water eventually reaches the Pacific Ocean. Part of the mountain system is in Canada, and the southern sections are in the United States.

Glacier and Waterton National Parks

Rapidly melting glaciers of the northwest U.S.

In 1895 the Canadian government recognized the unique character of the mountains, creating Waterton National Park in the Province of Alberta. In 1910 the United States responded by creating Glacier National Park in the state of Montana. The park contains about 1400 square miles (3626 square kilometers). Since the two parks occupied part of the same mountain system and the two countries have such a good relationship, they joined the two parks to make the Waterton/Glacier International Peace Park.

Glacier National Park

Glaciers are disappearing in our national parks.

The Vanishing Glaciers

The distinguishing characteristics of Glacier National Park are the large number of glaciers that existed inside the park, but the very features for which the park is named, will soon be gone. At the time of its founding, it is estimated there were about 150 separate ice fields. Today there are perhaps 25! At the time the park was established, it was possible to walk a short path to reach a glacier. Now it is a seven mile hike over rough terrain to reach the ice. A few years ago it was predicted that by 2050 all of the glaciers may be gone. That forecast date was later moved forward to 2030. Now a study reports the glaciers may be gone by 2020, just four years from now!

The demise of the snow and ice is due to the warming climate. The climate of the region has been on a slow warming trend since the end of the last ice age thousands of years ago. However, in the past few decades, the temperature has been rising faster and the ice melting at an accelerated pace.

Rising temperatures create earlier snow melt and warmer and drier summers. Today the spring floods from snow melt and the low flows of summer are occurring earlier by several weeks. As temperatures rise more precipitation in spring and fall comes as rain instead of snow. In the summer, temperatures of 90°F are now occurring in July and August. Since the park was established the number of 90 degree days have tripled. Like the rest of the United States, winter temperatures have gotten warmer as well. In the area outside the park, privately owned ski resorts have closed due to the shorter ski season.

Impact Of Vanishing Glaciers on Vegetation and Wildlife

The changing climate has had a huge impact on the vegetation and wildlife. The forests in the park are being affected in many ways. First, the treeline is moving upward in many areas of the park and there are more forest fires. Next, infestations of pests and diseases attacking the forest are on the increase. Finally, native fish, birds, and other animals are seeing their habitat changed.

Many, if not most, other national parks are changing due to global warming. Yellowstone, Mt, Rainier, Rocky Mountain, Redwood, and Joshua Tree are among those also being affected. With the rapid rise in temperatures it is probable that most national parks will see substantial changes.

Our rapidly disappearing glaciers!


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Earth Day, Earth Hour, and Other Happenings

Make Every Day Earth Day

April 22, 2016, Love the Earth You’re On!

“Whether it is rising sea level, rising global temperatures, more frequent severe storms, changing weather patterns, the problems of climate change are real.”

By Dr. John J. Hidore

April 14, 2016—-In the past year or so, environmental events have changed the public perception of global warming and climate change. Not only have the majority of people now endorsed the fact that warming of the planet is real, but also that something must be done to stop the rapid change to the global system. Making a difference has become the action mode. Politicians around the world, regardless of their political or economic philosophy, are being forced to take action to curb the process. They are taking action because they must deal with the effects of global warming. Whether it is rising sea level, rising global temperatures, more frequent severe storms or changing weather patterns, the problems are real. Heads of state and mayors of major cities are now beginning to deal with these problems.

Earth Hour Spreads

On Saturday March 12, a global event took place called Earth Hour. The purpose of the event was to call attention to the rising impact of global warming and climate change. The first Earth Hour was held in Sydney, Australia on March 31, 2007. The World Wildlife Fund organization asked the people to turn off their lights for one hour to call attention to the increasing effects of global warming. More recently, on Saturday, March 12, billboards in Times Square in New York and lights on some buildings were dimmed or shut down from 8:30 to 9:00 p.m. Many other cities around the globe also participated.
This year marked the tenth year of the event.

Earth Day

Clean Energy: Make It a Priority!

Earth Day is Global

Earth Day 2016 promises to be a significant event. In December 2015, a conference was held in a suburb of Paris, France to discuss the necessary action to slow global warming. Attending were more heads of state than had ever before attended a single conference. The outcome? Nearly all of the countries presented plans to reduce greenhouse gases in the near future.

This year on Earth Day, April 22, that group of over 190 governments have been invited by U.N. Secretary-General Ban Ki-Moon, to confirm the commitments they made in Paris by signing the agreement. The two largest greenhouse gas emitters, the United States and China, have agreed to sign. Unfortunately, most of the countries which participated in the Paris conference have not agreed to attend the UN signing. In order for the agreement to become a working document more countries, accounting for an additional 55% of greenhouse gases, must sign. It is extremely important that as many people as possible contact their representative leaders and encourage these countries to sign the agreement. Enacting this agreement would be a huge step forward in slowing greenhouse gas emissions and global warming!

Earth Day: Let's Clean and Green!

Agreement between China and U.S. will be signed on Earth Day 2016.

Rapid Change in Global Temperature Becomes Evident

Many global temperature records were broken in 2015 and the trend has continued into 2016. February continued a string of nearly a dozen straight months of record breaking monthly temperatures. Global average temperatures reached 56.08 degrees Fahrenheit which is 2.18 degrees above the average. The winter season, December through February, also set records. In February 2016 global temperatures were not only record breaking temperatures, but they rose drastically. Increases over the previous year were the highest since records began in 1880.

The Artic

In February of 2016, the arctic region experienced unusually warm average temperatures. In January 2016, land temperatures were 10oF (5.6OC) higher than the average, and in February 2016 they were 8 degrees F warmer (4.4 o C warmer). Warmer air temperatures in the arctic have had an enormous impact on ice cover in the arctic seas.

Melting of the Arctic

The Arctic sea ice is melting at a record rate.

Normally, the lowest amount of ice cover in the Arctic occurs in September and the maximum in February. The warmer temperatures have melted the winter ice cover. Scientists began recording the extent of melting of the winter sea ice in 1979. The winter freezing of the ice set a record in 2015. This past February the area of sea ice was lower than in 2015, setting another new record.

It is predicted that the Arctic could be entirely ice free in the next 20 years as greenhouse gases grow and the planet warms, resulting in even greater weather extremes in the Northern Hemisphere.

Earth Day 2016–Make Every Day Earth Day


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Global Warming Opens the Northwest Passage

Walruses need Sea ice

Walruses Cling to Melting Sea Ice.

Thoughtlessly expanding activity uses in a poorly understood region already under enormous stress could have dire consequences not only for the Arctic but for our entire planet.

By Dr. John J. Hidore

January 25, 2014—-European explorers in the late fifteenth century began sea voyages westward expecting to find Asia with its riches of spices and ivory. Instead, they located a land then unknown to them, eventually called the Americas. Once they learned there was another ocean beyond this newly found land, they began looking for a way through or around it. At the southern end of the land mass they found the Strait of Magellan. This provided a way around the Americas into the Pacific Ocean. It was, however, a long route.

Exploring a Route through the Islands of the Arctic Sea

Soon, they began looking for a water route around the north end of the land mass. Beginning in the late 18th Century, they started a concentrated effort to explore a route through the islands of the Arctic Sea. Exploration began from both the Pacific and Atlantic Oceans. The explorations were quit varied in mode of travel and resources available.

Many explorers were looking for an open route, including the Franklin expedition which launched in 1845. Though they were experienced and well equipped, the two ships in the search were lost along with their entire crews. Canadian scientists recently discovered the remains of the ship, Erebus, which was one of two ships in Sir John Franklin’s expedition to find the Northwest Passage in 1845. Other expeditions suffered the same fate. During the next century alternate routes through the passage were explored, discovering several possible routes. Various ships and small boats navigated the passage either in pieces or over more than one season.

Navigating the Northwest Passage of the Arctic

It was not until 1944 that a ship navigated a route in one season. Traveling from east to west, Henry Larsen, captain of the St. Roch, made the trip in a single summer. In order to claim navigation of the Northwest Passage, a ship must cross the Arctic Circle twice. Once in the Pacific and once in the Atlantic. Many transits of the passage took place in the second half of the 20th Century, all under special conditions and with the use of ice breakers.

Climate Change

The earth’s overall temperatures are increasing every year.

Declining Sea Ice of the Arctic Basin

Satellite images of the Arctic Sea have been available since the 1970s. The satellite data confirms that sea ice has declined throughout the Arctic Basin, but more in some places than others. In recent years the air temperatures over the arctic has been more than 10ºF (5.5 ºC) warmer than the average for the last 30 years. As a result of the warmer temperatures, the ice has been thawing further from shore and the remaining perennial ice pack has been getting thinner. In some areas, it is only half as thick as it was a few decades ago. The summer melting of sea ice has been taking place at an ever increasing rate. It is now taking place much faster than predictions made a decade ago.

Shipping has increased sharply in the past decade. Early forecasting of Arctic warming suggested a possible ice free path through the North West Passage in the summer months sometime between 2050 and 2100. However, at the end of the summer melt period in 2007, there was an open passage of water circling the Arctic Sea. It was hailed as the opening of the Northwest Passage between the Atlantic and Pacific Oceans.

Melting Arctic Ice Opens the Way for Commercial Use

Every summer for the past decade this area of sea ice has been below the average of the previous 20 years. An ore carrier loaded with 15,000 tons of coal sailed through the passage in 2013. The Nordic Orion owned by Bulk Partners left Vancouver, BC September 17 and reached Greenland in about a week. In the period September 19-30, 2014 a cargo ship made it through the Northwest Passage without the aid of an icebreaker to accompany it. The MV Nunavik left Canada’s Deception Bay and rounded Alaska’s Point Barrow on September 30 headed for the port of Bayuquan, China. The cargo consisted of nickel ore mined in Deception Bay in Nunavik province of Canada. The specially designed ship can force its way through up to five feet (1.5m) of ice.

The route from Deception Bay to the port of Bayuquan through the Northwest Passage is 40% shorter than through the Panama Canal. Through fuel savings the company expects to make substantial reductions in greenhouse gas emissions. Also, in the past year, a travel company announced it would offer a 32 day, 900 mile luxury cruise through the Northwest Passage. The cruise would operate between Seward, Alaska and New York City. Fares would start at $20,000.

The evidence of change in sea ice parallels other evidence that global warming is taking place much faster than past climate models forecast. If the passage remains open in future years remains to be seen. At its current rate of melting, the Arctic Ocean could be totally ice free in summer this century, if not in several decades. It is even possible a dependable summer ice free passage for shipping may be available within the next decade.

The Arctic is one of our planet’s last pristine ecosystems. As the Ocean Conservatory states, “We need a time-out to understand the implications of destroying this environment. The Arctic needs our help today. Thoughtlessly expanding activity uses in a poorly understood region already under enormous stress could have dire consequences not only for the Arctic but for our entire planet.”


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The Impact of Disappearing Ice Shelves

Melting of the Ice Shelves

Ice shelves are quickly melting in both the Arctic and Antarctic.

By Dr. John J. Hidore

The rapid melting that has taken place in recent decades suggests that with increased temperatures in coming decades there will be rapid melting of the ice shelves and more rapid advance of the glaciers that will cause a rise in sea level.

May 18, 2014—Near Earth’s north and south poles are the coldest areas on the surface of the planet. The area around the North Pole is referred to as the Arctic and that around the South Pole as the Antarctic. The reason these two areas are so cold is that during the course of a year they receive much less solar energy than areas nearer the equator. While they are both very cold regions, the Antarctic and the Arctic are fundamentally very different from each other. The Arctic is largely a sea surrounded by land. On the other hand, the Antarctic is a continent surrounded by sea. While they are basically very different geologically, they have many things in common. One, of course, is that they are very cold environments. Both have large ice sheets and moving glaciers. Another less known feature found in both regions is the ice shelf. Ice shelves are masses of floating ice that are frozen to the seashore. They originated as parts of continental glaciers that slowly flowed off the land and began to float. Though they are floating they are anchored to land.

The Arctic Shelves

Most of the ice making up these shelves is more than 3000 years old. Since their discovery in 1906, these ice shelves have lost 90% of their ice. Some of the ice shelves that existed in 1906 are entirely gone and others are on the verge of melting away. The largest known ice island found in the Arctic Sea is one that broke from the land in 1956. Most of the melting of these ice shelves has taken place in recent decades. In 2005, the Ayles ice shelf was just one of several remaining in the Arctic region of Canada. That year the entire ice shelf broke free from Ellesmere Island. The island is approximately 500 miles south of the North Pole. In fact, using a combination of satellite imagery and seismic data, researchers were able to determine that the shelf actually broke away the afternoon of August 13, 2005. Within a few hours the mass had formed a new ice island, trailing bits of broken ice. The ice island drifted some 30 miles out to sea and then became frozen into the sea ice.

August 2008, the Markham Ice Shelf detached from Ellesmere Island and floated away. Two large pieces of ice also detached from the Serson Ice Shelf, reducing the over-all size of the shelf to less that half what it was the previous winter. It is now largely gone. The Ward Hunt Ice Shelf is also breaking up. It lost 10% of its area in the summer of 2008.

One important aspect worth noting is the breakup of these ice shelves will not have a major effect on sea level since they are already floating in water. Ice floats in water because ice is less dense than water. When water freezes it expands some nine percent, making it less dense than sea water. So when the ice melts its density increases to that of the surrounding sea water. Thus the volume of water does not change. There is actually a slight change due to the difference in density of fresh water and sea water.

Antarctic Ice Shelves

Ice shelves along the West Antarctic Peninsula are either rapidly melting or have broken up altogether. These ice shelves have always shed icebergs. Large pieces of ice occasionally break off the edges of these floating ice masses and drift away from the land mass. In March of 2000, the second largest iceberg ever measured broke free from the Ross Ice Shelf and floated into the Ross Sea. The huge iceberg, B-15, was about 180 miles long and 18 miles wide. Within a week of this iceberg’s formation, three more large pieces broke free from the ice shelf.

Ice Shelves: Melting at an Ever Increasing Rate

Three of the ice shelves disintegrated in the last decade of the 20th century. Many of the ice shelves located on either side of the peninsula have been melting at an ever increasing rate. These ice shelves are the Prince Gustave Channel, Larsen A, Larsen inlet, Muller Ice Shelf, and Wilkins Ice Shelf. Larsen B and Wilkins lost 1180 square miles of ice in just two years from 1998 to 2000. In 2002 a section broke from the Larsen Ice Shelf that was 1200 square miles in size. On February 28, 2008, a large piece of ice broke from the edge of the Wilkins ice shelf. In contrast to the huge pieces breaking off from the Ross Ice Shelf, these shelves are disintegrating in small pieces, which is usually the case with warming temperatures.
Ice shelf     Location                             Year                          Size                 ________________________________________________________________________
Ayles                 Arctic                             2005                       41mi2

Larsen A         Antarctic Peninsula   1995                   1620 mi2(4200km2)

Larsen B          Antarctic Peninsula   2002                   1200 mi2 (3100 km2)

Markham               Arctic                        2008                  19 mi2 (49 km2 )

Ross                         Antarctic                   1987                 1834 mi2 (4,750 km)

Ross                        Antarctic                      2000              4,250 mi2-11,000km2

Serson                    Arctic                            2008              lost 50% of area

Ward Hunt            Arctic                           2003              150 mi2 (384 km2 )

Wilkins                   Antarctic                       2008              160 mi2 (416 km2 )

______________________________________________________________________

Collapse of Ice Shelves

What is of most concern is how the breakup of these ice shelves will affect the continental glaciers that are driving the ice shelves seaward. Since ice shelves are anchored to land they hold back the continental glaciers from advancing seaward. It is possible that the removal of these ice shelves will result in more rapid advance and faster melting of the glaciers. The Ross Ice Shelf is an example. It is one of the largest shelves on the West Antarctic ice sheet. The tides lift and lower the shelf twice a day. During high tide the shelf is lifted, there is less friction with the sea floor beneath, and the glacier behind moves forward. At low tide the rate of movement is slowed. Melting of the Ross Ice Shelf would allow the glaciers behind to move forward adding ice to the sea and raising sea level. Winter temperatures in the area have increased some 9 ºF (5º C).

The rapid melting that has taken place in recent decades suggests that with increased temperatures in coming decades there will be rapid melting of the ice shelves and more rapid advance of the glaciers that will cause a rise in sea level. How much sea level will rise depends on many factors which are hard to predict.