Global Warming

Global Warming

Global warming is a unique problem facing humankind that requires changes in

people's lifestyles. To know that one day the polar icecaps could melt is a

scary thought. If global warming continues to increase the earth's atmospheric

temperatures, the melting of the polar ice caps could become a reality. This

would cause dreadful devastation to many parts of the world. There would be

floods, heat waves, and destruction of aquatic life, scorched forests and

disappearing species. If global warming continues to go unattended, it will

slowly destroy the earth's ecosystems and the life that depends on them.

Melting of ice and snow

Further evidence of widespread warming comes from observations of seasonal snow

and frozen ground coverage. The extent and duration of frozen ground have

declined in most locations. Snow cover in the Northern Hemisphere has declined

about five percent over the past 30 years, particularly in late winter and

spring, and the freezing altitude has risen in every major mountain chain.

Alpine and polar glaciers have retreated since 1961, and the amount of ice

melting in Greenland has increased since 1979. Over the past 25 years, the

average annual Arctic sea ice area has decreased by almost five percent and

summer sea ice area has decreased by almost 15 percent. The collapse of the

Larsen Ice Shelf off the Antarctic Peninsula appears to have no precedent in the

last

Rivas 2

11,000 years.

The Role of Natural Variability

Human induced warming is superimposed on natural processes to

produce the observed climate. Because these natural fluctuations play a role in

determining the precise scale and supply of temperature in a particular year,

record heat in any year and find that it is not highly significant. What is

noteworthy; however is that global average temperatures experienced a net rise

over the twentieth century, and the average rate of this rise has been

increasing. When scientists attempt to reproduce these twentieth century trends

in their climate models, they are only able to do so when including human

produced heat trapping emissions in addition to natural causes.

Hottest years on Record

Global average surface temperatures pushed 2005 into a virtual tie with 1998 as

the hottest year on record. For people living in the Northern Hemisphere most of

the world's population 2005 was the hottest year on record since 1880, the

earliest year for which reliable instrumental records were available worldwide.

The year 2005 exceeded previous global annual average temperatures and is also

part of a longer term warming trend exacerbate by the rise of heat trapping

gases in our atmosphere that is due primarily to our burning fossil fuels and

clearing forests. Nineteen of the hottest 20 years on record have occurred since

1980. The record surface temperatures of the past 20 years reinforce other

indications that global warming is under way. For example, the observed rise in

average surface temperatures has been accompanied by warming of the atmosphere

and oceans, and increased melting of ice and snow. A 2005 analysis of

Rivas 3

satellite observations of temperature trends in the troposphere the layer of

atmosphere extending about five miles up from Earth's surface uncovered errors

in previous studies. Recent studies show that air temperatures has increased in

the past 20 years or so, consistent with the basic understanding