Showing posts with label Environment. Show all posts
Showing posts with label Environment. Show all posts
Tuesday, April 14, 2009
Monday, April 13, 2009
What is the Greenhouse Effect?
After 150 Years of Industrialization, Climate Change is Inevitable
The “greenhouse effect” often gets a bad rap because of its association with global warming, but the truth is we couldn’t live without it.
What Causes the Greenhouse Effect?
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet’s surface and is reflected upward again as a type of slow-moving energy called infrared radiation.
As it rises, infrared radiation is absorbed by “greenhouse gases” such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.
Although greenhouse gases make up only about 1 percent of the Earth’s atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet.
This phenomenon is what scientists call the "greenhouse effect." Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem.
How Do Humans Contribute to the Greenhouse Effect?
While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.
* Burning natural gas, coal and oil —including gasoline for automobile engines—raises the level of carbon dioxide in the atmosphere.
* Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
* Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and “global warming” that is currently under way.
* Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.
* Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.
Ultimately, more greenhouse gases means more infrared radiation trapped and held, which gradually increases the temperature of the Earth’s surface and the air in the lower atmosphere.
The Average Global Temperature is Increasing Quickly
Today, the increase in the Earth’s temperature is increasing with unprecedented speed. To understand just how quickly global warming is accelerating, consider this:
During the entire 20th century, the average global temperature increased by about 0.6 degrees Celsius (slightly more than 1 degree Fahrenheit).
Using computer climate models, scientists estimate that by the year 2100 the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (approximately 2.5 degrees to 10.5 degrees Fahrenheit).
Not All Scientists Agree
While the majority of mainstream scientists agree that global warming is a serious problem that is growing steadily worse, there are some who disagree. John Christy, a professor and director of the Earth System Science Center at the University of Alabama in Huntsville is a respected climatologist who argues that global warming isn’t worth worrying about.
Christy reached that opinion after analyzing millions of measurements from weather satellites in an effort to find a global temperature trend. He found no sign of global warming in the satellite data, and now believes that predictions of global warming by as much as 10 degrees Fahrenheit by the end of the 21st century are incorrect.
Scientists agree that even a small increase in the global temperature would lead to significant climate and weather changes, affecting cloud cover, precipitation, wind patterns, the frequency and severity of storms, and the duration of seasons.
* Rising temperatures would raise sea levels as well, reducing supplies of fresh water as flooding occurs along coastlines worldwide and salt water reaches inland.
* Many of the world’s endangered species would become extinct as rising temperatures changed their habitat.
* Millions of people also would be affected, especially poor people who live in precarious locations or depend on the land for a subsistence living.
* Certain vector-borne diseases carried by animals or insects, such as malaria, would become more widespread as warmer conditions expanded their range.
Carbon Dioxide Emissions are the Biggest Problem
Currently, carbon dioxide accounts for more than 60 percent of the enhanced greenhouse effect caused by the increase of greenhouse gases, and the level of carbon dioxide in the atmosphere is increasing by more than 10 percent every 20 years.
If emissions of carbon dioxide continue to grow at current rates, then the level of the gas in the atmosphere will likely double, or possibly even triple, from pre-industrial levels during the 21st century.
Climate Changes are Inevitable
According to the United Nations, some climate change is already inevitable because of emissions that have occurred since the dawn of the Industrial Age.
While the Earth’s climate does not respond quickly to external changes, many scientists believe that global warming already has significant momentum due to 150 years of industrialization in many countries around the world. As a result, global warming will continue to affect life on Earth for hundreds of years, even if greenhouse gas emissions are reduced and the increase in atmospheric levels halted.
What is Being Done to Reduce Global Warming?
To lessen those long-term effects, many nations, communities and individuals are taking action now to reduce greenhouse gas emissions and slow global warming by reducing dependence on fossil fuels, increasing the use of renewable energy, expanding forests, and making lifestyle choices that help to sustain the environment.
Whether they will be able to recruit enough people to join them, and whether their combined efforts will be enough to head off the most serious effects of global warming, are open questions that can only be answered by future developments.
The “greenhouse effect” often gets a bad rap because of its association with global warming, but the truth is we couldn’t live without it.
What Causes the Greenhouse Effect?
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet’s surface and is reflected upward again as a type of slow-moving energy called infrared radiation.
As it rises, infrared radiation is absorbed by “greenhouse gases” such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.
Although greenhouse gases make up only about 1 percent of the Earth’s atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet.
This phenomenon is what scientists call the "greenhouse effect." Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem.
How Do Humans Contribute to the Greenhouse Effect?
While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.
* Burning natural gas, coal and oil —including gasoline for automobile engines—raises the level of carbon dioxide in the atmosphere.
* Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
* Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and “global warming” that is currently under way.
* Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.
* Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.
Ultimately, more greenhouse gases means more infrared radiation trapped and held, which gradually increases the temperature of the Earth’s surface and the air in the lower atmosphere.
The Average Global Temperature is Increasing Quickly
Today, the increase in the Earth’s temperature is increasing with unprecedented speed. To understand just how quickly global warming is accelerating, consider this:
During the entire 20th century, the average global temperature increased by about 0.6 degrees Celsius (slightly more than 1 degree Fahrenheit).
Using computer climate models, scientists estimate that by the year 2100 the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (approximately 2.5 degrees to 10.5 degrees Fahrenheit).
Not All Scientists Agree
While the majority of mainstream scientists agree that global warming is a serious problem that is growing steadily worse, there are some who disagree. John Christy, a professor and director of the Earth System Science Center at the University of Alabama in Huntsville is a respected climatologist who argues that global warming isn’t worth worrying about.
Christy reached that opinion after analyzing millions of measurements from weather satellites in an effort to find a global temperature trend. He found no sign of global warming in the satellite data, and now believes that predictions of global warming by as much as 10 degrees Fahrenheit by the end of the 21st century are incorrect.
Scientists agree that even a small increase in the global temperature would lead to significant climate and weather changes, affecting cloud cover, precipitation, wind patterns, the frequency and severity of storms, and the duration of seasons.
* Rising temperatures would raise sea levels as well, reducing supplies of fresh water as flooding occurs along coastlines worldwide and salt water reaches inland.
* Many of the world’s endangered species would become extinct as rising temperatures changed their habitat.
* Millions of people also would be affected, especially poor people who live in precarious locations or depend on the land for a subsistence living.
* Certain vector-borne diseases carried by animals or insects, such as malaria, would become more widespread as warmer conditions expanded their range.
Carbon Dioxide Emissions are the Biggest Problem
Currently, carbon dioxide accounts for more than 60 percent of the enhanced greenhouse effect caused by the increase of greenhouse gases, and the level of carbon dioxide in the atmosphere is increasing by more than 10 percent every 20 years.
If emissions of carbon dioxide continue to grow at current rates, then the level of the gas in the atmosphere will likely double, or possibly even triple, from pre-industrial levels during the 21st century.
Climate Changes are Inevitable
According to the United Nations, some climate change is already inevitable because of emissions that have occurred since the dawn of the Industrial Age.
While the Earth’s climate does not respond quickly to external changes, many scientists believe that global warming already has significant momentum due to 150 years of industrialization in many countries around the world. As a result, global warming will continue to affect life on Earth for hundreds of years, even if greenhouse gas emissions are reduced and the increase in atmospheric levels halted.
What is Being Done to Reduce Global Warming?
To lessen those long-term effects, many nations, communities and individuals are taking action now to reduce greenhouse gas emissions and slow global warming by reducing dependence on fossil fuels, increasing the use of renewable energy, expanding forests, and making lifestyle choices that help to sustain the environment.
Whether they will be able to recruit enough people to join them, and whether their combined efforts will be enough to head off the most serious effects of global warming, are open questions that can only be answered by future developments.
How Do Humans Contribute to Greenhouse Gas Emissions and Global Warming?
Throughout most of human history, and certainly before human beings emerged as a dominant species throughout the world, all climate changes were the direct result of natural forces.
Industrial Age Accelerates Global Warming
That changed with the start of the Industrial Revolution, when new agricultural and industrial practices began to alter the global climate and environment. Before that time, human activity didn’t release many greenhouse gases, but population growth, deforestation, factory farming, and the widespread use of fossil fuels are creating an excess of greenhouse gases in the atmosphere and contributing to global warming.
Science Links Global Warming to Human Activity
In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists from more than 130 countries, stated that human activity "very likely" has been the primary cause of global warming since 1950. (In science, nothing is ever claimed to be "certain" or absolute, which leaves open the possibility of further research and discovery, but the term “very likely” indicates more than 90 percent certainty and is considered virtual confirmation.)
The IPCC report also said that human activity has been a major contributor to climate change since the start of the Industrial in the mid-1700s.
Industrial Age Accelerates Global Warming
That changed with the start of the Industrial Revolution, when new agricultural and industrial practices began to alter the global climate and environment. Before that time, human activity didn’t release many greenhouse gases, but population growth, deforestation, factory farming, and the widespread use of fossil fuels are creating an excess of greenhouse gases in the atmosphere and contributing to global warming.
Science Links Global Warming to Human Activity
In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists from more than 130 countries, stated that human activity "very likely" has been the primary cause of global warming since 1950. (In science, nothing is ever claimed to be "certain" or absolute, which leaves open the possibility of further research and discovery, but the term “very likely” indicates more than 90 percent certainty and is considered virtual confirmation.)
The IPCC report also said that human activity has been a major contributor to climate change since the start of the Industrial in the mid-1700s.
What Causes Global Warming?
Scientists have determined that a number of human activities are contributing to global warming by adding excessive amounts of greenhouse gases to the atmosphere. Greenhouse gases such as carbon dioxide accumulate in the atmosphere and trap heat that normally would exit into outer space.
Greenhouse Gases and Global Warming
While many greenhouse gases occur naturally and are needed to create the greenhouse effect that keeps the Earth warm enough to support life, human use of fossil fuels is the main source of excess greenhouse gases. By driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the atmosphere. Deforestation is another significant source of greenhouse gases, because fewer trees means less carbon dioxide conversion to oxygen.
During the 150 years of the industrial age, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, the level of atmospheric methane has risen by 151 percent, mostly from agricultural activities such as raising cattle and growing rice.
The Consequences of Global Warming
As the concentration of greenhouse gases grows, more heat is trapped in the atmosphere and less escapes back into space. This increase in trapped heat changes the climate and alters weather patterns, which may hasten species extinction, influence the length of seasons, cause coastal flooding, and lead to more frequent and severe storms.
Greenhouse Gases and Global Warming
While many greenhouse gases occur naturally and are needed to create the greenhouse effect that keeps the Earth warm enough to support life, human use of fossil fuels is the main source of excess greenhouse gases. By driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the atmosphere. Deforestation is another significant source of greenhouse gases, because fewer trees means less carbon dioxide conversion to oxygen.
During the 150 years of the industrial age, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, the level of atmospheric methane has risen by 151 percent, mostly from agricultural activities such as raising cattle and growing rice.
The Consequences of Global Warming
As the concentration of greenhouse gases grows, more heat is trapped in the atmosphere and less escapes back into space. This increase in trapped heat changes the climate and alters weather patterns, which may hasten species extinction, influence the length of seasons, cause coastal flooding, and lead to more frequent and severe storms.
What are Greenhouse Gases?
Many greenhouse gases occur naturally, such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Others such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) result exclusively from human industrial processes.
Human Activities and Greenhouse Gases
Human activities also add significantly to the level of naturally occurring greenhouse gases:
* Carbon dioxide is released into the atmosphere by the burning of solid waste, wood and wood products, and fossil fuels (oil, natural gas, and coal).
* Nitrous oxide emissions occur during various agricultural and industrial processes, and when solid waste or fossil fuels are burned.
* Methane is emitted when organic waste decomposes, whether in landfills or in connection with livestock farming. Methane emissions also occur during the production and transport of fossil fuels.
The Properties of Greenhouse Gases
Greenhouse gases vary in their ability to absorb and hold heat in the atmosphere, a phenomenon known as the "greenhouse effect." HFCs and PFCs are the most heat-absorbent, but there are also wide differences between naturally occurring gases. For example, nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide, and methane absorbs 21 times more heat per molecule than carbon dioxide.
Human Activities and Greenhouse Gases
Human activities also add significantly to the level of naturally occurring greenhouse gases:
* Carbon dioxide is released into the atmosphere by the burning of solid waste, wood and wood products, and fossil fuels (oil, natural gas, and coal).
* Nitrous oxide emissions occur during various agricultural and industrial processes, and when solid waste or fossil fuels are burned.
* Methane is emitted when organic waste decomposes, whether in landfills or in connection with livestock farming. Methane emissions also occur during the production and transport of fossil fuels.
The Properties of Greenhouse Gases
Greenhouse gases vary in their ability to absorb and hold heat in the atmosphere, a phenomenon known as the "greenhouse effect." HFCs and PFCs are the most heat-absorbent, but there are also wide differences between naturally occurring gases. For example, nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide, and methane absorbs 21 times more heat per molecule than carbon dioxide.
Tuesday, April 7, 2009
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