As solar radiation reaches our planet it does so as short wave radiation.
About 30 percent of short wave radiation is reflected back into space, while the remaining short wave radiation at the top of the atmosphere is absorbed by the Earth's surface and re-radiated as long wave radiation. Incoming solar radiation that strikes the earth's surface is partially reflected and partially absorbed, in proportion to surface reflectivity (albedo).
Newly fallen snow has an albedo of approximately 0.90, meaning that
it reflects
about 90 percent of incoming radiation. In contrast,
melting snow has an average
albedo of 0.50, meaning that it absorbs 50
percent and reflects 50 percent of the
incoming radiation. Because a
darker surface absorbs more solar radiation, snow
covered by dust
(dirty snow) melts faster than clean snow. The albedo of sea ice
varies
with ice age, but when snow covered is on the order of 0.70. Open
water
absorbs the most radiation of all Arctic surfaces. With an albedo
of about 0.08, it
reflects only 8 percent of the incoming radiation.
The albedo of a water surface
increases with decreasing solar altitude
and approaches a mirror-like 100 percent
near sunrise and sunset, or
when the sun is low in the Arctic sky.
Solar radiation that is not absorbed by the earth's surface is
reflected back into the
atmosphere as short wave radiation. Absorbed
solar radiation is then re-radiated
as long wave radiation.
Arctic sea ice is melting, that is a fact. There are those that would debate that this is part of earth's natural climate cycle, others that would argue it is anthropogenic. Yet as the debate goes on the ice continues to melt.
Sea ice will not directly contribute to sea level rise, as the water displacement caused by the ice is in equilibrium with the water locked into the ice. However as stated above sea ice has an albedo of 0.70 and as such reflects large amounts of short wave radiation up and away from the earth. On the other hand water has an albedo of 0.08 and retains most short wave radiation that it receives. Thus the water warms, in turn sea ice melt increases, and as a result there is an increase in the amount of long wave radiation re-radiated back into the atmosphere.Long wave radiation is then captured by gases such as water vapour, carbon dioxide, and methane. It is then re-radiated again this time in all directions, including back down towards the earth.
One of earth's natural cycles is the carbon cycle. Billions of tons of atmospheric CO2 are removed from the atmosphere by oceans and growing plants, also known as ‘sinks,’ and are emitted back into the atmosphere annually through natural processes also known as ‘sources.’ When in balance, the total carbon dioxide emissions and removals from the entire carbon cycle are roughly equal.
Balance being the operative word here.
If we as a species add even one percent of global carbon to the carbon cycle we are adding a percent that not only can not be dealt with by the Natural cycle, but that will remain and be added to each year. So if we have been adding say one percent to the cycle each year for the past ten years, we would now have increased the level of carbon by ten percent.
The Sceptics full video from SBS Insight
About 30 percent of short wave radiation is reflected back into space, while the remaining short wave radiation at the top of the atmosphere is absorbed by the Earth's surface and re-radiated as long wave radiation. Incoming solar radiation that strikes the earth's surface is partially reflected and partially absorbed, in proportion to surface reflectivity (albedo).
Arctic sea ice is melting, that is a fact. There are those that would debate that this is part of earth's natural climate cycle, others that would argue it is anthropogenic. Yet as the debate goes on the ice continues to melt.
Sea ice will not directly contribute to sea level rise, as the water displacement caused by the ice is in equilibrium with the water locked into the ice. However as stated above sea ice has an albedo of 0.70 and as such reflects large amounts of short wave radiation up and away from the earth. On the other hand water has an albedo of 0.08 and retains most short wave radiation that it receives. Thus the water warms, in turn sea ice melt increases, and as a result there is an increase in the amount of long wave radiation re-radiated back into the atmosphere.Long wave radiation is then captured by gases such as water vapour, carbon dioxide, and methane. It is then re-radiated again this time in all directions, including back down towards the earth.
One of earth's natural cycles is the carbon cycle. Billions of tons of atmospheric CO2 are removed from the atmosphere by oceans and growing plants, also known as ‘sinks,’ and are emitted back into the atmosphere annually through natural processes also known as ‘sources.’ When in balance, the total carbon dioxide emissions and removals from the entire carbon cycle are roughly equal.
Balance being the operative word here.
If we as a species add even one percent of global carbon to the carbon cycle we are adding a percent that not only can not be dealt with by the Natural cycle, but that will remain and be added to each year. So if we have been adding say one percent to the cycle each year for the past ten years, we would now have increased the level of carbon by ten percent.
Methane (CH4) is a gas that remains in the atmosphere for
approximately 9-15 years. Methane is over 20 times more effective
in trapping heat (long wave radiation) in the atmosphere than carbon
dioxide (CO2).
As greater amounts of long wave radiation are trapped in earth's atmosphere global temperatures begin to rise. This not only increases the rate of sea ice melt but also impacts on ocean temperatures and influences glacial ice melt.Earth’s average ocean surface temperature in July 2009 was the warmest since record keeping began in 1880, breaking the previous high mark established in 1998, according to an analysis by NOAA’s National Climatic Data Centre.
A NASA/University study published online on February 14th 2010 in Nature Geoscience finds that glaciers in West Greenland are melting one hundred times faster at their end point than at the surface. The melting of glaciers beneath the ocean surface causes deep, warm, salty water to be drawn up toward the glacier's face, where it mixes turbulently with the glacier's cold, fresh water. The water then rises along the glacier face, melting its ice along the way, then reaches the ocean surface and flows away from the glacier in a plume. An ocean temperature of 3 degrees Celsius can melt glacial ice at a rate of several meters per day, or hundreds of meters over the course of a summer.
Melting of the current Greenland ice sheet would result in a sea-level rise of about 6.5 meters.
If the Antarctic Ice Sheet melted, sea level would rise by about 60 meters.
Failure to make fundamental changes to the way our society operates will result in catastrophic changes to our environment. We can reconsider how we generate, and distribute energy. We have the technological capability to generate enough energy to run our own homes from our own homes. Through the use of solar and wind power generation, no more burning of coal, no more unsafe nuclear power. Then there is geothermal, wave, tidal,solar, and wind on an industrial scale, that would result in an abundance of energy. Even making only this change would result massive economic changes, but that is another subject.
As greater amounts of long wave radiation are trapped in earth's atmosphere global temperatures begin to rise. This not only increases the rate of sea ice melt but also impacts on ocean temperatures and influences glacial ice melt.Earth’s average ocean surface temperature in July 2009 was the warmest since record keeping began in 1880, breaking the previous high mark established in 1998, according to an analysis by NOAA’s National Climatic Data Centre.
A NASA/University study published online on February 14th 2010 in Nature Geoscience finds that glaciers in West Greenland are melting one hundred times faster at their end point than at the surface. The melting of glaciers beneath the ocean surface causes deep, warm, salty water to be drawn up toward the glacier's face, where it mixes turbulently with the glacier's cold, fresh water. The water then rises along the glacier face, melting its ice along the way, then reaches the ocean surface and flows away from the glacier in a plume. An ocean temperature of 3 degrees Celsius can melt glacial ice at a rate of several meters per day, or hundreds of meters over the course of a summer.
Melting of the current Greenland ice sheet would result in a sea-level rise of about 6.5 meters.
If the Antarctic Ice Sheet melted, sea level would rise by about 60 meters.
Failure to make fundamental changes to the way our society operates will result in catastrophic changes to our environment. We can reconsider how we generate, and distribute energy. We have the technological capability to generate enough energy to run our own homes from our own homes. Through the use of solar and wind power generation, no more burning of coal, no more unsafe nuclear power. Then there is geothermal, wave, tidal,solar, and wind on an industrial scale, that would result in an abundance of energy. Even making only this change would result massive economic changes, but that is another subject.
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