Earth in transition, welcome to global warming

Pacifica Tribune, Letters to the Editor, 6/20/12.  "Global warming" by John Blanchard

"Editor:  A basic layman's understanding of Global Warming science can begin with the concept of the 'greenhouse effect'. Just as a greenhouse collects and traps warmth from sunlight that transmits through its panes certain gases in the earth's atmosphere trap a portion of heat that normally would be reflected from the earth back to space.

This phenomenon of absorbing and reflecting heat can also be illustrated by a brick wall in sunlight. The brick absorbs the heat, warming it, but the heat can also be felt standing in front of the wall as it radiates out. This is infrared radiation. Virtually all solid objects have the ability to radiate heat in this way.

In the natural world the Earth is in balance with sunlight received and heat reflected as infrared radiation.

Representing the glass panes of the greenhouse, the earth's atmosphere is made up of multiple layers of gases that surround the earth and are held in place by gravity. Largely these gases permit heat from the earth to be radiated back out to space thus cooling the planet. But some gases are referred to as greenhouse gases because they absorb radiated heat and arrest its escape to outer space just as the panes of the greenhouse trap heat and create warmth.

Glacier ice melting

Just a little smog

Among these greenhouse gases is Carbon Dioxide (CO2). While CO2 only makes up about a quarter of the effect of all greenhouse gases that is still significant and its measurable increase in the atmosphere since the Industrial Revolution is directly related to human extraction and burning of fossil fuels such as oil, natural gas, coal or wood.

This fact is undisputed amongst the greater world's scientific community. The actual effects of global warming on all of us and the insidious denial of these inconvenient truths will have to be for another post."

Posted by Kathy Meeh