This Week's Post: Climate Change Homework Assignment

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Climate Change Homework Assignment

Here's a topic for every fifth-grader's science fair project.  Or, if you are a "climate change skeptic" or if you would like to challenge your friends who are, this is a simple exercise.

Background:  We know that the Earth's pre-industrial atmosphere contained certain trace gases that absorb heat energy.  During the daytime, the sun warms half of the planet as it rotates on its axis.  At night, some of the absorbed warmth is reradiated back into space.  Without the atmosphere's greenhouse effect, all heat energy would be lost to space and the Earth would be very cold-- less than 32 degrees F.  Water would be frozen and life as we know it could not exist.

So, the natural greenhouse effect created by water vapor, carbon dioxide, and a few other gases keeps the Earth a comfortable temperature for the life that has evolved over the past 3 billion years.

Since the industrial era began in the 1800's, however, humans have enhanced the natural greenhouse effect by emitting billions of tons of carbon dioxide, and by land use practices (plowing, forest cutting) that limit the Earth's capacity to absorb (sequester) some of the released carbon dioxide.  As a consequence, the atmospheric greenhouse has become more and more effective in trapping re-radiated heat energy.  This brings us to the homework exercise.

The Assignment:  Since the atmospheric greenhouse works primarily at night, by absorbing some of the heat energy absorbed the preceding day, nighttime low temperatures are trending above average.  This warming trend becomes apparent to anyone who pays attention to their local weather reports. 

For the next 30 days, record your local nighttime low and the average nighttime low. 

The null hypothesis(for your science fair project) is 'the actual and the average nighttime lows will not be significantly different over the 30-day period.'

Note:  The average nighttime low for your area is based on a 30-year record, and it is updated every 5 years. You might have to find a weather information source that reports an "almanac" that gives nighttime low averages for that date.

If you believe 30 days is too few data points, try 60 days or 90 days or a year.  If you search the weather/climate records for the last 10 or 100 years, you won't have to collect your own current date.

TV and radio weather presenters know about this trend, but due to commercial considerations on commercial stations, never mention it.

Environmental Science Classroom: Nature as Model

In an essay published in the Winter 2012-2013 issue of Edible Wasatch I attempt to outline the most fundamental of Nature's phenomena, processes, and emergent properties that support life on Earth. What follows are two paragraphs from that essay that explain one of the three phenomena. 

"Sun", a page from Fred Montague's hand-drawn artist book,  Garden Grace . © Fred Montague

"Sun", a page from Fred Montague's hand-drawn artist book, Garden Grace. © Fred Montague

"The first is sunlight.  It warms the Earth, evaporates water, causes winds, and powers, directly or indirectly, almost all of us Earth organisms. This energy is free, reliable, and reasonably well-distributed over most of the planet's surface.  Solar power defined our development as a species. And despite our obsession with all sorts of things to burn, react or blow up for bursts of energy (to provide speed, convenience, comfort, or thrills), sunlight still makes up about 99% of all of the energy that flows through the Earth's natural and human-built systems.  Nature's model for sustainability is sunshine-- the same sunshine that spills from the sky over the garden, even in winter."

"With respect to energy in general, and solar radiation in particular, the Earth is an open system.  Energy flows. On balance, all of the energy flowing into the Earth-atmosphere system must rather quickly be re-radiated into space, or else the Earth's temperature will increase.  For stability, 'energy in' must equal 'energy out.' If we impede the flow of heat energy away from the Earth (by enhancing the atmosphere's 'greenhouse effect'), then some of the re-radiated energy (heat) is retained, and the planet warms.  If you've ever been in a closed greenhouse on a summer's day, you know what I'm talking about.  Nature's model with respect to a greenhouse or to the Earth: maintain the normal energy flow to maintain the normal temperature. And in most cases-- especially where organisms or societies are adapted to 'normal,' normal is better than abnormal."  

Read the entire essay at