From: Michael Geluardi (geluardi@yahoo.com)
Date: Sat Jan 17 2004 - 22:13:28 PST
Message-ID: <20040118061328.32333.qmail@web41202.mail.yahoo.com> Date: Sat, 17 Jan 2004 22:13:28 -0800 (PST) From: Michael Geluardi <geluardi@yahoo.com> Subject: Global Warming Info
Hi Steve,
I just put together a 9th grade lesson on climate change (aka: Global Warming)
and here are the highlights I wanted to emphasize with internet sources
following. Note that a lot of confusion is generated by the colloquial term
"global warming" which implies a simple, all-over warming. The scientific
community prefers climate change which encompases the more complex patterns
expected.
The Global Warming Hypothesis: Modern industrial society is warming the Earth
through the accumulation of man-made, heat-trapping greenhouse gasses in the
atmosphere. The most important greenhouse gas is CO2 made by burning fossil
fuels in cars and electricity generating power plants.
Common misconceptions:
1. False: The ozone hole is caused by or is causing climate change. True:
These are largely independent atmospheric problems. There are some incidental
connections between the two but they aren't causing each other.
2. False: Climate change is caused by the heat produced by burning fossil
fuels. True: Climate change is caused by trapping in solar energy.
3. False: Climate Change means everyday weather will be warmer. True: There
is a very important difference between climate and weather. Climate refers to
long-term averages in temperature, precipitation, humidity, things like that.
Weather refers to daily conditions. On average, the climate is warming but we
will continue to have lots of cold days. In fact computer models predict that
some areas will experience a cooler climate which is one reason why the
scientific community prefers the term "climate change" to "global warming".
Another reason is that climate change is expected to bring greater fluctuations
in weather for most locations with more severe events such as droughts and
floods from one year to the next. Bottom line: it is a mistake to attribute
any given day's weather to climate change.
The basic numbers: The earth has warmed an average of 0.6 degrees C (1.1
degreed F) in the last 100 years. Nine of the 10 warmest years since records
began in 1860 have occured since 1990. Increasingly confident computer climate
models predict average future global temperatures to increase by an additional
1.4 - 5.8 degrees C (2.5 - 10.5 degrees F) in the next 100 years.
Expected Consequences of Climate Change: Warmer Temperatures on average. More
extreme weather events (droughts, floods, wildfires, heat waves, and extreme
winds.) Receeding glaciers and polar ice sheets. Widespread ecosystem
disruption and accelerated species extinction (ecosystems can't migrate
together to track suitable climates, especially across a fragmented landscape.)
Sea level rise. Increased spread of disease by mosquitos. Altered, but not
necessarily lowered, agricultural productivity.
The science, simple version: Greenhouse gasses make the atmosphere function
like a blanket traping heat next to the Earth. The Earth's surface is warmed
by sunshine but eventually the heat seeps back to outerspace through the
atmosphere. Some heat is good and greenhouse gasses have naturally kept our
planet cozy for billions of years with ups and down like ice ages and things.
But if the atmospheric blanket gets too warm too fast, then the planet will
warm up suddenly which is quite a shock for natural systems (and human systems
which depend on them.) For the planet, suddenly is counted in decades and
centuries. We seem to be doing this now by adding lots of extra greenhouse
gasses to the atmosphere.
The science, basic technical version: (Understanding the technical stuff
requires a solid familiarity with heat transfer by radiation.) The Earth's
surface is warmed by solar radiation the same way your face is on a sunny
morning. The Earth also cools by radiating energy back out into space the same
way an electric burner on a stove radiates heat out in all directions. The
incoming and outgoing radiation are different though and that makes all the
difference. The incoming radiation that warms the surface of the Earth is
mostly visible light and visible light passes relatively easily through the
atmosphere, greenhouse gasses and all. The outgoing radiation that cools the
Earth is largely infrared "heat" radiation (one notch down on the
electromagnetic spectrum) and infrared radiation gets absorbed by greenhouse
gasses. So greenhouse gasses preferentially allow sunlight in to warm the
planet's surface but then don't easily let the Earth's heat radiation out. In
this way, the atmosphere essentially warms from below by absorbing infrared
radiation from the planet's surface.
Some perspective: The greenhouse effect has been working for billions of years
to give our wonderful planet it's nice cozy climate that supports life. Most
greenhouse gasses are good and natural. The problem now is that we are quickly
adding more greenhouse gasses which are expected to cause a relatively rapid
increase in average temperatures over the next 100 years and more. Natural and
human systems are vulnerable to rapid climate change in some important ways.
(See NRDC and IPCC links below)
The controversy and who to believe: Since the global warming hypothesis was
proposed there have been scientists (and politicians and businessmen) who say
we can't prove it's true and why should we disrupt our good thing (fossil fuel
society) to head off something we don't know is actually going to happen. BUT,
the considerable scientific research on climate change over the last 30 years
overwhelmingly supports the hypothesis that we are changing the climate and
will change it a lot more in the not too distant future. The scientific
community has been moving steadily toward consensus. Meanwhile we are
essentially conducting a long term, one way, uncontrolled global experiment.
(Yikes) Believe who you want.
Three excellent sources of information:
1: http://www.ipcc.ch/ This is the Intergovernmental Panel on Climate Change
(IPCC) website, and is an authoritative source on all things related to the
science, economics, and politics of climate change. Click on the Summary for
Policy Maker links (SMP's) as the other stuff is mind boggling. This site has
some really good graphs and a free library of PowerPoint slides.
2: http://www.nrdc.org/globalwarming The Natural Resources Defense Council
website is biased to the environmental side but has exceptional integrity. It
can be considered an environmental authority on what we should do about climate
change.
3: Also check out the US Environmental Protection Agency website on global
warming. It has some easier to digest info but it is down as I write this and
so you'll have to google to find it.
Oh my, I've written a lot! Sorry to hog so much pinhole time...
-Mike Geluardi
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