First, let's be clear -- there is no longer anyone saying the earth
isn't warming. That fact has been drilled home even to the most
die-hard deniers. But there are still many doubters out there.
In
bumping around the internet, SkepticalScience.com, Climateprogress.org
and RealClimate.org have emerged as my three favorite sites.
SkepticalScience actually chronicles and rebuts the Climate Change
denier's arguments and ranks them by the number of occurrences online.
"It is the Sun" is argument number one at 6.8 percent. It's
true that without the sun warming the earth, it would be a very cold
indeed. But that's not the question; the real question is, what's
different now?
It has been claimed that recent solar activity is
the source of global warming. Bunk. The Naval Research Laboratory and
NASA reported in September 2009 that, "if anything," solar forcing
contributed negligible long-term warming in the past 25 years, and 10
percent of the warming in the past 100 years.
Let's look at the
"Milankovitch Cycles," named after the Serbian mathematician who first
proved that the reoccurring ice ages are a result of the Solar Forcing
from three reoccurring variances in the earth's relationship to the
sun. Precession (how close the earth comes to the sun), a 20,000-year
cycle; Eccentricity (earth's orbit goes from almost circular to
elliptical), a 100,000-year cycle; and Obliquity (changes in the
earth's tilt with reference to the sun going from 22.1 to 24.5
degrees), a 41,000-year cycle. Add up these three oscillating
variables, we get a reoccurring pattern (Solar Forcing) that accurately
predicted the past and future ice ages.
So why does that
matter? Well, first, the sun's variation in the last 100 years (and
more specifically the last 10 years) is not the source. Secondly, we
can quantify the solar forcing function to validate climate models. A
"forcing function" is how varying effects create climate change, a very
important concept to climate scientists. More recent observations show
clear evidence that global temperature has been very divergent from
solar radiation for the last 20 years. Which should finally put a nail
in the coffin of that argument.
SkepticalScience.com's number-two issue is "Climate has changed before," which ranked at 6.1 percent.
Man
affects the earth by burning fossil fuels (creating more CO2),
industrial processes (creating halocarbons, CH4 and N2O), cutting down
forests, flying jets making contrails, etc.
The earth reacts,
with both positive and negative feedback loops, affecting the total
Radiative Forcing function. The positive feedback loops mean we retain
more heat; the negative feedback loops mean we retain less heat. If we
could keep this in balance, we would have a stable climate.
Currently our little world can't keep up with the changes you and I are causing.
The
current Radiative Forcing is a scorecard of the climate's condition
(which clearly isn't good), but that's not our only problem. The
earth's land and water also respond to warming by releasing CO2
directly. This accelerates the amount of greenhouse gases beyond what
man creates, further accelerating (positive forcing function) global
warming.
How does warming cause a rise in atmospheric CO2? As
the oceans warm, the solubility of CO2 in water falls. This causes the
oceans to give up more CO2, emitting it into the atmosphere. When the
permafrost melts, CH4 (long stored in the frozen tundra) is emitted.
Molecularly, CH4 is 20 times more damaging than CO2 as a greenhouse
gas.
Which brings us back to Milankovitch Ice Age cycles.
Ever wonder what the ice core drilling was all about? From these ice
cores, scientists have obtained CO2 release data as the climate
changes. This evidence allows us to predict how much CO2 we can expect
the earth to produce relative to the earth's rising temperature. It's
interesting to note the roughly 800-year lag between peak temperature
and peak CO2. This indicates it takes a while for the CO2 out-gassing
from the ocean to catch up with the warming trend. So, in conclusion,
you ain't seen nothing yet, baby.
We humans release CO2 (with
our coal plants, cars, industrial pollution, etc.), the planet warms
and releases more CO2, we continue to release more CO2, and . . . well,
you can see where this is going. You've heard the phrase "Tipping
Point" . . . .
Coleman lives in Warren.
