Global Warming
Global warming is a cyclical event with each cycle spread across eons of time. However, happenings over recent
decades certainly indicate that the current rate of warming is more acute
because of influences attributable to human activity. The prognosis is that there is only a decade in which to begin to
reverse current trends before the trends become irreversible, and the truly devastating consequences occurring after
year 2100 would become inevitable.
James Hansen, director of the NASA Goddard Space Studies said in April, 2005:
"There can no longer be genuine doubt that human-made gases are the dominant cause of observed warming."
This stunning graph derived from the scientific analysis of miles of ice cores drilled deep into the World's ice
caps reveals the shocking proof of increases in the most significant of greenhouse gases carbon dioxideCommon gas found in the atmosphere. Has the ability to selectively absorb radiation in the longwave band. This absorption causes the greenhouse effect. The concentration of this gas has been steadily increasing in the atmosphere over the last three centuries due to the burning of fossil fuels, deforestation, and land-use change. Some scientists believe higher concentrations of carbon dioxide and other greenhouse gases will result in an enhancement of the greenhouse effect and global warming. The chemical formula for carbon dioxide is CO2. (CO2). Never before in the history of the past 650,000 years has there been such a sharp rise,
nor of such an extent as that occurring in our time today.
What is also most remarkable is that the average temperatures plotted on the same scale, again from evidence of the
ice cores, shows the low and high temperatures coincide with the lows and highs of the levels of the CO2
atmospheric levels. The graph below, first published in the magazine Nature, portrays this very well. It can be
argued which is causal, the heating or the CO2 concentrations in the atmosphere, or that they may be inter-related
and exacerbate each other.
However, there is a difference in the horizontal and vertical scales to the graphs of which we must be aware. The
above graph dates from the year 1 AD; the graph below dates from BP which stands for Before Present (a lateral shift of
2,000 years). Nevertheless, the title of the above is to the year 2004, and the vertical line intercepts appropriately
to the right of the year-0 mark on the horizontal scale.
The matrix superimposed on the graph below can also be misleading in that it relates to the right hand temperature
scale and not to the left hand CO2 scale. Moreover, the right hand scale has an upward shift such that the "0"
of that scale is not aligned with level of 275 ppm approximate to an average temperature corresponding with that level
of CO2 concentration in the atmosphere which keeps the earth comfortable for us to live here.
What is important to note, is that the lowest temperature levels during the last ice age (starting about 130,000
years ago) would only be about 8 °C below today's average, and the maximum level would be about a fraction of
that higher (say, 1.6 °C higher).
Quoting from a 2002 report by the National Academy of Science:
Recent scientific evidence shows that major and widespread climate changes have occurred with startling speed.
For example, roughly half of the north Atlantic warming since the last ice age was achieved in only a decade, and it was
accompanied by significant climate changes across most of the globe.
The effects of global warming seem to have a compounding effect with respect to time. A small event stimulating a
change of climate has accelerating unwelcome regional and global impacts.
What can have caused this phenomena? What can we do about it and what are the likely consequences if nothing is done
in the very short time before the effects become irreversible?
We must recognize that man probably had little to do with events prior to the end of the last mini ice age ten
thousand years ago.
A Note on Units used:
1 ton carbon, C = 3.67 tons of carbon dioxide, CO2, (carbon is the chosen metric, CO2, is the
gas)
1 billion tons carbon = 1 gigaton carbon = 1 Gt C
Concentration of CO2 = total stock of CO2, already in the atmosphere
Annual emissions of CO2 = the yearly new flow of CO2, into the atmosphere |
Until emissions fall to about one fifth of current levels, concentrations of CO2 continue to rise, with
rising concentrations of CO2, the pace of global warming and climate changes continue to accelerate.
- 2005 concentrations of CO2, in the atmosphere were 380 ppm (parts per million)
- 2025 concentrations of CO2, in the atmosphere are projected to be 420 — 430 ppm
- 2050 concentrations of CO2, in the atmosphere are projected to be 500 ppm
At 500+ ppm the irreversible trend is to melt the Greenland ice cap, raising sea levels by up to 20 feet.
Some help in forming an opinion on this subject is given in the items on Carbon Cycle, Glacial Periods, Human
Influence, Impact on Florida, and Possible Remedies. Refer also to the Alternative Energy page of this website.
To see a 14 minute video and links to other sites on this topic go to http://seastudios.org/ahead2_video_qt.php
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