The Global Warming Debate: Cause

The Global Warming Debate:
Is Human Activity the Primary Cause
of Global Warming?

Debate Outcome: (as of July 24, 2001)

Human activity is probably the primary cause of global warming.
(This conclusion was reached due to the fact that the proponents countered every argument posed by the critics).

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The Debate:

Proponents Yes, Human Activity Is the Primary Cause of Global Warming Because . . .	Critics No, Human Activity is Not the Primary Cause of Global Warming Because . . .	Proponents	Critics	Proponents	Critics	Proponents
The global mean surface temperature has risen between .5 - 1 degree Farenheit over the 20th century.	Satellite data (the most accurate information available) do not agree with these figures.	Recently, the satellite data were found to have errors. After these were corrected, it was discovered that they actually show a slight warming trend.	If the earth was actually warming, we would see some evidence of it, such as; rising sea levels and melting glaciers, but we haven't seen this yet.	Actually, glaciers are retreating, and sea levels have risen 10-25 cm over the past century. The sea level rise is 3 times faster over the past 100 years compared to the previous 3,000.	No argument.
This rise in temperature corresponds directly with rising levels of greenhouse gases, which corresponds directly with increasing fossil fuel use, farming & ranching, and deforestation.	Solar activity more closely coincides with temperature changes than do greenhouse gas increases/ decreases.	If solar activity was the primary cause of the earth's warming, summers would be warmer by a greater amount than winters, because in the summer, the earth captures more of the sun's total energy input. But studies show that this is not occuring.	Even if solar activity isn't the cause, the enhanced greenhouse effect theory still doesn't fit. Temperature records show that the earth cooled from 1940-1970, despite the fact greenhouse gas emissions were increasing.	The cooling effect experienced from 1940-1970 was due to an increase in release of short-lived sulfate aerosols in the atmosphere (from fossil fuel plants and volcanoes). Sulfate aerosols block out some of the sun's light, keeping the air cooler and temporarily masked the enhanced greenhouse effect.	In that case, the warming we now experience is most likely due to the earth's natural climate cycle. Since the 17th century, we have been coming out of an ice age; this would account for the warming.	While it's true we are coming out of a mini ice age, the rate of warming over the past century has been greater than experienced any time in the past 400 to 600 years. This leaves us with the same conclusion we began with: that human emissions of greenhouse gases are causing the enhanced effect.
The nine warmest years of the 20th century have occured since 1980.	No argument.
Warming in the 20th century is greater than any time in the past 400-600 years.	No argument.
The sea level has risen about 3 times faster over the past 100 years than compared to the past 3,000 years	No argument.
The IPCC (composed of 1,500 experts from 60 nations) has come to a conclusion that human induced warming is occuring.	No argument.

Cause

Effects

Action