Global Warming

There is currently a great deal of debate among Americans as to whether global warming is occurring or not, and if it is, whether it is caused by human actions or not. However, there is not much debate among scientists – most of them are convinced that the world is getting warmer, and that human activities are the cause of this change. In order to understand this, you must accept the fact that there is always a certain degree of uncertainty in scientific data, especially when dealing with a system as complex as a planet and its atmosphere.

Basic principles

When a system is in equilibrium it does not change. When a variable that affects the system’s equilibrium is changed, the system moves to a new point of equilibrium.

Examples:

The size of the sun: the inward pull of gravity is in equilibrium with the outward expansion caused by heat in its core, so it’s size stays constant. When the core gets hotter, the sun’s size will increase until a new point of equilibrium is reached.

The temperature of the earth: the temperature of the earth is in equilibrium when the amount of energy absorbed from sun light is equal to the amount energy radiated into space as infrared light. If less infrared light is radiated into space, the temperature will be pushed to a new, hotter equilibrium.

There is mounting evidence that the temperature of the earth is being moved out of equilibrium to a new, hotter temperature. The cause, in the view of most scientists, is the increasing amount of CO₂ in the atmosphere.

The basic concept is this: CO₂ absorbs infra red light, preventing it from escaping into space. Since the earth absorbs the same amount of visible light, but radiates less infra red into space due to increased amounts of CO₂ in the atmosphere , the earth is being pushed out of thermal equilibrium to a new, hotter, temperature.

Where does the CO₂ come from?

• CO₂ is produced any time carbon based fuels (coal, gasoline, natural gas, wood) are burned

• 85% of our energy needs are met by the burning of fossil fuels

• The problem comes from taking hydrocarbons out of the ground (where they have been for millions of years) and dumping then into the atmosphere as CO₂

Evidence

• The amount of CO₂ in our atmosphere as increased form 280 ppm in the 1800’s (when people began burning large amounts of fossil fuels), to over 370 ppm today. Most of this increase has occurred in the last 40 years.
• The average temperature of our planet has gone up 1 ^o F since 1940, while in Canada, Russia and Alaska it has gone up almost 7 ^o F
• In the Northern Hemisphere, the Spring thaw occurs 10 days earlier than it did a century ago, and the fall freeze occurs 10 days later than it used to
• The 1990’s was the hottest decade on record, and the five hottest years in recorded history were 1998, 2002, 2003, 2001, and 1997.
• All of the world’s glaciers are shrinking
• Polar sea ice is thinning at an accelerating rate and is likely to become seasonal in the coming decades
• Sea level is rising and the oceans are getting warmer

Consequences

• Unpredictable weather patterns leading to droughts, floods, forest fires, and crop failure
• Storms that are both more violent and more frequent
• Coastal flooding as sea level rises (over 100 million people will lose their homes, including much of Florida and Louisiana)
• Mass extinctions of many species (from Salmon, to song birds, to polar bear)
• Economic hardship and potential collapse

Possible Solutions

• Stop using fossil fuels and convert economy to other forms of energy (wind, nuclear, etc.)
• Capture CO₂ before it enters the atmosphere and find a place to safely store it
• Greatly reduce energy consumption by increasing efficiency (compact florescent lights, hybrid cars, etc)
• Increase production of bio-fuels

Counter Arguments

• There isn’t enough evidence that the world is getting warmer, recent winters have been quite cold
• If the world is getting warmer, it is a natural cycle that began long before industrialization
• Some scientists don’t agree that human activity is making the world warmer
• Global warming is a political ploy used for scaring voters
• Scientists used to say that the world would be getting colder

Risks of Switching to Alternative Energy Sources

• Economic hardship caused by increased taxes and consumer costs associated with transition
• Potential for major lifestyle changes (colder houses, less travel, etc.)

Benefits of Switching to Alternative Energy Sources

• Avoiding worse-case global warming scenario (see above)
• Independence from oil-producing nations
• Jobs created by manufacturing new energy infrastructure

Risks of Not Switching to Alternative Energy Sources

• See “Consequences” above

Benefits of Not Switching to Alternative Energy Sources

• No immediate economic hardships due to energy transition (lower taxes, cheaper goods, etc.)
• No change in life-style