CPSP218G Fall Semester: Earth, Life & Time Colloquium
Energy Resources and the Reality of Climate Change
By definition, we need to expend energy to do work. For most of history, the only energy resource
(other than fire for cooking and heating) was muscle (human and animals (for cultures with beasts
of burden). Some cultures also used wind (sailing, windmills) and water (boating, water wheels). But
these latter two are limited in availability (either time or place).
Steam power was known since at least classical time: heat up water, and it turns to steam, which can push
against surfaces or wheels to move gears and levers. Later, use steam to turn turbines and generate electricity:
this is how coal and nuclear fission plants work, for instance. Burning wood is sufficient for low level
steam activity, but really effective steam power needs greater concentrations of energy.
Coal, fuel of the Industrial Revolution:
- Actually is still one of the most important energy resources in modern times, too!
- Produced where abundant plant matter was buried faster than it could decay (generally, ancient swamps)
- Therefore, limited to places where such swamps were extensive. Most coal was deposited in the
Carboniferous Period in the once lowlying regions of what is now North America, Europe, and Asia.
- Consequently, these regions were able to take advantage of the Industrial Revolution, while southern
nations could not (even though they had the know-how, they didn't have the coal!)
- Easily mined, easily stored, easily transported, easily burned
- Burning produces ashes, smoke, smog, and carbon dioxide and other greenhouse gasses
- Geological surveys and studies of the historic and predicted rate of coal use suggest that we
have many centuries worth of coal yet.
- However, like all geological resources, the rate at which it forms is VASTLY slower than the rate
at which humans are using it up.
Petroleum (gasoline and natural gas resources), fuel of the modern age:
- Primary fuel for modern transportation, via the internal combustion engine
- Produced in environments in which vast amounts of organic matter (such as decaying plankton) gets
buried, distilled, and the organic goo is trapped
- Typically requires ancient warm conditions and subsequent development of features (like reefs and
salt deposits) that trap the petroleum
- Examples of this environment was the hot equatorial seas of the Cretaceous Period, in which
buried organic material got trapped in reefs of rudist clams and underneath salt layers
- These conditions were common in what is now the American Southwest and Gulf Coast, parts of South America,
northern Africa, and the Middle East. However, a related set of conditions were also present in the
North Sea and what is now northern North America (Does that list sound at all familiar with regards to
the distribution of petroleum today?)
- Easily drilled, stored, transported, and burned
- Burning produces smoke, smog, and carbon dioxide and other greenhouse gasses
- Surveys and studies show that known and predicted petroleum supplies will run out in the late 21st or
early 22nd Century.
Renewable Resources (solar, wind, water, geothermal, etc.):
- Energy density far too low (many orders of magnitude!) to handle transportation
requirements of modern world
- Also, most are only available for use in localized spots: not an exportable resource
- However, using such systems might take some of the load off of the non-renewables.
- FAR more energy per unit mass than chemically-based systems!!
- Essentially just a steam-powered turbine to generate electricity, using radioactive
materials to heat the water.
- However, fission plants are expensive to maintain.
- Nuclear waste is locally far more dangerous than coal or petroleum waste, but
is globally far more benign!
Potential future resources
Fuel Cell technology:
- Not a different energy resource per se, but a different approach
- Combine a hydrogen-rich fuel through a series of special sheets to generate electricty
- Waste product is just water, if pure hydrogen is used as fuel (other products as well if
hydrocarbons are used)
- However, currently requires a lot of energy to break water to make hydrogen, so have to
generate energy in the first place!
- Also, storage requirements for pressurized or liquid hydrogen limits size and range of
fuel cell vehicles.
Nuclear Fusion, Energy of the Future (and may always be!):
- Dwarfs the energy potential per unit mass of fission
- REAL solar power (i.e., this is how the sun works!)
- "Waste" material of fusion reaction would be helium, an inert (and useful!) gas
- Problem: currently, requires more energy to maintain a fusion reaction than we can get out
REALITY OF CLIMATE CHANGE
Climate is NOT the same thing as weather. Instead, it is the aggregate of many factors of
the interaction of land, water, air, and sunlight over many years. Climate drives the weather,
but is bigger than weather alone.
Geologic record and astronomy clearly show large scale changes in Earth's climate happen
naturally. Some of these changes are periodic, based on Earth's orbital parameters (such as
the Milankovitch Cycle.)
Other changes have to do with the particular set of circumstances of continental position, sea level,
mountain building, vegetation, etc.
Changes happen on the scale of days and months (i.e., weather), years, centuries, millenia, millions of
years, and more. The relative land-water ratio, the composition of the atmosphere, etc., are all subject to
Natural climate changes can still affect human societies and populations.
Human contribution to climate change comes largely from the release of greenhouse gases. The carbon
in the carbon dioxide from buring coal and gasoline had been sequested away tens to hundreds of
millions of years ago, when the carbon dioxide levels in the atmosphere were many times the
present level. In such situations, the world was much hotter than today, and there were no
continental glaciers and few alpine ones. The current meltback of glaciers around the world
(many of which had survived the glacier-interglacial cycles of the Ice Ages) shows that the
human-generated component of global warming is taking us outside of typical Ice Age cycles.
Studies of previous deglaciations show that freshwater flooding into the northern Atlantic
can temporarily shut down the Oceanic
Conveyor Belt which dominates modern oceanic circulation. This in turn disrupts global
distribution of heat, causing massive climate changes. Past events of this nature have taken only
5-10 years to happen once initiated, resulting in a quick switch to a world with very different