Preserving the health of
our planet is another big factor driving the change in transportation technology.
Petroleum motor fuels produce harmful emissions, not the least of which is emissions of
greenhouse gases. There are lots of other problems caused by harmful emissions - damage
from acid rain, respiratory problems and increased health care costs due to air pollution
- but global warming is potentially the most disastrous, and it’s one of the most
controversial.
There are lots of gases that contribute to the greenhouse effect - some
man made and some naturally occurring. Asking what causes the greenhouse effect is sort of
like asking what causes cancer. Almost everything including barbecued hamburgers and too
much exercise has been implicated in cancer. So it’ll come as a big relief to learn
that animal flatulence causes global warming due to increased methane in the air.
It’s not all our fault. And even global warming itself causes global warming because
when the planet’s hotter, the oceans evaporate faster, and airborne water vapor is a
powerful greenhouse gas. So it’s a complex issue, and there’s plenty of material
for turning it into something less than the serious matter that it is. But like cancer,
once you get it, it’s hard to get rid of it... and it can forever change our lives.
Carbon dioxide (CO2) is the most troublesome greenhouse gas
that comes from human activities. From the last ice age until the industrial revolution in
the last century (about 10,000 years), the atmospheric level of CO2 had varied
only about 5%. But beginning with the industrial revolution and projecting forward to
about 2030, the amount of atmospheric CO2 will have doubled - all in about 150
years time.
Global warming and the resulting climatic changes are about as close to
proven as something like this can be, and the post-industrial increase in greenhouse gases
looks like the culprit. One of the biggest contributions that humans are making to the
rise in atmospheric levels of CO2 is the burning of fossil fuels. With
hydrocarbon fuels, C02 emissions are roughly proportional to the amount of
energy consumed. So with a fossil-fuel-based energy system - and about 86 percent of the
world’s energy comes from fossil fuels (39% oil, 22% natural gas, 25% coal) - an
increase in energy consumption naturally increases CO2 emissions. And when
carbon dioxide is released into the atmosphere, it doesn’t degrade like some of these
other pollutants. Instead, it hangs around for 100 to 200 years. So even if we stopped
these emissions today, we would be forced to deal with the effects for several generations
into the future.
The main problem with global warming isn’t that it will be a little
hotter than usual. We can always dump a little more energy into the air conditioning unit.
The most devastating effects will come from shifts in the earth’s weather patterns.
At the very least, rainfall patterns will migrate toward the poles, and away from the best
agricultural lands on the planet. So food production will decline. But we’re in
really deep trouble if the ocean and atmospheric flows responsible for our global weather
system ever change. We don’t have a clue what we’ll end up with. But once it
happens, it will be very difficult if not impossible to reverse. And it could happen quite
suddenly once we reach a critical threshold.
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