When speaking about global
warming, people sometimes talk about fossil fuel reserves as a kind
of great threat to us that we must resist fully using, or else face
ruinous consequences. Some say that we have what is called a carbon
budget that we must stick to, to avoid a future temperature rise
greater than 2 degrees Celsius. The carbon budget has been described
as being no more than 1500 gigatons of carbon dioxide that can be
expended before the year 2050. Presumably a higher budget would be
allowed for the period up until 2075 and the period up until 2100.
It is argued that we must use great restraint in limiting ourselves
to this carbon budget, rather like some person who can take some
morphine pills, but who must restrain himself from taking too many,
lest he die from an overdose.
But there is actually a
reason for believing the chance of a carbon dioxide “lethal
overdose” is low, and perhaps nonexistent. The reason has to do
with the extent and nature of fossil fuel reserves. For one thing,
there are not unlimited amounts of coal, oil, and natural gas lying
about. The oil reserves of the
top 15 oil producers is only about 1540 billion barrels, which is
about 50 years of current global oil use, and considerably smaller
than that if we allow for future population growth and economic
growth. Some are worried that we may soon hit the “Peak Oil”
point that has long been predicted. Although it is claimed that coal
reserves are sufficient to last for 153 years of global production,
many think that we will hit “Peak Coal” within a few decades.
What is called a resource
pyramid is one of the reasons why both coal and oil production may
decline within a few decades. As shown below, the resource pyramid is
the concept that the easiest coal and oil resources to extract are
found in the smallest amounts. The resources that are found in the
greatest amounts are those which are hardest to extract.
A resource pyramid
Because coal and oil
resources are arranged in a kind of resource pyramid, with most of
the resources being very hard to extract, it is quite possible that
there is almost no chance that mankind will “overdose” on carbon
resources. By around the middle of the century, we may find it
harder and harder to extract coal and oil resources, as we work our
way deep down the resource pyramid of oil and the resource pyramid of
coal. The very distribution of these resources may put a brake on
runaway consumption, forcing humanity to reduce consumption and
switch more to alternate energy sources such as solar and wind.
David Rutledge of Cal Tech
has predicted that by 2069 the world will have produced 90% of the
coal that it will ever produce. If something like that happens, the
worst projections of the IPCC will not occur, and the world's
temperature will probably never rise much higher than 2 degrees
Centigrade above its current level.
These facts bring to mind
a very interesting question that has rarely been considered: what
would be the optimal distribution of fossil fuels that our planet
might have had? And also: is it possible that the earth's actual
distribution of fossil fuels is something close to an optimal
distribution?
First, let us consider
some distributions of fossil fuels that would not have been optimal.
One distribution we can imagine is one in which our planet simply had
no fossil fuels at all: no coal, no oil, and no natural gas. In such
a case there would have been no modern civilization of the type we
have enjoyed for the past 100 years or so. That obviously would not
have been an optimal distribution of fossil fuels.
Another distribution of
fossil fuels we can imagine is one in which oil and coal started to
run out at a time such as about 1980. That also would not have been
an optimal distribution of fossil fuels.
We can also imagine a
distribution of fossil fuels in which coal and oil resources were two
or three times higher than our planet has, with two or three times
more easily accessible resources. In that case there might have been
a much higher chance of catastrophic global warming caused by
excessive use of fossil fuel resources.
Instead of any of these
possibilities, what we may have on our planet is pretty much
an optimal distribution of fossil fuels. The fossil fuels we have are
enough to last us until the cost of alternate energy sources such as
solar power and wind power falls down so low that such things
(possibly assisted by nuclear fusion) can serve as replacements for
fossil fuels. But existing as they are in a resource pyramid, the
fossil fuels we have may be distributed in such a way so that the
easily accessible resources start to gradually run out just at about
the time that we will need for them to run out, so that we don't
overheat the planet by burning too much carbon. At just about the
best time for such a message, nature will in effect start telling us,
“It's time to switch away from fossil fuels -- I'm going to slowly make it harder and harder for you to get them.” And nature will
start delivering that message in a louder and louder voice over the
span of several decades. We will get this message from nature pretty
much at just the right time -- all because fossil fuels just happened to be distributed in a particular way that may turn out to be very lucky for us.
If we have such a nearly
optimal distribution of fossil fuels, we may wonder whether that is
an improbable lucky coincidence, or something that was set up in
advance for our benefit.
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