Remnants

People are hungry creatures. We eat food and utilize resources to ever greater extents. On a finite world, this can only mean that other living beings have less and less available. Certainly other living creatures don’t want petroleum. Most consider it a dangerous substance. Yet, as we use energy resources to expand our presence, less and less remains for other living beings. Only remnants remain of the once flourishing ecosystem that encompassed Earth.

As long as people can rely upon disparate ecosystems, our existence continues. However, should the remnants fade or the transportation network fail, we will need to rely upon the ecosystem that surrounds us. Given the great modifications of landscape and wildlife undertaken by people, this may not be possible. Further, as the rate of extinctions ever increase, the surviving life forms may be inadequate for the task.

Wise future planning would attempt to negate this possibility. Both the Royal Botanical Gardens (1) and the global seed bank in Longyearbyen (2) are indicators that some people and governments believe the future needs more care and planning than we now give it.

If we are planning for remnants, does this mean we’ve given up on trying to maintain the status quo? If we have, will a few repositories of some viable genetic material be enough to let the surviving life forms flourish. The future is indeed going to be interesting.

(1)Seed Bank

(2)Longyearbyen

Energy Source Energy Sink
Grasslands city
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First Estimate

Planning for the future means having an objective and then assigning resources so as to meet it. Without setting an objective we can still set the bounds by considering the limits to resources; in particular, energy.

Let’s assume that people are wise enough to choose not to imperile their future. In using the economist’s expression, we choose to live off the interest rather than the principle. For people needing energy, they would take energy for themselves but leave enough so that other life forms can survive. This enables all life forms to continue and should enable people to continue to utilize large quantities of energy. In short, this future ensures sustainability and human advancement.

A rough bounds for the amount of energy available from vegetation is 2.048 zettajoules (1). The following table gives an estimate of the number of people of various technological levels (2) who can live on the Earth given this energy limit. The number is the increase over our current population.

Technological Level Increase
primitive human 85.38
hunting human 34.28
subsistence agriculture 16.23
advanced agriculture 11.27
industrial human 4.24
technological human (US 1971) 0.92
Canada (2003) 1.09
world today 4.65
Future 0.17

Kardashev’s scale (3) presumes that future higher technological levels need more energy. The future civilization, to acheive the next technological step, will thus need an exponentially increasing amount of energy. Yet, the future population would have to number less than today’s population. For example, even if we tried to get everyone on Earth living at the same technological level as those of the United States of 1971, we’d need fewer people than today. This is shown in the table.

Let’s say an objective of our civilization today is to acheive a higher technolgoical level. This means that given Earth’s finite energy supply, the only way for us to achieve this is to reduce the number of people. This assumes we are wise enough to also choice a sustainable future.

This is a first estimate in energy calculations.

(1) Zetajoules

(2) Reference Book

(3) Kardashev

Example lifestyles for different technology levels;

Primitive Farming Adv Farm
Industrial Technical Advanced

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Legacy

Vicarious living gives great joy and pleasure but no surety about tomorrow. Experience and wisdom shows us to consider the future if for nothing more than experiencing greater heights of vicariousness.

Then there are those who have a grander vision. These are perhaps the people who have guaranteed their personal needs for the remainder of their lifetime and who want and can do more. For example, there is;

  • monument building as the Sheik’s Buraj Dubai,
  • feeding the hungry as with the Gates Foundation, or
  • science and technology with Allen’s SpaceShipOne.

SpaceShipOne Buraj

Each of these people have captured more than enough of the Earth’s resources for themselves and have chosen their own unique way to consider the future.

Yet, each of these people will be able to accomplish only so much during their lifetime. Once gone, their memorials will gradually subside. However, our civilization will continue on.

Individuals can achieve incredible amounts but groups can achieve more. The Apollo space program is an example of a nation of people coming together to achieve a goal.

Can humanity have a goal, a legacy? Should there be one? For the previous forty thousand years, we’ve built expansive cities across the globe, developed new technologies and made wonderful music. Yet, aside from racing after the current fad, our only common denominator is to increase our numbers. We have ever more people on planet Earth but for what purpose? Is the best we can do is to maximize the number of people at the highest level of vicarious living or can we do better?

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Zettajoules

The best source of energy is from the Sun(1). After 4.5 billion years, the best primary natural energy storage occurs with plants. These living organisms capture the Sun’s energy and store it within their bodies. Presumably their purpose is to ensure adequate energy for their survival and the propagation of their species. As long as they retain enough of the Sun’s energy, their future is assured.

We have made estimates of the amount of energy stored within all the plants and other living organisms of the Earth (2). As a means of estimating the energy availability, we can use these values and hypothesis our energy needs as in the following. First, consider the vegetation’s capture of solar energy as shown in the table below. In it, values of mass refer to dry matter.

Ecosystem type(3) Area Total NPP Mean energy of NPP Biomass Biomass Energy
x1012 sq.m. x1015 g/y x1018 J/y x1015 grams x1021 Joules
Tropical forest 24.5 49 873.8 1025 18.28
Temperate forest 12 15 267.5 385 6.86
Boreal forest 12 9.6 171.2 240 4.28
Woodland and shrubland 8.5 5.95 106.1 50 0.89
Savanna 15 13.5 240.7 60 1.07
Temperate grassland 9 5.4 96.3 14 0.25
Tundra and alpine 8 1.12 20.0 5 0.09
Desert and semidesert 42 1.68 30.0 13 0.23
Cultivated land 14 9.1 162.3 14 0.25
Swamp and marsh 2 4 71.3 30 0.53
Lake and stream 2 0.5 8.9 0.05 0.0
Total continental 149 114.85 2048.0 1836.05 32.74

From the above table, the total energy stored in biomass is about 32.74 zettajoules (x1021) while the amount of energy capture each year is 2.048 zettajoules. If we assume that all the cultivated land goes into food production, then there is 1.8857 zettajoules captured every year.

Total world primary energy consumption for 2005 was 10537.1 mtoe equivalent or about 0.44 zettajoules(4). We derive most (86%) of this energy from non-renewable fossil fuels. If our quantity of energy consumption remains at or above the 2005 level then after we completely consume all the fossil fuels, we will need 23% of all the energy captured annually by vegetation.

Presumably vegetation needs all its current NPP to maintain its own existence. If we were to allocate a quarter of the NPP for our own energy needs, can we expect the vegetation to survive?

Of interest, the proven petroelum and natural gas reserves is 13.67 zettajoules(3). From this, and knowing the rate of consumption of 0.44 zettajoules indicates a time of 31 years until their depletion if all our energy comes from them (rather than the true 60%).

(1)See Earth’s Energy Budget
(2)Global Carbon Cycle
(3)Whittaker, 1975.
(4)BPs Statistical Review

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