Closed Ecosystems

As Star Trek put it, ‘Space: The Final Frontier’. It’s not all make believe. We have travelled in space. However, building a sustained human presence in space is a whole other level. Effectively, we’d need to create and protect a sustaining ecosystem; a system akin to the one that’s keeping us alive on Earth. An obvious challenge to achieving this is knowing what’s essential to keep us alive while we explore the nether regions.

Looking at our current tentative forays into space, it would be easy to assume that all we need is a secure container full of breathable air. But if we want to live up there for more than a few hours, then we need to bring along food and water. And eventually, we’d need to dispose of our waste. Thus, to sustain ourselves over a long time, we’d also need to process our waste into something useful. With such a sustaining, closed ecosystem, we could travel to other solar systems or build bases upon Mars.

Vitally important to our planned, closed ecosystem is the energy that enables all these processes to perform. On Earth, the Sun provides nearly all this. And this also makes the Earth ecosystem an open system. Now, imagine travelling to other solar systems. Then, we expect no appreciable energy from our Sun. Instead, we’d need to gather and store all the energy before we departed. As we can’t gather anything in the void of space, our space-faring ecosystem has to be closed; except perhaps some radiant heat energy losses.

There is no manifest destiny drawing us into space-based habitation. We could remain on planet Earth. Our species could endure for many tens of millions of years, as did the dinosaurs. But we would always be limited by what’s available on Earth. After climbing every mountain and descending into every trench, writing every story and singing every song, then we’d live simply to relive the past. There would be nothing new to our destiny.

In space, there is no known limit. However, our current capability is nowhere near a sustaining, closed ecosystem. Further, we seem to be radically, negatively affecting the existing ecosystem on Earth. Why do we prefer to build roads, to play video games and to engaging in warfare on this functioning ecosystem? What do these preferences say about the development of a sustaining, closed ecosystem for humans in space? And what do they say about our future on Earth?

Gradually Abrupt

So we’re realizing that our species needs copious quantities of energy to sustain our technical wonders. How do we know? Well, even with all the recent research and reports on warming climate and species extinction, we’ve still increased our energy consumption by 50% since year 2000. Though renewable energy sources exist, their contributions remain trivial compared to the energy we extract from burning fossil fuels. If we maintain this trend then by year 2100, our consumption will increase by over 250%. Our consumption; mostly for our technology.

There is a desire, even an expectation, that energy reserves remain sufficient and that no actual harm will come to our ecosystem. This desire allows us to continue to burn oil, coal and biomass. If our expectation is met, then we are on a path of continual, immediate rewards. And we need care little about consequences.

Imagine if we are wrong. Let’s say that the energy reserves empty abruptly. And let’s say that the climate becomes unpredictable, and the weather varies enough to make living difficult. And let’s say that a homogeneous ecosystem covers the Earth’s surface, with the remaining species being overly susceptible to disease. Given these, will our species realize that our technical wonders do not provide the desired lifestyles?
Redwing Blackbird

Sustainable Development Goals

The United Nations’ Sustainable Development Goals (SDGs) promote equality. They also promote economic growth together with the preservation of the Earth’s ecosystem. The goals are admirable. Are they achievable? Let’s consider.

People who are rich consciously act to maintain their status. Certainly they’d be OK with everyone else being rich as long as they remained rich. This all inclusiveness wouldn’t be likely for two reasons. One, many people don’t care to be materially wealthy. Two, the Earth’s ecosystem can’t support an infinite number of wealthy people. Thus, we expect to always have a wealth disparity between people.

People who are poor don’t want to be poor. They may not realize that they are poor, as with some indigenous people who maintain a hunter/gatherer lifestyle. But, there’s a global expectation on child survivability, education and security. These expectations promote fairness. Achieving this requires the continual application of significant resources, such as energy. However, the Earth’s ecosystem can’t support the advancement of an infinite number of poor people.

Last, our current economic system could enable all the poor to be rich. The system enables us to transfer resources to any location on Earth and perhaps even off of Earth. But the Earth has finite resources. Also, our utilization of resources, such as fossil fuels, comes with detrimental pollution. Hence, while the system is capable, the result is unattainable.

Yet, the SDGs are our only blueprint for the future. And it is a good blueprint. So, what’s the best future? Do we control the number of rich? How many poor can the Earth accommodate? How do we preserve the Earth’s ecosystem while continually drawing down its capital? Perhaps most of all, what degree of achievement is optimal for each goal?
Chipping sparrow

Cement and Concrete

People seem to have a reluctant relationship with Earth’s natural world. We know that nature provides us with our necessary food. But most of us buy it in shops. And, with most of us living in cities, even our homes and workplaces are removed from nature. For these, concrete is the most effective separator. It’s a human invented material that is the foundation for most of our civilization.

Concrete results from mixing cement with water and with a suitable filler such as sand or gravel. Its use in the Roman era Pantheon demonstrates its durability. Its longevity can be further enhanced as we use rubble from destroyed concrete structures as filler for new concrete structures. However, cement can’t be re-used. New concrete requires new cement. And cement is costly.

Let’s scale the cost. Annually we produce over 4×109 tonnes of cement, equivalent to the cement for about 1000 dams the size of the 3 Gorges Dam. This amount is to remain constant to well past 2050. Its production calls for an annual expenditure of 3.5GJoules of energy per tonne. This amounts to an allocation of 1.4×1019Joules of energy annually, about 3% of total energy consumption. As most of the energy comes from fossil fuels then there’s resulting pollution at a rate of 0.54t of CO2 per tonne of cement, about 8% of global CO2 emissions. Because of this, cement is a significant parameter when modeling future climate change. Over history, humans have used about 128×109 tonnes of cement to enable living apart from nature, which is almost a thousand times greater than the weight of all humans. Concrete is costly both in energy consumption and pollution emission.

Concrete separates us from nature. And estimates are that we will continue this separation for decades to come. Should we continue to separate ourselves from the ecosystem? Or are you willing to fight this apparent primal urge to treat nature as a threat? For a prosperous future, we recommend you look for ways to live with nature rather than apart.