phases of the moon

Why it’s useful to think in lifetimes

Would you live for 200 years? How about the lifetime of a farm that needs to be thousands of years if humanity is to persist?

An adult mayfly has one task, to mate. They do not feed and have only vestigial (unusable) mouthparts, while their digestive systems are filled with air. They do not live very long. Adult female Dolania americana has the shortest adult lifespan of any mayfly, less than five minutes. 

Many plant species are annuals that complete their life cycle, from germination to the production of seeds, within one growing season, and then die. This might take only a few months for some species.

The average domestic dog has a modest lifetime of 10 to 13 years, depending on the breed. Long enough to see the human kids through the school, but only just.

Elephants live as long as people. Adult females even go through menopause presumably to prolong their lives and give their offspring the benefit of their memory of where the water was during the last drought.

Red sea urchins found in the shallow water of the Pacific Ocean along the West Coast of North America are known to live for more than 200 years. So do Bowhead whales that live in the cold Arctic and sub-Arctic seas—one whale was even found with fragments of a harpoon dating back to the 1800s in its blubber. 

The Greenland Shark can reach the age of 200 years old too, although one individual was found that was 400 years old making it the oldest vertebrate in the world. They live so long because they grow very slowly in cold water and only reach maturity at about 100 years old. Imagine human adolescence lasting that long.

Giant sequoia, Sequoiadendron giganteum, which occurs naturally only in groves on the western slopes of the Sierra Nevada mountain range of California, are the most massive individual trees in the world growing to an average height of 50–85 m (164–279 ft). Based on dendrochronology, the analysis of tree rings, the oldest known giant sequoia is 3,200–3,266 years old making sequoias among the oldest living organisms on Earth.

Photo by Nikolay Maslov on Unsplash

Sequoias might be the oldest living organism on earth.

Ecological time is long and short

All these lifetimes, from a few minutes to centuries, span ecological time. 

Periods long enough for a generation of an organism to emerge and for recognisable changes to the environment to occur. But because there are whole groups of organisms, notably trees, that live longer than the human perception of time, ecological time is longer than our typical frame of reference.

Ecological time is long compared to the turnover in human food production systems, business decisions and our political cycles. Decisions on almost all the things that affect our everyday lives happen in real time not in ecological time. This is one reason why we have such a hard time understanding trend from resource use, such as soil degradation and biodiversity loss.

But there is a contradiction here too.

Years to centuries of ecological time sound like a wide range of time from a human perspective, but all ecological time is infinitesimal relative to the age of the solar system, the age of the earth, and the duration of life on earth.

In evolutionary time that spans thousands to millions of years, the average mammal species will exist for around one million years. In this timeframe, the life of any one organism is infinitesimally small, ecology happens in the immediate.

Words that describe ecological time through a geological lens are rapid, dynamic, fast, short, and local. They are the things that happen when organisms interact with each other and with the environment around them. 

Ecology is quick compared to evolution.

Farm lifetimes 

The lifetime of the average farmer in the west is pushing 70 years, many of them still working the land well into their dotage. Likely the farm was passed down the generations through a succession with as much drama as the show of the same name. Many of these family farms would feel like heirlooms, old and part of the furniture.

But what about the lifetime of the farm? It has outlived several owners, and the incumbent has no reason to worry that it will persist long after he has passed on. Only the longevity question is important. How long would we expect a farm to exist as a productive parcel of land?

Realistically it should be centuries. Some farms in Europe have produced food for this length of time. They change their shape and size, and configuration throughout that life. So will the type and frequency of inputs to maintain the soil and the disturbance from the plough and the livestock. The kind of soil will make a difference, as will the weather. 

But for the sake of discussion, we can anticipate a thousand years of crop or livestock production before a farm dies. 

Photo by Jesse Zheng on Pexels.

Farm buildings like this one might last 100 years and can easily be rebuilt but will the soil last 1,000 years?  

Farm lifetime in Australia

In Australia, most of the rural landholdings are less than 200 years old. The majority are around a hundred years old given it took quite a while before the colonists managed to push their way into the dryer more remote parts of the continent. 

In other words, on our thousand-year timeframe, farms in Australia are pretty much in their early adolescence. 

They’ve gone through a fairly raucous youth of playing around with massive sheep and cattle production and then experimented with rabbits and other invasives. And they’re coming to the end of that party period with a hefty hangover.

Many farms look tired and haggard. As though they’ve been on the wrong end of too many late nights. Depending on who you ask, about two-thirds of agricultural land in Australia is depleted in carbon, has lost nutrients and structure or is degraded from erosion, salinity, acidity and contamination. If you’re expected to live a thousand years, it’s a bit of a challenge when you are knackered before you get to university. 

A zen moment is required, an awareness-raising and well-being exercise, to bring them mindfulness. If they survive intact for another nine hundred years or more. 

And before that, they need a holiday, some rest and rehabilitation. That would be for at least a decade in human time. 

Productive for a thousand years 

Just the notion of trying to think of lifetimes helps to understand what is needed to sustain the land for long-term production. Imagine thinking of the farm not as something owned and passed down to the children but has to be intact for dozens of human generations. 

A hundred human lifetimes and that farm will go through plenty of ups and downs and changes in context. The interesting moral conundrum presents to the current owners possessing a partying adolescent addicted to fossil fuel inputs. 

Do the farmers realize that as they pass into their own dotage, they’re actually looking after an adolescent? 

We suspect not. 

We suspect that landholders know that the farm will be there after they die. But perhaps their priority is the state they leave it in for their own offspring. Their sons and daughters they hope will come back from the cities and take over the family legacy. 

Photo by Amit Mishra on Pexels

There are at least 570 million farms in the world and most of them get passed down to the next generation.  

So who should be thinking about a farm as having a long productive life?

There is a role for the farmer. 

Owner, tennant or custodian the decisions the farmer makes on a day-to-day basis affect the lifestyle and longevity of the farm. 

The farmer is the one present and with the investment of time and money to manage the land for his livelihood, family and legacy. 

There is a role for government. 

Public policy should have the capacity to look longer than the lifetime of the ownership cycle. The challenge of course is that governments have a short lifetime, almost mayfly length. Politicians struggle to look beyond the next election cycle. 

This is why the planning departments are hived off into a little silo on their own. This helps protect them to some extent from the temptation that the politicians would have to leverage their decisions for their own short-term advantage. Not that that doesn’t happen, but you can see the problem. 

Decisions for the long lifetime of landholding are extremely challenging for governments. So much so that they barely even recognise such a timeframe. 

There is a role for scientists. 

Science is supposed to be objective and has the luxury of a long view, at least for those scientists trying to understand nature. 

Ecologists are more comfortable with time frames that extend to the lifetime of the oldest organisms in the habitat, but they are human. They can struggle with the thousand-year timeframe equivalent to multiple generations of the longest-lived animals.  

What science does have is the ability to abstract. Models, especially scenario analysis, can backcast and forecast in ecological and even evolutionary time. This capability is essential.

There is a role for everyone else.

We could leave all the thinking for the long game to the farmers and the people who define the social context of farming. Only that is abdication because every person on earth consumes food.

It is just as crucial for the people who eat the produce from the millions of farms worldwide to think about the lifetime of those farms. Our decisions on what we eat will change if we do.

What sustainably FED suggests

What sustainably FED asks in this anecdote about farm life is the need to look long. 

The solutions to meet our current demand for food and well-being and maintain that for humanity to pass through its demographic transition and still have natural capital left must have the long view.

Modern humans are believed to have evolved around 300,000 years ago and emerged from the African savannas to travel around the world, essentially becoming the only bipedal primate that survives on all continents by about 100,000 years ago. 

So humanity as a species lived its early childhood on the plains of Africa and then went on its gap year around the world and stayed.

Humanity might want its reproductive years to lie ahead, middle age and retirement to look forward to and make it to the million-year average for a mammal species. 

A thousand years for a landholding is not even a blink in the remaining time of Homo sapiens as a species if the average is what we will achieve. 

But unlike our psyche, which believes we’re above average at everything, humanity is on track to being one of those very short-lived animals unable to adapt to an environment that changed because of what we have done. 

As individuals, why should we care less? We have done our bit as long as we leave our house to our children. Unfortunately, that is actually how we treat the world at the moment. As though our four score and ten human lifetimes were all that mattered. 

And maybe that’s true, maybe in our universe, self is the one thing that matters. 

In the end 

Astrophysicists predict that the sun will follow its lifetime, expand and absorb the inner planets’ orbits. The earth will be consumed by the sun in roughly 7.5 billion years. 

Humanity won’t be there to see any of that. Not in our wildest dreams will we live that long? As a species or anything else. 

Exactly how long Homo sapiens persists is dependent on what we do now. Our future is dependent on thinking in lifetimes that are beyond our own.

Look long and prosper.

Hero image from photo by Daniel Sinoca on Unsplash


Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

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