For our grandson, who was born in 2011, anything before 2000 is ancient history. He understands that we were born in the early 1950s, but anything from the various decades of our lives seems to him impossibly ancient. Even though he has studied history in school, he lacks the experience that enables him to connect with timescales measured in decades, let alone centuries. Recently, we were discussing some Matchbox cars that we have. The bin of toys is most often used to entertain his 3-year-old brother, but he enjoys looking at the cars and talking about them. He is currently interested in cars and has asked about the cars we owned before his time. We’ve collected some of them as matchbox models. For example, we have a 1958 Ford F-100 matchbox. I drove a '58 F-100 when I was dating my wife. So far, we haven’t found a 1966 Opel Kadette, which was the car we had when we got married. Nor do we have a 1977 Ford Pinto, the first new car we purchased.

As I was talking with our grandson, the chiming clock in the room struck the half hour, and I commented on how much I enjoyed the clock. Somehow, in the conversation, I realized that he wasn’t making a distinction between the age of the clock and the age of the cars in our discussion. The clock is 100 years older than those cars. The distinction between the 19th and 20th centuries isn’t essential to him. Both represent former times - “the olden days.”

I am intrigued by his perspective on time and enjoy discussing things that occurred before he was born. I am equally fascinated by how my perspective on time has shifted as I have grown older. I recall a time when ten years seemed like a substantial amount of time. When I turned 40, 50 seemed a long way off, and retirement was far enough away that I didn’t give it much thought. Now, in my seventies, I occasionally catch myself thinking about events and activities that occurred 30 or 40 years ago as “recent.”

This September marks 24 years since a crew of eight people began living in the closed environment of Biosphere 2. Though the isolated environment was designed to last 100 years, the first mission of those eight people was set to last 2 years. They would live within an enclosed system, growing the food they needed, recycling water and air, and maintaining other life-supporting systems. The experiment did not proceed as planned. The sealed system failed to provide 100% of the resources needed to sustain human life. Oxygen levels in the closed system fell, and the crew suffered from illness similar to altitude sickness. Eventually, additional oxygen had to be added to the system. Some oxygen-producing plants proved more challenging to maintain than expected. Trees in an environment without wind failed to develop the strength to support their growth. Bacteria and fungi flourished more than expected, consuming more oxygen than anticipated. The food produced by the crew fell short of what they needed. Pollinator colonies failed. The UV filtering properties of the glass left bees without the information they needed to thrive. The crew had to pollinate some crops by hand. An injury to one of the crew members forced unsealing the biosphere to allow the member to receive medical treatment.

In science, however, much can be learned from experiments that don’t go the way planned. The Biosphere 2 campus remains a hub of scientific research. The campus is a complex of glass pyramids, domes, and towers covering about 3 acres. Inside are an artificial rainforest, a savannah, a fog desert, a wetland, and a saltwater “ocean” with a living coral reef.

Although the campus is now owned by the University of Arizona and managed by Columbia University, it originated as a privately funded experiment conducted by self-taught science enthusiasts rather than scientists with PhDs from academic institutions. Often touted as an experiment to pave the way for colonies living on other planets and traveling long distances in space, the original experiments were more focused on understanding the ecology of Earth. The 2 in the name refers to the planet Earth as biosphere 1.

The campus is now used for multiple ecology experiments, including several that test the impact of global climate change. One experiment raised the temperature. While the forest initially seemed resilient in the heat, it required increased water to thrive. Drought caused more stress for plants than heat alone. The coral reef has been the site of experiments demonstrating the effects of ocean acidification, which occurs when CO2 levels rise. Scientists have also raised the temperature in the ocean pond to test whether supplements, such as probiotics, can help coral survive in conditions of an extreme climate crisis.

When I first learned about Biosphere 2, the idea of a century-long experiment seemed far-reaching. Now, with a quarter of that time having passed, it is clear that we have much more to learn. Hopefully, the somewhat contained systems of Biosphere 2 will yield information on how we can better care for Biosphere 1, our only planet that, for the foreseeable future, needs to sustain human life in the universe.

Despite significant investments from very wealthy individuals, human exploration of other planets is dependent on developing long-term life-sustaining sealed systems. We have yet to create a fully functioning system on this planet, let alone one that is portable enough to be transported by rocket to a distant location.

It is impossible to predict what will be learned in the span of the lives of our grandchildren. They will likely live to see the 22nd century. With an accelerating rate of change, they will experience more change in their lives than we do in ours. The hope, however, is that some of the knowledge of our generation can be passed on to future generations in ways that enable this planet to continue sustaining human life. Our way of living has certainly created problems for future generations. Experiments including Biosphere 2 offer the possibility of making positive contributions to the future as well.