Six degrees below zero, as warm as it's going to get on an afternoon in early February. But the customary payoff for an arctic air mass is in place — an area of high pressure bestowing radiant sunshine, glittering snow, a galaxy of sparkles, and a sky so achingly blue it seems solid, an azure crown on a frosted conifer forest in northeastern Minnesota.

The cross-country skis elicit a soft rasp from a crystalline trail, and the rhythm of the poles is a reverie of motion, both less and more than each swinging stroke, as much paddle as spear, affirming that snow is sculpted water and blurring again — at least in my mind — the difference between ski and canoe. Feel the flow.

The trail is vaulted by pine limbs and bordered by 80- to 100-year-old trunks, or so seems the average age. But amid this wood of relative youngsters are a few grandmothers that overtop the general canopy. One is rooted next to the trail and here I often pause to offer my respect. She's about 90 feet tall and 3 feet in diameter at the base, a magnificent white pine.

Two hundred years old? Two hundred fifty? Maybe more. I frequently reach out to touch the furrowed bark. Sometimes I speak a word of greeting. I don't imagine my reverence impresses the tree or registers with the universe, but it's gladdening for me, a comforting ritual. Why not be respectful and courteous? Why not acknowledge such a presence?

It seems the least we can do, because the fact is we cannot live without snatching the lives of other beings and converting them into matter and energy for our own bodies. We are what we kill.

Our survival and proliferation depend upon the death of plants and other animals. It cannot be avoided. We all know this. If questioned, we readily admit it, and likely with a metaphorical shrug. So what? Is what it is.

I submit there is an important difference between understanding the fact and thinking about the fact — between purchasing the dead or doing the killing, and "going to the funeral," as it were.

When a human being you know dies, why do you attend the wake or funeral? Some or all of these reasons likely apply: respect, remembrance, duty, grief, socialization, ritual, curiosity. Increasingly, the term funeral is being superseded by "celebration of life," which for the following point is appropriate: when we eat, don clothing, shelter in our residences, feed our companion animals, or perform myriad other daily actions, they are only possible because of deaths, and ideally we should celebrate that reality. Celebrate in the sense of "honor or praise publicly." We might consider the Endangered Species Act, for example, as such a celebration, and as an expression of duty and respect.

Everything has a cost. The laws of physics, most particularly in the realm of thermodynamics, ensure this. Imagine anything you consider good. Doesn't matter what it is, there's a kind of "existence tax" collected by nature.

For example, if you value wind turbines as a form of renewable energy, consider that the metals required must be mined and refined by ways and means that are highly toxic; that the footprint of the structure monopolizes a parcel of finite land; that the blades can kill a shocking number of birds and that, like all machines, turbines demand the input of maintenance.

Those "taxes" don't mean we shouldn't deploy wind turbines, but costs must be tallied and judged. The quality of such judgments are enhanced by the "celebration of life."

It is a debt we owe to all we kill, not only because discharging a debt is honorable, but because the extent of our necessary predation threatens the existence of other species who have as much right to live as we do, and because our needs and desires also threaten the integrity of the biosphere upon which we also rely.

We tend to believe that humanity is special, that our killing is more justified than the killing of other predators — animals, bacteria, viruses — who are also attempting to survive. Our claim of exceptionalism is unacknowledged by other residents of the earth, or by the planet itself. We've been so successful at propagation and the colonization of ecosystems that we've fallen into the trap of manifest destiny: The arc of human history is simply what needs to happen, and is correct and worthy merely because it exists. A fallacy, and perhaps fatal.

But one way we are truly different is that our minds can recognize this fallacy. Any living creature takes advantage of whatever resources it can exploit — nobody turns down nourishment, shelter, reproduction. But how many other species have an awareness of the global system? Can understand the effects and potential effects of unbridled and wasteful expansion into a bounded biosphere? In that we are likely unique.

To put it in a contemporary, up-to-the-minute context, what other species can develop a vaccine against another predator? That's big. But it's notable that we largely downplayed and even ignored the inevitability of a deadly pandemic until it was sickening and killing millions while disrupting civilization. That's also big.

So it appears we have the mental capacity to think and to consciously change, but an emotional reluctance to rock our personal boats. We can see the big picture of say, mass extinctions, while implicitly denying that it has much to do with us as individuals. We are like a person holding a smoking pistol over a corpse and insisting, "I swear, the gun just went off!"

Individual inaction is understandable. Our lives are short and the eons of the earth are long. We are small and the world is vast. As biological creatures our priority is to take care of ourselves and our own, and for much of the human saga that worked out all right — we were relatively few and relatively feeble.

Now, however, we are legion and powerful, potent enough in our numbers and our tools to significantly sway the systems of our planet — and not to our benefit.

Inaction, of course, remains an option. The forces of nature will take their course, influenced by our contributions, and at some point all will be taken from our hands. The biosphere will become toxic to us and some other organism(s) will thrive on our waste. It's not an attractive option, but you can always take some solace from the viewpoint I've heard expressed by several people: "Well, I'll be dead before that happens."

Maybe. Probably. But is that selfish fatalism to be the philosophical culmination of our human enterprise? It need not be. We can think. We can change. We can still exert control over our fate — at least for a while.

Sometimes I resent the fact that I must kill to live. I see it as the great flaw in an otherwise beautiful universe. I'm reminded of a line from a poem by Robert Frost, in which he suggested his epitaph: "I had a lovers quarrel with the world." Just so, but it's not a violent dispute, and there will be no divorce — it's not possible, and every day brings a series of reconciliations.

Sometimes it's political action or the alteration of a personal habit. Sometimes it's just reaching out to the grandmother white pine and touching the furrowed bark on a brilliant winter day. I glean a little encouragement about the durability of the biosphere when I consider that she was alive and majestic long before I was born and could easily survive me by a half-century or more.

However, I also realize that with the run-of-the-mill, midsize chain saw sitting in our garage, I could put her on the ground in fewer than 10 minutes. Such is our power.

And while we still have some time and space to project our power differently, we might consider how we can make ourselves worthy of the COVID vaccines.

Peter M. Leschak, of Side Lake, Minn., is the author of "Ghosts of the Fireground" and other books.