Considering all the challenges we face in aging, challenges to our health, finances, memory and all the rest, there is one challenge that threatens us all and every human being on earth.

That is the unsustainability of current practices that degrade the air, oceans, fresh water and land that support us. We are not only fouling, we are destroying our nest.

This is not about king tides, flooded streets and property values. We are facing what David Attenborough described as “the collapse of our civilizations and the extinction of much of the natural world.” If there was ever a nonpartisan issue, this is it.

In last week’s “Aging for Amateurs” column, my medical colleague Bill urged us to pay attention to the changes in climate taking place today, all of which affect our health adversely. And he ended with a challenge not only to mind our own health but also to mind the health of the planet.

Environmentalist and author Bill McKibben raises the stakes on minding the planet. “We’ve got to get out of our comfort zones. Because the planet is outside its comfort zone. Way outside.”

We have known this for years, decades, in fact, that our generation has been “in charge” of things. And has largely ignored the warnings.

Reviewing the important new book, "The Uninhabitable Earth: Life After Warming," by David Wallace-Wells, John Lanchester points out that “The science of global warming has been settled for 40 years, but we have not just continued to pollute, we have accelerated the rate at which we’ve been doing so. Most of the carbon humans have put into the atmosphere has been emitted in the last three decades.

"As Wallace-Wells tartly puts it, ‘We have done as much damage to the fate of the planet and its ability to sustain human life and civilization since Al Gore published his first book on the climate than in all the centuries — all the millenniums — that came before.’ ”

What is he talking about? Nobody needs another list of environmental catastrophes. We’ve known about them for years and put off doing anything. Just one example, though, touched me recently.

A study group I belong to read “The Insect Apocalypse Is Here” in the Nov. 27 New York Times Magazine. We know that insects are vital pollinators, recyclers of ecosystems and they are the base of the food chain we depend on. In a 20-year period, monarch butterflies have decreased by 90 percent and bumblebees by 87 percent.

A German study published in 2016 shows that the bulk weight of insects in Europe has declined by 75 percent in 27 years. Have you noticed how you no longer have to clean the bugs off your windshield when you take a trip? The crash in the food chain is not trivial. Reading about the severe diminution of life forms, in this case insects, touched our group emotionally. It gave us a sense of the immense complexity of life and what it’s like to live amidst vast destruction of species and habitat, an extinction period not seen for tens of millions of years.

Sea level rise may seem like a nuisance or an abstract, distant threat. It is not. We’re all aware of the steps Charleston is taking to mitigate the flooding caused by rising water, and how difficult and costly these small steps are. Looking ahead a few decades, though, the forced migration of hundreds of millions of people who live along vulnerable coastlines strains our power to imagine the consequences in terms of starvation, political upheaval and war. If that dire scenario is to be mitigated, climate scientists tell us we have less than 12 years to take decisive action. Scientists are doing their part, but the power to change doesn’t lie with just them.

Our generation tends towards a crazy double-think about science and technology. On one hand the “science-deniers” are dominant enough to elect politicians who act as if all this is nothing but a hoax. On the other hand, many of us excuse ourselves from responsibility by placing great faith in science, thinking the looming disasters of climate change can and will be fixed by scientists and engineers.

Both attitudes may render the planet uninhabitable for our grandchildren. Science-deniers, funded by the giant oil corporations and other industrialists who profit from our society’s addiction to fossil-fuels, continue to govern by policies that are destroying the earth. Those who look to science for salvation may continue to live wasteful, “business as usual” lifestyles.

Both camps may take a lesson from Gus Speth, retired dean of the School of Forestry and Environmental Studies at Yale and a frequent visitor to Charleston.

“I used to think the top environmental problems were biodiversity loss, ecosystem collapse and climate change,” he is quoted as saying. “But I was wrong. The top environmental problems are selfishness, greed and apathy.”

Elders are good at charity and volunteerism. But all the charitable aid by all the churches and benevolent societies in the land can’t match the damage we are doing every day to our common nest. What is required is change: to stop burning fossil fuels.

We must grieve. Grieve for the earth, for the hundreds of species on the edge of extinction, for what we have already ruined or lost. Grieve fellow humans struggling to survive drought, flood and starvation.

Real change begins with a broken heart. Elders know the depths of grieving; and if we grieve deeply what we are doing to our planet and to future generations, then we will be moved to find out what else we must do.

Bert Keller and Bill Simpson write the occasional column, “Aging for Amateurs.” Keller, a retired minister and bioethicist, wrote this installment. Comments, questions and suggestions are welcome at agingforamateurs@gmail.com.

Bert Keller and Bill Simpson write the occasional column, “Aging for Amateurs.” Keller, a retired minister and bioethicist, wrote this installment. Comments, questions and suggestions are welcome at agingforamateurs@gmail.com.

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