"One of the rewards of growing old is that you can truthfully say you lived in the past," film critic Roger Ebert wrote right before he died. The gift of using a lens from the past to view the present is a gift indeed, and one that David Attenborough (born May 8, 1926) continually bestows upon those lucky enough to listen and look.

When I was 11 years old, I lived in Leicester in the middle of England. At that time it wasn't unusual for a boy of my age to get on a bicycle, ride off into the countryside and spend a whole day away from home. And that is what I did. Every child explores, turning over a stone and looking at the animals beneath is exploring. It never occurred to me to be anything other than fascinated when watching what was going on in the natural world around me.   These elegant lines remind me of Laurie Lee's childhood memories,:  
  
"I was set down from the carrier’s cart at age of three; and there with a sense of bewilderment and terror my life in the village began. The June grass, amongst which I stood, was taller than I was, and I wept. I had never been so close to grass before. It towered over me and all around me, each blade tattooed with tiger-skins of sunlight. It was knife-edged, dark, and a wicked green, thick as a forest and alive with grasshoppers that chirped and chattered and leapt through the air like monkeys."

Buddhist teacher Pema Chödrön wrote that holding life's complexity in both hands and still summoning peace is the key to contentment. It is also vital to our soul, and, argues the reverent David Attenborough in Life on Our Planet, to our life.

"This is the true tragedy of our time," Attenborough writes in precise words:

This is the true tragedy of our time: the spiraling decline of our planet's biodiversity. For life to truly thrive on this planet, there must be immense biodiversity. Only when billions of different individual organisms make the most of every resource and opportunity they encounter, and millions of species lead lives that interlock so that they sustain each other, can the planet run efficiently. The greater the biodiversity, the more secure will be all life on Earth, including ourselves. Yet the way we humans are now living on Earth is sending biodiversity into decline.

Fossilized coral turned into limestone with time. The modern presence of limestone indicates the ancient presence of coral structures, constant forces that move and shape the earth. Learn more.

Attenborough has a long history as a TV broadcaster and filmmaker; he brought the world's wilds into living rooms for decades. His rather furious scurry in the last couple of years has put him in all of our living rooms (and in the parts of our brains that beep when we toss a bit of plastic into the bin.)

I had believed from a very early age that the most important knowledge brought an understanding of how the natural world worked. It was not laws invented by human beings that interested me, but the principles that governed the lives of animals and plants; not the history or kings and queens, or even the different languages that have been developed by different human societies, but the truths that had governed the world around me long before humanity had appeared in it. Why were there so many different types of ammonites?   British author Penelope Lively wrote about ammonites in her memoirs as something which sustain her own personal narrative and anchor her to her past. They are such an extraordinary piece of history, of life. These wildly variant creatures that no longer exist but are the ancestors of octopus and squid, had pockets for air in their shells to create buoyancy which, through millions of years, enabled minerals to enter and petrify the space so that we can see and hold and cherish them today. (I also love ammonites!)

Ammonite fossil. Ammonites were sea animals that lived between 65 and 250 million years ago; their chambers were vacated as they grew and are, therefore, a measure of age. Learn more.

From a childhood traipsing along in awe and wonder at the immediate world and through his immense career as a BBC broadcaster, David Attenborough witnessed extraordinary events and changes.   All of which he writes about with intimate, gentle wisdom coupled with an accessible humanity and charm. Like his countryman Stephen Fry lecturing Greek myths or poetry. There is so much of Attenborough in his words.

The men stared at us, wide-eyed, as though they had never seen our like before. I doubtless did the same... to my surprise, I found it was not difficult to communicate with them. I tried by gestures to indicate that we were short of food. They pointed to their mouths, nodded and opened their bags to show us the taro roots they had been gathering. I pointed to cakes of salt we had brought with us. It is used as currency all over New Guinea. They nodded. We had started to trade.

The burden of witness is to expel memory lest it consumes us internally. To give history one of its critical chapters.

Plastic is invading oceanic food chains, and over 90 percent of seabirds have plastic fragments in their stomachs. Aldabra is a nature reserve which very few people are permitted to visit. When I landed on the island in 1983, while making The Living Planet, the only flotsam on the beaches worthy of mention were the giant nuts of coco de mer palm tree. Recently another film crew visited the island. They found humanity's rubbish on every part of the beaches. Giant tortoises that live on the island, some over a century old, now have to clamber over plastic bottles, oil cans, buckets, nylon nets, and rubber. No beach on the planet is free of our waste.

An early dinosaur footprint formed about 200 million years ago. The mounds are precisely what they look like: sand shaped by ocean currents. Learn more.

As I read A Life on Our Planet, I can't stop thinking about the enormity of the problem vs. individual impunity and ignorance.

Three hundred years to grow,
three hundred more to thrive,
three hundred years to die -
nine hundred years alive.
From Robert Macfarlane's incantation "Oak" in The Lost Spells

What kind of shift in consciousness is necessary? I think of Galileo pointing his newly-chiseled lens at the moon and saying, "Look here!" or how Rachel Carson connected agricultural fertilizer to widespread ecological devastation. If we can become desensitized to changes such as extinction, tuck those things under the mantel of knowledge, and press on, we can adapt to a world that bans plastic or feeds synthetic meat.   Nobel Prize-winning biologist Paul Nurse writes on the constant adaptation of life in his wonderful book What is Life?, a sturdy companion to Attenborough's work.

Ultimately, that is the beauty of A Life on Our Planet; it is urgent and empowering because it is written with hope.

The work of scientists who study the Earth's systems gives us the answer. In fact, it's quite straightforward. It's been staring us in the face all along. Earth may be a sealed dish, but we don't live in it alone! We share it with the living world - the most remarkable life-support system imaginable, constructed over billions of years to refresh and renew food supplies, to absorb and reuse waste, to dampen damage and bring balance at the planetary scale. It is no accident that the planet's stability has wavered just as its biodiversity has declined - the two things are bound together. To restore stability to our planet, we must restore its biodiversity, the very thing we have removed. It is the only way out of this crisis that we have created. We must rewild the world!

The great humanist and neurologist Oliver Sacks once wrote, "I am near death, but I am not done living." Attenborough delivers a voice for our era, from our era, and let's not mince words - at age ninety-six- one that will soon leave our era.

What must it have meant to him to write this statement and vision? Knowing he will not ever know if we listen?

Then again, we do not know either.

For this article, I photographed a few of the ultra-spectacular geological/biological specimens at London's Natural History Museum. Visit the museum yourself with this audio tour narrated by Sir David Attenborough.