About this episode:
Amid the energy of the IUCN World Conservation Congress, David meets legendary marine biologist, oceanographer, and explorer Dr Sylvia A. Earle — affectionately known as “Her Deepness.” Still diving at 90, Sylvia began her career with a PhD in phycology (the study of algae) in 1966, has graced the cover of TIME magazine, authored nearly 200 scientific papers and 13 books, logged over 7,000 hours underwater, and still holds the 1979 record for the deepest solo dive — 380 meters beneath the sea.
Joining her is conservation biologist Dr Tessa Hempson, Chief Scientist at Mission Blue, the nonprofit Sylvia founded in 2009. Mission Blue inspires global action to explore and protect the ocean through its network of Hope Spots — special places vital to ocean health. Partnering with local communities, scientists, and policymakers, the organization drives awareness, expeditions, and protection efforts toward one shared goal: safeguarding 30 percent of the ocean by 2030. Five years to go…
Sylvia speaks of the fish she calls her friends — sentient beings with personalities, intelligence, and an inherent right to thrive in their ocean home. She reflects on the species lost to time — from the Steller’s sea cow to the dodo — their fate sealed by humanity’s destructive hand. And with a glint of curiosity, she admits her wish to meet a megalodon, that ancient giant of the deep. Yet her message is not one of nostalgia, but of hope. Sylvia believes the youth of today hold the key to a blue future — one where curiosity, courage, and compassion can restore balance to the seas she has spent a lifetime defending.
David's thoughts:
Reflections written from the floor of IUCN’s World Conservation Congress, Oct 2025:
To meet Dr. Sylvia Earle at the World Conservation Congress was an absolute honour — and to have an hour in her company, doubly so. She was in immense demand at the event – as I entered the room alone to meet “Her Deepness”, 15 or so representatives from the UN departed…! I owe deep thanks to Tessa for making the meeting possible, it felt extraordinary to have that time together.
I have revered Sylvia from afar for many years. I’m rarely starstruck, but I can admit that my stomach was all a-jitter upon meeting her. This was someone whose life’s work had shaped my own understanding of the oceans and our relationship with them.
Despite growing up on the coast in Dorset, I came to diving relatively late. Most of my early years were spent on the shoreline, never as a particularly confident swimmer. It wasn’t until my thirties that I discovered scuba — and with it, the incredible biodiversity, the light, the colour, and the vitality beneath the waves. The world below the surface struck me as far more energetic and alive than much of what we see on the increasingly industrialised and denuded land of Great Britain. And, no – you don;t have to dive in the Maldives to witness such life; our oceans, albeit colder, are as inspirationally busy and colourful!
What moved me most in our conversation was hearing Sylvia describe how her diving began not as a pastime, but as a means to an end — a way to do the science she longed to pursue. For so many of us today, diving is a recreational joy; we marvel at what we encounter, and that is the “why?” But for Sylvia, it was always a tool of discovery, and through it, she has witnessed huge loss, despite that which remains continuing to inspire others. I cannot truly fathom the emotional toll of watching that decline unfold — seeing so much destruction caused by our own species — and yet still emerging hopeful and determined. I teased her, perhaps a little cheekily, about her oft-repeated line that ‘now is the best time to save our seas’, noting that she’d written those very words fifteen years ago. Yet she is right, of course, to keep saying it. If not now, then when? Each time she repeats the plea, one hopes a few more will finally listen. “Protect Nature like your life depends upon tt… Because it does.”
In my introduction to the audio, I remark on the reality we now face: global temperatures have risen by 1.4°C. Coral reefs are bleaching and dying faster than they can recover. The oceans, absorbing 90% of the excess heat trapped in our atmosphere, are under severe strain. Some species may adapt by moving deeper; whilst others are devastated by rising acidity and temperature. We are poisoning the lungs of our planet — murdering the algae and photosynthetic life that generate the very air we breathe.
And yet, amidst the bleakness, there are glimmers of hope. During the IUCN Congress, three devil ray species were sadly upgraded to Critically Endangered, but green turtles were downgraded to Least Concern. That is something to celebrate. It shows that when we pay attention, and act with intent, we can begin to heal the damage we’ve caused. Perhaps it’s no coincidence that turtles inspire such collective affection — they are charismatic, personable, and easy to rally around. But as Sylvia reminded me, we must also care for the invisible, the unlovely, and the overlooked. The microscopic life, the plankton and algae — the “ugly” things, in human terms — sustain everything else. If we lose them, we lose the very foundation of life in the sea.
So I end this reflection with gratitude — to Sylvia, to Tessa, and to everyone working with Mission Blue and beyond — for their perseverance and their faith. May we listen, and act, while there is still time.
LINKS:
Dr Sylvie Earle – https://en.wikipedia.org/wiki/Sylvia_Earle
Mission Blue & Hope Spots – https://missionblue.org/hope-spots/
JIM Diving Suit – https://en.wikipedia.org/wiki/JIM_suit
Coral Collapse – https://www.oceanrising.co/p/breaking-news-our-planet-has-hit
Devil Rays Upgrade – https://www.mantatrust.org/manta-and-devil-ray-species
IUCN – https://iucn.org/
