I'm actually getting to the stage where places I travelled to for the first time in the early 1990s are now unrecognisable. I go to coral reefs that I went to ten years ago when they were swarming with fish and sharks, and now they are barren deserts.
A lot of people think it's insane to swim out in blue water with a great white shark, but my experience tells me I can do it safely. Other people might consider it mad, granted, but then I might think what they do is mad.
I love what I do for a living and even if I wasn't getting paid for it I would still pursue an active, outdoors lifestyle, researching animals and looking after them.
There's nothing more paralysing or more likely to make people fall into a malaise of believing they are powerless than just hearing that everything's negative and everything's shot to bits. It's really important that we know we can change this planet for the better and that every single one of us, no matter how small we may feel, has that power.
If there remain places on the planet that are un-known, unspoilt corners, a laboratory for evolution still exists - a snapshot of what the rainforests, polar deserts and high mountains were once like, before man.
If the world's oceans have had nearly half a billion years with sharks as the apex predators, then the delicate balance of its food webs must rely on their presence in complex ways we cannot possibly predict.
The number one piece of advice that you would ever get with working with any large predator is don't run. If you stand confident up in its face it'll probably just wander away, but if you turn and run it triggers what's known as the predatory impulse.
People are used to seeing natural history programmes that have been filmed over many years which are concentrated, focused visions of natural history.
The flesh-eating cockroaches and venomous centipedes in the Gomantong cave in Borneo were pretty unsavoury. They turn the floor of the cave, which is itself the world's largest pile of bird and bat poo, into a seething mass of invertebrate horror!
Even my fiction novels are all about outdoor adventure, and have plenty of information to encourage the reader to get interested in adventure and conservation.
Fences split up the territory that a hedgehog has to forage in so having a little hole in your fence could well enable it to move in and out of your garden.
I made my first conservation series for National Geographic in 2000. Ever since I've been finding ways of making my own life as sustainable as it possibly can be.
I started climbing in my late teens, but I wasn't passionate about it back then. My first experience was being dragged up peaks by my parents; freezing cold with nothing to see.
I was always really into the facts and figures and the statistics about nature and I always loved learning about it and having a new fact on hand. For me it was non-stop dirt, climbing trees and catching lizards and beetles. That was my thing as soon as I could crawl.
I've been doing expeditions for a living for more than 20 years and know all about what you have to go through psychologically to separate yourself from the modern world.
Fiction was a massive, massive part of my formative years, far more so than television ever was, and I always hoped that my future would lie with writing.
I surround myself with books, kind of hoping the vast knowledge will just seep into my mind through osmosis.