Picture this: You’re out on a ship in the middle of the Arctic Ocean. From afar, the icebergs look like moderately-sized chunks. But as you get closer, you realize that your little ship dwarfs in comparison to these monstrous beings, and they’re actually not still at all, but slowly bobbing in the water. And every now and then, a hunk (the size of your head? your car? you can’t tell from here) breaks off the side.

It might sound nerve-racking, but polar and environmental photographer Dave Walsh lives for this kind of adventure. “The frozen regions of our planet have the power to ignite imaginations,” says Dave, “but for most of the 7 billion people on Earth, the Arctic and Antarctic remain abstract and unreachable.”

Dave has worked extensively on environmental and science stories, and has sailed aboard several Greenpeace expeditions to Antarctica and the Arctic. His images have also appeared in National Geographic, The Financial Times, The Guardian, and Smithsonian to name a few.

To help demystify this frozen world, Dave shared the three things that most photographers don’t know about shooting ice:

1. You’ll have better luck in the middle of the night

Photographers know that a sunny day often doesn’t mean the best light. So what do you do when you’re in a place with 24 hours of sunlight?

Dave found that the best time of day was between 2-4am, when the sun is low in the sky and the glare is less harsh coming off the ice.

“Some of my images were taken in northwest Greenland, between June and August in what are actually desert conditions. There’s practically no humidity, and it’s not really all that cold,” he says. “At that time of year, you can go hiking across a glacier at 3am in a t-shirt, even in the high Arctic. But I do recommend you still bring warm clothes!”

2. Icebergs are always on the move

The word “iceberg” literally means ice mountain, and while they’re enormous, they also float freely in the ocean. “I’m aware that many of my iceberg images have a certain stillness to them,” says Dave. “But in reality, nothing stops moving at sea – every iceberg is moving, changing shape, and slowly melting.”

Getting close to an iceberg means using inflatable boats, and even though they’re stable, it add even more movement to his shot. Plus, a one degree change of angle can give a radically different perspective.

“This isn’t landscape photography in the normal sense – where a moving sky is what you’ve got to deal with. When you’re on the sea, photographing ice, the sky is about the only thing that’s a constant,” says Dave. “The temptation is to try and make a blockbuster image – to go all wide-angle and dramatic. Whenever I feel like doing this, I stop, try and put the camera on a tripod, or shoot at 50mm. I give to let the subject itself empower the image.”

3. Nothing is actually completely white

You might think much in the Polar Regions is pure white – glaciers, snow, polar bears, etc. But in fact, these environments are bursting with incredible colors.

“We tend to think of polar bears as pure white, because they’re so reflective, when in fact they’re a yellow gold,” explains Dave. “And the’re a  rich blues to the icebergs due to highly compacted snow squeezing out the red part of the spectrum. Photographing this is a privilege, as it’s not something most people ever get a chance to see”.

Even on dark, overcast days, Dave says he is often still shooting at ISO 100.  “When you point a lens at an iceberg, it’s as if it sucks in light from the sky, then radiates it and amplifies it,” says Dave.

“Climate change is a real, measurable phenomenon,” concludes Dave. “Our behavior is causing melting, particular of the Arctic sea ice, and Greenland ice cap. What happens at the poles has reverberations elsewhere. Through my photography, I want to make people not only fall in love with their home planet, but to start giving a damn and take action to protect it.”

Dave’s polar images were recently featured at the Copper House Gallery in Dublin, Ireland in The Cold Edge exhibition. The curators described his series as a collection of “ethereal photographs of the unforgiving wilderness, wild animals and blue icebergs question our romantic relationship with remote, harsh and pristine environments.”  You can also follow Dave on Twitter: @davewalshphoto.