As sea levels rise and oceans become warmer, the consequences will hit us all. But some, like Knud Knudsen, a man who walks through the Wadden Sea to deliver the mail, are better placed to notice the shifting tides.
Knud Knudsen was born and bred on the German island of Pellworm, and thereby into a life at very close quarters with the sea. DW spoke to him about what has changed on the island over the decades, whether the local population is feeling the effects of climate change and rising sea levels, and whether he really walks barefoot to one of the low-lying little islands, known as Halligen, to deliver the post.
DW: How would you describe life here on Pellworm?
Knud Knudsen: I was born and raised here. I know this place, the way it is. I couldn't live in the city, I know that. I don't think I'd survive there.
Has the island changed a lot during your time here?
Yes, when I was a kid, Pellworm was really different. It's changed a lot since my childhood. Even where I live buildings have gone up everywhere. In the past, it was all fields. Nature here used to be different. There's a lot of monoculture nowadays, and you barely see any flowers anymore. I remember the times when you'd find chamomile or daisies growing along the edge of the road. You barely see that anymore.
Knud Knudsen walks across the mudflats and through tidal channels to deliver post to the nearby Hallig island of Süderoog
You also take the post over to Hallig Süderoog. And you walk barefoot through the Wadden Sea to get there?
Yes, I take it over twice a week. I go according to the tides, because I have to walk over at low tide. Mostly I go once at the weekend, usually on Sundays and once during the week after work, or I take a day's holiday from work to go. I walk over the mudflats for an hour and a quarter to get there, stay for about an hour, and then turn around and come back the same way. I walk barefoot until November, but it gets a bit difficult after the first night frosts.
What do you like about the sea?
The sea is movement. It's always different. I can't imagine life without the sea. I couldn't imagine being here on Pellworm without the water. It's the sea that makes me feel comfortable here. If the tide were always out, or if the water just didn't come back one day, that would be strange. Water is life. For me at least.
We live in times of climate change. Have you noticed changes here on the island?
The dikes around Pellworm are a complex structure of levels and materials designed to separate the sea from island
I can't say for sure that it's really due to climate change. But the tidal surges we have are much more intense. Although, we've not had one for a while. The last one was [cyclone] Xaver in 2013.
It's worrying to think of how fast the glaciers have melted in the last few years. But I can't say for sure that rising sea levels are due to climate change. The only thing I can say is that when we were kids, the differences between spring, summer, fall and winter were clearer. These days you could go so far as to say winter is actually a cold summer and summer is a warm winter.
How important are the dikes on the island of Pellworm?
The dikes are our only flood protection. The houses built on dwelling mounds would be able to hold out against the water for a bit longer, but if we didn't have our dikes, the lowest areas — which are one meter (0.3 feet) below sea level — would be flooded at every high tide.
It is important to maintain the dikes. A lot of people don't understand but if it weren't for the dikes, it would look different here.
Do you feel safe on an island that is partly below sea level?
I feel safe. The dikes are in a good state, but I also grew up here. When people come over from the mainland and really experience a storm surge, it's definitely scary. I also think the mood is different when the water is three-quarters of the way up the dike. But I'm not afraid in that sense. I have a healthy respect. But I don't feel a sense of panic.
There are a lot of nature conservationists who prefer to limit dikes, use softer measures. How do you see that?
The conservationists want us to do as little as possible to protect ourselves. And I'm a little concerned that that's the wrong approach. They always see the extremes, but there is something between these extremes. I think our coastal protection should be more intense than it is at the moment. I think we should be really determined to do anything possible to ensure that the dike is not endangered.
I started working in coastal protection as a young man, and in the past much more was done, which is why we have all this embankment foreland. Foreland is the best protection for the dikes. It takes so much of the energy out of the water that the dikes don't need to be so high.
If we were to do nothing or less than we do at the moment, this would be a threatening place. If we don't do more than we are at the moment, I give Pellworm between 300 and 400 years before it becomes a Hallig island. But I'll be gone by then. At least, I won't be sitting here on the dike like this.
The interview was conducted by Tamsin Walker and Mabel Gundlach and was edited and condensed for clarity.