I read and watch a lot of bikepacking/touring content. This time of year especially it's away from the UK, somewhere warm. Which is great, I can understand the desire when home is so cold and wet; except for the environmental cost.
It nearly always involves flying. Magazine articles discuss riding sections of various grand tours, and I'd like to do them. But the default way to get there isn't by train or ferry, both much better choices. I know they still pollute, certainly more than visiting local destinations, but not the amount that a plane does. One problem is cost, flying is subsidised, and train travel is not. No tax on aviation fuel for example.
The wider picture is that going abroad is still considered a proper holiday, anything closer to home, or a "staycation" less so; I hate that word. I think it was invented by the travel industry to further push their agenda and make not flying a sign of having missed out.
I have looked a train travel; it's not good if you want to take your bike. Some companies don't allow bikes, other do but require them to be boxed up. This is similar to flying so maybe not so big a deal. If you have to change services, it could become one.
Driving as an alternative is a consideration, but it's still not as efficient as public transport. And our roads can't cope. Between 1994 and 2021 the number of cars grew by 10,679,421. That's an increase of nearly 40%. Not to mention the cost of pasking, not what you pay into meters etc. The space needed to park is finite. And looking at my local area there isn't any left. Pavement parking blights the lives of too many. Being forced to walk on the road is unsafe, and may even be impractical if no dropped curbs are available.
Bike hire in popular locations is growing. The quality of the kit available seems on the whole to be good. So traveling without your bike could be an option.
Ferry travel is usually just ride on with little hassle. But it won't be suitable for many destinations, and is slow.
The furthest you can go in one hop is northern Spain. Which could get you to some Vuelta stages, and with a bit of riding to the Pyrenees.
The problem is time; it takes a day from Portsmouth to Santander. I think it's worth it to cut-out air travel though.
Hitching a lift on a cargo ship is another, even slower, option if you want to go further. This is becoming more widely available.
I'm not suggesting everyone only uses bikes, or never travels any other way. Just that more consideration needs to be given to the impact of destination and transport choices. And it's not just for holidays. Day to day decisions can have positive outcomes.
In short, we need to re-evaluate the way we travel.