WHAT follows is all about endings. Mine, yours, humankind's. That will do for a start won't it? Louise Welsh and I are sitting over tea and Tunnock's Teacakes talking about mortality, viral pandemics, gender, sexual violence repackaged as entertainment, complexity and the dangerous desire for political simplicity. It is the day of the General Election and neither of us is optimistic about what will result tomorrow. Our conversation is, as a result, somewhat gloomy.

Then again, that's partly Welsh's fault. The reason we're here is the publication of her new book No Dominion, the last in her Plague Times trilogy, which takes us from an isolated community on the Orkney islands trying to hold onto civilisation and from there on a road trip through a post-apocalyptic Scotland to Glasgow itself. It's a thriller that thrills, but it's also a platform fora wry, spry platform for discussions of civilisation, urbanism and connectedness, human and environmental. It is – if you can use the word in the context of a series during which the majority of the population has been wiped out – fun.

As is Welsh, of course. We are in the book-filled home she shares with her partner and fellow writer Zoe Strachan. She has given over five years to these three books so she's thrilled she has reached the end. And now she's taking the chance to say hello to all those people in her life she's neglected. "You turn up at their house and they go: 'Who are you?'" she laughs.

Welsh must have been asked that question more than a few times then. Formerly a second-hand book dealer, she came to prominence with her first novel The Cutting Room, set in the book-dealing world and involving old-school pornography and gay sex (that's booksellers for you), published in 2002. Another four novels followed before she started the Plague Times trilogy with A Lovely Way To Burn in 2014.

The trilogy posits a world beset by a virus, the sweats that kills off the vast majority of the population. In short, the three books are very much part of the current literary trend for "end of the world" novels. "I'm just total zeitgeist," she jokes. "You imagine that you have independent thinking but, actually, you're subject to all these forces that you don't notice. And so are other people.

"But I've been thinking about plague for quite a long time."

Indeed. She has talked to me before about her fascination with the Black Death which decimated the medieval population of Europe. Her Plague Times trilogy is her attempt to reimagine it in modern times.

"We live in a hyper-modern time. We live in this quite magnificent civilisation and I think that always invites those visions of ruins. I guess we like to confront fears we have. And we are aware of other civilisations that have collapsed. And I'm not saying we're in one now but every civilisation worries if it will survive or not."

All of this death and destruction. It seems incongruous from someone so polite and well-mannered. Louise, are you really a Goth at heart?

"I think my message is: 'Ah, we're all going to die,'" she says, offering me another teacake.

Not that we really like to think about that, of course. She cites the famous Damien Hirst sculpture of the shark in the tank. "What does he call it? 'The Physical Impossibility Of Death In The Mind Of Someone Living?' I think that's a brilliant title because I think that's true."

Have you ever thought that there are books on those shelves you will never read, I ask her? "Worse than that. When I was little I used to go to the library and think: 'What will I do when I finish all these books?' It was an anxiety. And then there was a moment when I realised I will never read every book in the library. That's a hard one, isn't it? But maybe there will be an app and we can download it all. We'll be buffering."

There speaks an optimist, I tell her. "It goes with writing about death. You get it out of your system."

Well, so she says. And then Welsh tells me about her current side project called Death Of The Author: "I'm trying to work on 100 deaths because there are some brilliant author deaths. Poor old Roland Barthes was hit by a laundry van.

"There was someone hit by a dune buggy, which is a miserable comedy death." (That would be Frank O'Hara perhaps.) Tennessee Williams, meanwhile, choked to death on the cap of a bottle of eye drops.

What will we leave behind us? Authors leave books. The rest of us. Hundreds of years from now you can find us in the ruins we leave, I suppose. Welsh tells me she loves a good ruin.

"Zoe and I just had our holidays in the Western Isles. Zoe studied archaeology at uni and I have always had an interest in history so I do spend a lot of time looking at things that are ruined." she says. "We live in a hyper-modern time and I think that always invites those visions of ruins as well. Online if people want to find pictures of decaying malls there's tonnes.

"I guess we like to confront our fears. Every civilisation worries if it will survive or not. We've had civilisations on the edge of Scotland that have collapsed. Think of the Romans.

"The Romans knew how to make pots and glass and lavatories, things that the indigenous population didn't know how to do and in the National Museum of Scotland you find these very touching things like bowls where people have tried to make it the same and they know that writing's important so they try to copy it but they're just copying a pattern, a magical idea.

"I thought about that a lot. What would we do about technology? I can make a cake and I can make a mess, but if my car breaks down I take it to the garage. If the internet breaks down I phone somebody and hope it gets fixed. So we have all this fabulous stuff but if it went what point would we go back to?"

She pauses, thinks about this, and then adds: "This is a very central belt discussion. If you're on an island and it's 30 miles to the shops you learn how to do things."

Perhaps it's no surprise, then, that Welsh locates her functioning society in the post-plague world of No Dominion on the Orkney Islands. Does she herself ever desire retreat, isolation? "I think most of us want several things at once. You want to be connected and you want to be alone. I'm sort of alright with long periods on my own but I'm very sociable as well so I need to go out.

"Zoe is away for a month and that's unusual – I'll miss her but I'll be OK. And we have a little static caravan that we go down to on the South Ayrshire coast and sometimes I'll go down there on my own. You can go down there and write. No internet, no interruptions.

"I do have these fantasies about the big skies and I've always liked the Scottish landscape, especially when you get up above Ullapool. It's magical. But I don't think I've got what it takes [to live there]. I think I could do it for three months. I think you need to be more resourceful or resilient than I am."

If the end of the world comes, then, Louise, you're not ready for it? "I think I'd probably be hiding under the covers."

Well, at least that's a harmless way to meet the apocalypse. "You hope you wouldn't be actively bad," she agrees.

"I was reading about a crisis on a plane and all the passengers had to get off and somebody sees this man picking up a little girl and the man watching thinks: 'Good, he's saving that little girl.' But he actually picks her up and puts her behind him. How did that guy feel? Did he come to and think: 'Oh my God, what did I do?'"

Indeed. This is the question that these end-of-the-world narratives confront us with. What are we capable of?

At one point in No Dominion, our heroine Stevie is the victim of an attempted rape. Welsh says that this is probably what would happen. At the same time, she ensures that Stevie has agency in the sequence.

Even so, it's hard to read. We live in a culture where violence against women is a building block of our culture. We read books, watch television and films that open with the discovery of a murdered woman. In a world in which one in three women globally will experience violence at the hands of a male partner are we actually reinforcing that abuse structurally by making it the thing we read and watch?

"I think so," says Welsh. "I've not written the serial killer novel where three women get murdered and each time it gets worse. I've not written something that's predicated on the naked, tortured female body. But you see it all the time. It's used to turn a page. It's used for Sunday evening family viewing.

"I don't want to write that and I don't want to read it – and I don't think I'm unusual in that. I think a lot of people are sick of that. Maybe it will never go away because it's something that's been throughout literature since the beginning of the novel. Sex and violence. Eros and Thanatos."

We talk about the election and what we expect. It's frightening, I suggest, when the world has never been more complex and interconnected that people seek simplicity when it comes to choosing their political leaders. It's a desire for easy answers.

"I don't know if any of that is new," Welsh suggests. "I can't explain Trump. I honestly can't. I can't explain where that went. I cried. I honestly cried.

"It just seems that education is very important because if you're not educated then people can tell you mad stuff."

There are reasons for optimism though, she adds. "I do various work at times with young people and I do think they are magnificent. I think they are better than our generation was. People talk young people down in the way that they always have done but actually the young people I meet are more optimistic than we were. I think they are very creative and they are aware of gender and, I hope, aware of rights in a way that perhaps we weren't."

Ah, yes, gender. Here's the question Louise. Are men from Mars after all?

"I hope not. There is still institutional sexism and there is still sexism on the street and clearly a lot of sexism against young women – all of that is horrible but I think there are some very nice young men.

"My least favourite reaction to men by women is when they treat men like children. Men aren't children. They're grown-up people. Let's try and deal with each other in terms of respect and equality. We need men to stand shoulder to shoulder with us."

After the end of the world the idea of the nuclear family makes no sense. Maybe, you could argue, it doesn't make any sense now. "I did love the adoption campaign posters that Glasgow Life put up a few years ago. They showed families that were mixed race and same sex, saying 'We need people to adopt and we're happy to recognise that there are many ways of being a family'. I thought that was great.

"Clearly people still face prejudice but hopefully that is lessening and, let's face it, during the Second World War nobody had a problem with single-parent families. Nobody had a problem with women working."

Now, though, Welsh fears there is pressure to push women back into the home. "I think we should be alert for that." Equally, she says, the culture of overworking is not helpful to family life either.

Has she herself ever wanted to be a mother? "No, I haven't and I think that's totally legitimate as well. I think lots of people don't. It doesn't mean you don't like children. I guess for a lot of my life it was very financially precarious and you can't send the person back. You can send them to granny and grandad, but that feels a bit unfair."

Is there any light to be had, Louise, I say, as I finish my tea? Is there room for hope? "I think there's hope everywhere. And we're going to vote today."

And is there still space for love? "That's it. Love is everything isn't it? Yeah, that's what remains.

"I don't know if you saw the concert the other night," she says referring to Ariana Grande's Manchester gig. "I didn't know who this person was. I didn't know she existed and it's not my thing. But I thought: 'Isn't that brilliant? This young, tiny woman singing about love and coming together.' I found it very moving."

The world goes on. There is despair and destruction and death. But there's hope and love too. And Tunnock's Teacakes. That's something, isn't it?

No Dominion by Louise Welsh is published in hardback by John Murray on Thursday, priced £16.99. The author will be talking about the book at Waterstones in Sauchiehall Street, Glasgow on Wednesday at 7pm. Phone 0141 332 9105 to reserve a seat.