Having dismissed my year 9 class at my secondary school in Cumbria, with a free period ahead of me, I got out my phone to check if there were any messages from London. One voicemail – "There's nothing to worry about, but your wife, Jo, has been arrested..."

Arrested for climbing over a barrier onto the road on Lambeth Bridge. Carried off the bridge by four police officers (and she's not even that heavy). Four police officers who, had she not been threatening to obstruct Lambeth Bridge, could have been doing something more useful with their shift like tackling knife crime in our capital.

Or perhaps four police officers who weren't even supposed to be on duty that morning, but had been called in to do an extra shift because of the expected disruption.

She was taken into police custody for nearly 24 hours, during which time other members of the police force will have spent time logging the details of her arrest, taking her to a cell, checking on her, bringing her food and contacting the solicitor she'd asked for. She was released the following morning without being charged because the solicitor had been too busy with lots of other similar cases and hadn't got as far as her. She may still be charged at a later date, so more police resources may be taken up in deciding how to proceed and then writing a letter instructing her to return to the police station.

Meanwhile, back at the bridge, I'm told that while the police were arresting her, with four officers to one relatively lightweight Methodist minister, there weren't enough police leftover to prevent eighty other protesters from swarming onto the bridge and occupying it. It took the police hours to clear the bridge, with further arrests and even when they had, they had to keep the bridge closed to all traffic to stop the protesters from retaking it.

Whilst the bridge was blocked, through most of the day, many people will have been stopped or diverted on possibly urgent journeys, including perhaps some other emergency services. What's more, other route across London will have been congested as a result. It will have cost businesses and individuals extra money that day and yes, might have endangered lives.

So overall, a thoroughly irresponsible thing for my wife to have done and our legal system should ensure that she is given the maximum possible penalty for the crime that she has committed. Agree?

But try to cast your mind forward, if you can, to what things could be like just three decades from now. I'll be 74. My children will be 46 and 42, around the same age as I am now. The climate in London will apparently be more like the climate of Barcelona today. "Nice", I hear you say, but then what about the climate in Barcelona, or Nairobi, or Mumbai in thirty years time? So perhaps in thirty years time, our police will be overstretched on a daily basis, dealing with climate refugees who have come to our relatively temperate island from homelands that have become uninhabitable. Or perhaps there will be even more serious knife crime problems on our streets because of people fighting over the reduced food resources or lack of jobs for all the people who live here.

Our streets may not be blockaded but they will be made impassable by floodwater because of rising sea levels and the increased frequency and severity of what were once called freak weather events. Lives will be endangered on a regular basis when the number of people affected by such events far outnumber what our emergency services can cope with.

Now maybe you think I'm being a bit over dramatic, but if I'm not, if I have correctly interpreted what scientists are predicting for our future, it calls for something pretty dramatic to be done about it now.

Yes, my wife and I could both write letters to our politicians (we have done). But when our prime minister is someone who mocks climate protesters as "uncooperative crusties", and at the same time promises to loosen some of our environmental legislation once we leave the EU, in order to satisfy US trading terms, I'm not sure that just writing letters is dramatic enough.

Yes, my wife or I could put ourselves forward to be parliamentary candidates for the Green Party. But if we did that, how many of you would vote for us?

Or perhaps we should just focus on doing everything we can to reduce our own family's carbon footprint and encourage others to follow our good example (we are trying). But without radical legislation and working together as a whole nation, and indeed a whole world, I'm afraid that will simply be too little, too late.

Boris Johnson also claimed that Margaret Thatcher took climate change seriously long before Greta Thunberg. Well that may well be the case, I couldn't be certain. But I know one thing for certain – we've not been nearly serious enough in our efforts to prevent it. We're like my son who, having had an extended homework project to do for the last few weeks has, over the last couple of days finally started doing something about it. Except if he doesn't hand it in, or if what he hands in is a bit less than his best, the worst he'll get is a detention for a fraction of the time that my wife spent in detention on Monday.

What we are facing as a world is more serious than a detention for not doing your homework. More serious than a normally law abiding Methodist minister being banged up for a day. More serious than Lambeth Bridge being out of action for the day. More serious than the wasting of hundreds of hours of police time.

Believe it or not, I am an optimist and I believe that it is possible to get things done in time to stop the impending climate catastrophe. But only if we do something dramatic, right now.