Avoiding climate catastrophe: Never too small to make a difference

"You say you love your children above everything else, and yet you are stealing their future in front of their very eyes."

A wake-up call to world leaders at the climate change conference in Poland last week.  15-year old Greta Thunberg tells them that they are not mature enough to be brave and do the only sensible thing - pull the emergency brake.

Greta is absolutely right, the leaders of almost all the world's countries - if not in Trump-style denial - are simply shying away from taking the necessary steps to cut back greenhouse gas emissions.  They are, understandably, afraid of the reaction of their countries' people when they are told that they need to make drastic lifestyle changes to avoid catastrophe.

There are, however, hopeful signs that some leaders are facing up to the challenge.  Last week, the Mayor of London, Sadiq Khan, unveiled a "1.5C Compatible Climate Action Plan" in response to a call from the London Assembly.  The Assembly had passed a motion tabled by Green Party member Caroline Russell calling on the Mayor to declare a climate emergency and produce a plan to tackle it.

The Mayor duly complied, at a speed that suggests that he was already on the case.  The very specificity of the plan's title suggests that it is a serious attempt to map out what needs to be done, which is not just to reduce carbon emissions, but to cut them down to zero and do so quickly enough - he has set the deadline as 2050.  Between now and then, there would be "carbon budgets", shrinking over time.  As completely preventing carbon emissions is simply impossible, residual emissions would continue (10 per cent), but be offset through negative emissions technologies such as carbon capture and storage or tree planting.

How would it be done?  By a switch from fossil fuels to carbon-free electricity, requiring a major upgrade of the electric grid.  Cars, trucks, buses would either be electric (battery or fuel cells) or hydrogen-powered.  More active travel - walking and cycling.  Compulsory insulation of homes to higher standards.  The gas distribution network to be switched to hydrogen or gas heating to be completely replaced by electric heating or heat pumps.  And more measures besides.  Working out exactly what mix of these options is the right one is one of the shorter-term priorities.

It's not something that the Mayor could achieve alone - government regulation and funding will be essential.  Ordinary people will have to make lifestyle changes - less driving, far fewer flights, changes to their homes.

But what is the point of a single city - even one the size of London - going zero carbon?  The world has a single atmosphere, the air above London is a tiny portion of the whole. We consume goods that are produced by carbon-emitting technologies in other countires.  The whole world has to go zero carbon to stay below 1.5C.

Of course, but every country, every city, every person has to do their bit, has to act -  and the sooner they start, the sooner progress will be made and others will see the example being set.  So the Mayor is setting out to ensure that London "does its bit".

More words of wisdom from Greta:  "We can't save the world by playing by the rules, because the rules have to be changed.  Everything needs to change.  And it has to start today."

With new year's resolutions a few days away, it's the perfect time to start taking action.  Turn the heating down a degree, drive less, consume less, waste less - get started with saving our grandchildren's world.