An open letter to Greta Thunberg

My son asked me the other week: "who starts wars?"

The sheer anger in his question was palpable. At eight years old, he knows enough to hate and fear the idea of war. Why would anyone do such a thing? What kind of villain would condemn so many people to so much pain? I tried to tell him that people don't, usually, mean to start wars - it's something that happens when things go wrong, and the leaders lose control. They misjudge their enemies - or their friends - and do something that provokes a much stronger reaction than they wanted.

Like everything we tell children, that's only partly true. Of course lots of wars have been started on purpose, sometimes by people who were every bit as evil as the cartoon villains of young Tilly's imagination. But even they were reacting to pressures - trying to solve problems of their own, although these may not have had anything to do with the enemy they chose to fight.

It is our nature to see problems as like obstacles - things to be overcome one at a time, each one letting us make a little more progress to reach the next problem. We seldom give much thought to the issues behind us, that our ancestors overcame to get us this far - they don't seem relevant any more. Nor, when a problem seems very pressing, do we think that much about the legacy our "solution" will leave to the next generation. It's not easy to foresee what the next generation will see as their most critical problem, so there's not much we can do to help them with it - but if we can clear this one out of the way first, they'll be that much better placed to handle - whatever they decide to.

Thus from 1945 to 1991, the first priority for every decent European - politician or not - was to prevent another major European war. Some of those politicians did great things, others - less so, but one thing they all had in common was a cold determination that World War Three should not break out on their watch. Everything they did, they did with one eye on keeping the peace. It was to that end that they made "economic growth" the yardstick of progress: if you can create "more" (of everything), that means less fighting about how to share it.

Now there's another danger: climate change. Which, if we don't figure out what to do about it, threatens to bring about WW3 anyway, despite all our efforts to avoid it through other routes.

Greta Thunberg and her followers are right to be scared. But whether they are right to be angry, that's another question; anger may not produce the reaction they are looking for. Because although climate change is a huge threat to us all, it's not the only such threat. And in demanding that leaders focus solely on this - Ms Thunberg is every bit as guilty of tunnel vision as those same leaders she is hectoring.

What evades everyone so far - and Thunberg doesn't pretend to have an answer to this - is how to fix it. If we just halt all new emission-generating activity now (or, say, phase them out over the next ten years), that means crippling developing economies - leading directly to World War Three. If the elites try to impose restraint from the top down - we will get revolutions all over, leading to WW3. If we make some countries take the lead (on the grounds that they're richer and better placed to do so), then the peoples of those countries will protest because (as they see it) the rest of the world isn't sharing their sacrifice - and you get leaders elected like Trump, and Bolsonaro, who appeal to voters by promising to protect them from this injustice. This may allow us to stave off WW3 for a few more years, but only at the cost of increasing emissions.

None of these options looks particularly good.

Dear Ms Thunberg: I am sorry to break this to you, but that "67% chance of staying below a 1.5 degrees global temperature rise" is not going to happen. Nor is the 50% version. Those are the real fairy tales, concocted by scientists who have never stopped for a moment to think about politics. If you have a key to untie this knot, then please do share it - but don't imagine you can cut it with a sword, because that we really would not survive.

What you can do, and I think you may have already started this, is to help reconcile the public in the rich world to that poorer future that they will have to face. By speaking so bluntly to their leaders, you have also spoken to their voters. For that I thank you, although I fear what may come of it.

Leaders of the generation of Eisenhower and Adenauer did not foresee climate change - their goal was to overcome the problems of their time, while building as strong a system, with as many tools, as they could think of, to help your generation to overcome the challenges of its time, whatever they may prove to be.

In the same way, you don't know what will be the biggest problems of the 2070s; and if the policies you promote today tie the hands of future generations to deal with those, then it will be your turn to be unforgiven.

To return to Tilly's question, who starts wars? All kinds of people. Some wars are started by rich, strong, evil men who want to get richer and stronger. But others may be started by good, honest, innocent schoolchildren who want nothing more than "a future". There are many roads to hell.