Jeb Bush may look and sound like a clown, but we have to take him seriously. He is the frontrunner - so far - for the Republican nomination to contest the US presidential election. By the end of next year, he could become the most powerful man in the world.

So what has he to say about the brilliant speech in which Pope Francis warned about the threat posed by climate change to the human race?

He says that although he is a Catholic, he doesn't care what the Pope says. In other words, the world in general and the United States in particular can carry on with the over-consumption which has brought about the looming catastrophe.

It can still be averted, but very narrowly and only if the world adopts the (quite painful) measures necessary to prevent the global temperature rising by more than two degrees.

Can it be done in the face of the enormous and influential - and lavishly funded - lobby which denies that climate change is happening at all? Possible, if only barely possible.

Opinions have changed, even in the United States. Lately, 400,000 people marched in New York to demand action against global warming. That reminded me of earlier protests. A million people took to the streets of London in opposition to the invasion of Iraq. The figure in Dublin was 100,000 - a neat reflection of the two cities' relative populations.

But those who rule the planet - and how badly they rule it! - took no notice. They played 'Lanigan's Ball': out again, in again. The continuing conflict in the Middle East is now wider, more bitter and more destructive than it was when the last Bush president, George W, proclaimed "mission accomplished".

We have now reached a point where there can be no satisfactory solution. Probably the best we can hope for is a series of wars culminating in a redrawing of frontiers and further huge transfers of population.

These transfers have recently taken on a particularly appalling aspect. Thousands upon thousands of people are trying to flee the war zones. They pay traffickers large sums to afford them passage across the Mediterranean in unseaworthy vessels. At least 1,000 of them have drowned. Those who make it to Europe are held, often in deplorable conditions, and threatened with deportation.

Thankfully, some countries have shown that human feelings still exist. Several have sent naval vessels to rescue migrants and take them to the safety of (usually) Italy. In Ireland, we can be proud that one of these ships, LÉ Eithne, is Irish. Its crew have saved huge numbers of people.

However, most European countries still behave as if, for various alleged reasons, they cannot accommodate the migrants. One result has been the grotesque scenes in Calais.

There and elsewhere, the migrants are taking hair-raising risks. They think them justified because it is simply no longer possible to live in their home countries.

They also know that prospects throughout the Middle East are worsening and will continue to worsen even in the event of a settlement.

Few in the West know anything about the Kurds. But the Kurds are a formidable people, numbered in millions in Iraq, Syria, Turkey and Iran.

They have done most of the fighting in the war against Isil. They have created what amounts to an independent state and will fight again to preserve it.

Against this background of endless and expanding wars, what of Europe, that "zone of peace"?

The ancient East-West frontiers have grown fragile again. Nato and Russia are playing dangerous games. Even in prosperous and supposedly stable countries we can see the revival of far-right and far-left organisations. The EU has walked itself into a trap, unable to go forward but equally unable to go back. And then there's Greece.

It's fashionable to blame the Greeks, especially Alexis Tsipras and Yanis Varoufakis, for their own misfortunes. But it was earlier Greek governments that created the financial crisis. And it was the European Union that brought Greece into the EU - for strategic reasons, closing its eyes to the dreadful state of the country's finances.

Now Greece stands on the brink. Not just in terms of failing to reach agreement with its creditors. Not just in terms of whether or not to leave the Eurozone. At stake now is the survival of Greece as a democratic country.

Tsipras and Varoufakis are unfairly mocked. Do the grandees of the European Central Bank or the International Monetary Fund think they can find something better? The greatest - and a terrifying - danger is not a left-wing government but a fascist dictatorship.

Often in the past, great minds were set to pondering how to prevent wars and other disasters. Sometimes they succeeded, often they failed.

Where are the great minds of the 21st century? Certainly not in the White House or the Kremlin. Can we settle for second best - someone who understands how to wield power?

Angela Merkel has power. Does she know how to use it, or can she see no farther than German interests? Can she grasp the magnitude of Europe's economic troubles and their scary political implications and devise - or impose - a solution?

Nobody else can.

Irish Independent