A gathering of 192 countries at which all have to agree in detail may not be the most sensible way to thrash out a new agreement on something as complex and important as climate change.

As I wrote a fortnight ago, ‘14 days when everything will be agreed and revealed’ was never going to happen.

China and the USA, now the two main superpowers, were always going to get in the way of anything like that.

But I do believe that what has been agreed can be a new start, or perhaps just another step on the tortuous but desperately necessary path to pulling back the rise in global temperatures.

Of course, some people are laughing when they look out at the snow and ice in the past week. It’s ironic that this year’s winter solstice, yesterday, was our wintriest for years.

But November was our warmest and wettest on record. 2009 will still be our planet’s fifth hottest year in modern times.

It takes me back many years to when I taught A-level geography in Nelson and Colne. A classic exam question was to ask whether in our climatic belt we don’t really have ‘climate’ – just ever-changing ‘weather’.

It’s true of course, though our climate is made up of all the variable weather over many years.

In regions near the equator such as the Amazon or the Congo – or even hot deserts like the Sahara – every day is much like the next. Not for us!

Here it all depends on where the wind is coming from. We all know that ‘when the cold north wind bloweth’, it brings its own special weather.

And as we saw last week, air that comes from eastern Europe in winter is usually cold and often brings snow.

South-westerlies that blow off the Atlantic have been warmed and moistened by the Gulf Stream and often bring the kind of horrid grey soggy conditions we saw in November.

When different kinds of air meet, we get weather fronts and lots of rain.

One result of global warming is more extreme weather.

The warmest November, massive floods in the Lake District, and now even the chance of a White Christmas!

It all suggests we still need for a lot more action than they agreed at Copenhagen.