My impression is that all climatologists agree that average, annual, atmospheric temperatures worldwide have been trending higher for thirty years.

The controversy is about its significance and

1. how much results from human activity, rather than from perfectly normal, natural cycles

2. whether it presents a long-term danger to national economies and even civilized life (in coastal cities that could be inundated, for example, and if deserts develop in vital food-producing areas)

3. what if anything can be done about it (if it truly is a threat)

4. how much time is left to do those things, should they need doing

5. whether it's worth doing those things at all, since the problem may be irreversible and it's mostly our grandchildren who'll have to deal with it, not us.

The issue, then, is not as simple as certain politicians want you to think - and it's smug politicians, not scientists, who insist that nothing at all is happening.

The earth is steadily getting warmer. Period. For now.

Does it matter? The course of least regret would be to assume that it does. But that's also the course of maximum immediate expense and discomfort, especially since almost every nation on earth wants to get more thoroughly industrialized so it can improve its standard of living - by pumping more global-warming pollutants into the air. But if industry isn't responsible, say industrialists, why penalize us and wreck the economy? And the most short-sighted industrialists have every motive to deny, by all means necessary, that anything is happening at all, even though it is. They don't want to "believe in" it.

So if the warming is largely man-made, it will worsen as long as we do nothing about it. And if it's still reversible, it soon may not be.

Climatologists and atmospheric scientists, of course, do not set policy anywhere in the world. So expect the worst.

But maybe everything will just work out fine in this best of all possible worlds!