In his lectures and movie, Al Gore gives an example of how we don't notice gradual changes. He explains that if you put a frog in a bowl of hot water, it will jump right out of it - but if you put a frog in a bowl of cold water and heat it gradually, the frog will not notice. He will enjoy the gradual heating until it reaches a point where the heat of the water kills the frog. I don't know if this has been proven in a real lab experiment, but it seem to be what the world is going through at present.

The changing world weather is at a point where it is beginning to be noticeable. Take this winter in Israel, for example. It started out with a very rainless December. Then as the year came to a close, there was a one-day winter onslaught with snow in the Galilee and Jerusalem and downpours of rain along the Coastal Plain. Then the rain and snow stopped, but the air remained cold. Freezing cold.

Forty years ago, in my youth in Tel Aviv, I remember completely different winters. The winter started at the end of November. Then, until the beginning of March, rain spells occurred for four or five days. Between the rain spells, the days were clear, sunny, and warm. During the clear days, we even went to the beach.

Slowly, this pattern has changed completely. Today the rainy season starts at the end of December and is over by the end of February. Rain spells are shorter - two or three days - and downpours are heavier. Cold spells, once very rare in Tel Aviv, have become a regular feature of our winters.

The water in the frog bowl is hot. Something has to be done before it begins to boil.