Monday, April 10, 2006

La Niña, El Niño and global warming

Here in Sacramento we've been experiencing a very wet winter and spring. Rivers are at dangerous levels and just to the south the San Joaquin river system is at its second highest level ever.

Sacramento is ranked as having the lowest flood protection of any major U.S. city, including New Orleans. Two major rivers meet near the downtown area and many streams run into the city from the nearby foothills. Like New Orleans much of the metropolitan area depends on levee protection.

Prolonged wet and cold weather has been blamed on the La Niña weather pattern. Both El Niño and La Niña are cyclical phenomenon that occur in the east Pacific Ocean.

La Niña involves cooler than normal waters in the tropical Pacific. However, both weather oscillations are related, and many scientists believe they are also linked with global warming.

There are two major theories that connect global warming with these patterns. One claims that the higher temperatures cause increased seawater evaporation, charging the atmosphere with greater moisture. This, in turn, results in wetter storms.

The other theory states that the weather patterns act as a type of 'pressure valve' ejecting heat from the Pacific region. As global warming means more heat, the frequency of the oscillations increases and we have more El Niños and La Niñas .

Unfortunately many countries still have not warmed up to the Kyoto Protocol to control greenhouse gases that cause global warming. Even after the Pentagon listed the weather trend, and not terrorism, as the greatest threat facing America, the world's largest polluter still refuses to go along.

Remember global warming as caused by industrial pollution is not normal or natural. For some 10,000 years, we have enjoyed relatively predictable weather patterns that have become part of our traditions. For the first time in history, humans have been able to directly effect climate to some degree.

Just a small degree, but that is enough to have major impact on the way we live.

Greenhouse gases caused primarily by fossil fuel burning trap heat in the atmosphere warming the world's oceans. The increased heat fuels tropical storms and may effect oscillations like El Niño-La Niña. It can also increase melting of polar ice caps and glaciers and possibly change the course of ocean currents. The former can increase sea levels causing coastal flooding while the latter changes normal weather patterns.

Put simply, not dealing with global warming is like playing global celebrity poker. You don't know what hand you will be dealt. However, practically any change will likely have a negative effect because it upsets the current balance and setup.

Just something to think about as another big storm heads this way.

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