Two Plus Two Newer Archives - Humans have made the skies more moist

Humans have made the skies more moist

Human activity is behind the rising levels of water vapour in the lower atmosphere over the past few decades, climatologists have concluded. The rises in humidity could affect patterns of extreme storms, they warn.

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The researchers simulated atmospheric moisture levels using a computer model that evaluates the effects of various natural factors, such as changes in solar activity and greenhouse-gas emissions. They then compared the trends seen in the different simulations with the real-world results.

The simulations that incorporated the effects of human activities most accurately reproduced the real-world trend, Gillett and his colleagues report in this week's Nature 1. The best-fit simulation was so good that it even mimicked variations in the real data, such as the spike seen in 1997–98, when a strong El Niño event warmed Caribbean waters and led to increased humidity.

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The research shows that climate models are performing well, Stott adds. But predicting the incidence of highly localized, extreme events such as tropical storms will require new models with finer detail, he adds. "Basic climate models don't have the high resolution needed."

Here's how I read this, the models are working well because we can fit the output of the models with known historical data but they're not that useful in making predictions.

I wouldn't make the conclusion that the models are working well because their outputs fit with known historical data. I would say that the output of the models have to fit with known historical data or the models are useless. When I was an engineering student a wise cracking math professor stated that there were three rules in engineering:

1. You can't push a rope.

2. F = MA

3. Know the answer before you start.

To me the conclusions about humidity and the self patting on the back for the output of the models is a prime example of number 3.