Reply #3: 100 years? I doubt it. [View All]

[Dogmudgeon]

With all due respect to the Max Planck Institute, it will be a lot quicker than that.

Most climatologists now agree that global climate change events occur over time periods of 5-50 years; even Wallace Broecker, who discovered the link between oceanic thermohaline circulation and the ice ages, thinks that such changes take place on a scale of about 65 years.

What we're seeing now is global warming happening on its own. The Arctic has become a giant engine for increasing biogneic greenhouse gasses (CO2, Methane (CH4), Ammonia (NH4), and water vapor) as the now-unusual summer thaw brings billions of kilograms of microbes to life. This process has overtaken anthropogenic (human-caused) global warming, and the curves of the data for global temperature, CO2, and weather changes, have begun to accelerate. Instead of taking 100 years for these changes to happen, they could be here in less than a decade.

What happens after that depends on the mechanism by which a new balance is achieved. In a Heinrich Event, the trend is a cool-down; in a Dangaard-Oeschger Event, the trend is to maintain the warm-up. These are not gentle climatic returns to normal but episodes of violent change. Global temperature swings of 15C and CO2 level changes of 50% (upwards of 200 ppm) are probable, within as little as ten years.

As we heat up, not only does the Arctic become more active, but more water vapor migrates toward the poles. Although the increase in equatorial hurricanes have been a major "inconvenience", the development of a zone of highly active northern storms would be disastrous, bringing blizzards and flooding rains depending on the season.

Right now, we're on the upswing of the curve, and based on other such events seen in data proxies -- ice cores and tree rings -- we're more than halfway to the top of the "spike". A rapid re-normalization of temperature and atmospheric gasses would be a tremendous challenge to civilization, to say the least.

All of this has been triggered by human "forcing" of the climate by approximately 2C over a period of 180 years. Even two years ago, I held out hope that we could stop the process by stopping our addition to global greenhouse gas. Today, I think we're past the point of no return. However, as our response to Hurricane Katrina illustrated, the real killer isn't the weather so much as the way we handle it. An era of violent weather change need not be a major killer if we take appropriate steps to reduce our exposure. That's the real challenge. Based on recent experience, I'm pessimistic, but based on the overall history of Humanity, I'm optimistic. All it will take is the political and social will -- and that may be history-making in itself.

--p!