Years or Centuries?

Via Wikimedia Commons

Via Wikimedia Commons

We’ve all heard enough predictions about the long-term consequences of global climate change to make us want to cover our ears and run screaming from the room. Most of the warnings (which are issued with depressing regularity) concern effects taking place over many decades, even centuries. In comparison to geological time, we are like mayflies – our human perception of time makes it difficult to extrapolate threats that extend beyond our own lifetimes or that of our children or grandchildren. The time lag laid out in many of the analyses of climate change in is one of the principal challenges in corralling the political will to mitigate humanity’s impact on the environment.

Last week the National Academy of Sciences issued a lengthy report on the changes which may visit us suddenly, in a matter of years. The study, sponsored in part by the National Oceanic and Atmospheric Administration and the U.S. intelligence community, warns of large and abrupt changes in the physical climate system brought on by suddenly and unexpected  tipping points. In addition to gradual, incremental changes in the environment, the report warns against abrupt ecological or socio-economic disruption as environmental conditions accelerate unpredictably. The report notes that we don’t yet know what the thresholds for such rapid changes are, and calls for a kind of early warning system composed of more vigilant monitoring of key species and environments, including the use of satellites, data collection, model testing and improvement, and model predictions that suggest future data needs. Alluding to early maps of the America’s which carried the warning, “Here be dragons”, the report details a number of possible rapidly-escalating threats, and lays out a map of its own showing how to avoid modern day dragons.

One of the studies co-authors, Richard Alley of Pennsylvania State University compared the prospect of abrupt climate change to avoiding the dangers of a drunk driver on the road. “You can’t see it coming, so you can’t prepare for it. The faster it is, the less you see it coming, the more it costs. If you see the drunk driver coming, you can get out of the way.”

The report’s good news, such as it is, is that some potential threats don’t appear to be quite as imminent as once thought, as long as you don’t think 100 years is imminent: the precipitous release of underwater or frozen methane (a potent climate-altering gas) or a shutdown in the Atlantic Ocean circulation patterns (which could plunge Europe into a mini ice age) don’t appear to be in the cards in this century.

You can read the whole report as an interactive PDF here.

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