A new paper by climate scientists, including ex-NASA scientist James Hansen, warns that our climate could dramatically change within decades, not centuries.
Virtually all climate scientists agree with Dr. Hansen and his co-authors that society is not moving fast enough to reduce emissions of greenhouse gases, posing grave risks. The basic claim of the paper is that by burning fossil fuels at a prodigious pace and pouring heat-trapping gases into the atmosphere, humanity is about to provoke an abrupt climate shift.
Non-linear systems, man. Gradually, then all at once.
Update: Slate's Eric Holthaus has more on the paper and its potential implications.
In addition to the risk of "several meters" of sea level rise this century, which Hansen calls the most important finding, the final version of Hansen's paper gives new emphasis to the possibility that the ocean's heat circulation system may be in the process of shutting down. The circulation shutdown would precede the rapid increase in global sea levels. If the shutdown happens, simultaneous cooling of the waters near Greenland and Antarctica and warming in the tropics and midlatitudes could spawn frequent strong storms on the order of Hurricane Sandy or worse.
If that sounds a lot like the plot of The Day After Tomorrow to you, you're not alone.
Hansen also released a 15-minute video about the paper:
Where have I seen this before, a massive long-lasting Arctic storm that looks a lot like a hurricane? Oh right, The Day After Tomorrow.
The storm had an unusually low central pressure area. Paul A. Newman, chief scientist for Atmospheric Sciences at NASA's Goddard Space Flight Center in Greenbelt, Md., estimates that there have only been about eight storms of similar strength during the month of August in the last 34 years of satellite records. "It's an uncommon event, especially because it's occurring in the summer. Polar lows are more usual in the winter," Newman said.
Arctic storms such as this one can have a large impact on the sea ice, causing it to melt rapidly through many mechanisms, such as tearing off large swaths of ice and pushing them to warmer sites, churning the ice and making it slushier, or lifting warmer waters from the depths of the Arctic Ocean.
I love The Day After Tomorrow. I know it's a cheeseball disaster movie (which is pretty much why I love it) but it's also looking more than a little prescient. Well, as prescient as a cheeseball disaster movie can be anyway. In the Washington Post the other day, prominent climatologist James Hansen wrote that human-driven climate change is responsible for an increase in extreme weather.
My projections about increasing global temperature have been proved true. But I failed to fully explore how quickly that average rise would drive an increase in extreme weather.
In a new analysis of the past six decades of global temperatures, which will be published Monday, my colleagues and I have revealed a stunning increase in the frequency of extremely hot summers, with deeply troubling ramifications for not only our future but also for our present.
This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened. Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.
In many ways, the phrase "global warming" is grossly misleading. "Oh," we think, "it's gonna be a couple degrees warmer in NYC in 20 years than it is now." But the Earth's climate is a chaotic non-linear system, which means that a sudden shift of a degree or two -- and when you're talking about something as big as the Earth, a degree over several decades is sudden -- pushes things out of balance here and there in unpredictable ways. So it's not just that it's getting hotter, it's that you've got droughts in places where you didn't have them before, severe floods in other places, unusually hot summers, and even places that are cooler than normal, all of which disrupts the animal and plant life that won't be able to acclimate to the new reality fast enough.
But pretty Arctic cyclone though, right?