Key aspects of the climate are changing faster than expected and if we stay on our current emissions path, we face catastrophe
In 2009, the scientific literature caught up with what top climate scientists have been saying privately for a few years now:
- Many of the predicted impacts of human-caused climate change are occurring much faster than anybody expected — particularly ice melt, everywhere you look on the planet.
- If we stay anywhere near our current emissions path, we are facing incalculable catastrophes by century’s end, including rapid sea level rise, massive wildfires, widespread Dust-Bowlification, large oceanic dead zones, and 9°F warming — much of which could be all but irreversible for centuries. And that’s not the worst-case scenario!
- The consequences for human health and well being would be extreme.
That’s no surprise to anybody who has talked to leading climate scientists in recent years, read my book Hell and High Water (or a number of other books), or followed this blog. Still, it is a scientific reality that I don’t think more than 2 people in 100 fully grasp, so I’m going to review here the past year in climate science. I’ll focus primarily on the peer-reviewed literature, but also look at some major summary reports.
Let’s start with the basics. Heat-trapping greenhouse gases are at unprecedented levels, and the paleoclimate record suggests that even slightly higher levels are untenable:
- World carbon dioxide levels jump 2.3 ppm in 2008 — highest in probably 20 million years
- Science: CO2 levels haven’t been this high for 15 million years, when it was 5° to 10°F warmer and seas were 75 to 120 feet higher “” “We have shown that this dramatic rise in sea level is associated with an increase in CO2 levels of about 100 ppm.”
In two key papers, we learned that the planet is warming from those GHGs just where climate science said it would “” the oceans, which is where more than 90% of the warming was projected to end up (see “Skeptical Science explains how we know global warming is happening: It’s the oceans, stupid!“). The key findings in the second study are summed up in this figure:
Figure : Time series of global mean heat storage (0-2000 m), measured in 108 Jm-2.