Climate extremes and the Critical Zone

As people who had planned to live ordinary lives face early-onset climate change, we are discovering that it not the change in average temperature or precipitation, but the extremes that will change our future. In the US alone, we are already seeing parched landscapes throughout western North America, while deluges and storm surges destroy crops and infrastructure throughout the Midwest and the East coast. Droughts and heat shocks, or deluge and super-storms, are following atmospheric and ocean warming, because, as Gregory Johnson’s haiku version of the IPCC 2014 report states,

“Wet will get wetter/and dry drier, since warm air/ carries more water.”(

By now, we have little ability to correct the atmospheric and ocean conditions that have triggered weird, often violent weather around the globe (although we should rapidly change our energy sources to avoid making it worse).   Instead, we must turn our attention to the skin of the Earth, where life meets rock, and cycling water is received, stored, transformed, and released back to the atmosphere, or as runoff to surface waters. We call this Earth skin the Critical Zone. It extends from the top of the vegetation to weathered bedrock deep beneath our feet. The lower part of the Critical Zone is largely unobserved, but of crucial importance. It begins where fractures in bedrock give plants and microbes access to stored water, and provide flow paths feeding the springs, rivers, wetlands, lakes, and estuaries on which most terrestrial life depends. Careful stewardship of Critical Zones—the vegetation and the soil and bedrock beneathe–could help us buffer, and even ameliorate, temperature and precipitation extremes at local, regional, and, perhaps some day, global scales. But to steward something, anything, it must be understood. That is the purpose of the network of Critical Zone Observatories, funded by the US National Science Foundation.

See the Research section of this web site for reports from studies at the Eel River Critical Zone that 1) explain how uplift and drainage affect the ability of bedrock underlying Coast Range hillslopes to store and slowly release the water that keeps springs, streams and rivers flowing during drought (Rempe and Dietrich 2014); and 2) predict that temperatures in our wooded landscapes would be elevated 1-2oC if we replaced all the broad-leafed trees with conifers (Link et al. in preparation).