Remember Harry Potter's new improved broom, the Nimbus 2000? The one with the curvy bits where an ordinary household broom is straight? Imagine that handle grafted onto a hockey stick.
What does that have to do with climate change? A recent analysis published in the journal Science examined reconstructions of climate data back 11,000 years. The resulting graph of temperature anomalies through time looks sort of like Harry Potter's broom merged with the hockey stick. Sort of.
What this means: although some past climates may have been warmer than the current one, the today's speed of change has no precedent. That is, our climate has warmed faster in the past 100 years than previous climates over a 4,000 year period.
This month, Davis voters will weigh in via an all-mail ballot on whether or not the city should tap into Sacramento River water in a project shared with the city of Woodland. The Davis Enterprise recently asked CCWAS PI Graham Fogg and co-PI Jay Lund to comment on technical aspects of the proposed project.
CCCWAS trainee and Ecology grad student Michael Levy also weighed in about Measure I via an op ed .
Update, 13 February 2013: The Sacramento Bee quoted Graham in its editorial supporting Measure I.
- Author: Michael Levy
As anyone familiar with California water and politics could probably guess, in thinking about climate change, water and society, we end up thinking about the Delta quite a bit. For those who don't know, the Delta is the confluence of the rivers that are formed high up in the Sierras, run down the Sacramento and San Joaquin Valleys (i.e., the Central Valley), and meet just east of the San Francisco Bay. It is the largest estuary on the west coast of North America and was historically a great wetland with a variety of habitats that supported incredible fish and wildlife (check out fellow CCWAS Trainee Alison Whipple's great work on the history of the delta in map form here). Now, it's mostly agricultural land, with a little modern development, and canals instead of wetlands and networks of rivers.
The academic learning without the experience of a place can feel hollow, so a few of us headed down to the Delta last weekend to get a little taste of the flavor of the delta. Here are some pictures of what we saw...
- Author: Alison Whipple
With the underlying premise that re-establishing physical processes to which native species are adapted improves ecosystem functions and resilience, the seven invited speakers and panel discussion explored connections between hydrologic regimes, landscapes, and ecosystems and outlined ways more functional hydrologic regimes might be achieved. The workshop was introduced by Peter Goodwin, convener and Lead Scientist for the Delta Science Program. Geoffrey Petts, Vice-Chancellor of the University of Westminster, offered the plenary lecture and established a number of important concepts that were carried throughout the day’s discussions. Petts introduced the term “smart hydrology,” which focuses on minimizing flow alteration through flexibility in operations, management tailored to individual systems, and diverse flow regimes in terms of magnitude, timing, duration, and frequency. He explained how riverine system resilience, or ability to withstand perturbations, relates to factors such as spatial variability of flows, morphological or landscape complexity (including hot spots of ecological importance), and interannual variability in flows.
The audience then heard from Chris Enright, with the Delta Science Program, who explored aspects of a hydrograph in relation to physical, chemical, and biological processes and emphasized the importance of geomorphic context for natural hydrographs. Robin Grossinger, director of the San Francisco Estuary Institute’s Historical Ecology Program, drew from examples in the historical Delta (work I have been heavily involved in) and Santa Clara River to speak about the reciprocal interaction between hydrologic regime and landscape. Bruce Herbold, with the U.S. Environmental Protection Agency, discussed his examples using conceptual models illustrating the connections between natural physical drivers, elements of hydrologic regime alteration, associated stressors, and biological responses. Sarah Yarnell, with the Center for Watershed Sciences at UC Davis, spoke of the ecological importance of predictability in a hydrologic regime, such as the spring snowmelt recession rate, suggesting management considerations such as the timing of flow releases from dams. Cliff Dahm, former Lead Scientist of the Delta Science Program, provided a number of examples from around the world of managing for functional flow regimes, including minimum flow criteria for different seasons, certain percentages of available flows, and focus on particular aspects of the hydrologic regime thought to be of ecological significance (e.g., baseflows, first storm event of the season). Finally, bringing the discussion to science as it informs policy-making, Les Grober, with the State Water Resources Control Board, spoke about flow regulation changes recommended for the San Joaquin River.
Over the course of the talks and panel discussion, several themes emerged. These include managing toward variability, considering different components of a hydrologic regime as they relate to specific functions, looking to the value of high flow and low flow periods, acknowledging important interactions with the landscape (e.g., duration of floodplain inundation), and the importance of habitat diversity to support resilience. Climate change wove throughout, arising as a concern particularly in changing water availability in space and time and in the potential for large disturbance events, but also as potentially forcing much needed variability and causing a shift toward softer approaches that allow for adaptation.
As Goodwin explained, this workshop was exactly the type of scientific synthesis conversation needed for science to better inform policy. We should look forward to similar events coming from the Delta Science Program in the future. A video of the day along with the lecture slides should be available soon on CABA’s website.