By Ken Ott, Research Associate, SustainLane
Sustainability research, Government Division
I rode Amtrak to the 4th Annual California Climate Change Conference in the state capitol on Tuesday, September 11th. By doing so, I enjoyed nice views of the San Francisco Bay and farmland in between the two cities. I also read more about the event before arriving.
This was my first California Climate Change Conference and it was a nice refresher course, in addition to a source for reams of new information which I still haven't finished reading. The California Energy Commission and California Resources Agency put on this conference and are the state's primary policy and planning agencies for energy and natural resources, respectively.
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I'd like to share what I learned at the morning session on water in this post. Instead of merely reading about climate change issues, in contrast, it was great to speak with panelists and other attendees in person. Although magazines or online articles can be important resources, there is no substitute for conversation and one-to-one dialogue.
The morning panels focused on probable climate change impacts such as: water (flood risk and mitigation) and air quality (soot effects on snow melt rates). I was able to listen to and speak with a great number of people who are experts in their fields.
Some of them included Michael Dettinger, Scripps Institution of Oceanography who works on observing increased flood vulnerability, and Sam Earson, Desert Research Institute, who studies groundwater supply issues, using gas tracers. All of the panelists do good work and contribute to a greater understanding of climate change issues as they affect the Western US as well as the global community. All of them are supported by state agencies or deparments and in turn report back to these bodies.
Below are synopses of most speakers' presentations with their respective conclusions as well as mine. If you are already knowledgeable in general you can skip my commentary and just read the indented text boxes. These contain much of my verbatim notes. You can also attend the sessions virtually. Sessions are archived in PDF and streaming audio/video for your convenience: Conference Home.
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CLIMATE CHANGE AND WATER RESOURCES IN CALIFORNIA
Session Chair: Jamie Anderson (California Department of Water Resources)
The early morning sessions were well attended and very clear in assigning further certainty to likely extreme weather events in the future. The main culprit in all cases was a human induced warmer biosphere.
“California Flood Risks in a Changing Climate”
Michael Dettinger of the Scripps Institution of Oceanography presented a model in which a global climate +3 degrees Celsius warmer leads to “flood friendly” conditions in California and along the entire West Coast. These conditions include increased winter snow melting and a stronger phenomenon of “Atmospheric Rivers.”
West coast more likely to get more rain
More rain than snow
Double area of rain --> double flooding
Additional winter melting: much wetter soils in northwest, slightly drier soils in CA --> but doesn't reduce flood risk
"atmospheric rivers" -- the storms to worry about. warm pacific storms.
"pineapple express" -- source of big storms/floods
More flood risk: rain rather than snow; wet snows & soils; more large storms; need to have better flood management through increase observation of snow, weather patterns...
|Michael Dettinger gives his presentation. Click for larger photo.|
As an example of possible consequences, doubling of rain would double the number or magnitude of floods. Soils are a big part of the temperature and precipitation equation, and higher temps would create much wetter soils in the Northwest, though slightly drier soils in California. This might sound good for California with respect to flood danger, but it doesn’t reduce flood risk. It's a wash. Really.
Overall, Dettinger concluded that we face “flood friendly antecedents”—meaning the stage is set for more extreme flooding events. In my mind, examples include the 2005 Napa floods, or possibly a Katrina-level event in the Sacramento Delta. See the slide below, or check Mike's full presentation for details (see PDF handout or streaming audio and video).
As for the “Atmospheric Rivers” mentioned above, these virtual rivers exist around the world and are uptakes of ocean water vapor via small air passages from tropical to non-tropical areas. You can see examples of these in the satellite image below.
|From CEC Climate Conference photos...|
The “river” from near Hawaii to North America is nicknamed the
“pineapple express” and the importance of these ARs, is that they are
the primary cause of big storms/floods. If you check Mike's Powerpoint (PDF here, 2.1MB) you can also view other ARs.
Conclusions about California's future climate:
• More rain rather than snow
• Wetter snows and soils
• More large storms from the Pacific Ocean
• Need to develop better flood management through 21st century monitoring
Lessons learned can be applied to the entire Pacific Northwest. If you want to know more about the "Atmospheric River" phenomenon, keep reading! Mike's colleague Fred Ralph also presented on them.
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According to Fred “Marty” Ralph, our problems now and going forward will include a climate change induced 25% reduction in snowpack by 2050. At the same time, we will see more flood risks, need more water storage capacity and better reservoir management to avoid increased flood damage to built and natural environments.
Ralph covered Atmospheric Rivers (ARs) as well, stressing their contribution to overall increasing vulnerability to extreme weather events. In particular, he studies Atmospheric Rivers and the need for improved and expanded weather forecasting tools.
"Atmospheric Rivers" make California rivers more susceptible to flooding
Atmospheric Rivers transport water vapor as previously mentioned, and exist everywhere—there are 4 to 5 per hemisphere and contribute to 90% of the water transport (via clouds) through 10% of the ocean’s surface area. That’s a pretty amazing finding. These ARs cause:
• Extreme rain events and high “snow levels” --> increased flooding
• Contribute the most out of any source to annual rainfall
• Their time/place/magnitude is difficult to predict
General observations of current weather patterns are below, pulled from the powerpoint:
"21st Century Observations" (slide #3 PDF)
* Flood Risks
- 6 highest flows (flood conditions) on American River since Folsom Dam built
- Earlier snow melt, heavy spring storms increase flood risk
* Water Resources
- increased variability (uncertainty) of storm strength
- should state build more storage or change operation procedure at existing sites?
* Climate Change
- 25% reduction in snowpack by 2050
- earlier snow melt causes more intense dry season (more water when not needed and vice-versa)
Weather prediction is basically very coarse right now and not terribly useful for local or regional water managers, media or the public. Thus, the need for better weather forecast tools through an observation-based framework.
What California weather forecasters and climate scientists need:
• National Weather System warning system
• Medium-range forecasting, 2-14 days
• Monitoring climate change impacts
• Weather and Climate science programs to reduce uncertainty (anxiety and hand-wringing) about near-term and future weather conditions
Solution: Four Tiers to Modernize Weather Forecasting
• T1: Well-defined needs: more sensors; latest basic technology, proven, cheap
• T2: Expand on T1: wind profilers, Atmospheric River observatory; proven, slightly more expensive
• T3: Newer technology: gap-filling radars, ocean wind profilers; less proven, somewhat more exp.
• T4: Offshore recon: aerial/ocean monitoring; untested, most expensive, possibly best data
Tier 1 includes GPS-enabled weather, soil moisture, and snow level radars, or “peppering the steak with low cost technology where there is already existing old technology.”
Tier 2 comprises wind profiler machiner and Atmospheric River observatories (early warning systems)
Tier 3 of gap filling x-band radars would patch blank spots on radar screens: add these to Sierra Nevada range. Also add buoy-mounted wind speed testers (wind profilers) to the ocean—NOAA cannot now measure wind speeds/shear over sea surface. (NOAA blind spot.)
Tier 4 includes aerial surveillance as exists already in the Atlantic for hurricanes. Need two planes, off the Los Angeles and San Francisco coastlines. In 1998, NOAA ran a one-time test with a plane over the Pacific. Good, because weather forecasters had a 96-hour lead time on flash floods due to the El Nino effect that year. The affected counties lost no people, compared to 12 people a decade earlier in a similar storm, with this superior observation method.
California faces similar dangers as Japan to typhoons/winter storms. Japan has a good model—plenty of observation equipment and similar size as California. The California Dept of Water Resources (DWR) is considering T1, T2 solutions right now. Nationally, NOAA is considering T3-T4 solutions.
Interesting Q&A question: unlike Japan, California does not have
summer typhoons/hurricanes. How will the program be cost-effective this
half of the year?
Answer: Move air assets to Atlantic, Hawaii or Alaska/Arctic; other assets can measure heat waves, wildfires and air quality over California during summer months (dual purpose).
My conclusion: it seems that regardless of cost-benefit analyses, these technology-focused solutions would help mitigate any future climate change-induced extreme weather events if funded properly. Even without threat of “global warming” the Four Tier system would still improve public safety through better storm watch capabilities and management of water resources.
Link to Powerpoint (PDF format)
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“Adaptation to Climate Change Impacts on Water Resource Systems:
A Case Study of the Merced River Basin”
Sebastian Vicuna, University of California-Berkeley PhD researcher
The gist of the first presentation was, given higher temperatures and precipitation, what is the optimal reservoir management plan to mitigate flooding and water supply issues? This was fairly straightforward.
Vicuna models future water use with A) climate change and B) climate change with adaptations, as shown below.
There are two strategies to optimize water basin use of reservoirs and
aquifers, for agricultural and other uses, in the face of climate
1. Start flood control earlier in the rainy season (store more water)
2. Increase storage capacity (store more water)
3. Artificially recharge aquifers
You might notice the first two strategies are very similar. The third consists of “conjunctive,” or coordinated, management of reservoirs and aquifers. Policies would include reduced groundwater pumping and more river diversion (artificial recharge). Said Vicuna, this last strategy provides a “no regret, robust option.”
Get the presentation (PDF).
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“Assessing the Risks of Shifting Climate on Water and Power Operations in the
Levi Brekke, U.S. Bureau of Reclamation
To be quite honest, I was in over my head on this presentation, I hadn’t gotten enough sleep and coffee, or all three.
This last water presentation covered scenario modeling of climate change impacts on the California State (1) and Central Valley (2) water projects. Using 75 different climate change models, Brekke wanted to expand risk analysis beyond the usual “scenario --> impact, probability” exercise with weighting.
Of all the models he examined, each had a primary focus of one or two metrics perspectives: water supply, hydropower, or flood control.
With scenario weighting, he could get better estimates of average “carryover” at Lake Shasta -- yearly water left over after summers.
Brekke said that his research culled out “increased draft from November to March of about 10%” as being an optimal future flood control method. Increased draft means increased water intake, as you might gather from the unrelated but relevant book quotation below:
Catch the presentation here (PDF).
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Q1: “Can we handle worsening floods with existing reservoirs?”
A: Levi Brekke: “No comment [laughter]... flood control diagrams are rearview mirror-looking for right now."
Q2: from Gina at CEC: Are any of you working with biological scientists to study effects on environment/ecology?
A: New flood controls will affect lakes and stream temps. Jamie, DWR: DWR has a department-wide effort to roll together climate change strategies.
Q3: from someone at Sandia Labs: Are the lessons learned here transferable to the world?
A: Sebastian: Yes: Atmospheric Rivers exist worldwide and affect the Andes in South America. Mike Dettinger: Taiwan is dealing with similar flooding issues. Fred Ralph: HMT techniques apply worldwide.
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All in all, fairly comprehensive and deep morning session on water challenges. My understanding of challenges to the state's water supply and management of water-related events increased substantially. I'm sure it was helpful for state employees as well. Kudos to the California governing bodies--Energy Commission, EPA, Resources Agency, Dept of Water Resources, and others--for sponsoring a solid lineup of speakers for the benefit of State practitioner and general public understanding of climate change issues. Thanks also to Adam Gottlieb, CEC Information Officer, for his assistance.
California state and local agencies have their work cut out for them and for the most part seem to be quite on top of things. If you have any questions about the conference, feel free to email me at ken(at)sustainlane.com.