Considering climate change in water resources planning

CWC JanuaryA look at the DWR’s efforts to address climate change impacts, as well as the modeling tools used in climate change analysis

Climate change presents critical challenges for California water resources management.  In recognition of this fact, the Department of Water Resources conducts a wide range of climate change activities, including support for climate change analysis and adaptation planning by local and regional water managers, funding for climate change monitoring and research, and the development of comprehensive water sector policies and management practices.  DWR is also addressing climate change for programs, projects, and other activities over which it has direct control through its Climate Action Plan.

california water commissionAt the January meeting of the California Water Commission, DWR staff gave a presentation on how the Department of Water Resources addresses climate change.  Assistant Deputy Director John Andrew provided an overview of DWR’s Climate Change Program; Elissa Lynn, Climate Change Program Manager focused on climate science and the impacts of climate change in California, as well as DWR’s Climate Action Plan. Andrew Schwarz, Senior Engineer, discussed some of the key tools and resources used by DWR in climate change analysis for planning purposes.

Overview of DWR’s Climate Change Activities

The presentation opened with John Andrew, assistant deputy director of DWR, giving a broad view of the Department’s climate change activities. The Department has been working on climate change since the late 1980s when chief hydrologist Maury Roos began publishing articles and analyzing data, and climate change has been incorporated into the California Water Plan since 1990, so it’s hardly a new issue, he said.

Climate change management is one of five core values for DWR, and to support that, we have a small matrixed organization of about 10 people in the department,” he said. “They revolve around three regional specialists, one in each of our regional offices that works with local entities specifically on Integrated Regional Water Management but other local technical assistance related to climate change.”

CWC John AndrewMr. Andrew said they were focused on building capacity; the team has been in place now for six years and has really developed expertise across a lot of complex technical issues related to climate change. They are supported by $2.5 million annually from Prop 84 as well as a small amount of greenhouse gas emissions reduction funding from the California Air Resources Board of about $300,000 each year. They have no consultants, but have had several interns and graduate students helping out. They have been participating in the Governor’s Climate Action Team, a cabinet level group that coordinates climate policy across state government for about 10 years. There is also a broader group within DWR which has representatives from all the major divisions and programs which meets quarterly.

The Department’s climate change program is comprehensive and can be broken down into four focus areas: science and research, mitigation – reduction of greenhouse emissions, adaptation – coping with how climate change is affecting our environment, and also outreach.

They have been involved with the implementation of AB 32, both the scoping plan and the updates to the scoping plan, as well as served as the water sector lead for the cap and trade investment plan. They have been using their cap and trade funds to administer a water-energy grant program which has awarded $28 million in cap and trade funds to local entities to implement projects that reduce water and energy and carbon; another $20 million to be distributed this year, and the Governor’s budget proposes another $10 million, should it be approved by the legislature in the coming year, he said.

The Department of Water Resources was an early adopter of calculating and disclosing their carbon footprint, Mr. Andrew said. The Department joined the California Climate Action Registry in 2007, one year after AB 32 was passed. The registry went national a few years ago, it’s now called the National Climate Registry. “We remain one of only four agencies in state government that actually calculate, independently verify, and disclose our carbon footprint,” he said. “There are between 50 and 60 agencies, so I still find it remarkable that the Department was one of the early adopters of performing that activity and still has consistently done it.”

Mr. Andrew noted that out of the literally hundreds of water agencies in the state, there are only a dozen that do the same thing. “So there’s a lot of room for improvement in terms of being able to calculate what the water sector’s carbon footprint is, and having it independently verified and disclosed to the general public,” he said.

With respect to adaptation, the main focus is Integrated Regional Water Management with four regional specialists providing technical assistance to regional water management groups around the state, he said. They played a large role in the most recent update of the California Water Plan and its greatly expanded emphasis on climate change and water and energy. They are the water sector lead for the Safeguarding California plan, the cross-sector adaptation plan across all parts of state government and all sectors of California for how to adapt to climate change.

They are the water sector lead for the Adaptation Planning Guide, a joint effort of the Natural Resources Agency and the California Office of Emergency Service that is a technical guide for adapting to climate change at the local level. “We produced this climate change handbook for regional water planning to provide local water planners with a way to incorporate, and basically it’s a cookbook on how to incorporate climate change into local water planning,” he said.

Elissa Lynn: Climate science and the impacts of climate change in California

CWC Elissa LynnElissa Lynn then took to the podium to talk more in detail about climate change and the impacts for California, the adaptation strategies for the water sector, and how DWR is playing a role in assisting local and other state agencies.

Today you might have heard an alarming report that 2015 just blew out the global records for the warmest year on record,” Elissa Lynn began. “El Nino can only be blamed for about 10% of that warming that we saw globally this past year, so it’s definitely more the man-made anthropogenic greenhouse gas emissions that are causing these climate change problems.”

Lynn Slide 2In addition to the warming trends, there are also other impacts being felt in California. “There is a transition to less snow and more rain as things warm up; earlier greenup dates, enhanced wildfires, earlier snowfed streamflow, less snowpack, and habitat changes, and for those you can see the indicators report from EPA,” she said. “Additional concern is the ongoing drought. The last four years have all been in the top ten driest, and with climate change projections indicating the depth and the duration and certainly the temperature of the droughts we’ll see in the future are going to be increasing, so we want to make the connections between climate change and drought, and concern ourselves with what the precipitation projections are for California water management.

Lynn_Page_03Ms. Lynn then reviewed the basics. “The energy from the sun comes in to our atmosphere, but certain chemical constituents within the atmosphere don’t allow all of the sunlight or the temperature transition that takes place,” she explained. “All the heat doesn’t go back out, some of it stays in the atmospheric layer and those are the greenhouse gases, primarily CO2.”

Lynn_Page_05This model portrays the atmosphere, the oceans, the land and the interaction that make the climate model, she said. “In a typical earth-climate system with the sun at the top, earth underneath, some of that sunlight is reflected back out into space, heat from the surface is trapped in some places to some degree, and those greenhouse gases play a large role in determining how much heat and what the surface of the earth’s temperature actually is. … If a planet has an atmosphere, it has some greenhouse effect, but with this enhanced heating from the surface and the additional trapping in the atmosphere with the radiation being absorbed by these greenhouse gases, you end up with higher surface temperatures then you would have had at the base state. You have a warmer temperature, a different climate, and the amount of warming is highly dependent on how much of those gases are emitted.”

The current Co2 levels are higher than the past 800,000 years, she said. “The temperatures on earth right now that we are seeing globally are warmer than the past 2000 years from our temperature records,” she said. “The regional scale and local scale impacts may be very different than just the direct warming. Even with the whole global average temperature being warmer, an individual location may not just be hotter, it may be windier, it may be rainier, in some cases it could be drier, or it could even be cooler in some areas, depending on the entire circulation of the global air, atmosphere and moisture content. So it’s very complicated … it can mean different things on the ground.”

Lynn_Page_06Ms. Lynn pointed out that the computer models cannot duplicate the warming already being seen without including manmade Co2. “The actual observed temperature record is in black, and if you only included the natural forces – sunlight and the different things that impact the atmosphere, we cannot duplicate what is already observed without putting the Co2 that humans have emitted into these models.”

Lynn_Page_07She then presented another slide that shows the attribution to the greenhouse gases and other things that drive the atmosphere, such as the sun, ozone, volcanic emissions, and sulfates. “Greenhouse gases of the preponderance of the reason that we’re seeing the warming,” she said. “They offset any of the others that are leading to a cooling trend, and they are much larger than the others that oscillate as well. So yes, it’s us; yes, it’s warming.”

Ms. Lynn then discussed some of the key observations that of impacts that have already occurred and those that are projected for the future, noting that this information is discussed in detail in the brochure, California Climate Science and Data for Water Resources Management.

Lynn_Page_09She presented a chart or projected temperature change by region from page 13 of the brochure. “It matters where you are,” she said. “It’s not just a straight warming in all cases in California; we do warm in most of our regions. They have a wide range in the temperature impacts that are going to be seen by the end of the century and are from 3 to 6 ½ degrees Fahrenheit. Summer warming will be a little more significant than winter; the inland areas will experience more warming than coastal areas, and evening and nighttime warming will be more significant than what occurs in the day.”

Relating that to what the change would be like for Sacramento with an average annual temperature of 61 degrees, Ms. Lynn said a 4-degree Fahrenheit increase in temperature for Sacramento would be like Bakersfield’s average temperature for Sacramento; a 7 degree Fahrenheit increase – the high end of the end of century projections – would be equivalent to Las Vegas average temperatures of 68 degrees per year.

Lynn_Page_10Another observed change is a transition to more rain and less snow, as shown on page 3 of the brochure, she said. “Precipitation isn’t exactly a clear signal from the climate models like the temperature trends; with most of those climate models, temperature patterns for California are much more clearer than what the precipitation changes will be. But what we’ve already seen for our precipitation is an observed change,” she said, noting that the graph shows the rain and snow ratio. “The red lines indicate a mean that is somewhere above the average, meaning more rain, less snow, and a preponderance of those in recent decades. … We’re seeing a transition in the temperatures that mean that as the storms come through year upon year, even if we get the same amount of precipitation, more of it is falling as rain than snow, and that’s a problem for water supply, that’s a problem for snowpack, and it’s already observed, so this is something that is already taking place in the state.”

Lynn_Page_11The latest climate change projections for snowpack are on page 5 of the brochure. “We’re anticipating a 48-65% lower snowpack by the end of the century than the historical range of 1961 to 1990,” she said. “The other two warming ranges, the orange and the red, depends on how much Co2 is emitted, but right now we seem to be doing our best to hit the high end of the emissions globally. It doesn’t depend just on local emissions, even though California’s doing its part; it depends on global emissions that set how warm things will get.”

The state has already experienced a 10% loss of its snowpack in the last 30 years,” she said. “That’s a trend that’s occurring across the whole West, too – anywhere from 10 days to 3 weeks earlier in snowmelt, and also a reduction in snow, although some years can be very, very snowy. We still have normal climate variations which bring us a variability in the record, and climate has to be considered on the decades-scale of averages to see how you’re doing. One year alone is tough to determine.”

Lynn_Page_12The timing of runoff has been changing, as shown on page 3 in the brochure. Ms. Lynn explained that the red line is for the first half of the century and the blue line is the second half of the century. “The time frame that we’re seeing most of the runoff coming is actually earlier in the season,” she said. “Another big factor in our ability to have reliable water supplies under our changed climate is what time of the year is that snow melting, how much space do we have for future precipitation in the season and snowmelt, because since that’s occurring earlier, what do we want to consider about our storage patterns in the year?

The climate models don’t say necessarily that it will be absolutely dry all the time, or that there will be a big change in the amount of precipitation over the whole state entirely, she said. “Probably Southern California is going to get dry and stay drier than it is, but the northern part of the state may have the same amount of the precipitation, but it will come at a different time of the year or in a different form.”

Lynn_Page_13Projections for sea level rise are on page 8 of the brochure. DWR ran the contract for the National Research Council’s 2012 study on West Coast sea level rise. “Storm surges and El Nino can make it even worse, but the projected sea level rise ranges from about a half a foot to a foot in 2030, by 2050 about 1 ½ feet to 2, and 2100 perhaps as much as four or 5 feet,” Ms. Lynn said. She noted that while DWR isn’t overly impacted by sea level rise because they don’t have many coastal facilities, the state overall will be quite impacted by sea level rise.

Lynn_Page_14Ms. Lynn then presented a figure highlighting the key vulnerabilities for the water sector by region, noting there is a more detailed list on page 14 & 15 of the brochure. “Climate impacts to water supply are very regional,” she said. “What we’ve done is take out some of those important impacts by region, what they might be for air and water temperatures and ecosystems and snowpack storage and infrastructure near the coast, and put this together in map form. We think that it’s very helpful for citizens to see what’s taking place in their individual area.”

Lynn_Page_15These impacts can be addressed in two ways: by adaptation or by mitigation. “Climate adaptation are the efforts by society or ecosystems to prepare for or adjust to changes that are occurring in the climate,” she said. “They can be protective, they can be opportunistic, but they are important measures that we have to take. … The draft Sacramento-San Joaquin Basin Study being compiled by the Bureau of Reclamation concluded that annual investments of $2 – 5 billion per year may be necessary to achieve long-term adaptation that is sufficient to address the major system vulnerabilities. So adaptation is not impossible, but it’s expensive.”

Lynn_Page_16Climate mitigation refers to the efforts to prevent or reduce the emission of greenhouse gases,” she said. “DWR is leading the way among state agencies for reduction of GHGs, including using new technologies and renewable energies, making older equipment more energy efficient, or changing management practices or behaviors.

Lynn_Page_17Many of these adaptation strategies will be included in the new Safeguarding California implementation plan due out this year. “DWR is the lead for the water sector plan,” she said. “DWR is taking the lead to help local water managers understand the risks and develop their own adaptation strategies. It’s important for adaptation because it’s an opportunity to create a more sustainable society be connecting planning in both the built and the natural environments. This plan will outline the specific vulnerabilities to modified hydrology, and the ongoing and inevitable climate impacts. The current actions that the state government takes will reduce those vulnerabilities. The plan will also lay out the next steps necessary to continue progress in adapting to threats and climate change. We are the lead but not the only contributors to this chapter, but the water sector chapter of the plan is probably a little more hearty than some of the other sectors, so we’re looking forward to continuing to lead the way.”

Ms. Lynn then turned to the Department’s own Climate Action Plan, noting it has three phases:

Lynn_Page_19Phase 1: Greenhouse gas reduction plan for DWR:Our goals are to reach 50% emissions reductions from the 1990 levels by 2020 and 80% emissions reductions from 1990 by the year 2050,” she said. “We are definitely on track to meet these goals which are more aggressive than state requirements. Our GHG reduction plan won the National Climate Leadership Award in 2015; we’re one of only two public agencies to have won that award for our plan to reduce our emissions.”

Lynn_Page_20Phase 2: Climate Change Analysis Scenario Selection and Guidance: “This phase is more about the modeling – what kind of climate future should we prepare for, what scenario should we consider in our planning? We have a number of planning horizons that DWR does projects for and that’s going to impact what kind of climates are going to be tested for, but what we want to do is make a framework for consistent handling of climate change. How do you model for climate change, which scenarios do you consider, do you do an absolute worst case, do you do something that’s a little more likely, how do you come up with the right numbers?

The goal is to establish a standard and have better quality in the climate change analysis across all of DWR’s programs, she said. “We did a study a few years ago that showed there were 13 different approaches already being taken by the Department. We reseated the Climate Change Technical Advisory Group, which is a group of independent climate change scientists and practitioners from key disciplines in water management, climate science, and practitioners to provide guidance and perspectives. This group released their recommendations report … Their studies and their assessment of the models in California and which climate models do a better job in California is very important for us internally in DWR and also to help other state agencies. … We’re hoping that this will help us implement policies with climate change in a more responsive manner, a little more realistic as to what climate scenarios to select.

Lynn_Page_21Phase 3: DWR Vulnerability Assessment and Adaptation Plan:This refers to DWR’s people, facilities, and programs, and to identify the vulnerabilities to our business practices and assess the risk levels and identify the most vulnerable activities and to develop adaptation goals and create a plan of action for DWR. We are underway, and the vulnerability assessment portion will be out this year, 2016.”

Andrew Schwarz:Modeling and climate change analysis for planning purposes

Andrew Schwarz, Senior Water Resources Engineer for DWR, then discussed the tools and tradeoffs used in climate change analysis.  He began by saying there are two specific types of analysis they do:

Schwarz_Page_03Climate change specific analysis:These are analyses within a larger project of regional or statewide watershed level impacts or existing systems where we’re really looking at what is the effect of climate change on the project,” he said. “In a climate change specific analysis, we usually have historical operational experience, and we can look out at the system and see what we have and what we have lived through for the last 100 years. A lot of these analyses are typically high level and many of them don’t have any specific decision to be made, but they are informational. The climate change analysis in the California Water Plan, the State Water Project Delivery Capability Report, and the forthcoming Sacramento San Joaquin Basin Study are all types of this kind of analysis.”

Project specific analysis:With this type of analysis, we don’t have any historical performance record because we are talking about something we might want to build in the future; we have the ‘without project’ situation that we can look at how that performed in the past, but we don’t have the actual record of having that project. Oftentimes, there is operational uncertainty, so we might have to be looking at multiple configurations or alternatives or operational schemes. There is another kind of dimension of uncertainty of how this thing would actually operate in the future, and most of the time these are highly detailed with a go, no-go type of decision at the end, such as CEQA projects, the Water Storage Investment Program, and probably the SGMA plans as well.”

Schwarz_Page_04He then presented a graphic to illustrate the point. “On the top set of illustrations, we have a piece of land, we have a sun and a cloud, and then we want to build that project, so we want to compare these two situations and see what the project does,” he said. “Then our sun is going to get bigger and our cloud is going to get smaller, so we have a different future that we might want to evaluate to see how that project performs with the bigger sun and the smaller cloud. We want to compare those two futures, so in that project specific analysis, we’re really concerned about the impact of the project. We can compare across whether we have the project or whether we don’t have the project.”

Schwarz_Page_05Alternatively, with climate change specific projects, we’re looking more at this situation where we have the project or the system that we want to evaluate, and we’re just evaluating it under a different climate, he said. “Often, in those kind of climate change specific project analyses, we typically do many, many climates to try and evaluate across the range of uncertainty of climate because what we’re really concerned about is that changing climate. We’re sometimes more limited with the project-specific analysis because evaluating a lot of different climates can be overly resource intensive or not tenable.”

Schwarz_Page_06For both climate change specific analysis and project specific analysis, we typically start with the global climate models, he said, presenting the graphic of the output of 20 global climate models and noting that there are over 60 in the pantheon of models that are used and accepted by the IPCC. “These are temperature departures from historical average over the coming century,” he said. “First thing you notice is there’s a huge fan here – these expand out, especially as you get further out into the future. By mid-century, you have a range of almost no change to 2 degrees Celsius (or 4 degrees Fahrenheit) on a global scale – that’s roughly the entire globe changing from what Sacramento’s average temperature is to Bakersfield’s average temperature.”

By end of century, the range is from almost no change to projections that are over 4.5 Celsius higher on a global scale or 8-9 degrees Fahrenheit change globally, which is like the entire earth warming by the difference between what Sacramento is like today and what Death Valley is like today. Wrap your head around that … That’s life as we know it being totally different.

The point is there’s a huge range here and as we move out into the late century especially, we have to really think about all the things that are going to change, aside from climate, or as a result of climate; if we get that kind of climate change … we’ve got huge problems at that point,” he said. “The other thing is that that’s 85 years from now at the end of the century. That’s a long time. If we think about what’s happened in the last 85 years – that’s 1930 and the average cost of a new house was about $7000, cost of a gallon of gas was .10, the desk phone hadn’t yet been invented, TV was just starting to take off, and the first photocopier was still 8 years away, and Hoover Dam hadn’t been authorized by Congress yet, so a lot of things can happen in 85 years besides climate. Schwarz_Page_07We have to consider the uncertainties that grow as we move further out into the future as we pick not just the range we want to evaluate but the distance out into the future that we really want to consider.

The projections that come from global models are at a coarse scale with grid cells of 100-200 km a side, but much more detailed information is needed, so the information must be downscaled. DWR obtains downscaling from Scripps and other scientific organizations that provide that downscaled data, he said.

Schwarz_Page_08The downscaled data, which is temperature and precipitation information on a daily scale or so, is then put a hydrology model where precipitation is converted into snowfall, snowpack, and streamflow and other useful information at the watershed level scale.

Schwarz_Page_10Because the Delta plays a big role in the operation of the State Water Project and the state’s water delivery system, sea level rise has to be considered. “We take those global projections of sea level rise, we add some local coastal characteristics, digital elevation maps, and the like, and we use Delta simulation models to understand how salinity in the Delta is going to change,” he said. “Those salinity models with the hydrology go into our operations model, and basically what comes out of that is State Water Project deliveries, CVP deliveries, reservoir storage, canal flow, Delta conditions, and those kinds of things that we use for planning.”

Schwarz_Page_11It’s a complicated, resource-intensive chain of modeling that is needed to analyze what a certain degree of temperature change or precipitation change means for the future, he said. “It’s not impossible, and I’m not saying that we shouldn’t do it – of course we have to do it, but understand that each time we run through this, we have to go through that generally that whole chain of models.”

For a local or regional system, this process can be fractal, Mr. Schwarz noted. “Maybe they are getting State Water Project water or CVP water into their system, they’ve also probably have one or more local sources that they may have to do this whole process to get information on those local sources, and many local agencies don’t have all of the technical tools and resources that we have, so this becomes difficult,” he said. “Oftentimes we add impact or economic models on top of that to understand what the cost benefit analysis of additional water at different times of the year, or what is the impact of reducing streamflows at a certain time of year might be on aquatic resources or Delta conditions, so that’s another level of analysis that happens.”

The Department started looking at what were the primary questions they needed answers to, such as what future climate or climates should we be evaluating, how should we be using this GCM data, how do we tackle that whole range of outputs we get from the GCMs, what are the best ways to downscale that GCM data, what’s the best way to go from changes in climatology to changes in hydrology, and when should we use stress tests and how would those stress tests be conducted, he said.

To answer these questions, the Department empaneled the Climate Change Technical Advisory Committee, 14 folks in hydrology, engineering, climatology, local water management, a lawyer, a groundwater expert and others – a broad smattering of expertise. “We had a wide range of perspectives, and they came up with this consensus report in August of 2015, culminating the work we spent with them meeting about monthly for over 3 years,” he said. “We use that report as a guide for the recommendations that we make and the things that we’re doing within the Department and when we provide advice to staff at the Water Commission and others.”

Mr. Schwarz said that what is practical has to be balanced with what the research or scientific community might think should be done. “It’s easy to say we need more research, we need more studies, and we would like to do more models, but at some point, we have to make decisions about going forward and doing things, so there’s a balance there.”

Schwarz_Page_16The most useful thing that came out of the report was the process for selecting which Global Climate Models were most effective for California water resource studies. “We had a filter at the global scale, a filter at the Western regional scale, and then a filter that really looked at California processes and climate phenomena that were very important for California hydrology and extremes, so we got down to 10 global climate models from the 60 or so other models.”

The spaghetti plot in the upper left hand corner gives the averages across the 20 models for a given emissions scenario. “We don’t have any certainty about how global GHG scenarios are going to play out over the next 80-100 years in terms of whether the global community is going to get its act together and really reduce GHG emissions or if it’ll just going to keep pumping CO2 into the atmosphere, so we run multiple scenarios of GHG emissions into the climate scenarios. We get very divergent results, depending on how good or optimistic or pessimistic you are about climate scenarios.

Schwarz_Page_17Mr. Schwarz explained that they took the ten recommended models, ran those with two emissions scenarios, and collapsed those down to a single metric for each model to understand whether that model is really showing a trend for the future that is warmer or wetter or drier or cooler. He noted that the current climate is denoted by the star on the left. “The first thing that’s clear is every single one of them is at least 3.5 degrees Fahrenheit warmer, and some as warm as 6 degrees warmer” he said. “In terms of precipitation, they are scattered almost equally around the zero change in precipitation, so about half of them are wetter and about half of them are drier; the ones that are wetter show some really wet condition, the ones that are drier, -12% versus +22%.”

When we talk about a region of median change, the consensus of the models, we’re talking about a model that would fall in that range, certainly not showing no change in temperature and no change in precipitation, but a wide change in temperature and the median, the consensus of the models for the projection of what the change in precipitation is,” he said.

CWC Andrew Schwarz 2When we talk about how we might want to use all of those scenarios in an analysis and how many of those to use, there’s a lot of different ways we can choose, but the first thing we have to remember is that each one of those scenarios is a full chain of models through, so when we add another scenario, it’s not just adding a global climate model, it’s adding a hydrology simulation, downscaling hydrology simulations model and all those additional tools,” he said.

There are different ways this can be done. “Typically for a project-level analysis, it’s important to have a median consensus of the models approach of analysis through; we might add a worst case scenario of hot and dry,” he said. “Another way to do it would be to bookend it, to try and select two, so you don’t get a consensus approach but you get the worst case-best case scenario. We could do a four corners analysis and look at hot-wet, cool-wet, hot-dry, cool-dry, and then add a central tendency, that is what the California Water Fix has evaluated, the corners and the center, and then it’s just a balancing act of how much analysis you want to do and how much additional information does that additional projection give you about the future. These projections are just at mid-century, so do you want to look at mid-century and end of century … what time periods do you want to look at.”

Schwarz_Page_19Mr. Schwarz pointed out that each one of those dots on the map are one those projections brought down to a single metric of change to characterize that scenario – is it wet, is it dry, is it hot, is it cool, and inside of that, is a daily time series of temperature and precipitation all the way through from 1950-2100 with all of the interannual variability, temperature change, drought, and wet seasons built into it. “The point is that you could potentially look at a series of years within this run and get information about how does this project or the system that we’re trying to analyze perform during a very dry period. … so if you’re looking for a stress test, you don’t need to actually run an addition simulation, you can look at a specific period within the run and get your really stressed conditions.”

Mr. Schwarz then wrapped it up with some questions to ponder, noting that these are questions experts can disagree reasonably about, so maybe it comes down to decision makers trying to find the right balance for the types of projects that need to be analyzed. “The first one is how far out into the future should we be planning? Uncertainty grows about everything – population, technology, climate, politics, land use, and regulations the further we move out into the future, so what’s the right balance between preparation and uncertainty that we want to strike,” he said. “I don’t necessarily have an answer, but 35 – 60 years into the future is kind of a reasonable thing. As we go beyond 60 years, I think a lot of things change beyond what we can really comprehend might be the situation, that far off into the future.”

When evaluating projects or plans throughout the state, how do we handle these regional differences in climate change? “There are clear benefits to having intercomparability across the state, but a simulation that’s spatially consistent across the state will not equally stress every region, so what’s our priority in evaluating projects?” he said. “Is it intercomparability or making sure that everybody gets an equal level of stress?”

And lastly, what does a stress test performance tell you about the decision that you’re trying to inform? “If a project performs really well under highly likely circumstances but fails to perform under highly unlikely but stressful circumstances, should we build it or not?” said Mr. Schwarz. “If you have a project that does a lot for you on a regular basis but then when you get into a very deep historic drought, it can’t provide much benefit, do you want to build that project or not? I don’t know, but it’s worth thinking about.

With that … “

John Andrew: Outreach efforts

John Andrew then returned to briefly discuss the Department’s outreach efforts. “What you just saw was one form of the communication of climate change, through power points and through discussion,” he said. “It requires a lot of time, but there are a lot of people in California that we need to reach who are not going to spend an hour and 20 minutes like all of you just have. We might get a minute with them.”

Mr. Andrews then gave three examples of some of the outreach materials used for different audiences. “We have a ‘climate menu’ which we use in agricultural settings and other settings to discuss how agriculture is going to change, and how the food on your plate is going to change with the changing climate. I have a printout from the DWR magazine about an experiment that we did two years ago at the first California adaptation forum where we tried to use art to communicate climate change. The very large document you are getting is something we worked with tribal members on how to describe climate change is going to affect issues that are specifically of concern to tribal communities.

So with that, I want to thank you again,” he said. “We appreciate having this extended period of time to talk to you about climate change, and we are here as a resource to you as you grapple with this issue.”

For more information …

Daily emailsSign up for daily email service and you’ll never miss a post!

Sign up for daily emails and get all the Notebook’s aggregated and original water news content delivered to your email box by 9AM. Breaking news alerts, too. Sign me up!

(Visited 500 times, 1 visits today)

Leave a Reply