Dr. Glen MacDonald discusses California's changing climate and demography, and what the implications are for the future
Dr. Glen MacDonald is the John Muir Memorial Chair of Geography at UCLA; his research focuses on climate change and its causes and impacts on the environment and society. He gave this speech at the 12th Biennial State of the San Francisco Estuary conference, focusing on why the current drought is so severe, and also highlighting how the state's changing demographics could affect land and species efforts in the future.
He began with a discussion of the drought, saying that the punch line is, ‘Welcome to the 21st century, ladies and gentlemen.'
We all know that we are in a severe drought and have been for four years now with severe to extreme drought conditions embracing the entire state, he said. “This is not our first rodeo; obviously we had droughts before, and we have a tremendous infrastructure for moving and storing water. And yet as we know, that infrastructure we put in place is sorely tested right now so that we are pushing the limits of our current engineering adaptive capacity in terms of drought.”
He presented a slide of California’s precipitation from 1900 to 2015, and noted that this is not the lowest precipitation year on record. “We have experienced lows in annual precipitation which are greater than we’ve seen here on a statewide basis,” he said.
“When we take a look at runoff or snow water equivalent from the Sierra Nevada, our great storehouse of water where we capture water as snow, and when we look at the models which combine the precipitation, infiltration rates and things like this, we see again that in terms of snow water equivalent, this is not been the worst drought in the historical record in terms of the delivery of water,” Dr. MacDonald said. “It’s bad, don’t get me wrong, but not the worst we’ve seen. This is not about this being the lowest period of precipitation or water which has landed in the state.”
It’s also not demand for water that is making the drought so bad, either, he said. “If we take the results from the UC Davis study that looks at water use in the state, what we see is that urban water use, despite the fact that population has increased, has more of a flat line from the droughts in the 1990s,” he said. “We have become much more efficient in terms of urban water use for a number of reasons. Agricultural water use has not increased either over that time period. This is not that this drought compared to the late 80s and early 90s has increased precipitously. We cannot say that it is in fact demand that has driven this drought to be so important and requiring so much special regulation and water restrictions.”
To really understand this drought, you have to look at temperatures, Dr. MacDonald said. “That’s where we do see we are beginning to go off the charts and where this is exceptional,” he said, presenting a chart of average temperature from 1900 to present. “Look at the final year there. We are off the charts, and that high value comes from a period of almost two decades of relatively high values of temperatures, so it’s the temperature which is really making this drought exceptional and extremely scary.”
“When you think about temperature and drought, you are talking about increasing rates of evaporation and increasing rates of transpiration from plants,” he said. “It’s the water loss that accompanies those high temperatures and dry air masses over the surface. We can put these together into something called the Palmer Drought Severity Index which incorporates evapotranspiration as well as water delivery and it looks at how the soil will lose water.”
He then presented a graph of the California Palmer Drought Severity Index from 1900 up until present day. “What you see is there has been a long term trend of increasing aridity on a statewide basis as measured by both precipitation and temperature, and that’s not surprising because it follows this increase in temperature that we’ve seen,” he said. “When you look at drought as it should be looked at – as a combination of high temperatures, high evaporation and transpiration, coupled with low precipitation, we’re in record-breaking territory. That’s why this is so severe.”
Studies of tree rings going back 1000 years have concluded that there have been other severe droughts and similar low periods of precipitation, he said. “But when we combine the high temperatures that we have today with the low precipitation, in some of the indices we look at, we are in record breaking territory for the last 500 years of so.”
A recent analysis looked at whether this could be attributed to increased greenhouse gases and climate warming, Dr. MacDonald said. “Is there a smoking gun here? In terms of the low precipitation, no,” he said. “In terms of the high precipitation, this analysis suggests that somewhere around 20-25% of the high temperatures that are pushing this drought into historical status are contributed by increasing greenhouse gases. This is a greenhouse gas climate warming driven drought. Not entirely – some of it is natural variability, but a significant portion of this seems to be related to the increasing temperatures driven by increasing greenhouse gases.”
The dry conditions experienced over the last ten to twenty years are not limited to California’s borders, but it is a southwestern and intermountain west phenomena, Dr. MacDonald pointed out. He presented maps showing the difference in temperature, precipitation, and Palmer Drought Severity Index in the first decade of the 21st century as compared to the 20th century. “All these nice warm colors, the reds and yellows, they are showing us higher decadal temperatures, lower precipitation, and greater drought, not just in our state, but throughout our neighboring and intermountain west and the southwest,” he said.
This has resulted in large decreases in the reservoir storage on the Colorado River, with Lake Mead just dancing above 1075 feet in elevation. “If the water hits 1075 feet in elevation or below that, and the Bureau of Reclamation can predict that a year in advance, it will be the first time in history for a Level 1 water scarcity declaration, which will start cuts in the delivery of Colorado River water to Arizona and Nevada. Will there be litigation as California gets no cut? You bet. This is unprecedented. We can’t depend on increasing amounts of water coming from outside the state; it’s not going to happen.”
Groundwater has been the fallback for agriculture as well as for some urban areas, Mr. MacDonald said. “We have had terrible ability to study groundwater here in the state,” he said. “We have had terrible legislation and regulation in terms of groundwater reporting and control. Our groundwater systems are essentially based on medieval English common law.”
However, the GRACE satellite is a real game changer. “The GRACE satellite measures gravity differences on the surface of the earth,” he said. “The more water you have and the more mass you have, the greater the gravity. As the water disappears and you lose that mass gravity, it decreases.”
He presented images from the GRACE satellite mission from 2011 to 2013, noting that the red area indicates where the water table height has decreased up to about 160 millimeters or beyond. “Now you can see from space how California’s aquifer or groundwater system being depleted and water mined, and the level of groundwater falling,” he said. “We will not be able to continue to fall back on that resource to support our agriculture, particularly in the Central Valley as we move forward. Replenishing that aquifer is going to be hard enough.”
“It is probably not going to get better,” said Mr. MacDonald. “This drought will end, but there will be more droughts like this. They will be hot droughts, evaporation rates will be high, and we have to be concerned.”
Now for some really bad news, he said.
“I’m the John Muir Memorial Chair of Geography,” Dr. MacDonald said. “In an article published in Boom, I looked at what’s happened to the state in terms of conservation over the last 100 years since his passing. It was Muir who put together the model and the constituency which has driven conservation in this state, the nation, and globally in many parts of the world.”
A lot has changed in the last 100 years, he said. “Muir was looking at state with a couple million people; we’re now in a state with 38 million people,” he said. “I think that would have been an unimaginable increase in population. The demand for resources and the demand for space to live has just increased incredibly as has the demand for water has increased incredibly. The nation has also grown; we’re the largest agricultural producer in the nation; 80% of our water goes to grow crops. This has put tremendous pressure on the environment and the ecosystems, and on the conservation work that you all are doing.”
Not only has the population increased, but the complexion is changing, Dr. MacDonald pointed out. “The center of gravity for political power is changing in the state and the cultural touchstones that we have is changing in the state,” he said, presenting a graph of population by ethnicity projected out to 2060. “What you see is that we end up with not with a majority of any one group but certainly with a very strong Latino plurality and decreasing proportional numbers of white Caucasians; who were Muir’s audience – the educated white early 20th century, late 19th century American power elite. That’s who he preached to – the people who could afford to visit Yosemite and could afford to spend time with the Sierra Club. That demography is changing – not only more people but the complexion of the people is changing.”
We’re organized differently too, he said. “California is the most highly urbanized state in the union; 95-97% of the people of this state live in cities,” he said. “We are an urban state, despite the size of our population. But that means people are removed from the rural agrarian wilderness experience that Muir had growing up as a child in Wisconsin, or that he experienced here in California in the 19th and early 20th century.”
The ability of the federal and state governments to provide resources for park creation or land conservation has changed significantly, Dr. MacDonald pointed out. “The national debt at the time of Muir stood somewhere less than about 10% of gross domestic product; the national debt today stands somewhere around 80% of GDP,” he said. “The amount of money, the capacity, relative capacity of the government to throw money at these issues has declined; that’s the single reality of what’s happened.”
“This means then that you have to take that growing population and the changing demography of that population and you have to build a constituency who will use less limited money and less limited resources to conserve natural environments, ecosystems, and species we think are important,” he said. “You have to be even more persuasive than you or I with regard to the 21st century. Is that happening?”
He then presented a slide showing visits to the National Park System from 1945 to 2010. “’Bring them to Yosemite, they will see the light; show them Yellowstone; they will become disciples,’ Muir said, but they are not going to those places in the same proportion that they were in the past,” said Dr. MacDonald. “Projections based on current demographic use of the parks by race suggests that National Park visits will decline as we move into the 21st century. It’s flatlined – and not just nationally; it’s flatlined in Yosemite.”
Visitorship to national parks does not reflect the complexion of this nation, and this is a concern for the National Parks System, he said. “Park visitorship here in California is typically 70 to 78% Caucasian with Hispanic and African-American groups being particularly being underrepresented in park visitorship.” He noted there are reasons for that are beyond the scope of this talk, but don’t reflect well on the management of the parks in the early 20th century.
There is also a disconnect between the demographic realities of this nation and the membership and leadership in environmental organizations and environmental government agencies, he said. We also see a disconnect between the demographic realities of this nation and the leadership in those organizations.
He presented a slide from a study by Dorceta Taylor in 2014 showing percent of whites and minorities on the boards of conservation organizations, and on paid staff of conservation and preservation organizations. “Only 4.6% on the boards of those organizations are minorities; 12% on the paid staff of conservation organizations and that should be frightening to all of you.”
He then presented a slide showing results of a recent USC Dornsife poll looking at different ways to respond to the drought. “It compares Caucasian versus Latino responses,” he said. “Many of the things have very similar responses; improve stormwater capture, more water in underground aquifers, desal – they are almost identical. But down here at the bottom, ‘suspend environmental regulations that protect fish and wildlife’: White voters strongly favor that by 22%, Latino by 31%. White voters strongly oppose that by 42%; Latino population by 33%. We’re talking a 9 to 10% difference there.”
“Now in many environmental questions, Latino populations and people of color often come out higher on the conservation and the progressive side than Caucasian voters, but in this case, that’s not the case, and there’s a 9 to 10% difference,” Dr. MacDonald pointed out. “We should not take any comfort in that. If that continues, we’re going to have a lot of trouble getting the support for the type of conservation efforts that we’re talking about.”
There are really great signs too, he said. “For instance, Aaron Mair, a person of color, was elected to presidency of the Sierra Club,” he said. “And if we look at the entry level internship and people that are coming into the conservation organizations, we see that there is increased minority representation in terms of the interns and the incoming people and that’s a really good thing.”
Dr. MacDonald then ended by referring to recent articles in the San Francisco Chronicle about the importance of local efforts to conserve large ecosystems, species, environment and habitat in local watersheds. “They are part of the urban fabric and why what you’re doing is important – which is basically introducing urban people to nature, to wildlife, and to conservation successes at their doorstep, not 300 miles away in the Sierra Nevada where they may never visit.”
He presented a map of habitat restoration projects and pointed out that they are inter-fingered right on top of a huge population center, and one of the most racially diverse regions of the nation. “This is the perfect place to build a new generation and to build upon Muir; to introduce people in their backyards to the beauty of the estuaries, to the diversity of the interesting wildfowl that come through this, to the ecological function of a tidal marsh and the immense ability to capture carbon,” he said.
“It’s also a chance to show that in the face of large urban pressure, in the face of changing climate, and in the face of rising sea levels, there are strategies that allows us to have a vibrant economy, a vibrant urban cultural life, and a diverse cultural life with a lot of people, and at the same time, to not just preserve nature, but bring it in and have it intermingled with life here.”
“Folks it’s a big charge, go get ‘em.”
For more from Dr. Glen MacDonald …
- Introduce urban Californians to what John Muir sought to protect, commentary published on SF Gate
- Beyond the Perfect Drought: California’s Real Water Crisis, commentary published on Yale 360
- John Muir, A Century On, article in BOOM
Your help is needed for Maven's Notebook to continue operations in 2016.