Mountain Counties addresses climate change
On March 15, Mountain Counties Water Resources Association, in conjunction with the Association of California Water Agencies Region 3, met at The Ridge Golf Course and Event Center in Auburn to hear the latest on climate change.
NASA defines climate change as changes in the long-term averages of daily weather. Long-term forecasts are that some areas in the world will experience drier periods and some will experience wetter periods than they have in the past.
Given that Northern California has historically experienced wide variability in climatic conditions, with alternating periods of drought and flooding, and given that recent scientific technology has provided more data and information on weather patterns, what effects does this have on water management in the Sierra Nevada mountain counties, and what steps can and should be taken to best adapt to climate changes now and in the future?
“Mega Drought: Will it happen again? Will we be ready?”
John Kleppe, Ph.D, Electrical Engineering is Professor Emeritus at University of Nevada, Reno, where he was chairman of the Electrical Engineering Department.
Kleppe, whose home is on the shore of Fallen Leaf Lake, often takes his boat out to fish. Fallen Leaf Lake is one mile south of Lake Tahoe and 500 feet higher. It is almost three miles long and a mile wide. The average depth is 240 feet. The deepest part is 492 feet.
For many years, Kleppe’s line kept bumping into something and he was puzzled why. What he caught was not a rare species of fish, but something even more rare – a tree from a forest dating back to medieval times.
Although the clarity of the lake is high, he could not see anything underwater. As a scientist, this was a mystery he had to solve. He tried SONAR, but got no soundings. In the late 1990s, he hired a diver, who quickly surfaced with a branch in hand. Kleppe sent a sample to Lawrence Livermore National Laboratory for carbon dating.
The tree, a yellow pine, dated back to around 1215 A.D. It had mineralized, and was as perfectly preserved as a marble statue. It was waterlogged, so it absorbs SONAR.
Further investigation revealed a number of trees nearly 100 feet tall and 15 feet in diameter, indicating they were over 200 years old when they died. This signifies that a “mega drought” occurred during the medieval period around 850 to 1150 A.D. The dry period was followed by an extremely wet period. There are signs that another lengthy drought occurred later.
Three older trees were discovered, suggesting that severe droughts happened farther back in time.
These longer cycles are different that the shorter fluctuations that have been recorded in the last 150 years.
Graham Kent, University of Reno Seismology Lab director, used a remotely operated underwater vehicle to create high-definition fault mapping of the bottom of Fallen Leaf Lake. His team traced the west Tahoe fault line. It is a 7.3 capable normal fault. Kleppe said Kent believes it may be ripe for action.
Kleppe said there is “a disconnect between science and society. We need to separate funny science from real science. We need to start saving water.”
“Climate Change–Is the time to act now? What is the risk of doing nothing?”
Glen MacDonald, Ph.D, Botany
Michael Dettinger, Ph.D, Atmospheric Sciences
Michael Anderson, Ph.D, Civil and Environmental Engineering
Moderator: Mary Aileen Matheis, Director, Irvine Ranch Water District
Glen MacDonald has studied drought conditions all over the world. He lived in Tahoe City, and is familiar with Sierra Nevada conditions. As director of the UCLA Institute of the Environment and Sustainability, he echoes the results of scientific investigations at Fall Leaf Lake.
MacDonald’s research using tree rings indicate that local dry spells can go on for more than a decade. In the 12th century, California experienced sustained low flows in the Colorado and Sacramento rivers and low rainfall for a period of 40 to 60 years. At the same time, there was a drop in volcanic activity and a spike in solar radiance, leading to natural climate warming. It affected forests and fires. We have similar conditions today, he said.
The Palmer Severity Index measures soil moisture. The map shows that as of March, the western United States, with the exception of the Pacific Northwest, and a portion of Colorado, are in various states of drought. Northern and Central California are designated moderate drought zones, Southern California as severe drought, and the northeastern area as extreme drought.
MacDonald said many people believe we can cope with climate change through technology, but the past can tell us a lot about what kinds of general strategies allowed societies to survive over time. Some previous civilizations successfully managed their resources for many centuries and some did not. We may be in for a long-term drought, and there are lessons we can learn.
Michael Dettinger provided a preview of the next Climate Change Assessment Report, No. 5, which is being done by the Intergovernmental Panel on Climate Change and will be made final in 2014. As research hydrologist for the U.S. Geological Survey National Research Program and research associate at Scripps Institution of Oceanography, Dettinger participated in the research.
The three major conclusions of their research are: 1) Projected warming trends in California will be moderated somewhat by coastal and mid-latitude locations. 2) Precipitation extremes are expected to increase. Flood risks caused by “atmospheric river” storms may increase. Drought risks will increase. Reporting on flood research, Dettinger said that flows of vapor (atmospheric rivers) have unleashed massive floods every 200 years. Climate change could bring more. The last major flood occurred in 1861-62 when it rained for 43 days, turning the Central Valley into an inland sea 3) Southern California and much of the Colorado basin are the focus of predominantly declining precipitation projections. Projections for northern California are more uncertain.
Projected higher temperatures and less precipitation in the Sierra Nevada forecasts snow seasons will gradually shorten from six to three months toward the end of the century.
Michael Anderson, California’s State Climatologist at the Department of Water Resources, followed by saying the peak of the snow load in the Sierra Nevada may not be April 1, when last measurements of the season are taken each year, but may be in March in the coming years.
Anderson said the most extreme California storms result from a rare alignment of key processes. He cited the storm of Jan. 4-6, 2008, when severe high winds, heavy rains and significant snowfall wreaked havoc in the western United States from the Pacific Coast to Montana and Colorado. Weather records were set throughout the region. On Jan. 4, Bishop had four inches of rain, the highest daily total on record. Bishop has an average annual total rainfall of 5.02 inches.
Anderson emphasized that California has extreme geographical diversity, from coastal to mountains, valleys and deserts. Climate change will affect them to different extents.
He referred to two studies. One is “Climate Change and Integrated Regional Water Management in California: A Preliminary Assessment of Regional Approaches.” One of the authors is DWR North Central Region Climate Change Specialist Erin Chappell. The study calls for routine regional vulnerability assessments and integrated regional adaptive water management.
MCWRA Executive Director John Kingsbury reflected on the panel’s presentation, and observed, “Water is vital to the environment, economy and our way of life in this state. Ongoing adaptive water management is critical to counter climate change effects in the Sierra Nevada, the state’s largest natural winter reservoir. The experts provide us with the best available science. It is our job to analyze the data, determine the risk, and act responsibly if we are to provide a lasting legacy for future generations that ensures a vibrant economy and healthy quality of life inseparable from this special landscape.”