After four years of drought California is now at its driest for 500 years, scientists have found. The heat has left the Golden State with almost no snowpack in the mountains, which is critical for replenishing the state’s water reservoirs.
An analysis of blue oak tree rings in the state’s Central Valley has led scientists to “astonishing” results.
Scientists have compared their measurements of tree-ring data to previous Sierra Nevada snowpack level recordings that have been recorded since the 1930’s and found that oak trees’ growth seem to accurately reflect the lowest snowpack seasons.
“We combined an extensive compilation of blue oak tree-ring series that reflects large-scale California winter precipitation anomalies with a California February-March temperature reconstruction in a reconstruction that explains 63 percent of the Sierra Nevada snow water equivalent variance over the instrumental period,” the scientists wrote.
The answer lies in the rings of Blue oaks that show high winter rain levels with wide bands in the rings, while low levels result in narrow bands.
It became clear after analysis of the new core samples and those taken in previous years that 2015 had the lowest snowpack levels in 500 years.
“The results were astonishing,” Valerie Trouet, an associate professor at the University of Arizona, a senior author for the study, told the Wall Street Journal. “We knew it was an all-time low over a historical period, but to see this as a low for the last 500 years, we didn’t expect that. There’s very little doubt about it.”
- So just how bad are the fires?
- Around 700,000 acres have burned this year in California, compared with about 500,000 in a typical year, and the fire season is nowhere near over. Right now, 15,000 people are deployed fighting wildfires across the state. But what has officials on edge is less about the total acreage than about how readily new fires start, and how quickly — and unpredictably — they grow. “We’ve had fires in California since the beginning of time,” said Mark Ghilarducci, director of the governor’s Office of Emergency Services, “but what we’re seeing now that’s different is the extreme rapid spread of the fires, and the extreme volatility.”
- Why is it this bad?
- Two words: Drought and heat. Vegetation in California, from the mesquite scrub in the desert to the tall pines in the Sierra Nevada, is as dry as kindling after a yearslong drought, the worst in the state’s recorded history. So fire catches more easily, spreads faster, and carries farther on the wind.
The state’s major reservoirs hold less than half as much water as they typically would at this time of year, many wells have run dry, and underground aquifers are so depleted that in some places, the ground has been sinking as much as two inches per month.
- With such a severe drought, do firefighters have enough water to do their work?
- Yes, but it requires some creativity. Ordinarily, pumper trucks and helicopters with water buckets can tap into the streams, lakes and reservoirs closest to the flames. But in many places, those sources are now too low to rely on. Firefighters are making more use of tanker trucks and big, portable plastic water basins to do what is known as “water shuttling” — moving water close to the fires. And helicopter pilots are often having to travel farther to find places to dip their buckets.
- How bad have the drought and heat been?
- Last year was the hottest on record in California, and this has been a hot summer. But even the hottest weather would not have created the extreme fire danger the state is seeing, if there had been enough rainfall. California is in the fourth year of a severe drought. One important indicator of just how severe it is came this spring, when state scientists measured the Sierra snowpack at 5 percent of normal — that is not a misprint — the lowest ever recorded.
- Is this about global warming?
- The governor says it is. Climate scientists say the clearest link is that a warmer climate causes more evaporation, so that even when rain and snow do fall, less stays on — and in — the ground and the plants. California has had extreme swings between dry years and wetter ones in the past, but the increasing heat of recent years is something new.
Top administration officials wrote Congress on Tuesday to urge it–once again–to change the way it budgets for firefighting in light of the disastrous wildfire season in the western United States.
The Agriculture Department just informed lawmakers this week that it will have to transfer $250 million to fighting the forest fires now raging, which brings this fiscal year’s emergency spending total to $700 million. Unlike other disaster spending, caused by tornadoes and hurricanes, the federal government must stay within existing budget constraints and divert money from other programs to pay for firefighting.
In a letter to 16 Senate and House members, Agriculture Secretary Tom Vilsack, Interior Secretary Sally Jewell, and White House Office of Management and Budget Director Shaun Donovan wrote that the current funding method is no longer sustainable. The administration has proposed allowing agencies to bust their discretionary budget caps when fire suppression exceeds 70 percent of the 10-year average, but Congress has yet to approve the budgeting change.
“With the dramatic growth in wildland fire over the last three decades and an expected doubling again by mid-century, it only makes sense that Congress begin treating catastrophic wildfire as the natural disaster that it is,” the three wrote.
The cost of the U.S. Forest Service’s wildfire suppression reached a record $243 million in a one-week period last month, and it now spends a record 52 percent of its budget to fighting wildfires. In 1995 it spent just 16 percent: by 2025 it projects that it will spend two-thirds of its budget on fire suppression.