Driven by climate change and a persistent ridge of high pressure over the Pacific Ocean that caused California’s drought, 2014 was the state’s hottest year ever recorded.
Temperatures last year averaged 61.5 degrees Fahrenheit in California — 4.1 degrees hotter than the 20th century average, according to a new report Thursday by federal scientists.
Three other Western states — Alaska, Arizona and Nevada — also experienced their hottest years since 1895, when modern instruments were first used. And Anchorage, Alaska, didn’t have a single day in 2014 in which the temperature dropped below zero, the first time in 101 years of record keeping.
“We do have a long-term warming trend across the globe, across the U.S. and in California,” said Jake Crouch, a climate scientist with the National Oceanic and Atmospheric Administration, which released the data. “This really warm year is just an exclamation point on top of a warming trend for that part of the country.”
Temperatures in the nation as a whole, however, did not break the all-time heat record.
In seven states in the Midwest and the Mississippi Valley, 2014 was one of their 10 coldest years since 1895. As a result, last year was only the 34th-warmest for the United States overall.
Scientists say the severe differences between the East and West were driven by the same cause: a ridge of high-pressure air off the West Coast present for much of the past three years.
Although it disappeared in December, leading to wet weather for California, the so-called Ridiculously Resilient Ridge has caused the state’s drought by forming a wall of air several miles high that diverted storms barreling in from the Pacific Ocean north into Canada.
The ridge recently has returned and is responsible for a hot, dry January, with high temperatures this week into the 70s across California. But it also has caused cold, snowy weather in the eastern half of the U.S., as the storms that the ridge detoured north have moved down from Canada, loaded with frigid air.
Scientists disagree about how much climate change may be responsible for the high-pressure ridge. But NOAA researchers noted Thursday that the cold weather afflicting the eastern half of the country was rare in 2014. The region was one of the only places in the world where temperatures were colder than historic averages.
NOAA, which oversees the National Weather Service, is expected to release new reports next week showing that 2014 was the warmest year ever recorded for the globe as a whole. Last week, the Japan Meteorological Agency already came to that conclusion, issuing a report showing that 2014 was the Earth’s warmest year on record. Already, the 10 hottest years globally, dating back to 1880, have all occurred since 1998.
Climate change has occurred through time over millions of years. But the current trend over the past century is being driven largely by the buildup of carbon dioxide from the burning of fossil fuels such as coal, oil and gasoline. And it is occurring faster than in the past, the overwhelming majority of the world’s climate scientists say. The carbon dioxide traps heat, acting like a greenhouse, and warms the planet.
Last spring, carbon dioxide concentrations in the Earth’s atmosphere exceeded 400 parts per million, according to NASA. That was the highest level in at least 400,000 years.
Before the Industrial Revolution, carbon dioxide concentrations were about 270 parts per million, as measured in air bubbles in ice cores.
Despite political disagreement over how to address climate change, the evidence of it is all around and easy to measure, experts say.
“We know that global average temperatures have increased decade over decade,” said Chris Field, a Stanford University biology professor and leading climate change researcher.
“And there’s no question we’ve seen a dramatic loss of mountain glaciers and Arctic sea ice — and an increase in sea level,” he added. “There have been people saying maybe there is something wrong with the temperature record. But many efforts to find a problem with those data sets haven’t found a problem. In fact, whenever we look we’re seeing the trends getting more robust.”
On Monday, California Gov. Jerry Brown made climate change a centerpiece of his inaugural address. He proposed changing a state law that now requires utilities to produce 33 percent of their electricity from solar, wind and other renewable sources by 2020 to 50 percent by 2030, in addition to doubling the energy efficiency of buildings and cutting petroleum use in cars and trucks by 50 percent.
“California, as it does in many areas, must show the way,” Brown said. “We must demonstrate that reducing carbon is compatible with an abundant economy and human well-being. So far, we have been able to do that.”
The state already has the nation’s most far-reaching energy efficiency standards for buildings and appliances, along with the toughest air pollution laws and most robust climate change regulations. Most important, the state has the only law in the nation requiring major industries, power plants and oil refineries to cut greenhouse gas emissions.
Beginning Jan. 1, that law, signed by Gov. Arnold Schwarzenegger in 2006, also required oil companies to reduce emissions from gasoline, leading to fears that it would spark price increases at the pump for motorists.
So far at least, that hasn’t come to pass. On Thursday, amid falling world oil prices, the average price of gasoline in San Jose was $2.64 a gallon, according to AAA, down 5 cents from a week before and down 33 cents from a month earlier.
Paul Rogers covers resources and environmental issues. Contact him at 408-920-5045. Follow him at Twitter.com/PaulRogersSJMN
