Despite a cool East Coast, U.S. helped boost planet’s record hot spell

By Gayathri Vaidyanathan | 01/09/2015 08:15 AM EST

Except for a cool Eastern Seaboard, the planet as a whole experienced the warmest year on record in 2014, the National Oceanic and Atmospheric Administration confirmed yesterday.

And even the United States was not all that cool. The nation experienced temperatures 0.5 degree Fahrenheit above the 20th-century average, making 2014 the 18th straight year with an anomalous temperature record. In addition to high temperatures, there were eight natural disasters in the United States last year that cost $1 billion or more in damages, NOAA said.

The West Coast drove the higher temperatures. California, Alaska, Arizona and Nevada all experienced the warmest years on record. And temperatures in Anchorage, Alaska, stayed above zero F in 2014, the first time this has happened since record keeping began 101 years ago.

In contrast, the East Coast became cooler than average, though no temperature records were set.

"If we look at global temperatures, it is really just eastern North America that is experiencing these colder temperatures during 2014," Jake Crouch, a climate scientist from the NOAA National Climatic Data Center, said during a press call. "So, we really are the exception to the rule across the globe."

The cool temperatures in the East and the warmer West have been tied by meteorologists to very warm sea surfaces in the northern Pacific Ocean, which triggered the formation of an atmospheric ridge over the West Coast of the United States. This coincided with a trough along the East Coast, which lowered temperatures, Crouch said.

Whether these atmospheric patterns that persist over weeks or months can be linked to long-term climate change cannot be determined, Crouch said. But the high temperatures, particularly on the West Coast, stand out in a long-term trend of global warming seen throughout the world, he said.

Calif. becomes an ‘exclamation point’ for heat

Temperatures in the past year were the highest on record for California, at 0.18 F above the previous record in 1934.

"We do have a long-term warming trend across the globe, across the U.S. and in California, and this really warm year is just an exclamation point on top of the warming trend for that part of the country," Crouch said.

The high temperatures have helped exacerbate an ongoing drought that began in 2011. Nearly 32 percent of the state remains in exceptional drought, and 78 percent of the state is in extreme drought, the U.S. Drought Monitor announced yesterday, despite near-average rainfall in the state last year.

The snowpack on the Sierra Nevada, which provides a third of California’s water supply when it melts in the spring, is less than half of normal for this time of year, the Drought Monitor stated.

The drought could have been exacerbated by the record heat in the state, Crouch said. Dry soils cause temperatures to rise, which in turn leads to more evaporation and increased release of water vapor by plants.

"It’s kind of a feedback mechanism where the drought and the heat reinforce each other," he said.

Whether the multiyear precipitation deficit between 2011 and 2013 that caused the ongoing drought can be linked to climate change has been unclear, with scientists coming down on both sides of the issue.

Hotter nights and more weather extremes

The drought on the West Coast counted in a list of eight disasters that each cost more than $1 billion in damages and that cumulatively killed 53 people.

The number of such events equaled the average seen over the past decade.

Other natural disasters on the list included hail and high winds in Colorado, Texas and Kansas in September and October last year; flooding in Michigan and the Northeast in mid-August; tornadoes; hailstorms; and winter storms.

Islip, N.Y., received 13 inches of rainfall in a single day Aug. 12, setting a record for the state. Flooding was also recorded in Maryland and Long Island, N.Y.

In Nebraska, baseball-sized hail and 90 mph gusts of wind in June caused damage to property and killed two people.

Eighty-three tornadoes were reported across the Midwest in April, with Mississippi recording the third highest number in a single day since the 1950s. These tornadoes, together with floods in the Southeast, killed 33.

Winter storms in the Northeast, Midwest and Southeast led to the loss of 16 lives.

NOAA did not link such storms to climate change because attributing specific events to long-term climate trends can be challenging.

But these events underscore the fact that extreme temperatures, precipitation and storms are occurring more frequently in the United States. Extreme weather is tracked by the Climate Extremes Index, which was 35 percent above average last year, according to NOAA. Extremely warm nighttimes and high single-day rainfall events were particularly frequent.

These extremes have had profound impacts on local economies, said Adam Smith of the NOAA National Climatic Data. The Western drought has had impacts on agriculture, tourism and hydroelectric power generation, he said.

"Indeed, a drought is a silent disaster, but the impacts are quite profound," he said.