Autumn Makes a Sultry Entrance

California’s heat wave came late and is staying late

Sunset on San Pablo Bay. Coastal areas saw a balmy end to September, accompanied by air quality alerts.

The Great American Heat Wave of 2012 arrived later in California than in many parts of the country — and it’s in no hurry to leave.

Having nudged the upper 90s on Sunday, Sacramento closed out the month of September with a record 26 days of 90-plus highs, surpassing the 1974 record of 24 days. The trend is forecast to continue into the first several days of October, with a chance of hitting 100 for the first time since mid-August. Farther north, Sacramento Valley towns like Redding and Red Bluff are suffering similar bake-offs. Continue reading

How California Dodged the Summer from Hell

If the nation’s epic heat this summer seems like a distant bad dream, you must live on the West Coast. Not only did California largely escape the bake, it moved in the opposite direction, with temperatures running anywhere from one to five degrees (F) below normal in many areas.

The National Oceanic & Atmospheric Administration (NOAA) has released a map that provides a telling snapshot of summer aberrations around the nation.

While most of America cooked this summer, California bucked the trend.

David Kroodsma’s recent post for Climate Central provides excruciating detail of what the rest of the country was going through:

Using Climate Central’s record temperature tracker which draws on the National Climatic Data Center’s database, we found that June, July, and August saw more warm temperature records tied or broken than any other summer in the past decade: more than 26,500 record warm temperatures were set across the nation. By comparison, fewer than 3,500 record low temperatures were set — the fewest of any summer in the past decade.

It was a summer that brought new meaning to the term “Texas barbecue,” with NOAA confirming that the Lone Star State suffered the hottest summer on record for any state in the nation. Continue reading

Climate Study Predicts Deadly Heat for Older Californians

California’s heat waves are going to be getting longer and hotter in the coming decades, according to a new climate modeling study commissioned by the California Air Resources Board (CARB) and the EPA. The authors predict that heat-related deaths among California’s 65-and-over population could spike more than nine-fold by 2090. According to the study, currently more than 500 elderly people die annually from heat-related causes.

Using IPCC climate projections, the study models how climate change will impact California up and down the coast, including coastal cities like San Francisco and inland cities such as Riverside and Fresno.

Lead author Scott Sheridan, a geographer at Kent State University, says that the projected increase in heat-related deaths among those 65 and over are due in part to physiological reasons, but also to growing population size of this age group. By the end of the century, he says, the state’s population of people in this age bracket will increase from 4 million to 15.7 million. Sheridan says California communities that are already used to dealing with hotter temperatures, like the inland city of Fresno, may be better prepared to deal with the heat than relatively cooler coastal cities. Continue reading

The Long, Hot Summer: Longer & Hotter

Stanford study predicts the point of no return for hotter summers

By Katrina Schwartz

Just as many Californians are puzzling over winter-like weather in June, climate scientists are saying hotter days are ahead for most of the West. According to a new Stanford study (available soon at this link), we may be in for permanently hotter summers sooner than expected. Of course, for climatologists, “sooner” is a relative term.

Photo: Craig Miller

Plenty of climate scientists have studied the relationship between climate change and extreme temperature shifts, but until now no one has tried to pinpoint a moment when summer temperatures will permanently shift into a new “heat regime”, in which the coolest summer temperatures will be hotter than the hottest summer temperatures of the previous regime. Findings by the Stanford team suggest that the shift will likely happen sooner and be more widespread than expected. Continue reading

A Tale of Two Coasts: The East Roasts While the West Shivers

By Andrew Freedman

People along the West Coast from Seattle to San Diego, who have shivered through an unusually cool summer, can be forgiven for being just a little bit jealous of residents of the East Coast, where warm temperature records have repeatedly been smashed this summer. During June, July and part of August as well, it seemed that many coastal areas of the West were missing out on summer entirely.

Continue reading

Heat Records Set in 17 Countries — So Far

This post also appears at Climate Central, a content partner of Climate Watch.

By Andrew Freedman

California’s freakishly cool summer has been bucking a global trend this season. You’ve seen the headlines from Moscow and Pakistan–but that’s just part of the story. 2010 has featured several extreme heat events, as well as record flooding, in many countries worldwide. The number of countries that have set new national records for the warmest temperature recorded — 17 — would beat the old record of 14, provided that all of the new records are verified by meteorological agencies. According to meteorologist Jeff Masters of the private weather forecasting firm Weather Underground in Ann Arbor, Michigan, the countries that have set new records thus far this year comprise about 19 percent of the earth’s surface area. Continue reading

More Heat Waves and Health Problems Ahead

A backyard thermometer in upstate New York (Photo: Craig Miller)

I wore a wool coat to work today.  And I’m ashamed to say that last night I turned the heat on in my apartment.  San Francisco is obviously a special place, particularly in July.  And by “special,” I mean foggy, windy, and cold.  Weather.com says that it was in the 50’s last night and this morning, but I have trouble believing that.

So I found it a little bit hard to relate this morning on a conference call with journalists and scientists talking about climate change, heat waves, and public health.   It seems that much of the world beyond San Francisco has been experiencing some unprecedented heat lately.  According to NOAA, global combined surface and ocean temperatures for January through May 2010 are the warmest on record.   But in California, according to Tom Evans of the National Weather Service (NWS), so far this summer we’ve experienced pretty normal average temperatures, and that’s what the NWS Climate Prediction Center is forecasting for the rest of the summer for most of the state, he said, although the southeastern portion of the state may be in for some hotter-than-normal weather in the coming months.

On the call this morning, which was put together by the Union of Concerned Scientists, the speakers were careful to point out that one or two heat waves cannot be considered evidence for global warming, just at the snowstorms on the East Coast this winter couldn’t be used to refute it.  (This recent article in the Christian Science Monitor has more about the heat waves and changing attitudes about climate change.)

However, said NOAA climatologist David Easterling, “Warming temperatures increase the probability of heatwaves.  By the end of the century, what we currently consider a heat wave, or an extremely hot day, might become the norm.”

Warming temperatures can impact public health in a number of ways, said Michael McGeehin, director of the National Center for Environmental Health at the Center for Disease Control.

“Climate scientists predict that the U.S. will see an increase in the duration, intensity, and frequency of heat waves, and we know that heat waves are a public health disaster,” he said.  “They kill.”

And they could kill in large numbers in the centuries to come, according to a recent paper by Matt Huber of the Climate Change Research Center at Purdue.  Huber was on the call this morning to discuss his analysis, which found that if CO2 levels continue to rise over the next 200 years, hotter temperatures could make areas that are home to 50% of the world’s population uninhabitable during heat waves in the the centuries after 2100.  Problems start happening when the heat index is about 130, he said.  (A temperature of 105 degrees F with a humidity level of 50% has a heat index of 134.)

“I personally think that we’ve already committed to at least 2 degrees (Celsius) of warming, but the kind of warming we’re talking about here, which is on the order of at least 10 degrees Fahrenheit, maybe more like 15 degrees Fahrenheit, that’s something that we can still decide to avoid,” he said.  “And from our calculations it looks like we should really try and avoid that.”

And it looks like that potential warming could be becoming reality faster than some expected.  A new study out of Stanford announced today finds that “exceptionally long heat waves” could become commonplace in the United States in the next 30 years, particularly in the western US.  The study, headed up by Noah Diffenbaugh of the Woods Institute, used climate models to analyze what might happen if global temperatures rise two degrees C above pre-industrial levels by 2039. (An increase of two degrees Celsius is the limit agreed upon in the non-binding  2009 Copenhagen Climate Accord (PDF).)

The Stanford researchers found that “an intense heat wave – equal to the longest on record from 1951 to 1999 – is likely to occur as many as five times between 2020 and 2029 over areas of the western and central U.S.”

The analysis predicts during the 2030s the worst heat waves maybe be even more frequent.

It’s 57 degrees in San Francisco this afternoon, and I am wearing a winter scarf at my desk.  Despite all these grim predictions, right now it’s hard not to think that a little extra heat might be nice.

Ag Rules: Heading Off the Heat

Water cooler imprinted with heat safety tips. Photo: Sasha Khokha

Water cooler imprinted with heat safety tips. Photo: Sasha Khokha

It was like a pageant of farmers in plaid shirts; nearly a dozen speakers  in a Fresno County meeting hall, surrounded by vineyards. Farm leaders offered glowing praise of Cal OSHA’s new guidelines and training seminars that will help them comply with the state’s first-in-the nation heat safety rules–passed three years ago.

The love-fest with Cal-OSHA sets a new tone for agriculture. Growers have traditionally been at odds with the agency tasked with protecting the state’s workers. Farmers have challenged fines and complained about inspections. But despite the regulations,  six workers died last summer, including a pregnant teenage farmworker (some of the victims worked in construction or other outdoor jobs).

Part of the problem was that neither Cal-OSHA inspectors nor farmers had a very clear understanding of how to implement the rules. Is it enough to have an umbrella folded up in the back of a pickup in case it got hot? How hot? How much shade and water is enough?

Today, Cal-OSHA chief Len Welsh made it clear: when it’s 85 degrees or hotter, shade tents or umbrellas have to go up. And that shade should be no more than a two-and-a-half-minute walk away, according to the rules, which also require enough shade so that one-in-four employees are protected from the sun at any given time.

That’s still worrisome for leaders of  the United Farmworkers Union, who were conspicuously absent from the press conference. There are times, they say, when the temperature soars well above 100 or spikes suddenly and everybody should get a break. The UFW says the new guidelines are too vague, and Cal-OSHA’s publicity campaign to educate farmers isn’t enough. Union leaders say the state should impose more fines and criminal penalties when workers die in the heat.

Despite a Cool Summer, LA is Getting Hotter

It was looking like a cool summer in Los Angeles until a couple of weeks ago.  Temperatures in downtown LA topped 90 degrees Fahrenheit only once this summer until September 25th.  Since then, according to the National Weather Service’s Climatological Report, the city has seen 4 days above 90, including today. Which is what a group of university and NASA scientists say Southern Californians had better get used to.  

The scientists analyzed 100 years of temperature data collected in downtown Los Angeles  and found that between 1906 and 2006 the average number of extreme heat days – those over 90 degrees – increased from 2 per year to more than 25 per year.  In that time, the average maximum daytime temperature for the city climbed 5 degrees.  Heat waves have also increased, from 2-day events to sweltering stretches that last for 1-2 weeks. The scientists predict that in the coming decades, 10-14 day heat waves will be the norm. 

The bottom line? Even though this summer was a cool one, Southern California is going to get warmer, for longer periods of time. “Our snow pack will be less, our fire seasons will be longer, and unhealthy air alerts will be a summer staple” said study co-author Bill Patzert, a NASA climatologist and oceanographer.

The scientists assert that the main cause of this increase in temperature and heat days in Los Angeles is due the “urban heat island effect,” which makes urban areas 2-10 degrees Fahrenheit warmer than the surrounding rural areas.

Check out a historical temperature chart for downtown Los Angeles and a full report on the study here.