They call it “global warming” but where you fall on the warming scale depends a lot on where you live. Not everywhere has warmed the same amount (or at all), and it certainly hasn’t happened at the same rate.

A new analysis from Climate Central, a climate education organization (and content partner with Climate Watch), breaks down the warming trends in the continental U.S., state by state.

Some states show an increase in average temperatures (Minnesota, Maine, Arizona and New Mexico, for instance), and some show nearly none (Florida, Alabama, Georgia). California ends up pretty much in the middle of the pack. One reason is its size: California is big and geographically diverse.

Though states have experienced different amounts of warming, the report finds that beginning in the 1970s, the pace of warming has accelerated across the country.

Tebaldi stressed that while the overall warming trend is consistent with what scientists expect the effects of greenhouse gas emissions to be, this study isn’t about causation. “It’s really not possible to [determine that] at this geographic scale of states,” she explained. This study also doesn’t project what’s to come. “The problem with future projections is we are pushing the system more and more, so what has happened in the past is not a very good sign of what is going to happen in the future,” she said.

Tebaldi and her co-authors used temperature data from the United States Historical Climatology Network, which has temperature records from more than 1,200 weather stations around the continental U.S. That allowed them to get more specific, and to go beyond national or regional trends.

“My interest in doing this as a scientist is to communicate the diversity in the behavior of climate at the local level,” she said. “But also to invite people to have a larger view of what’s going on, and not be bogged down by the fact that the Southeast is not warming. Because the bigger picture is one of warming, especially when you look at the most recent acceleration of the trends.”

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.

“On a hot 90-degree day in Riverside, everyone has the AC running. In San Francisco, not everyone has that luxury.” says Sheridan.

Sheridan says that heat-related deaths are projected to go up more in coastal cities like San Diego than in inland cities because people on the coast may be less acclimatized to extreme heat and the cities themselves may lack the preparation to deal with the public health consequences of lengthy, intense heat waves.

Projected heat-related deaths based on various climate change scenarios in San Diego. The red line indicates a high fossil fuel intensive scenario. Chart: CARB/EPA

“People that are acclimatized to warmer temperatures have a greater threshold for heat.” says Sheridan.

CARB spokesperson Dimitri Stanich says the study could lead to more local health policies in cities that are more vulnerable.

“Previously studies have focused on a macro approach to heat impacts but couldn’t specify impacts on California cities.” says Stanich.

Sheridan says one potential model for California cities is Philadelphia.  The health department there helped residents get fans, and it developed a buddy system to for neighbors to keep in touch during hot days. Philadelphia also has 60 cooling stations running during the summer, which can be found using this interactive map developed by the city’s Office of Emergency Management.

To see how temperatures are expected change in your region of California, check out the interactive Cal-Adapt tool from the California Energy Commission.

A new study finds large losses of springtime snow cover in the West in recent years, raising concerns about water supplies.

Spring snowpack in the West is an essential water resource, particularly in Southwestern states that are prone to summer drought, like California, Nevada, Arizona and New Mexico. (Credit: Wolfgang Staudt on Flickr)

Head south across the 40^th parallel, however, and things are dramatically different. While there is still above average snow throughout the Sierra, a relatively snow-less winter and spring has left much of the Southwest in a drought that has fostered record wildfires. Already local officials are worried there won’t be enough water to get through the summer months ahead.

This kind of contrast for the western spring snowpack is not unusual, though. It’s completely normal, and it’s exactly what climate scientists and meteorologists expect during years when the average weather pattern is influenced by La Niña, a climate cycle associated with cooler than average water temperatures in the tropical Pacific Ocean.

But while this north-south dichotomy turns out to be a regular feature of western climate, new research published today in the journal Science shows that, when compared to typical snowfall during the past 1,000 years, snowpack patterns appear to be changing as average temperatures climb. Scientists say that as temperatures continue to rise, this reduced snowpack will lead to more frequent water shortages in increasingly thirsty western states.

“We’re talking about simultaneous snowpack decline in the western watershed that supports 70 million people,” says U.S. Geological Survey (USGS) climatologist Julio Betancourt, who co-authored the new study. “We have to be concerned.”

For several years, scientists have observed that spring snowpack all across the West — in both northern and southern areas — has been decreasing. But now, Betancourt and a group of other climate scientists have found that the recent decline is a departure from patterns of the past 1,000 years. As part of the study published in Science, USGS ecologist Greg Pederson investigated tree ring data to learn how snowpack in the West, on either side of 40^th parallel, changed from year-to-year and from decade-to-decade. Looking back over nearly a millennium, he found that when the north had high snowpack, the south typically experienced low snowpack, and vice versa.

But Pederson and Betancourt noticed a change starting in the mid-1980’s. On average, the amount of snow on the ground at the beginning of April each year was decreasing everywhere across the West. It’s a trend that other scientists studying snowpack have pointed out. This has important consequences for water supplies for drinking water and agriculture, since many areas, including much of interior California, are dependent upon spring runoff for much of their water supplies.

Betancourt says that as average spring temperatures have risen, the snowpack has begun to melt earlier in the year (not the case this year, with record cold weather locking in substantial amounts of snow in many western ranges). Moreover, he says that in many places, the warmer temperatures mean that precipitation falls more as rain than as snow. So while the actual amount of precipitation hasn’t changed dramatically, the amount of rain has.

Snowpack in much of the West remains well above average, thanks to a cold and snowy winter and spring. In the Southwest, however, snowpack was well below average. (Image: NRCS)

“Snowpack is the water resources of the West,” says Greg McCabe, a USGS hydrology expert who was not directly involved in the new study, “and temperature has a dominant impact on the snowpack.” If warming temperatures in the West cause the snowpack to decrease even more, McCabe says, or if the timing of the melt each spring changes, then summer water shortages could happen a lot more often.

McCabe says the research provides valuable evidence about how snowpack has changed historically, and also how unusual the recent patterns appear to be.

According to Pederson and Betancourt’s findings, the way snowpack has changed in the past 30 years isn’t entirely unprecedented. There were two brief periods in the mid-1300’s and early 1400’s where there was less snow built up throughout the West.

“At both those other times in the past, we know it was warm then too,” explains Betancourt.

Now, however, climate scientists are predicting that average temperatures in the West are going to keep rising this century, due in large part to the buildup of greenhouse gases in the atmosphere. Compared to the past, when snowfall returned to normal as temperatures dropped, researchers now expect that warmer spring weather could keep spring snowpack on the decline for years to come.

“What’s happening in the spring for snow is critically important [for water availability] compared to what is happening in the dead of winter,” says Betancourt.

So what do the authors make of a year like this, which has brought frequent snowfall to the Sierra, even into June?

“There isn’t anything that has happened this year that isn’t consistent with what our new findings are,” says Pederson. Even as average temperatures increase in the coming years, there will still be cool years where above average snowpack builds up in parts of the West, particularly during La Niña years. “But these years will tend to be weather noise over top of the larger climate changes we will see over many years,” he says.

NPR’s Richard Harris interviews Pederson in this story for Morning Edition.

A version of this post also appears at Climate Central, a content partner of KQED Climate Watch.

(Photo: Reed Galin/Lone Tree Productions)

In the last decade, tiny forest-dwelling beetles have wiped out pine trees on millions of acres in the Canadian and American West, including Southern California. The rest of the state has been largely spared, but forest ecologists say that’s likely to change.

Reporter Ilsa Setziol recently spent some time tracking these bugs with an entomologist from the US Forest Service. They found beetles at work in Jeffrey pines and coulter pines in the San Bernardino National Forest, east of Los Angeles.

You can hear her radio feature on The California Report, produced by KQED Public Media. She also put together a slide show, so you see for yourself how these tiny creatures — normally part of a healthy forest ecosystem — can, under the right conditions, quickly run amok.

Scientists studying urban heat islands in 42 cities in the Northeastern U.S. have found that the greatest temperature differences between urban areas and the surrounding environment are in places you might not expect.

Cities located in forest environments have higher heat island effects than those in grasslands or deserts. The bigger the city, the greater the heat island effect. And the more densely-populated cities are worse off than the sprawling ones in this respect.

The results may seem counterintuitive. Isn’t sprawl supposed to be bad? And in one city – Las Vegas – the heat island effect was actually negative in one study, meaning its temperature was lower than the surrounding desert environment. That’s not because of all the water fountains at the Venetian or the Mirage casinos.

“People tend to have some trees, or parks, or lawns around the house or in the street and that’s why the temperature in Las Vegas is sometimes cooler than in deserts because there’s not much vegetation in the deserts,” said Ping Zhang, a research scientist at NASA’s Goddard Space Flight Center.

Zhang says the differences in heat effects come down to the amount of vegetation a city has. Densely populated areas tend to have less vegetation than cities that sprawl. That makes the more compact Providence, Rhode Island, have almost double the heat island effect of the more sprawing Buffalo, New York, despite their similarly-sized populations.

These differences have a big impact on urbanites. About half the world’s population lives in cities, an amount expected to increase to 80 percent by 2030. Hotter cities can exacerbate the effects of heat waves, which are increasing in frequency and intensity because of climate change.

Air conditioning is unlikely to make the circumstances better, said Cecíl de Munck of the National Center of Meteorological Research in France. Parisians still sweating over the 2003 heat wave, which killed more than 5,000 people, may turn to air conditioning as heat waves hit more frequently. But doing so would increase the city’s outside temperature by as much as 3.6 degrees Fahrenheit because of all the hot hair venting from AC units.

“We are faced with a vicious cycle since an increase in air temperature leads to an increase in demand,” de Munck said.

Best thing to do? The scientists agree that the answer is planting more vegetation.

Alison Hawkes is a freelance journalist in San Francisco and co-founder of Way Out West News.

Some say storing carbon underground as a way to curb greenhouse gas emissions is risky. The container has to last essentially forever, and what if an earthquake rips through the seal? But new research is showing that pumping CO2 underground could itself trigger earthquakes.

Stanford University geophysicist Mark Zoback looked at saline aquifers, one of the main types of geologic formations under assessment for carbon sequestration. He found that adding CO2 gas could increase the geologic pressure underground and set off a quake. Not a big one, mind you. Most likely you’d feel some shaking on the surface at a magnitude three or four. But underground the scenario would be a different story.

“At depth those earthquakes represent slip-on faults and if those earthquakes threaten the integrity of the geologic seal that’s keeping the CO2 in place, then they pose the hazard of inducing long-term leakage of the CO2 out of the repository,” said Zoback. “And of course that’s why it’s being injected in the first place, to keep it out of the atmosphere.”

The Earth’s crust is brittle because of shifting continental plates and just a bit more pressure can set off a quake in otherwise seismically safe areas. Never mind quake-prone California,” he said. “Even quiet places that have been eyeballed for carbon storage like the Midwest still have fault lines.”

To make a dent in global warming using carbon sequestration, about a billion tons of CO2 per year needs to be pumped underground by mid century – equivalent to the volume produced by burning oil and gas. Zoback figures that represents about 3,500 storage sites, or 75 new projects per year by 2050. He’s skeptical that all those sites can be found: “Are we going to invest the huge sums, we’re talking about many tens of billions of dollars only to find that when the earthquakes start occurring we’re going to have to stop the injection and find alternative strategies?”

Zoback presented his findings at the American Geophysical Union’s Fall Meeting in San Francisco.

Alison Hawkes is a freelance journalist in San Francisco and co-founder of Way Out West News.

A misty Lake McDonald in Glacier National Park; metaphor for the park's murky future? (Photo: Craig Miller)

Last month, in a post from Glacier National Park, I noted that Park Service director Jon Jarvis was not in a mood to mince words, calling climate change “the greatest threat to the integrity of the national park system that we’ve ever faced.”

That assertion was underscored last week in a new report on potential impacts to the parks from climate change. The collaboration by the Natural Resources Defense Council and the Rocky Mountain Climate Organization, attempted to zoom in on specific parks and projected changes ahead for ten national parks in California, as well as impacts on the state’s economy.

Death Valley is already the hottest spot in North America. The highest recorded temperature there is 136 dF. (Photo: Craig Miller)

Some conclusions under a “medium-to-high” emissions scenario, toward the end of this century: Higher temperatures in Joshua Tree National Park would mean the end of, well, Joshua trees in the park. Muir Woods could be as warm, on average, as San Diego has been historically, making it less hospitable to the park’s legendary coast redwoods. Death Valley, already the hottest spot on the continent, could become virtually uninhabitable during the summer, as average temperatures rise by more than eight degrees, Fahrenheit, over average readings from 1961 to 1990.

And of course, for Montana’s Glacier National Park, the report’s authors cite projections that the last of the park’s glaciers will be gone within 20 years, if not sooner.

This is, perhaps, a good place to pass along a favorite mantra of park rangers of late; that Glacier park wasn’t actually named for its glaciers, but for the geologic history that formed the region’s spectacular features. But it’s logical that Glacier, tucked into the northwestern corner of Montana, has become the “poster child” of climate change in the national parks. Scientists estimate that its 25 remaining glaciers could well be gone in a dozen years or so. Superintendent Chas Cartwright conceded that may be a small part of why Glacier is seeing record numbers of visitors — more than two million this year, which is the park’s centennial.

“Glacier isn’t the only place we’re seeing direct effects from climate change on the ground, right now,” Jarvis said, standing on a gravel bar in McDonald Creek. The parks chief cited apparent climate effects throughout the park system, including receding glaciers, withering water content in the mountain snowpack, and rain-on-snow events shifting from spring to fall. “That completely changes the system,” said Jarvis, who said they’re also seeing wildland fires burning an average of 20 days longer into the season, encroachment of more exotic plants, and species moving up in elevation or vanishing from the landscape entirely. “We’re not just gonna sit around and not do anything about it.”

The question is what to do about it, which presents some unprecedented dilemmas for park managers and scientists, which, Jarvis says, are “causing us to rethink even the fundamental principles of national parks.” Where as in years past, for example, new species moving into a park were looked upon as invaders to be dealt with inhospitably, now “they may be coming in because this is their last refuge.”

Accommodating migrating species is one thing. But also on the table is direct, possibly radical intervention to save others. Jarvis recounts the time when a park scientist asked him, sardonically, “When do you put a sprinkler system on the giant sequoias?” Jarvis asks rhetorically, “Where is the next habitat for the giant sequoia and are we as a society willing to move them, or plant them (somewhere else)? “The biggest step in climate change is starting to ask those kinds of questions and to bring the very best minds to help us begin to wrestle with those as a society.”

To this end, Jarvis is advancing a strategy with four key components:

- Expand the science and develop long-term data sets

- Embrace adaptation and multiple-scenario planning “at the landscape scale”

- Continue mitigation efforts, reducing the carbon footprint of the parks themselves

- Communication, leveraging the “extraordinary bully pulpit” that the parks provide, training scientists to speak to the layman, seizing opportunities to talk to the public about climate change.

Park managers worry about the "downstream" impacts of vanishing glaciers. (Photo: Craig Miller)

Jack Potter, who directs science at Glacier, reinforced that this isn’t just tomorrow’s problem. He noted that spring “green-up” is occurring about three weeks ahead of the 40-year average at Glacier, which means that the landscape is drying out sooner in the season. “No matter what scenario you look at, it’s going to be drier,” said Potter, pointing toward distant mountain snowfields. “That has all kinds of cascading effects downstream.”

Potter said park managers are being forced to re-examine “the role of parks as reservoirs for biodiversity” and “how we view the type of appropriate management…in the face of the possible scenarios that are out there relating to climate.”

To read about another challenge facing the parks, see Lauren Sommer’s story on air pollution impacts at Yosemite.

Photo: Craig Miller

It reached 113 degrees in Los Angeles on Monday, a record. And while a string of hot days in California doesn’t signify climate change any more than do record snowstorms in Washington D.C., the summer of 2010 did set quite a few records for high temperatures and heat waves. Although for us here in California, this week notwithstanding, we’ve had a pretty cool summer.

But this week’s heat — especially in Southern California — is a reminder of the ripple effects that could become commonplace if predictions of more frequent and severe heat waves come to pass, with a changing climate. Utilities pleaded with customers to conserve power as temperatures triggered record spikes in the electricity load and subsequent strain on the electrical grid.

But as Jennifer Skene writes for the KQED’s Quest blog, research suggests that it won’t take much “global warming” to make heat waves a regular feature:

As heat waves become more and more frequent, will people see them as evidence that global warming is happening? Or will people just get accustomed to the hot weather? New York City had the hottest summer on record; Russia suffered through horrible heat and fires. Are all these heat waves the result of global warming?

Several climate studies have found that heat waves are likely to become more frequent — and hotter  — as the earth warms up. In a recent paper out of Stanford University, two researchers ran several different climate models to see how a one-degree Celsius increase in average global temperature would affect heat waves over the next 30 years. They found that even with this relatively optimistic increase in average temperature, heat waves are predicted to happen more frequently — especially here in California.

One event is just one data point. To know whether there is a trend, we have to look at a whole cloud of data: heat wave incidence across several years. But, 2010 is shaping up to be a really hot year. So far, heat records have been set in 17 countries since the start of 2010.

Heat waves have some serious consequences. Heat stresses and kills organisms. Its effects in the marine intertidal zone have been particularly well documented, affecting seaweed, mussels, barnacles, and more. Heat can make trees drop their leaves, and can damage and kill crops, creating economic havoc. And people, particularly the elderly, can perish, as a result of dehydration and hypothermia.

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.

Temperature departures from average during July, 2010. Note the cooler-than-average weather along the California coast. (Credit: NOAA/NCDC)

For example, whereas Washington, D.C. tied its record for the warmest month on record, with an average temperature of 83.1 degrees F in July, San Francisco recorded its coolest average July maximum temperature since 1971. Only one day reached the 70 degree mark in San Francisco during July. The Climate Central infographic below shows some of the contrasting statistics from early to mid-summer. The data goes through the end of July, but in general the pattern of warmer weather in the East and cooler conditions along the West Coast has continued through much of August, with a few exceptions. For example, a heat wave briefly brought record warmth to the West Coast in mid-to-late August, but such heat was the exception there this summer.

Comparison of early to mid-summer conditions along the eastern seaboard vs. the West Coast. The data in this graphic goes through the end of July. (Credit: NOAA/NCDC; California State Climatology Office. Design by Russell Freedman.)
Click on the image for a larger version.

The cool temperatures along parts of the West Coast may be related to the emergence of a La Nina event in the equatorial Pacific Ocean, which is characterized by cooler-than-average water temperatures. In addition, an area of cool waters persisted offshore of California, Oregon and Washington, and this may have contributed to the below average conditions as well. Persistent onshore winds blew cooler air into coastal California during July, according to the National Climatic Data Center. The cool water temperatures off the California coast, extending northward into the Gulf of Alaska, can be seen in the image below, along with the La Nina conditions along the equator.

Sea surface temperature anomalies from May 30, 2010 to August 28, 2010. Note the cool waters in the equatorial Pacific, related to La Nina. Cool water anomalies can also be found off California, Oregon, and Washington. (Credit: NOAA/ESRL)

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.

This graphic shows the new record-high temperatures for the 17 nations that have broken their national records so far in 2010. If verified, the record set in Pakistan would also stand as the warmest temperature ever recorded in the continent of Asia. Click on the graphic for a larger version. (Graphic: Russell Freedman).

Masters wrote on his blog: “This is the largest area of Earth’s surface to experience all-time record high temperatures in any single year in the historical record. Looking back at the past decade, which was the hottest decade in the historical record, 75 countries set extreme hottest temperature records (33% of all countries.) For comparison, fifteen countries set extreme coldest temperature records over the past ten years (six percent of all countries).” According to Masters, Guinea, which is located in northwestern Africa, is the one nation so far this year to break its coldest temperature record, which occurred in early January.

The new record high temperature set in Belarus occurred during the Russian heat wave, which is still gripping portions of that country. Although Russia did not set any all-time record high temperatures, Moscow did, breaking 100 degrees Fahrenheit for the first time since records have been kept.

Temperature departures from average for July 2010, as measured by NASA. Note the warmth (in red) centered over western Russia. (Map: NASA Goddard Institute for Space Studies)

For the planet as a whole, 2010 has been extremely warm, with the June-to-July period ranking as the warmest on record for those two months combined.

Part of the warmth earlier this year may have been due to an El Nino event in the Pacific Ocean, which tends to warm the planet, but that event is no longer taking place. According to scientists, including Climate Central’s Claudia Tebaldi, man-made global warming is likely also playing a role in the record heat. Tebaldi and others have published studies showing that as the planet warms due to increasing concentrations of greenhouse gases, warm temperature extremes become more likely to occur.