Climate change could dramatically affect the microclimates that have made California wine country so successful.

You've probably heard of the wines that made Napa and Sonoma famous, like Cabernet Sauvignon or Chardonnay. But what about Negroamaro or Nero d'Avola?

They're wine grapes that are well-adapted to hotter climates – the kind of conditions that California may be facing as the climate continues to warm. But for wineries that have staked their reputations on certain wines, adapting to climate change could be a tough sell.

Talk to any wine lover in California and they'll tell you how lucky they are to live in such rich wine-producing region. Take the recent meeting of the San Francisco Wine Lovers Group at Toast wine bar in Oakland, where the favorites are California Pinot Noir, Russian River Zinfandel, and Napa Cabernet.

In fact, the type of grape – or varietal – is how most of us think about wine.

"That's the big problem," says Andy Walker, a grape breeder in Viticulture and Enology at the University of California-Davis. "We've spent the last 100 years emphasizing varieties and we've really marketed those names very effectively."

Walker is strolling through UC Davis's test vineyard, where hundreds of different wine grapes from around the world are grown. The vast majority are unknown to consumers, because most wineries focus on only a handful of grapes. "Chardonnay, cabernet, merlot, pinot noir – those would make up probably a large percentage," he says.

Those are all French varieties, mostly suited for cool climates. California is warm by comparison and thanks to climate change, it's expected to get a lot warmer. Extreme heat can be the enemy of good wine. "It destroys acidity primarily and it changes color and aromatics," says Walker.

According to a recent study from Stanford University, about two degrees of warming could reduce California's premium wine-growing land by 30 to 50 percent. That could happen as soon as 2040. Water supply is also expected to be an issue.

"I think the interesting thing for me as a breeder is to take advantage of this and say, OK, here's a chance now to change thought and let's actually readapt varieties to California," he says.

Andy Walker walks through UC Davis's test vineyard.

But in many circles, grape breeding is a dirty term, according to Walker.

"Viticulture is the most backward form of horticulture that exists. We use these varieties that haven't been changed for decades, for millennia in some cases. And it really doesn't make any sense."

The problem starts in today's vineyards. If you look at rows of Pinot Noir vines, you aren't just looking at the original varietal. You're looking at clones. That's because vines are grown from a branch that's taken off an existing plant.

"Pinot noir is being propagated year after year after year. This essentially means that grapes have not been having sex very much," says Sean Myles , a geneticist at the Nova Scotia Agricultural College.

He says breeding is key for other crops, since farmers need seeds to plant every year. Wine grapes miss this opportunity to develop adaptability and disease resistance, since vines don't grow from seeds

"That means that we're not allowing the genetic material to be shuffled anymore. That genetic material is now standing still in time. And while the pathogens are evolving, the pinot noir is not," says Myles.

Andy Walker says there's plenty of genetic diversity out there for breeding, if you wanted to make today's varieties more heat tolerant or drought resistant. But there's a very big problem. Once your breed your pinot noir with something else, you can't call it pinot noir anymore.

"The last decision that hardest. Can we market this variety? We know it produces exceptional wine. We know the quality is better. But the next step is can we actually market it," says Walker.

That's a deal breaker for many vineyards, who think consumers won't buy varieties they don't recognize. Walker says looking ahead to climate change, there are already varieties out there today from Italy and Spain that would do well in a warmer California. "We could produce Barbera instead, or Negroamaro or Nero d'Avola from southern Italy and we'd be far better ahead."

These lush reds are popular in Italy but not so well known to Californians. Walker says it'll come down to marketing. "I don't think it's the consumer that's gonna make the shift. They have to be directed."

"I think it's really a pull from consumers," says Nick Dokoozlian, a Vice President at E & J Gallo Winery, the largest family-owned winery in the US. "In most cases, we're responding to consumer demand for a cultivar."

Dokoozlian says Gallo has been testing new wine varieties throughout its vineyards and has found some promising grapes. "The problem is we can't necessarily sell those varieties. Consumers aren't aware of them. The marketing aspect of climate change and the adaptation to climate change, really, the hurdles on the marketing side are much, much more significant."

Since vineyards can last up to 30 years, he says switching varieties is a major financial gamble. "The wine business is an extremely capital intensive business. The financial risk of planting the wrong variety in the wrong place is pretty significant."

Still, given the temperature and water supply changes projected for California, Dokoozlian sees the market shifting eventually. "I'm looking forward to having world-class California Nero d'Avola soon."

The Golden Gate Bridge, in its summer cloak of fog. Photo: kqedquest.

Another foggy morning. Why is the Bay Area so foggy in summer? To answer that question, look west—at the Pacific Ocean.

If you’ve ever tried to swim at the beach in Northern California, your chattering teeth will tell you that the water is cold. This cold water makes fog form. The cold water cools down the air above it, and cool air can’t hold as much moisture as warm air. The moisture condenses into fog.

The water along the coast of California is cold for a couple of reasons. First, the California Current brings cold water from Alaska southward along the coast. And second, cold water from the deep ocean comes up to the surface through a process called upwelling. From March through September, wind blows southward along the coast. This wind, combined with the rotation of the earth, creates surface currents that move water from the coast out into the ocean. Something has to fill in the space that was left behind when the surface waters moved out to sea. So water from the deep ocean is sucked to the surface.

The water from the deep ocean is full of nutrients. Upwelling is super important for ocean dwelling creatures—the nutrients in the water feed the phytoplankton and move on up the food web. The lush kelp forests along the California coast exist because of upwelling. And the water from the deep ocean is really cold, which makes fog form over the areas of upwelling.

The fog rolls in from the ocean onto land in the morning as the rising sun heats up the land. Warm air rises, and something has to fill its place—the foggy air that’s hanging out above the ocean.

So to summarize, summer winds create upwelling, fog forms over the cold water, summer sun heats the air above the land and makes it rise, and the fog gets sucked in.

However, the amount of fog has declined by 33% over the past 60 years. UC Berkeley professor Todd Dawson talks about this in QUEST’s Science on the SPOT: Science of Fog. Fog is declining in part because upwelling along the coast has weakened, thanks to global warming.

Warmer air temperatures are heating the surface layer of the ocean. As the surface layer gets warmer and thicker, it becomes harder for the cold deep water to mix with the warm surface layer. This weakens the upwelling. Weak upwelling means less fog is produced.

Someone (though maybe not Mark Twain) once said that the coldest winter they ever spent was a summer in San Francisco. That San Francisco summer was cold because of the fog. Which brings to mind another (potential) Twain quote: “Everybody talks about the weather, but nobody does anything about it.” San Francisco is getting less and less foggy, thanks to global warming, and so far we aren’t really doing anything about it.

Grasses blow in the wind near Toms Point in Marin County, on the east side of Tomales Bay. Most of the grasses in the photo are exotic. Photo: Brody Sandel.

Full disclosure here: Brody, Emily and I were all grad students together in the same lab at UC Berkeley. So when Emily told me she had a new paper, I was curious to see what it was all about. It turns out their study is really cool. It looks at the interaction of two major world-changers: invasive species and climate change. Their paper talks about exotic species—species that are not native to a particular habitat but are not necessarily detrimental, and noxious weeds—species that are somehow disruptive, because they outcompete native species or alter the habitat. Noxious weeds are what we would also call invasive plants.

Brody and Emily’s study draws on existing datasets on current plant distribution across the state, plant traits, and current and future climate. They mapped the distribution of all the different species in California grasslands, using data from the Jepson Manual (the bible of California plant life), and a few other sources, to fill out an 800-cell grid of the state. They looked at the traits of the species—including how tall the plants are, whether they are annual or perennial, how much of their leaf mass comes from nitrogen, and the size of their seeds—and examined how the traits relate to the climate where the plants live today. Especially important was the proportion of exotic species in each of the grid cells. Then they turned up the temperature. They predicted the proportion of exotic species in each grid under climate change scenarios: higher average temperatures and less available water.

They found that as the temperature increases and water availability decreases, the proportion of exotic species increases. And, the proportion of noxious weeds increases. Higher temperatures favor traits that tend to be possessed by exotic species, such as tall plants with big leaves and annual lifestyles. These are the same traits that made the plants successful invaders in the first place. For example, a tall plant extends above a short plant, stealing its light. But burly exotic plants like Holcus lanatus outcompete native species for light. And generally, plants with big seeds grow to be hearty seedlings, which are better competitors than scrappy little seedlings grown from modest sized seeds. This study predicts that noxious weeds will become even more prevalent, because they have traits that will serve them well under the conditions of climate change. The changing climate acts as a filter, straining out the native species.

The noxious weed Holcus lanatus, a.k.a. “The Hulk,” so named because it towers above native grasses and outcompetes them for light. Photo courtesy of Brody Sandel.

Years ago, I asked a grad student friend why she studied grasslands. I just couldn’t understand the appeal of a field of grass—it seemed boring. My friend Tasha explained that she just loved the way grasses look when they blow in the wind. A few weeks later, I went with her to her field site near Point Reyes, and I immediately understood the aesthetic appeal of grasslands. If you’re picturing a green manicured lawn with short little blades of grass, toss that idea right now. Instead, think of taller grasses, shin height or higher, in all shades of green, brown, gold and even purple. Think of the colors shifting as the wind blows. It is really a beautiful sight. California’s grasslands are expected to expand as the climate changes. But the inhabitants of these grasslands won’t be the grasses that were there 100 or 200 years ago. Instead, there will be a bunch of weeds blowing in the wind.

To learn more about the interplay between California’s native plants and exotic species, check out the California Native Plant Society, the California Invasive Plant Council, or take a workshop with the Jepson Herbarium at UC Berkeley.

How one climate model breaks the planet into a 10,242-cell
spherical geodesic grid. Source: Prabhat, LBNL.

In my QUEST radio story this week, we learn about how faster supercomputers will help scientists run climate simulations. One of the trickiest aspects of that is dealing with clouds. To find out why, I sat down with Bill Collins, head of Climate Science Department at Lawrence Berkeley National Lab.

How important are supercomputers to climate change science?

We understand the climate by making observations using satellites and ice sheets. But the only crystal ball we know about, short of a time machine, is the supercomputer.

We started with by running simple climate models on supercomputers that included simulating the weather, rainfall, and carbon dioxide. In the last 20 years, the complexity of models has vastly increased. They now include ocean dynamics, glaciers, sea ice and the exchange of carbon dioxide between the ocean and the land, known as the carbon cycle. All of that has required an immense increase in computing power.

Climate models today simulate the atmosphere and carbon cycle by breaking up the planet into a grid and running the calculations in those segments, right?

Right, in modern climate models, we simulate the weather every two to five minutes and then average that to see how the climate is going to change across that grid. We simulate the weather in segments that are 25 kilometers wide.

Our goal is model something the size of San Francisco County, which is about 10 kilometers wide. Once we get to that scale, we're going to be able to provide local projections of climate change. We're honing in, but we're not there yet. We need bigger computers to get there.

The other reason is we'd like a higher resolution is that we're having to make educated guesses about certain things, like clouds. And those educated guesses are a source of uncertainty. Cloud systems can be very large or very small. We don't know how they work at the large scale, but we do know how they work at the small scale. So the trick is to simulate them at the small scale.

What role do clouds play in the climate?

Clouds stabilize the climate. They reflect sunlight, so they act like a sun shield. But they also trap heat from the Earth. They both heat and cool, but their net effect is to cool the planet. So the question is, what happens if climate change makes the cloud cover decrease or increase? Understanding how clouds will be affected by climate change has become a critical question.

Where clouds form in the atmosphere makes all the difference. High clouds reflect sunlight, but they're mostly very efficient blankets. Clouds low in the atmosphere aren't very good blankets. They act as a big sunscreen, reflecting energy.

How do climate models today treat clouds?

Models today represent clouds throughout statistical methods over large areas. That models their effect, but not really how they work. And you don't want to assume how they work now is how they'll work in the future. We want to get to a level of physical modeling of clouds.

To do that, we need to be able to resolve them at a small scale. The current Intergovernmental Panel on Climate Change projections use a 50 kilometer grid, but that's still not good enough. The scale we need to get to is about 10km or so. So once supercomputers can get us there, we'll be on a much more solid footing to predict how clouds might be affected by climate change.

If we tried to run climate models at that resolution now, it would simply take too long. The rule of thumb is that we'd like to simulate the climate a thousand times faster than it happens. So simulating three years in a day is our rule of thumb. If we increase our resolution from 50 kilometers down to 10 kilometers, that increases the computation demand by a factor of 125. At that point, you're doing 9 days in a day. We can't afford to do that and make the kind of projections that policymakers need in the next century.

Climate model resolution of California. Source: LBNL.

What will we learn about California with better climate models?

Temperature changes are happening faster in the mountains than in the valley. So climate change in California is locally specific. A big questions is how much snowfall we'll get in the future. That's going to hinge on what the temperature is at the peaks of the Sierras. So knowing how fast the temperature change is going to happen at the peaks is going to make a big difference to our water supply.

Local climate predications are really important for state and local policymakers. How should building codes be changed? How will local areas adapt? We need accuracy at the state and local level to pull off that planning.

If you can resolve clouds better in the future, will that change overall projections about climate change?

I'd be shocked if they did. The physics of climate change is really basic. We're not going to get out of global warming. We know based on the projections that we've had in hand for the last 20 years that the time to act is now. The longer we wait, the harder the solutions are to avoid dangerous levels of climate change.

What better resolution of clouds is likely to give us is a better idea of changes in rainfall. That's really important to our water supply, our forests, and our crops. Higher resolution will also give us better predictions of climate change extremes, like when droughts happen or the impact of downpours on rivers and dams.

We want to know about climate change that goes bump in the night. We're concerned about abrupt climate change – the type that occurs quickly over a large region, like the melting of the permafrost. We're also worried about extreme climate change – intense, highly-localized changes like heat waves, hurricanes and tornadoes. Both of those are stressors on society and the environment. They've been difficult to simulate since we haven't had the computing power. But now, thanks to advances, we're getting there.

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The life history cycles of the bay checkerspot butterfly and its host plant, Plantago, don’t match up anymore. When the butterfly eggs hatch, the plant is no longer edible. Photo: kqedquest.

Tomorrow is our summer solstice—the longest day of the year here in the Northern Hemisphere. For folks in the Southern Hemisphere, tomorrow is the winter solstice, the shortest day of the year. The solstices occur thanks to the tilt of the earth. Humans have been recognizing and celebrating the solstices throughout history; Stonehenge is just one example. But we humans are not the only creatures that pay attention to day length. The life cycles of myriad plants and animals are controlled by the length of the day.

Many plants and animals are sensitive to the photoperiod, or day length. As day length grows longer throughout the springtime, many species of plants begin to flower. Other plants are triggered to reproduce when the day length becomes shorter. In these plants, a protein is actually responding to the number of hours of darkness, not to the hours of light. Many animals respond to day length, too. For many bird species, a critical day length initiates their reproductive maturation and is their cue to begin migrating. Decreasing day length also prompts hibernation in many animals. In all of these examples, photoperiod is controlling organisms’ phenology—the timing of life events, like plant flowering and bird egg laying. Phenology is often tied to the seasons, because of organisms’ responses to day length.

Phenology can also be controlled by other factors, like temperature and the amount of rainfall. As the days grow warmer because of climate change, the timing of organisms’ life cycles is shifting. Spring happens earlier than it used to, and many springtime life events are happening earlier too. In major 2003 study of nearly 700 species, including birds, insects, frogs, flowering plants, and trees, 62% of species’ life cycles had shifted over an average of 45 years. Birds and frogs bred earlier, migrating birds and butterflies arrived sooner, and plants flowered and buds burst earlier.

This is likely leading to a widespread phenological mismatch; while some organisms are responding to earlier springtime temperatures, other organisms are still tracking day length. This means that insects emerge ready to feed on particular plants, but the plants are not yet edible. The insects don’t get their food, and the plants don’t get pollinated. Or migrating birds arrive hungry, and their food source has not yet ripened.

It is difficult to know to what extent phonological mismatches are taking place. A proper study of phenology requires a lot of data—many widespread observations of when a particular plant is flowering, or when and where a particular migratory bird is present. This is where you come in. The National Phenology Network has a citizen science program that allows people across the country to record their observations of plants and animals. This crowd-sourced data will be used to determine the extent and effects of shifts in the timing of organisms’ life cycles.

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I just got back from a month-long rock climbing trip near Barcelona, Spain—and though I’d never been there before, the vegetation looked a bit familiar. Hiking around, my skin was constantly scratched by the stiff, sharp leaves of shrubby plants—similar to California’s chaparral. Lizards I almost recognized darted across dry patches of dirt. The weather was similar to California’s, too—being summer, it was hot and dry. This was no coincidence. Spain, in the Mediterranean Basin, is California’s climate cousin.

On every continent except Antarctica, the west coasts share a similar climate, called the Mediterranean climate. It is characterized by warm to hot summers with basically no rainfall, and winters that are short, mild, and wet. A world map of Mediterranean climate regions shows that in addition to the Mediterranean Basin and the coast of California, the west coast of South America from Peru to Chile, the northwest part of Africa, parts of western and southern Australia, and parts of South Africa all share the Mediterranean climate. The sweet spot is at about 35 degrees latitude, both north and south.

Climate is a product of ocean currents and the up-and-down movement of air above Earth’s surface. In the northern hemisphere ocean currents swirl clockwise, and in the southern hemisphere ocean currents swirl counter-clockwise, thanks to Earth’s rotation and the resultant Coriolis Effect. The direction of the currents means that water flowing along the west coast of all continents is cold, having recently come from the poles. Air follows the ocean currents, binging storms and precipitation in winter. In summer, the effect of the up-and-down movement of air in the atmosphere kicks in and influences climate. In summer, dry air sinks along the latitude band of about 30 degrees to 35 degrees. The dry sinking air prevents storms from moving in, and is largely responsible for Mediterranean regions’ summer droughts. Sinking and rising of air on Earth’s surface is due to the Sun’s uneven heating of Earth.

Those scratchy shrubs that plagued me throughout my vacation are the signature flora of Mediterranean climates. Drought-tolerant evergreen shrubs exist in every Mediterranean region. In fact, the word to describe California’s scrappy shrubs, chaparral, has Spanish origins—chaparro (initially txapar in Basque) means dwarf evergreen oak. We now use the word chaparral to refer to the whole habitat type, not just the shrubs themselves. Elsewhere, this habitat type goes by other names. In the Mediterranean region, it is called maquis; in South Africa, it is the fynbos; and in Australia, it’s called kwongan.

These shrubs are not phased by the fact that Mediterranean summers are bone dry. They have evolved plenty of adaptations to drought: small, light-colored leaves that reflect sunlight, rather than absorb it; leaves that often point towards the sky, to minimize the amount of sunlight (and heat) they absorb; and the ability to hang on to those leaves from year to year, rather than waste energy making a new set each spring. But by autumn, the crispy vegetation is pretty flammable. Spain appears to be prepared; it seemed like half the rock climbers I met were bomberos, or firefighters. However, climbers are probably drawn to this career not because they could potentially save their favorite climbing areas from fiery infernos, but because the hours (24 hours of work, 72 hours of weekend, repeat) facilitate frequent climbing trips.

The similarity of climates at about 35 degrees latitude is not lost to the wine industry. A map of wine producing regions of the world matches up almost exactly with a map of the Mediterranean climate regions. Growers can take advantage of the perfect conditions for growing grapes. And vacationers can take advantage of these conditions, too—I returned from my vacation relaxed, suntanned, and having tasted quite a few good wines.

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Water forecasting could be thrown off by a changing climate. Credit: Craig Miller

The severe flooding on the Mississippi River has left a lot of damage in its wake. It's an extreme event that government and insurance companies try to plan for by predicting the risk. But climate change is throwing a wrench in those calculations.

Most of us don't think about risk. We think about randomness. That's illustrated by a scene in the 1982 movie, "The World According to Garp", where Robin Williams is shopping for a new house with his wife. They're standing in front of one home when…a plane crashes into it.

Despite the crash, the Robin Williams character agrees to buy the house saying, "It's been pre-disastered! We'll be safe here."

That may not be a typical reaction, but climatologist Kelly Redmond says it reveals a lot about how we think about risk. "It has to do with how we describe rare things. We spend societally an enormous amount of resources and time and attention guarding against the very worst possibilities."

Listen to the QUEST radio story Insuring for Extreme Weather

You've probably heard of the "100-year flood." That's a flood so severe that it has a one in one hundred chance of happening every year. But how do we know that?

"About the only way we can get at how rare a rare thing is is by looking at a past record," says Redmond. So for floods, government agencies look into the historical record to see when floods happened in the past. They use that record to predict future flood risk.

But this relies on a very basic assumption. According to Redmond, the assumption is that the statistics of the future will look like the statistics of the past.

There's a fancy term for this – it's called stationarity. But there's a problem.

"What we don't know but what we suspect with changes in climate is that those statistics, especially about rare things, may change," says Redmond.

The US is already warming. Climate models show that western states could see more extreme weather as the climate continues to change. So, Redmond says, chances are good the future won't look like the recent past.

Jeanine Jones of the California Department Water of Resources agrees, saying "a lot of California's existing infrastructure was designed on assumptions that are no longer valid."

History of Water Forecasting in the West

Jones says using the past as a guide for the future is a huge part of water planning and building codes. The idea was first adopted in the 1940s and 50s, when dams and infrastructure were built at record speed in western states.

"Congress was looking at all these water development plans coming in from the Corps of Engineers and the Bureau of Reclamation and wanting a common standard to compare all the projects," says Jones.

So they forecasted flood risk and water supply by looking at historical data. "But they had very short data records. Maybe they only measured records of 20 years, 50 years. And that's not really very long," Jones says.

Today, everything from building codes to home insurance is based on this short window of data. And so is another critical forecast.

During the winter, surveyors measure the Sierra Nevada snow pack every month, so they can crunch the numbers and predict the year's water supply.

"It is very widely used by reservoir operators, by water agencies, by farmers who are looking at what are my chances for having a full water supply," says Jones.

But climate models show that more precipitation will fall as rain in California, instead of snow. And that means spring runoff could behave very differently. "At some point, conditions will change enough that we've reached a tipping point where those statistical approaches really aren't valid anymore," Jones says.

An accurate water forecast is crucial to California's economy. So Jones says water officials are looking at using computer models to forecast spring runoff.

But when it comes to updating flood risk and building codes to reflect climate change, Kelly Redmond says that could take decades. "We have to get a buy in from the engineering community, the city planners. Because there's so much expense to goes into building a bridge or a culvert or a building."

A New Breed of Insurance Company

There is one industry that's taking note of climate change – insurance.

"The increased variability in climate is going to start to dramatically affect the profits of corporations worldwide," says David Friedberg, CEO of San Francisco-based Weatherbill.

Weatherbill is something of a next generation insurance company. They start with computer models that simulate weather and climate patterns. "We then use those sorts of models to determine what sort of price we should charge for certain weather events occurring," says Friedberg.

Weatherbill works mostly with farmers, insuring them against extreme weather for between 40 and 400 dollars an acre. "There's a range of things that can occur and that range is certainly widening. And as a result we should start to charge more for those sorts of events when we're insuring them."

Friedberg says this kind of insurance makes sense to a lot of farmers they work with, who are already noticing changing weather patterns. Investor Vinod Kholsa and Google have also noticed and put millions into the company. They're betting new software will be the answer when today's methods no longer work.

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El Nino temperature anomalies in the eastern Pacific Ocean.

Jennifer Skene's post earlier this week here on the QUEST Community Science Blog about the potential effects of this winter's La Niña is a great lead-in for discussing this climatic phenomenon in a bit more detail. As Jennifer noted, the La Niña weather pattern is the flip side of El Niño, which is when unusually warm waters of the eastern Pacific Ocean affect weather patterns for large swaths of North and South America. For California, El Niños typically result in increased precipitation in the winter months and La Niñas are characterized by drier conditions.

El Niño is the nickname of the climate pattern called the El Niño-Southern Oscillation, or ENSO. Although we don't hear much about the Southern Oscillation part, it is the atmospheric component of this linked ocean-atmosphere phenomenon. Although the physics of ENSO is still not fully understood and the subject of current research, the regularity of the pattern is well documented. The image below is a time series plot of ENSO events for the past 60 years. The positive values filled in with red are the warm ENSO phase (El Niño) and the negative values in blue are the cool ENSO phase (La Niña). The regularity isn't perfectly on beat — it varies from 3-7 years between measurable events. But this is enough regularity to make ENSO one of the more predictable patterns climate scientists have studied.

While the timing of ENSO cycles might have some predictability, the magnitude of ENSO (the height/depth of the peaks) can vary significantly. Some are weak while others are quite strong. The 1997-1998 El Niño is considered to be one of the strongest of the past 100 years and is still in the memory of many Californians because of the intense precipitation and subsequent flooding it unleashed.

What's really interesting is that this 3-7 year pattern of alternating ENSO phases is just the shortest timescale in a climate phenomenon with multiple rhythms superimposed. Paleoclimate research has revealed that ENSO also beats at timescales of hundreds to thousands of years. The image below is very similar to the above diagram — it has time in years on the horizontal axis and occurrence of ENSO events on the vertical axis. (Important difference to note are that the present is on the left side on this plot instead of the right side and time is in 'years ago' and not a date.)

This plot goes back to 10,000 years ago and shows the variability in ENSO at a much longer timescale. Within those taller peaks in the plot are numerous individual El Niños that are grouped together in time. This doesn't mean that every single El Niño is very strong — just that during a few hundred years there more of those strong El Niños. In addition to the peaks every several hundred years there is also an even longer-term trend of increasing ENSO events over 5,000 to 6,000 years.

Like a complex musical composition with multiple interacting rhythms, the interacting timescales of this climate phenomenon might result in weather patterns that defy our ability to predict confidently. The authors of the study looking at ENSO patterns for the past 10,000 conclude that bigger-scale changes in global climate (due to changes in the Earth's orbit around the sun) are driving those longer-timescale changes. A big question right now is how modern global climate change will affect ENSO. A warming ocean suggests El Niños will get more intense, but perhaps there are some unanticipated effects from the multiple interacting factors that still needs to be studied. We are improving our understanding of the Earth's climate systems but, as always, much more work needs to be done.

Images: (1) El Nino anomalies in the eastern Pacific Ocean; image from McPhaeden et al. of NOAA (2) ENSO Index from 1950-2010; image from McPhaeden et al. of NOAA; (3) Figure from Moy et al. (2002); Nature 420

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Satellite image of the western United States, taken on Thanksgiving Day. Image: NASA.

The defining sign of a La Niña is cooler-than-average sea surface temperatures in the Pacific Ocean, near the equator. Cooler water evaporates less than warmer water, so there is less moisture in the air. This means that during a La Niña, there is less precipitation in some areas, like California and the southern United States. Other areas, like the Pacific Northwest, get more precipitation during a La Niña. (Book your winter ski trip strategically!)

Sea surface temperature anomalies on November 25, 2010. The equatorial Pacific is cooler than usual (note the blue color), a characteristic of a La Nina event. Image: NOAA.La Niña also affects air temperature. During a La Niña, the South is typically warmer, while Southern California and the Pacific Northwest are cooler. You can see climate predictions for the next three months, from the National Weather Service Climate Prediction Center.

A La Niña is basically the opposite of an El Niño. El Niños are characterized by warmer-than-average sea surface temperatures in the equatorial Pacific. This happens when the atmospheric pressure system gets a bit out of whack. Usually there is high pressure over the Pacific Ocean and low pressure over the Indian Ocean—picture a see-saw anchored over New Zealand, with the heavy kid sitting on the end over Indonesia. For reasons we don’t quite understand, sometimes the see-saw tilts the other way—now the heavy kid is sitting in the southeastern Pacific, and the kid on the Indonesian side is way up in the air.

This swap in atmospheric pressure has quite a few consequences. The trade winds (which typically blow across the Pacific from the east to the west) get weaker. The water that the trade winds usually push westward instead piles up and moves east. This water is warm, and it evaporates, causing more rainfall along the west coast of South America. Meanwhile, places like Indonesia and Australia get less rainfall, along with drought and fire.

The weakening of the trade winds and westward flow of ocean currents in the Pacific has a second effect. Under non-El Niño circumstances, the trade winds carry the top layer of water to the west, and so water from deeper in the ocean moves up to take its place. This is called upwelling. The water from deep in the ocean is cold and full of nutrients, and it drives the fisheries along the coast of Chile and Peru. Without the trade winds and the upwelling, fisheries crash. A strong El Niño has big economic impacts, not all of which are negative; some agricultural areas are benefited by the extra rainfall, and people in places with unusually warm weather can save on heating bills. Of course, La Niña events have economic impacts too.

As scientists learn more about predicting the climate during El Niños and La Niñas, we can plan accordingly and mitigate the economic impacts of these events. My comment about planning your ski vacation according to this year’s La Niña was a little bit serious! Rainfall predictions based on El Niño and La Niña models can help farmers decide which crops to plant. And, here in drought-prone California, La Niña precipitation predictions are influencing water allocation decisions for the coming year.

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Elegant Chilean flamingos help visitors gain a new perspective on our changing environment in the Monterey Bay Aquarium's newest special exhibit: "Hot Pink Flamingos: Stories of Hope in a Changing Sea." ©David Barnhardt/Akron Zoo.

Reported by Marjorie Sun.

The California Academy of Sciences and the Monterey Bay Aquarium have a big advantage that some educational institutions in other parts of the country do not: most of their visitors — who tend to be Californians — believe that climate change is real. That means their global warming exhibits can focus on solutions, for example, rather than laying out the basics of atmospheric science.

Californians’ concern about climate change has translated into political support for cutting greenhouse gas emissions. According to survey results released in July by the Public Policy Institute of California, two-thirds of Californians strongly back the pioneering state law known as AB 32. The law requires a reduction of greenhouse gas emissions to 1990 levels by 2020. And the recent defeat of Proposition 23 by 22 percentage points would appear to affirm that support (though in 15 counties, support for 23 was at least 47%).

Listen to the QUEST radio story When Teaching Climate Gets Controversial.

Californians appear to buck some national trends on climate change issues. A declining number of Americans say there is solid evidence that the world is warming. The number dropped from 71% in April 2008, to 57% in October 2009, according to a study last year by the Pew Research Center. Adults who believe that climate change is a “very serious problem” declined sharply in the same time period.

New Yorker journalist Jane Mayer details in a recent, in-depth article that billionaires David and Charles Koch, titans of the oil industry, have been spending millions of dollars waging a covert disinformation campaign to thwart climate change legislation in the United States.

Aboard the Bio-Bus

A local organization has launched a mobile counter-offensive. The Alliance for Climate Education, a non-profit based in Oakland, has created a hip, multimedia presentation spiced with animation and rock music to reach teens. Think "An Inconvenient Truth" goes MTV. The alliance has shown it to more than 420,000 high-schoolers across the nation in the past year. The presentation teaches teens the basics about climate change and urges them to “do one thing” to fight it.

Alliance staffers also have tricked out an old school bus with clean tech, driving it to schools and museums to showcase renewable technology. The blue bio-bus runs on used cooking oil collected from restaurants. Solar panels on the bus charge cell phones and computers on board.

A cow wearing a gas mask created controversy at the Monterey Bay Aquarium's climate change exhibit. Photo Credit: Craig Miller

Unmasking the Cow

Meanwhile, keeping the climate change exhibits up-to-date scientifically is a concern for the museums. At the Monterey Bay Aquarium, outfitting a life-size model cow with a gas mask was prompted in part by a 2006 study by the Food and Agriculture Organization. The FAO study said that industrial production of livestock in general, including cattle, pigs, and poultry, accounts for 18% of all greenhouse gas emissions. But another FAO study released in April — about the same time the climate change exhibit opened — examined the GHG emissions for the dairy industry alone, not beef production. It concluded that dairy production contributes just four percent of emissions. The study (PDF download), along with howls of protests from the local dairy industry, helped convince the aquarium to unmask the Holstein.

One last tidbit about interactive exhibits: One of the most popular — common to the Academy and the Monterey Bay Aquarium — is surprisingly low-tech. Thousands of visitors write on comment cards about what they can do to fight climate change and hang them on display boards there. One of them, in a child’s handwriting, read “Reduce, reuse, recycle and homework is bad for the environment."

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