As the whole ocean gets warmer, NOAA scientists must redefine what they consider “average” temperature in the central tropical Pacific, where they keep watch for El Niño and La Niña.

According to the U.S. Drought Monitor, an estimated 58 percent of the contiguous United States was in some level of drought as of January 29, with an additional 12 percent in the “Abnormally dry” category.

After running the numbers for 2012, NOAA reported that the global average temperature in 2012 was 1.03° Fahrenheit above average, ranking it as the 10th warmest year since record keeping began in 1880. Although 2012 warmth did not top the charts, it was unusual in another way: it was the warmest “La Niña year” on record.

The entire Northern Hemisphere was warm during 2012. Drought affected agricultural regions in North America, Europe, eastern Russia, the Ukraine, and Kazakhstan. These warm conditions impacted grain yields, water supplies, and heat-related illness. Global food prices rose by 10 percent during July. Learning how our neighbors around the world cope with and adapt to extreme events can help us make better decisions, become more resilient, and be “climate smart.”

Drought, cold, and massive storms were among the devastating climate-related events that struck the United States in 2012. These events were incredibly destructive and disruptive for people across the country. A better understanding of the relationship between climate and extreme weather is challenging, but it’s important, and it will help our nation become even more “climate smart.”

The past year included the nation’s fourth-warmest winter, a record-warm spring, the second-warmest summer, and a warmer-than-average autumn. Average annual temperature was 3.2° F warmer than the 20th-century average and 1.0°F warmer than the previous record.

The average global temperature for November 2012 was the fifth warmest November since record keeping began in 1880. It also marked the 36th consecutive November and 333rd consecutive month with a global temperature above the 20th-century average.

When the Pacific Ocean warms and cools with El Niño and La Niña, global temperatures rise and fall. Because there was a La Niña event in the early part of this year, the global surface temperature for 2012 won’t break the high temperature record. However, the odds are that this will be the warmest of the La Niña years in the global climate record.

It may seem remote from our everyday lives, but the Arctic exerts a powerful influence on the rest of the planet. From rising sea level, to U.S. and European weather, to bird migrations, NOAA Administrator Jane Lubchenco describes how Arctic climate change can influence the rest of the planet.

It’s natural to associate drought with heat and with summer, but drought also impacts us during winter months. Winter wheat yields are declining, and the Mississippi River is approaching an all-time low. Understanding drought conditions and how they are affecting us is part of being “climate smart.”

November precipitation was nearly an inch below the long-term average in the U.S., making this the eighth-driest November on record. Not surprisingly, drought expanded and worsened as a result.

The central Arctic was not as unusually warm in 2012 as it has been in many years this decade, and yet new records were set for sea ice extent, terrestrial snow extent, melting at the surface of the Greenland ice sheet, and permafrost temperature. According to the 2012 Arctic Report Card, these converging indicators “provide strong evidence of the momentum that has developed in the Arctic environmental system due to the impacts of a persistent warming trend that began over 30 years ago.”

Few real-world signs of climate change are easier to read than changes in the growing season of familiar vegetation. Most of the high-latitudes of the Northern Hemisphere are experiencing longer growing seasons now than they did more than two and half decades ago.

By the time the summer melt season came to an end in mid-September, the ice extent had shrunk down to just 1.3 million square miles (3.41 square kilometers), setting a new record low that was 18 percent smaller than the previous record and nearly 50 percent smaller than the long-term (1979-2000) average. For sea ice to have shrunk to half its historic summer extent is as much a transformation of the environment as if half the forests of New England had been replaced by Saguaro cactus.

In June 2012, snow cover extent over Eurasia and North America hit a new record low. It is the third time in five years that North America has set a new record low, and the fifth year in a row that Eurasia has. The rate of snow cover loss over Northern Hemisphere land areas in June between 1979 and 2012 is -17.6% per decade—a faster decline than September sea ice loss over the same period.

On a yearly basis, Arctic temperatures are strongly influenced by natural climate patterns, including the Arctic and North Atlantic Oscillations. Over the span of a decade, though, Arctic amplification of climate change is evident: no part of the Arctic was cooler than the long-term average.

Shallow melt ponds on the surface of consolidated sea ice act as skylights that promote massive under-ice phytoplankton blooms. These under-ice blooms may boost estimates of Arctic phytoplankton productivity by a factor of 10.

Melt ponds, snow loss, and other warming-induced changes are making the surface of the Greenland Ice Sheet far less reflective in the summer than it was even a decade ago. The darker ice surface absorbs more sunlight than it once did, accelerating warming and melting.

The summer of 2012 brought Greenland far more extensive melt than anything observed in the satellite record: in July 2012, surface melt extended over nearly the entire ice sheet. The standardized melt index was nearly double the previous record.

At the edge of southern Louisiana sits Port Fourchon—the hub through which 20 percent of our nation’s oil and gas supplies are distributed to the rest of the country. The only road leading to and from this major port is the Louisana-1 Highway. A drive down the LA-1 through a vulnerable but vibrant coastal landscape shows what is at stake if ‘America’s longest main street’ fails to stay above water.

Port Fourchon sits on the very edge of the country, all the better for vessels shuttling supplies to and from deepwater oil platforms across miles and miles of ocean. Keeping it open is a big deal because the port services 90 percent of all deepwater activity in the Gulf of Mexico. Port Director Chett Chiasson tours the harbor while discussing the importance of preparedness, adaptation, and resilience.

Life in Fourchon Parrish, Louisiana is good. Abundant shrimp, crabs, oysters, and access to the Gulf of Mexico make this an attractive place to live and work. But increasingly, life on the coast introduces difficult challenges. Building levees and re-engineering drainage systems are some of the near-term ways people are adapting to a changing landscape. But will they, too, retreat inland, leaving the coast to time and tides?

Josh Kent of Louisiana State University gives a simple explanation of how sea level rise from climate change and sinking of the land both contribute to coastal changes.

Windell Curole knows what it means to see a community washed away. He’s seen it. On this tour of Leeville, Louisiana, Windell explains how storms and rising sea level have forced people to retreat inland several times in the last century.

How do you measure sinking land and rising seas at the same time? Randy Osborne of Louisiana State University and Tim Osborn of NOAA’s Office of Coastal Survey explain how a constellation of global positioning system (GPS) satellites in space provides a stable platform for measuring both.

David Miller of the Louisiana Department of Transportation and Development was one of the engineers given the task of determining how high to raise several miles of the Louisiana-1, or LA-1, highway. Climate data were essential for making sure that the roadway would last 75-100 years into the future.

Up to 1,200 trucks a day travel in and out of Port Fourchon by way of the LA-1 highway, carrying supplies and materials for rigs and platforms in the Gulf. Keeping the highway above water is a challenge for engineers. Henri Boulet of the LA-1 Coalition and Tim Osborn of NOAA’s Office of Coastal Survey explain how engineers use climate data, specifically sea level rise projections, to anticipate impacts and to keep the oil industry in business in Port Fourchon.

When you visit the ocean, you walk over sand dunes to get to the beach. When you visit South Lafourche Parish and Grande Isle in Louisiana, you realize the ocean crosses dunes to work its way inland, for example, to reach New Orleans. The mayor of Grande Isle describes how his local dunes are the state’s first line of defense against surging storms from the Gulf.

Much of the western and southern central United States could be in for a warmer-than-average winter this year, while the upper Midwest and Florida peninsula could experience colder-than-average temperatures. Most of California and western Nevada could experience well-below-normal precipitation, while parts of the southeast could receive well-above-normal precipitation.

Global temperature for October 2012 was the fifth warmest since records began in 1880. It was the 36th consecutive October and the 332nd consecutive month with a global temperature warmer than the 20th-century average. The last below-average October temperature was October 1976.

Pecan and chili growers along the Lower Rio Grande can tap groundwater during droughts, but the aquifer water is salty and harmful to the soil over the long term.

After 16 consecutive months with warmer-than-normal conditions, October brought fairly average temperatures to the United States. But we are still on track for the warmest year in the United States’ climate record.

October 2012 ended the 16-month streak of above-average monthly temperatures for the contiguous United States, with an average temperature of 53.9° Fahrenheit, 0.3° Fahrenheit below the long-term average.

We can’t immediately link Hurricane Sandy itself to climate change, says climate scientist Cynthia Rosenzweig, but the flooding damage we can. Partly due to global warming, sea level has climbed about a foot in the NYC area over the past century, giving storm surges a “step up” along the coast.

The average U.S. citizen consumes around 3.5 pounds of peanut butter a year. Will global warming make climate conditions less peanut-friendly in the U.S.?

For James Overland, an Arctic oceanographer at NOAA’s Pacific Marine Environmental Laboratory, six exceptionally slushy summers in a row in the Arctic demanded an explanation that went beyond the obvious: that global warming is raising the Arctic’s temperature. After analyzing winds and pressure patterns, Overland and several colleagues documented an unusual shift in the prevailing June winds—from westerlies to southerly—that amplified Arctic warming and sea ice melt.

With the end of the most active part of the Atlantic hurricane season approaching, there is still plenty of water in the western Atlantic basin that is warm enough to fuel hurricanes.

September 2012 tied with September 2005 as the warmest September worldwide since record keeping began in 1880. See which countries saw warmer-than-average temperatures during last month, and learn how weak El Niño conditions might progress into the Northern Hemisphere winter.

The continental United States, particularly in the far west, has had warmer-than-average temperature for 16 straight months and lower-than-average precipitation through the summer. These climate conditions combined with weather to spark one of the region’s largest wildfire seasons yet.

According to the latest statistics from NOAA’s National Climatic Data Center, September 2012 marked the sixteenth consecutive month with above average temperatures for the Lower 48. Meanwhile, warm and dry conditions persisting in the Northwest have led to yet another month with above-average wildfire activity in the region.

On the Rio Grande—historically the wellspring for more than five million people in Colorado, New Mexico, Texas, and Mexico—coping with scarcity has become a reality, and water management and use in the region may be a leading example of how to adapt to drier times.

Arctic sea ice extent set a new record low at the end of the summer melt season on September 16, 2012. But extent is not the only quality of the ice that is changing. Wind and ocean circulation patterns are conspiring with a warmer climate to reduce the amount of year-round (multi-year) ice, transforming the remaining ice into a younger, thinner version of its old self.

According to NOAA’s Climate Prediction Center, weak El Niño conditions may develop this fall. How might a full-fledged El Niño event this winter influence weather where you live?

The rainy season in India arrived late and delivered far less precipitation than usual in summer 2012, leading to severe drought across large parts of the country. More than half the labor force in India makes a living in agriculture, which makes drought a widespread social and economic hardship.

It’s been more than three and a half decades since we’ve had an August with temperatures below than the 20th-century average. Global temperatures in August 2012 were the fourth warmest of any August on record.

In a place routinely afflicted by drought, water managers in Tampa Bay use climate forecasts to ensure a water supply to people’s taps without sucking the region’s rivers, wetlands, and groundwater dry. The limits of their innovation might be tested in a future which could pose even more challenges to ensuring the oasis remains green.

A scorching July contributed to the third hottest summer on record for the contiguous United States. Most of the U.S. was also drier than average. Rains from Isaac did little to relieve drought.

From scorching July heat to well-below-average summer rainfall, NOAA’s Deke Arndt, Chief of the Climate Monitoring Branch at the National Climatic Data Center, recaps summer climate conditions across the United States.

Deke Arndt of NOAA’s National Climatic Data Center reports that heavy rains from Hurricane Isaac in late August fell too late–and mostly in the wrong places–to provide much relief from U.S. drought.

Imagine heat waves like the one in July 2012 coming more often & lasting longer: that’s the projection from climate models for the middle of this century based on one future emissions path.

As of August 26, Arctic sea ice appears to have broken the 2007 record for smallest daily extent of the satellite era. The pace of ice melt in late August 2012 was roughly 29,000 square miles per day, nearly double the normal rate for this time of year.

It’s a discouraging fact that drought reinforces drought, especially in the summer. The Southern Plains were in the tight grip of that feedback loop in August 2012.

There was plenty of variability in surface temperature from place to place in July 2012, including unusually hot conditions in Canada and the United States and unusually cool conditions in Northern Europe and Australia. Averaged across the entire globe, however, warmth won out: the average temperature was more than 1°F higher than the 20th-century average, making July 2012 the 4th warmest since records began in 1880.

July 2012 wasn’t just the hottest July on record, it was the hottest month ever recorded for the contiguous United States since records began in 1895.

A series of unusually strong, long-lasting high pressure systems has parked over Greenland this summer. As many a weather forecaster has explained, high pressure generally leads to calm winds and sunny skies, both of which boost temperatures during the all-day sunshine of mid-summer at high latitudes. The conditions contributed to widespread melting of the ice sheet.

The current drought in the Southwest is not drier or longer-lasting than historic episodes documented in tree rings, but the current dry conditions stand out from the historical record by being hotter, according to Jonathan Overpeck, professor of geosciences at the University of Arizona.

Unusually warm waters in the Bering Sea in the early part of the last decade have given fishermen and scientists a preview of the challenges they may face keeping Alaska pollock—the fish-stick fish—on the menu as climate warms.

Jeff Privette describes the challenges of using satellites that people designed for observing changes in the weather from day to day to study changes in climate from decade to decade.

Deke Arndt, Chief of the National Climatic Data Center’s Climate Monitoring Branch, uses a football field to explain how NOAA creates its Climate Extremes Index.

Anthony Arguez, Normals Program Manager at NOAA’s National Climatic Data Center explains what scientists mean when they compare current weather conditions to “normal.”

In early July 2012, conditions throughout most of the contiguous 48 states ranged from abnormally dry to exceptional drought. Only three states, all in the Northeast, were spared.

The average global temperature for June 2012 was the fourth highest for any June since record keeping began in 1880. Land-only surface temperatures were the highest on record for the month. June 2012 also marks the 36th consecutive June and 328th consecutive month with a global temperature above the twentieth-century average. The last June with below-average global temperatures was June 1976.

Each year, following months of number crunching and fact-checking, hundreds of climate and earth scientists contribute to a global-scale evaluation of climate and environmental conditions over the previous year. This analysis—our planet’s annual check up—is known as the State of the Climate report. Highlights of the 2011 State of the Climate report include wild weather extremes, a double-dip La Niña, and continued evidence of long-term climate warming.

In 2011, global sea levels fell below the long-term trend of sea level rise, but as La Niña waned late in the year, global ocean levels began rising rapidly.

In 2011, annual snow cover extent over Northern Hemisphere continents (including the Greenland ice sheet) averaged 24.7 million square kilometers, which is 0.3 million square kilometers less than the long-term average.

Except for some La Niña-cooled regions of the tropical Pacific and a few other cool spots, the upper ocean held more heat than average in 2011 in the Pacific, Atlantic, Indian, and Southern Oceans.

Data from 2010 indicate that mountain glaciers predominantly lost mass, and preliminary data from 2011 indicate a continuation of the same long-term trend.

In 2011, Earth’s atmosphere was cooler and drier than it had been the previous year, but it was more humid than the long-term average.

In September 2011, Arctic sea ice reached its second-lowest minimum extent in the satellite record.

In early 2011, stratospheric temperatures rose over the tropics, due to La Nina while temperatures over the poles fell below the long-term average.

Despite the double-dip La Nina that occurred throughout the year, 2011 was still among the 15 warmest years on record. Including the 2011 temperature, the rate of warming since 1971 is now between 0.14° and 0.17° Celsius per decade (0.25°-0.31° Fahrenheit), and 0.71-0.77° Celsius per century (1.28°-1.39° F) since 1901.

In 2011, La Niña and the Pacific Decadal Oscillation cooled parts of the Pacific Ocean, but unusually warm temperatures predominated elsewhere.

This animation tracks sea surface temperature anomalies in the tropical Pacific throughout 2001. La Niña—the cool phase of the El Niño-Southern Oscillation—dominated the Pacific at the start of the year, subsided in summer, and returned in fall.

The average temperature for the contiguous United States during June was 2°F above the twentieth century average. Scorching temperatures during the second half of the month broke or tied over 170 all-time temperature records in cities across America. June temperatures also contributed to a record-warm first half of the year and the warmest 12-month period the nation has experienced since record-keeping began in 1895.

The 2012 Hurricane outlook suggests slightly below average number and strength of storms in the central Pacific basin and a near-average season in both the Eastern Pacific as well as the Atlantic basins. This forecast is the result of competing climate influences, some that favor heightened activity and some that favor low activity.

In late-April 2011, an unusual, post-winter Nor’easter brought much-needed rain the Northeast United States.

Ned Gardiner discusses how spring storm tracks across Europe and the Mediterranean Sea swept away a high pressure system that had been fostering increasingly dry conditions over the Horn of Africa in early 2011.

The average global temperature (land and ocean) for May 2012 was the second warmest May temperature since recordkeeping began in 1880, and the temperature over land surfaces was the warmest on record for May. May 2012 also marks the 327th consecutive month with a global temperature above the 20th-century average.

The average temperature for the United States during May was more than 3°F above the long-term average, making it the second warmest May on record. The month’s high temperatures also contributed to the warmest spring, warmest year-to-date, and warmest 12-month period the nation has ever experienced since record keeping began in 1895.

Deke Arndt, Chief of the Climate Monitoring Branch at NOAA’s National Climatic Data Center talks about the unusual heat in May 2012.

Kristin Laidre, a marine mammal biologist, has taken more than thirty trips to the Arctic, many of them to study the mysterious narwhal. Although the narwhal has appeared in stories throughout history, scientists are just beginning to understand this quirky creature with a fierce survival instinct. But in recent years, a series of unusual events led Laidre to wonder if narwhals are being caught off guard by changes in their unforgiving environment…

NOAA scientists have documented a new impact of the increasingly thin blanket of Arctic sea ice: gases escaping from the thinner ice in spring are affecting air chemistry, reducing ground-level ozone, and likely increasing mercury contamination.

Since the beginning of 2012, drought conditions have worsened along the eastern seaboard, adding to a dry picture for much of the United States.

Since the beginning of 2012, the contiguous United States has been experiencing drier than average conditions. This lack of precipitation is affecting water availability for agriculture and municipal use, as well as increasing concerns about soil quality and wildfires.

From poor soil to scorching summer heat, farmers in the U.S. Southeast face some significant challenges. Two Southeast growers are looking to seasonal climate forecasts to give them an edge.

After a record-breaking drought last summer, dry conditions continue to linger in large portions of the South this spring.

Grower Kirk Brock talks about adapting to rainfall extremes on his dryland farm in Florida and how seasonal climate forecasts should help him improve his operation.

Alabama farmer Myron Johnson talks about how adding seasonal climate outlooks to his decisions about when to plant and harvest his cover crops helped produce a bumper cotton crop during the 2010 growing season.

Although one climate pattern can’t explain every bit of wacky weather that happens on Earth, when it comes to making seasonal forecasts, the occurrence of an El Niño or La Niña event is the single most useful predictor that climate scientists have for forecasting if seasonal precipitation and temperature are likely to be above or below normal. According to NOAA’s April 2012 ENSO Diagnostics Discussion, La Niña is fading and will likely be over by the end of April.

NCDC climate scientist Deke Arndt talks about the record March heat and the cumulative effect of a warm fall, winter, and early spring on “heating degree days,” an estimate of the energy demand during the U.S. cold season.

Although solar flares can bombard Earth’s outermost atmosphere with tremendous amounts of energy, most of that energy is reflected back into space by the Earth’s magnetic field or radiated back to space as heat by the thermosphere.

Record and near-record breaking temperatures dominated the eastern two-thirds of the nation and contributed to the warmest March in the contiguous United States since records began in 1895. The average temperature was 8.6 degrees above the 20th century average for March. In the past 117 years, only one month (January 2006) has ever been so much warmer than its average temperature.

In the Great Lakes region, conservation and resource managers are already fending off attacks by multiple invasive species. In the future, climate change will present new challenges, such as anticipating the invaders’ next move and dealing with new, emerging threats — some of which could be swimming around in your aquarium right now.

As March began, people living the eastern United States were enjoying warmer temperatures, budding flowers, and other signs of the approaching spring season. But on the opposite coast, a series of wintry storms rolled through the already snow-packed Cascades, leaving behind several feet of powder and sparking avalanche warnings throughout the region.

According to NOAA’s 2012 Spring Outlook, odds are that dry conditions and above-average temperatures will persist in much of the South, where drought is still lingering after making headlines in 2011. But last year’s most devastating flood events are unlikely to repeat.

When NOAA’s National Climatic Data Center crunched the numbers for December, January and February—”meteorological” winter for 2011-2012—it stacked up as the fourth warmest of the past 117 winters. Virtually all of the West received less than its average precipitation.

The U.S. had its fourth warmest winter on record. In this episode of ClimateCast, NOAA’s Deke Arndt recaps the 2011-2012 winter.

It is virtually certain our world will continue to warm over this century and beyond. The exact amount of warming that will occur in the coming century depends largely on the energy choices that we make now and in the next few decades.

For Europe, the first two calendar months of winter were mild. As if to make up for lost time, however, exceptionally cold weather arrived in late January and remained firmly entrenched for weeks.

Modeling predicts that increasing greenhouse gas emissions will significantly increase thermal stress on Pacific Northwest salmon in coming decades, making the hard job of restoring endangered wild salmon even harder.

What scientific evidence exists that Earth’s climate is changing? What’s the difference between climate change and climate variability? How does a changing climate affect people and the natural environment? What can we do to lessen and adapt to the impacts of these changes? This collection of videos presents experts’ lectures and discussions on these topics in a series of public forums hosted in 2011 by NOAA and the Osher Lifelong Learning Institute at George Mason University.

Social scientist and communication expert Mathew Nisbet talks about the state of public climate literacy today. What actions are people likely or not likely to take, and why? How might scientists better engage the public in critical decision-making forums? Constant debates about whether or not global warming is really happening have grown stale and miss the point entirely. Shouldn’t we be talking about how society can leverage climate science in ways that promote economic growth; save lives and valuable natural resources; and create new markets for jobs, products, and services?

Drawing on The State of the Climate in 2009, Dr. Deke Arndt presents the preponderance of scientific evidence that climate change is occurring and that humans are the primary cause. He also elaborates on the modern methods that scientists use to monitor many different aspects of Earth’s climate system.

In this evidence-based presentation, climate scientist Anthony Janetos makes it clear that climate change isn’t some future abstraction, nor is it a far-off phenomenon happening to people in other parts of the world. Rather, there are real and substantial ongoing impacts happening here in the United States that affect people’s lives, the economy, the environment, and our valuable natural resources.

Claudia Mengelt and Robert Fri talk about coping with climate change. What short-term actions can be taken to respond effectively to climate change? What promising long-term strategies, investments, and opportunities could be pursued? This session summarizes the findings from a recent series of reports by the National Research Council of the National Academies of Science highlighting options for adapting to and mitigating global climate change.

Although they are related, meteorology and climatology have important differences, particularly in how scientists develop and use weather and climate models. What makes climatologists think they can project climate scenarios decades into the future when meteorologists cannot accurately predict weather more than two weeks in advance? This presentation by Wayne Higgins of NOAA’s Climate Prediction Center clarifies the relationships and differences between weather and climate, as well as the differences between natural climate variability and human-induced climate change.

Most major theories about why Earth’s global climate warmed and cooled over the last million years were formed by the early 1900s, but it wasn’t until the 1970s that scientists began to put all the pieces together in a new, holistic approach to studying the climate system. Historian James Roger Fleming presents a historical perspective on how our understanding of Earth’s climate system evolved through a succession of pioneering scientists in the 1800s and 1900s who asked, and answered, fundamental questions about the causes and effects of global climate change.

Humans currently release about 70 million tons of carbon dioxide every day into the atmosphere and about 20 million tons is being absorbed regularly by the oceans. Scientists monitoring the world’s oceans have observed a substantial increase in the acidity of seawater due to the increasing absorption of human-emitted carbon dioxide. Using present-day emission scenarios, we could see a further increase in acidity of another 150 to 200 percent in this century. In this lecture, Chris Sabine describes current impacts of acidification on marine ecology and projections of likely future impacts on marine life if this trend continues.

In this lecture, climate scientist Michael MacCracken explores some of the scientific, legal, and ethical implications of “geo-engineering” options that have been proposed by some people to address global climate change.

Jim Wilczak describes the information NOAA provides to guide optimal wind energy development, as well as the observation technology the Wind Forecast Improvement Project has deployed to improve wind forecasts.

Felix Kogan talks about using satellites to observe and forecast the climate conditions that lead to mosquito–and malaria–outbreaks.

Dave Brown of the National Climatic Data Center talks about the impacts of this year’s record-breaking Texas drought and whether there is any relief in sight.

Jake Crouch of the National Climatic Data Center recaps the temperature patterns of 2011, emphasizing the much greater than average warmth across Arctic latitudes and the influence of La Nina in the tropical Pacific.

Last year on Groundhog’s Day, large swaths of the country were covered in two feet of snow or more after a large storm pounded the eastern United States. This year, Punxsutawney Phil emerged from his den on a balmy day after the third-least snowy January on record. A comparison of snowfall (or lack thereof) so far this season to last year’s winter white-out shows what a difference a year makes.

During the third week of August, portions of southern Europe and western Russia experienced a heat wave. Temperatures skyrocketed near 90 to over 100°F over several consecutive days, prompting emergency heat alerts.

Cuba experienced extreme drought conditions in 2011, marking one of the driest years in the nation’s history and causing serious shortages in water supplies.

Amid months of persistent heavy rains, some areas in Zimbabwe received their heaviest rainfall in 30 years during January, causing flooding and damage to crops.

In August 2011, over seven inches of rain fell in a six-hour downpour in southwestern Nigeria. The torrential rains caused flooding and damage to instrastructure, buildings, and homes.

For the record books: A review of the ten most significant or unusual global climate or weather events of 2011, as ranked by NOAA’s National Climatic Data Center in its yearly review of the Earth’s climate.

Each year, scientists from around the world synthesize what they have learned about the Arctic system. This year’s report emphasizes that climate change is more prominent in the Arctic than at lower latitudes.

More than half of the United States experienced heat, drought, or flooding during 2011, demonstrating the power and momentum of climate extremes.

Temperature in the Arctic has risen twice as fast as the global average. That means: even if you haven’t experienced climate change, people in the Arctic have

The Arctic of recent years—warmer, greener, less icy—is likely to be the new normal for the Far North. One sign of the ongoing transformation of the Arctic is the spread of shrubs across the tundra.

For the record books: A review of the ten most significant or unusual U.S. climate or weather events of 2011, as ranked by NOAA’s National Climatic Data Center in its yearly review of the nation’s climate.

From October 10-20, 2011, two separate storm systems dumped nearly five feet of rain across southern Central America, causing flooding and landslides in several areas.

More than a week of torrential rain in mid-September 2011 caused deadly floods across Sichuan, Shannxi, and Henan provinces in China.

Cold weather settled over Japan and the Korean Peninsula in January 2011, and for the first time since 1986, Japan experienced below-normal January temperatures.

Seasonal precipitation patterns across the globe showed large differences from average in 2011, with several areas receiving heavy rains during more than one season of the La Niña-influenced year.

The past year included the nation’s fourth-warmest winter, a record-warm spring, the second-warmest summer, and a warmer-than-average autumn. Average annual temperature was 3.2° F warmer than the 20th-century average and 1.0°F warmer than the previous record.

A year-long La Niña contributed to dramatic variability in seasonal temperature patterns in 2011.

In the 2011 Arctic Report Card, scientists report that the bright white surface of the Greenland Ice Sheet has grown less reflective. The darker surface absorbs more sunlight, accelerating melting.

Climate forecasters often describe the Arctic Oscillation as the “wild card” of the winter forecast. So far in 2011, the Arctic Oscillation has been in its positive phase, playing the card that favors a milder winter in the eastern United States.

NOAA’s official Winter Outlook for 2011-2012 is unlikely to please many residents of either the still-soggy Missouri River Basin—which experienced historic flooding this past spring and summer—or the parched south-central United States, where severe to exceptional drought has been in place since spring.

What’s in store for the U.S. this winter? Odds favor cooler, wetter than average conditions in the North and West, and warmer and drier conditions in the South.

On December 1, NOAA released its annual Arctic Report Card. Like a yearly check-up at the doctor’s office, the report summarizes conditions in the Arctic atmosphere, ocean, and on land.

The surface melt season on Greenland lasted up to 30 days longer than average in 2011, and it affected 31 percent of the ice sheet surface. Ice mass loss from Greenland in 2011 was about 430 gigatons—enough ice to raise global sea level by just over 1 millimeter.

Satellite observations show that as the Arctic tundra has grown warmer in the past three decades, it has also grown “greener.”

Continuing a decade-long phenomenon, above-average warmth in the Arctic this year was two or more times greater than warming observed at lower latitudes.

Phytoplankton productivity has increased 20 percent over the past decade as sea ice extent declines and more open water habitat is available.

In the past decade or so, the annual seasonal thaw on Greenland has grown more dramatic. This animation shows visible melting along the western edge of the Greenland Ice Sheet near the Jakobshavn Glacier each August between 2000 and 2011.

Severe flooding overtook the Missouri River and her tributaries during spring and summer of 2011. Understanding this extreme event requires a close look at the climate system.

This spring, the Northern Great Plains experienced record snowmelt and record rains. Flooding swept away crops, soil, homes, and more throughout the Missouri River Basin. A La Niña climate pattern helped set the stage for this event.

In the wake of historic flooding along the Missouri River in spring and summer 2011, NOAA scientists are exploring how climate patterns like La Niña and others can set the stage for floods or drought in the Northern Rockies and the Upper Great Plains.

Molly Heller is part of a team of scientists who processes flasks of air samples in NOAA’s Earth System Research Laboratory in Boulder, CO. Week in and week out, Heller and her colleagues unpack sealed glass flasks shipped back to Boulder from dozens of remote sites around the world. What’s inside is priceless: air captured from a site near Tasmania’s Cape Grim; from Summit, Greenland; the Canary Islands; the South Pole.

The types of tree species that grow in a particular region determine the range of bright colors that paint our landscapes during the fall season. In the future, scientists project that the forest habitats all around us may undergo major changes to due to warming temperatures.

Compared to the large ozone hole that forms over Antarctica each year, Arctic ozone loss has generally been much more limited. But in 2011, Arctic ozone declined to surprisingly low levels. What did climate have to do with it?

In the mid-1980s, the winter sea ice pack in the Arctic was dominated by multi-year ice—ice that had survived at least one summer melt. Today, less than half of the sea ice at winter maximum has survived at least one summer.

The low ice extent recorded this September continued the downward trend seen over the last 30 years. Meanwhile, scientists are finding that the ice cover has grown thinner, making it more vulnerable to melting during the summer.

Following a brief interlude of “neutral” sea surface temperature conditions this summer, La Niña has returned to the tropical Pacific Ocean. The cool phase of the El Niño-Southern Oscillation climate pattern is expected to persist through winter.

The remnants of Tropical Storm Lee brought record rainfall amounts to the East Coast in the first week of September, swelling rivers and forcing evacuations in some areas of Pennsylvania and New York.

Population and development conspire with regional climate patterns to concentrate the country’s most expensive weather disasters in the U.S. South and Southeast.

Maps of locations where heat records were broken in summer 2011 make a nearly complete picture of the United States.

The soaking rains from Tropical Storm Lee provided some drought relief in the South in the first week of September, but exceptional drought persisted across Texas and the Southwest.

Pietro Ceccato describes the role satellites play in monitoring vegetation health, rainfall, and soil moisture in drought-stricken places in East Africa.

An intense drought has gripped the southern tier of the United States for several months, accompanied by destructive wildfires, low water supplies, and failed crops. With a forecast of above-normal temperatures and below-normal precipitation, the latest Drought Outlook from NOAA’s Climate Prediction Center indicates little relief this fall for much of the Southwest and Southern Plains.

The Brazos River runs dry in Knox County, Texas, in summer 2011.

In summer 2011, the South was in the grip of one of the worst droughts on record, and the fall drought outlook issued by NOAA’s Climate Prediction Center provided little hope of relief, especially for the Southwest and Texas.

Ponds that were built to hold significant amounts of water for cattle are dwindling away under the hot temperatures, dry winds and lack of rain.

Cattle ranchers face tough decisions about feeding and watering their herds as extreme drought continues in the South in late summer 2011.

As early as November of last year, NOAA scientists were able to forecast extreme drought conditions that would likely lead to high fire risk in the South, allowing fire managers time to prepare for an active season.

An expert on climate conditions and food security explains why some parts of East Africa are so vulnerable to climate shocks like the ongoing drought.

For much of the United States, summer 2011 was sweltering, and the outlook for fall is not a cool one.

At the peak of this year’s drought, a record 12 percent of the U.S. was experiencing exceptional drought conditions.

In summer 2011, the South was in the grip of one of the worst droughts on record. Many parts of New Mexico and western Texas have received a small fraction of their normal rainfall over the past 10 months.

After enduring months of drought and baking summer heat, residents of the Southwest and Southern Plains will hardly be excited about the fall 2011 temperature and precipitation outlooks.

An expert on climate conditions in East Africa describes the climate factors behind the 2011 drought, which has contributed to food insecurity and famine.

As the East Coast prepares for the arrival of Hurricane Irene, New Englanders may be recalling a similarly threatening storm that walloped the area 73 years ago.

Each summer, the seasonal unraveling of the Arctic’s blanket of ice exposes large areas of the ocean to solar heating. The smaller the ice extent, the larger the potential warming influence. Arctic sea ice extent in July 2011 was the lowest for that month in the satellite record.

What began as an ordinary Sunday on August 21, 2011, became anything but ordinary for residents of Goderich, Ontario, as an EF-3 tornado (winds between 136-165 mph) ripped through their historic town. Environment Canada’s local weather forecast had called for non-severe thunderstorms across the lower Great Lakes region but at 3:48 p.m. EDT, it issued [...]

From drought in the Amazon to Australia’s record spring rains, this interactive map highlights significant regional climate events in 2010 that were influenced by El Niño and La Niña.

A map of each location where a daily heat record was broken in July 2010 creates a nearly complete image of the contiguous United States.

In the semi-arid Horn of Africa, rain comes in two seasons: the “short rains” of October-December and the “long rains” of March-June. In late 2010 and early 2011, both rainy seasons brought scant rain to the region, which led devastating drought across several countries in 2011. In Somalia, the drought escalated to famine.

A pattern of unusually warm and cold spots alternated around high northern latitudes in 2010—a classic sign of the negative phase of the Arctic Oscillation.

Between January and April 2010, sea surface temperatures in the tropical Pacific Ocean were under the warming influence of a fading El Niño episode. Meanwhile, temperature patterns across the Northern Hemisphere were largely dominated by a strong negative phase of the Arctic Oscillation.

In early 2010, water temperatures in the eastern tropical Pacific were warmer than average, but a summertime reversal cooled the region off over the rest of the year.

In 2010, global temperatures were marked by near-record warmth and strong natural variability. This is the first in a series of posts highlighting findings from the “State of the Climate in 2010″ report.

Two natural climate patterns, the Arctic Oscillation and the El Nño-Southern Oscillation, had strong influences on the patterns of unusually warm and unusually cool spots worldwide in early and late 2010.

Starting in July, when you hear that a day was hotter, or colder, or rainier than normal, that ”normal” will be a little different from what it was in the past.

Normally invisible, wind turbine wakes come to life over the ocean, fascinating scientists who study winds in the lower atmosphere.

For decades, the City of Boulder, Colorado, has been successfully managing its water supply despite the challenges of being located in a semi-arid climate. But a local water manager wonders if climate change will change the rules of the game…

All but a handful of weather stations across Alaska reported well below-normal precipitation in May 2011, placing that month in a statistical tie with May 1974 as the driest May since records began in 1918.

NOAA’s Annual Greenhouse Gas Index (AGGI) is a yearly report on the combined influence of long-lived greenhouse gases on Earth’s surface temperature. As of 2010, the warming influence of greenhouse gases had risen 29 percent. Carbon dioxide alone accounts for about 85% of the increase.

Climate models project that 100-degree days will become more numerous and widespread by the end of the century if greenhouse gas emissions continue to rise.

Above-average sea surface temperatures, a natural cycle of increased hurricane activity, and a fading La Nina have influenced the 2011 Atlantic hurricane outlook.

The tornado outbreak across the southern United States in late April 2011 was deadly, devastating, and record breaking. NOAA’s “CSI” team is investigating the possible connections between global warming, natural climate patterns, and tornadoes.

They’re always warm and frequently rainy, but the tropics do experience seasonal change. This animation shows the north-south migration of Earth’s tropical rain belt over the course of the year.

As far back as August 2010, NOAA’s seasonal climate models predicted that rainfall would be heavier than normal across Indonesia and Southeast Asia in early 2011. The cause? La Niña.

Arctic sea ice extent for the month of March was the second lowest in the satellite record. Ice cover at winter maximum continues to be dominated by young, thin ice.

Natural climate phenomena—the North Atlantic Oscillation & La Niña—can explain much of the winter temperature patterns across North America.

Large-scale shifting of the weight of the atmosphere between mid- and high latitudes creates climate patterns known as the Arctic and North Atlantic Oscillations. These patterns have a big influence on winter weather in the Eastern U.S.

How did this year’s storms compare to the worst in recent history?

Sea level around the Chesapeake Bay is rising faster than the global average. How are the state of Maryland and coastal residents planning for change?

The ocean’s tremendous ability to store and release heat over long periods of time gives it a central role in stabilizing Earth’s climate system.

Present since the last ice age, most of the world’s glaciers are now shrinking or disappearing altogether.

Precipitation has been 25 percent of normal—even less in some places—across much of Arizona, New Mexico, and western Texas since the new “water year” began on October 1, 2010.

Deep snow that fell across the Great Plains and the Northeast in late January and early February is the latest installment in the second very wintry winter in a row for the eastern U.S.

Records from the last five decades show that on average, spring snow is disappearing earlier in the year than it did in the past. Across the Northern Hemisphere, the total area covered by snow during March and April has shrunk over time.

Computer climate models help scientists such as Dave Dewitt predict the life cycles of individual El Niño or La Niña events and their effects on weather patterns throughout the world. While the accuracy of these models continues to improve, they still have limitations.

El Niño and La Niña can significantly alter seasonal climate conditions, such as temperature and rainfall patterns, in many parts of the world. Scientists Brad Lyon and Paul Block explain the potential impacts of La Niña in different parts of Africa.

Will climate change affect frequency or intensity of El Niño and La Niña? There is still little consensus among scientists on this, explains the International Research Institute for Climate and Society’s Lisa Goddard.

Capping off the warmest decade on record, the average global temperature in 2010 tied 2005 as the warmest year since reliable records began in 1880.

Dry mountain slopes hidden in the rain shadow of the Big Island’s volcanoes are especially susceptible to drought conditions.

Few winter storms and El Niño conditions brought severe drought conditions to the Hawaiian Islands this past year.

A La Niña event that is cooling the central and eastern tropical Pacific is expected to peak sometime between November 2010 and January 2011, but it will continue through spring.

Rising ocean temperatures are increasing the frequency of coral bleaching events in tropical oceans. Not yet recovered from mass bleaching and disease in 2005, many Caribbean corals bleached severely again in 2010.

The average global surface temperature in October 2010 was 58.07°F (14.54°C), which is 0.97°F (0.54°C) above the historical average, according to the monthly assessment from NOAA’s National Climatic Data Center.

Reducing carbon dioxide emissions to limit global warming to 2°C this century may also keep ocean acidity from doubling its pre-industrial levels. Lack of regulation may lead to a five-fold increase in acidification, conditions unlike any in the past 21 million years.

How do warm waters in the Caribbean this year compare to conditions in 2005, when high ocean temperatures triggered the worst mass coral bleaching event ever seen in the region?

Facing the possibility of a massive coral bleaching event in the Caribbean Sea in late summer and early fall 2010, a USGS biologist based at U.S. Virgin Islands National Park hopes that the season won’t have the same devastating outcome as a similar event in 2005.

When the winds are right, dust from the deserts of the U.S. Southwest blows onto the snow-capped Rocky Mountains. How do dirty snowfields contribute to the loss of more than 250 billion gallons of water in the Colorado River?

Identifying ocean areas with a deep layer of warm water—places that are storing large amounts of heat—is important for scientists trying to predict whether or not a hurricane will intensify.

Each of the last three decades was warmer than all earlier decades in the instrumental record, and each set a new and statistically significant record, culminating in the 2000s, which was the warmest decade of all.

Dr. Gerry Bell, the Lead Seasonal Hurricane Forecaster at NOAA’s Climate Prediction Center, talks about the 2010 Revised Hurricane Outlook and the importance of coastal residents having a preparedness plan.

Christopher Landsea, of NOAA’s National Hurricane Center, works with tropical storm data and other hurricane experts to figure out how our warming world will affect hurricanes. Find out what current research tells us about hurricanes in the future.

This report presents a comprehensive appraisal of Earth’s climate in 2009, and establishes the last decade as the warmest on record. Reduced extent of Arctic sea ice, glacier volume, and snow cover reflect the effects of rising global temperature.

Recent studies show the world’s ocean is heating up as it absorbs most of the extra heat being added to the climate system from the build-up of heat-trapping gases in the atmosphere. This climate trend, and many others, are documented in NOAA’s newly released 2009 State of the Climate Report.

CalNex—an intense data collection campaign to characterize the complicated interactions of air quality and climate over California—used an array of instruments and platforms this spring for a close look at greenhouse gases and pollutants.

The impacts of climate change and sea level rise have the potential to contaminate facilities and natural resources in the Pacific Northwest. Now, coastal managers have a new tool to help them visualize future changes and decide how they might avoid these problems.

In 2007, Arctic sea ice retreated so dramatically that it broke all previous records for sea ice minimum for July through October. Is this year’s summer ice melt season on track to surpass 2007?

Will ocean currents carry oil and byproducts from the Deepwater Horizon wellhead beyond the Gulf of Mexico and out into the open Atlantic Ocean? Climate data and computer models help scientists predict how and where.

In 1938, an unexpected Category 3 hurricane plowed across Long Island and into Connecticut.

Could history repeat itself?

Matthew Shupe installs weather instruments—and blogs about life as a scientist—in Greenland.

Research suggests global warming isn’t increasing the number of hurricanes, but is likely to increase their average strength.

The International Best Track Archive for Climate Stewardship (IBTrACS) stores information for all known tropical cyclones recorded since the 1850s. See how advancements in observing technologies have improved our ability to observe cyclones worldwide.

The combined land and sea temperatures for last month were the warmest April temperatures on record.

How is climate change affecting bird migration patterns? Birdwatchers across the country and around the world are contributing their time, both in the field and online to answer that question.

Scientists examine data from computer models to generate simulations of sea ice thickness now and three decades into the future.

Six managers of State Coastal Zone Programs and National Estuarine Research Reserves comment on their plans for adaptation in response to climate change.

Twice a month, scientists send weather balloons into the air to collect data about the atmosphere, from the ground all the way up to the darkness of near space. Many gathered for the launch of last week’s balloon, which marked 30 years of NOAA water vapor measurements in Boulder.

Scientists use satellite data, observations, and their knowledge of past volcanic eruptions to assess whether Iceland’s Eyjafjallajökull Volcano packs enough punch to affect Earth’s climate.

The Global Hawk research aircraft soars to hard-to-reach areas of the atmosphere to collect samples of trace gases and chemicals. Find out just how high the Global Hawk flies.

“Curiosity is a cruel master,” says Dave Bertelsen. Over the past 25 years, he has hiked over 12,000 miles through a desert canyon, just to see what was blooming. He found a few surprises along the way.

In the summer of 2009, sea ice receded to its third-smallest area in recorded history. The reduced sea ice cover in the Arctic allowed an international group of scientists to study areas of the ocean that they have never been able to reach before.

As the sun sinks below the horizon at the South Pole, NOAA researchers stationed at the bottom of the world settle in for six months of darkness. Throughout the Antarctic winter, the researchers will collect air samples to help maintain long-term records of trace gases, aerosols, and solar radiation.

NOAA’s Climate Scene Investigators analyzed why the mid-Atlantic region had record-setting snowstorms this winter. The team looked for but found no human ‘fingerprints’ on the severe weather. Instead, they fingered two naturally occurring climate patterns as co-conspirators in the case.

We can have record-setting blizzards and global warming at the same time. NOAA scientists explain climate variability, how it influenced our weather this winter, and how it differs from climate change.

Watch what happens when an invasive insect takes its toll on eastern hemlock trees in the Southern Appalachian Mountains.

Richard Feely discusses new findings about how increased carbon dioxide in the atmosphere is making the oceans more acidic, and how that will affect ocean ecosystems and the marine animals that inhabit them.

Along coasts, people are waking up to the need for adaptation to climate change. This article points the way to information for getting started.

Visualization of sea level rise in Charleston, South Carolina, courtesy of NOAA.

A snowy, wet winter sets the stage for record floods in some parts of the country this spring.

Global climate models project how Earth’s future climate will look based on human decisions in the next century.

Almost two months after a devastating earthquake rocked Haiti, nearly half a million people there are displaced from their homes, and a million more are living without proper shelter. What climate-related risks will they face in the coming months?

Aerial view of temporary shelters in Port-au-Prince, Haiti. United Nations photo courtesy of Logan Abassi.

Despite efforts to reduce emissions of a HFC-23, a potent greenhouse gas, research shows that concentrations of the compound have increased in recent years.

In early February, two weather systems brought record snowfalls to Washington, D.C., and other parts of the U.S. mid-Atlantic region. At the same time, organizers of the 2010 Winter Olympics in British Columbia, Canada, were dealing with a deficit of snow.

From the African savanna to North America’s boreal forests, NOAA’s CarbonTracker tool provides insight into what natural and human processes affect the uptake, release, and transport of carbon dioxide in Earth’s lower atmosphere.

NOAA researchers have built a “time machine” for weather that provides detailed snapshots of the global atmosphere from 1891 to 2008. The system’s ability to “hindcast” past weather events is emerging as a powerful new tool for detecting and quantifying climate change.

Incorporating IRI’s seasonal climate forecasts into humanitarian-preparedness and early response operations in West Africa, the International Federation of Red Cross/Red Crescent was able to save lives and minimize damages during a severe flooding event in 2008.

Every year, hundreds of adult Hawaiian green sea turtles migrate to the beaches of French Frigate Shoals — one of many Northwestern Hawaiian Islands that could be inundated by rising sea levels.

The “Scarlet Knight” becomes the first unmanned underwater glider to successfully cross the Atlantic. The technology promises to improve our understanding of the ocean and its role in climate and weather.

A wave of cold Arctic air gripped much of North America, Europe, and northern portions of Asia through the month of December 2009.

Two photographs, taken 18 months apart, show a significant decrease in Lake Powell during the most serious period of recent drought.

Has global warming stopped? That’s what some people claim, based on global temperatures recorded since 1998. But, scientists say, not setting a new record high temperature each year doesn’t mean the globe is cooling.

Instruments located high atop NOAA’s Boulder Atmospheric Observatory tower help scientists track carbon emissions and air quality in Colorado.

The International Research Institute for Climate and Society and Google are offering a guided tour of Africa to teach you about the relationship between climate and deadly meningitis outbreaks there. No need to pack your bags, though. It’s a virtual tour that you can take via your computer, narrated by IRI scientist Judy Omumbo.

At the United Nations Climate Change Conference, Dr. Alexander E. “Sandy” MacDonald, of NOAA, used Science on a Sphere® to illustrate how climate change will transform the planet if humans do not reduce emissions of greenhouse gases.

Susan Solomon, of NOAA, was awarded the 2009 Volvo Environment Prize. Her pioneering contributions in atmospheric chemistry and physics have had major impacts on environmental policies.

In the summer of 2007, as oyster growers and hatchery managers in Washington state were experiencing yet another failed oyster harvest, Dr. Richard Feely set off on a research cruise to find out if the seawater itself was the culprit…

In NOAA’s version of CSI, Marty Hoerling leads a group of climate and weather researchers who investigate killer climate patterns—heat waves, tornadoes, and floods—to figure out what may have triggered them.

For years, people have been pointing to El Niño as the culprit behind floods, droughts, famines, economic failures, and record-breaking global heat. Can a single climate phenomenon really cause all these events? Is the world just a step away from disaster when El Niño conditions develop?

New tool gives advance warning of coral-stressing heat.

Climate scientists explain why they’re sure the primary cause of global climate change today is increasing human emission of greenhouse gases — mainly carbon dioxide.

Climate scientists discuss what they know about global climate change today, and how they know it.

NOAA Earth scientists discuss their roles and responsibilities in sharing what they know about the climate system with the public.

“The fact is scientists really can’t predict at this time what the impacts will be on any particular species.”

“If the sea level goes up two or three feet along the coast of Maine in this century, that’s a very significant change.”

As Earth’s ocean continues to absorb carbon dioxide from the atmosphere, marine organisms will have a harder time accessing the minerals they need to build their shells and skeletons.

Temperatures over land and sea during August 2009 made it one of the warmest months on record.

In September 2009, Arctic sea ice shrank to its third smallest extent ever recorded.

In May and June each year, speculation about the coming of the monsoon fills newspapers and conversations across India. Everyone is concerned about if, when, and how much rain will arrive. But none have more at stake than India’s over 100 million farming households.

Improved computer models help scientists understand Earth’s ocean.

Rhode Island’s coasts are already feeling the impacts of rising seas. The Rhode Island Coastal Resources Management Council and Rhode Island Sea Grant are working with the legislature to explicitly address sea level rise and climate change in the state’s building code.

Carbon dioxide is everywhere: in the air, rising from cracks in the ocean floor, and in your soda can. Now it’s showing up in the news! Find out why carbon dioxide is such a hot topic, and why it’s going to be around for a long, long time.

Richard Feely discusses new findings about how increased carbon dioxide in the atmosphere is making the oceans more acidic, and how that will affect ocean ecosystems and the marine animals that inhabit them.

Richard Feely discusses new findings about how increased carbon dioxide in the atmosphere is making the oceans more acidic, and how that will affect ocean ecosystems and the marine animals that inhabit them.

Scientists sometimes describe Earth’s climate as if it were a machine — a complex system with different cycles that move energy and matter around the planet. For example, the climate system has a water cycle, a carbon cycle and an energy cycle. In this analogy, the Sun is the main source of power for the [...]

A pattern of anomalous air pressure at four locations over the Pacific Ocean and North America correlate with regional temperature and precipitation anomalies across North America. This pattern, known as the Pacific-North American teleconnection pattern or PNA, influences regional weather by affecting the strength and location of the East Asian jet stream, and subsequently, the [...]

Just as ponds and lakes in northern states develop a layer of ice on their surfaces during cold winters, the surface of the Arctic Ocean also freezes, forming sea ice. Seawater has a lower freezing point than fresh water, but once it is chilled to around -2°C (about 28°F), the salty liquid begins to solidify. [...]

Global sea level is on the rise. The total amount of water on Earth isn’t increasing, but the volume of liquid that fills the ocean basins is growing, raising the elevation of the sea’s surface and spilling ocean water onto low-lying land. The extra volume of seawater comes from two places. Clearly, melting of ice [...]

Carbon dioxide gets a lot of coverage in the news these days, increasingly attracting the attention of government leaders in the United States and around the world. Not bad for a gas you can’t see or smell… Why so much buzz? Carbon dioxide belongs to a category of gases known as “greenhouse gases.” These gases [...]

Temperatures measured on land and at sea for more than a century show that Earth’s globally averaged surface temperature is experiencing a long-term warming trend. The concept of an average temperature for the entire globe may seem odd. After all, at this very moment, the highest and lowest temperatures on Earth are likely more than [...]

The Arctic Oscillation (AO) refers to an atmospheric circulation pattern over the mid-to-high latitudes of the Northern Hemisphere. The most obvious reflection of the phase of this oscillation is the north-to-south location of the storm-steering, mid-latitude jet stream. Thus, the AO can have a strong influence on weather and climate in major population centers in [...]

The El Niño – Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean. On periods ranging from about three to seven years, the surface waters across a large swath of the tropical Pacific Ocean warm or cool by anywhere from 1°C [...]

In addition to the Ocean Niño index, atmospheric measurements can indicate the status of the El Niño – Southern Oscillation cycle. As El Niño conditions develop, sea surface temperatures in the eastern Pacific Ocean increase and air pressure over the region decreases. Simultaneously, higher air pressure develops over the cooler sea surface in the western [...]

Late in the 16th century, a missionary who had traveled back and forth across the Atlantic Ocean for several years noted that mild winter conditions in Greenland often coincided with severe winter conditions in Denmark, and vice versa. The severe-versus-mild phenomenon he described is now recognized as an impact of the North Atlantic Oscillation or [...]