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"There has not been a seasonal forecast of 23 storms put out for this country before," said Holland.  Like forecasters from NOAA and elsewhere (see More pre-season predictions of a very active Atlantic hurricane season, at the WunderBlog for a summary of forecasts), Holland cited high SSTs as a principal factor underlying his assessment. The SSTs during the first month of the hurricane season did nothing to diminish concerns.  As the figure below indicates, high SSTs characterized the tropical Atlantic in June, with many areas again seeing record high temperatures for the month. 

"So what’s happening?" asks Holland.  "Well it’s a combination of global warming and natural variability."

This is consistent with research results published in Geophysical Research Letters on 29 April 2010.  In Is the basin-wide warming in the North Atlantic Ocean related to atmospheric carbon dioxide and global warming?, Chunzai Wang and Shenfu Dong of NOAA's Atlantic Oceanographic and Meteorological Laboratory, conclude that "both global warming and AMO [Atlantic multidecadal oscillation] variability make a contribution to the recent basin-wide warming in the North Atlantic and their relative contribution is approximately equal."

Large-scale storm systems are the dominant weather phenomenon during the cold season in the United States. Although the analysis of these storms is complicated by a relatively short length of most observational records and by the highly variable nature of strong storms, some clear patterns have emerged.112 [Kunkel et al., 2008] Storm tracks have shifted northward over the last 50 years as evidenced by a decrease in the frequency of storms in mid-latitude areas of the Northern Hemisphere, while high-latitude activity has increased. There is also evidence of an increase in the intensity of storms in both the mid- and high-latitude areas of the Northern Hemisphere, with greater confidence in the increases occurring in high latitudes.112 [Kunkel et al., 2008] The northward shift is projected to continue, and strong cold season storms are likely to become stronger and more frequent, with greater wind speeds and more extreme wave heights.68 [Gutowski et al, 2008]

The northward shift in storm tracks is reflected in regional changes in the frequency of snowstorms. The South and lower Midwest saw reduced snowstorm frequency during the last century. In contrast, the Northeast and upper Midwest saw increases in snowstorms, although considerable decade-to-decade variations were present in all regions, influenced, for example, by the frequency of El Niño events.112 [Kunkel et al., 2008]

Then we have this apparently as yet unpublished research presented by Dr James Overland of the NOAA/Pacific Marine Environmental Laboratory at the recent International Polar Year Oslo Science Conference (IPY-OSC) where he was chairing “a session on polar climate feedbacks, amplification and teleconnections, including impacts on mid-latitudes.” “Cold and snowy winters will be the rule, rather than the exception,” says Dr James Overland…. Continued rapid loss of sea ice will be an important driver of major change in the world’s climate system in the years to come…. “While the emerging impact of greenhouse gases is an important factor in the changing Arctic, what was not fully recognised until now is that a combination of an unusual warm period due to natural variability, loss of sea ice reflectivity, ocean heat storage and changing wind patterns working together has disrupted the memory and stability of the Arctic climate system, resulting in greater ice loss than earlier climate models predicted,” says Dr Overland. “The exceptional cold and snowy winter of 2009-2010 in Europe, eastern Asia and eastern North America is connected to unique physical processes in the Arctic,” he says.

Even though these storms occurred during warmest winter on record, I think the best way to talk about it until Overland publishes his work is the way NCAR’s Kevin Trenberth did on NPR (audio here): RENEE MONTAGNE, host:  With snow blanketing much of the country, the topic of global warming has become the butt of jokes. Climate skeptics built an igloo in Washington, D.C. during last weeks storm and dedicated it to former Vice President Al Gore, who’s become the public face of climate change. There was also a YouTube video called “12 Inches of Global Warming” that showed snowplows driving through a blizzard.For scientists who study the climate, it’s all a bit much. As NPRs Christopher Joyce reports, they’re trying to dig out. CHRISTOPHER JOYCE: Snowed-in Washington is where much of the political debate over climate change happens. So it did not go unnoticed when a Washington think-tank that advocates climate action had to postpone a climate meeting last week because of inclement weather. That kind of irony isnt lost on climate scientists. Most don’t see a contradiction between a warming world and lots of snow. Heres Kevin Trenberth, a prominent climate scientist at the National Center for Atmospheric Research in Colorado. Mr. KEVIN TRENBERTH (Scientist, National Center for Atmospheric Research): The fact that the oceans are warmer now than they were, say, 30 years ago, means there’s about, on average, 4 percent more water vapor lurking around over the oceans than there was, say, in the 1970s. JOYCE: Warmer water means more water vapor rises up into the air. And what goes up, must come down. Mr. TRENBERTH: So one of the consequences of a warming ocean near a coastline like the East Coast and Washington, D.C., for instance, is that you can get dumped on with more snow, partly as a consequence of global warming. JOYCE: And Trenberth notes that you don’t need very cold temperatures to get big snow. In fact, when the mercury drops too low, it may be too cold to snow. There’s something else fiddling with the weather this year: a strong El Nino. That’s the weather pattern that, every few years, raises itself up out of the western Pacific Ocean and blows east to the Americas. It brings heavy rains and storms to California and the South and Southeast. It also pushes high-altitude jet streams farther south, which brings colder air with them. Trenberth also says El Nino can lock in weather patterns like a meteorological highway, so that storms keep coming down the same track. True, those storms have been big ones – record breakers. But meteorologist Jeff Masters, with the Web site Weather Underground, says it’s average temperatures — not snowfall — that really measure climate change. There’s more water vapor lurking around the oceans, and whatever the proximate cause of any one snow storm, there is little doubt that global warming means the overwhelming majority of East Coast storms will be sweeping in more moisture and dumping it on the ground.

Hampton Roads in southeastern Virginia is unusually vulnerable. It is flat, and its land is sinking. It has nearly 2 million residents. It is home to popular beaches, waterfront homes, military bases, a huge tourism industry and ecologically valuable marshes.

"Hampton Roads is one of the most vulnerable regions in the United States to sea-level rise, in terms of population and assets at risk," said Eric J. Walberg, a former staff member for the Hampton Roads Planning District Commission.

Rising sea levels around the world are attributed to warming. When water warms, it expands. Melting polar ice sheets also raise the waters. In Virginia, sea levels are rising faster than the global average because the land is sinking

The sea level in this region has been rising about a foot a century -- the highest rate on the East Coast. Scientists project a potentially devastating rise of 2 to 7 feet by 2100.

Many of the piers at the Norfolk Naval Station were built around World War II. During storms or even higher-than-normal tides in recent years, the water began to rise so high that it flooded low-lying areas of the base and covered utility lines, including high-voltage electrical cables, suspended beneath the old piers. That meant frequent losses of power and other services to the base's ships. "Sea-level rise was having a negative impact on the readiness of the combat forces at the base," said Joe Bouchard, the base's commander from 2000 to 2003.

The Navy was already planning a multimillion-dollar project to replace the aging piers at Norfolk, the world's largest naval base. To cope with the rising waters, Navy engineers designed double-deck piers with the utility lines suspended from the main, upper deck, about 20 feet above sea level.

Cmdr. Wendy L. Snyder, a Defense Department spokeswoman, acknowledged that flooding occurs at the Norfolk and Langley bases. The department is concerned and is studying the problem, she said. "We are going to assess the impacts of climate change for all of our installations." As for possible base closings in Hampton Roads, Snyder said she did not want to speculate.

A powerful storm hit Virginia's coast in 1933. But the less-powerful Hurricane Isabel in 2003 -- which became a tropical storm about the time it entered Virginia -- caused similar flooding because the sea level by then had risen 9 to 10 inches. Isabel gained extra destructive power by sending its storm surge inland on higher waters, Hershner said. Isabel caused hundreds of millions of dollars in damage. On top of all that, scientists predict global warming will cause more-powerful storms in coming decades. And in Hampton Roads, more and more people are building near the shore, putting themselves and their property at risk.

Low-lying parts of Hampton Roads flood now from fairly routine storms and tides, said Skip Stiles, director of Wetlands Watch, a Norfolk environmental group. "Anywhere you go, people have stories" about how the water comes up higher than it used to.

The Southeast, South and Central regions experienced their second, fifth and seventh warmest June on record, respectively.

Record-warm June temperatures were observed in Delaware, New Jersey and North Carolina (tied), where each had average temperatures 5 to 6 degrees F above the long-term mean. Many other states ranked in their top ten based on 116 years of data.

Midway through 2010, four New England states (Maine, New Hampshire, Vermont and Rhode Island) have experienced their warmest January-June period on record. Eight other states in the Northeast and Great Lakes areas had a top-ten warm such period.

Persistent warmth made the year's second quarter (April-June) much warmer than normal for every state east of the Mississippi River, and several to its west. Louisiana and ten Atlantic Seaboard states (Maine, New Hampshire, Massachusetts, Delaware, Rhode Island, Connecticut [tied], New Jersey, Maryland, Virginia, and North Carolina) had a record-warm second quarter. In all, twenty states had their warmest or second-warmest such period on record. The warmth in these areas contributed to both the Northeast and Southeast climate regions' warmest April-June period.

"Frankly, I was expecting that we'd see large temperature increases later this century with higher greenhouse gas levels and global warming," Stanford climate scientist Noah Diffenbaugh, who headed up the research, said in a prepared statement. "I did not expect to see anything this large within the next three decades."

Many fishermen switched to lobster as winter flounder, a cold-water fish once abundant in fishing boat holds, declined. But lobster stocks are stressed in some areas now. Biologists on a multi-state Fisheries Commission committee have found that warmer waters, disease and fishing have depleted lobster stocks, and they recently recommended a five-year ban on lobstering from Cape Cod to Virginia.

"One of the grim realities of global warming is that it is bringing change to fisheries. There are going to be regime changes in the oceans and management is going to have to adapt to that,"

Greg Walinski believes he has seen first-hand the workings of warmer waters on fish stock. The 53-year-old Cape Cod fisherman used to hunt for large bluefin tuna. "In the '80s and '90s we would get 60 to 80 giant bluefin in a season," he said. "But we started to see less and less. It got to a point where it wasn't even worth going out. Most of the big fish are up in Canada," he said. "We get the little bluefin that used to be further south."

He switched to cod, but in what seems to be a repeat of the pattern, Walinski said he finds himself chasing the fish further and further out. He now travels 120 miles in a 35-foot boat - an arduous and somewhat dangerous commute - to reach Georges Bank for codfish.

regulators say they have seen little evidence of a similar rebound in cod on the George's Bank, and some other cold-water species, like winter flounder and pollock, remain low.

When plant plankton plummet — like they do during El Nino climate cycles_ sea birds and marine mammals starve and die in huge numbers, experts said.

Worm said when the surface of the ocean gets warmer, the warm water at the top doesn't mix as easily with the cooler water below. That makes it tougher for the plant plankton which are light and often live near the ocean surface to get nutrients in deeper, cooler water. It also matches other global warming trends, with the biggest effects at the poles and around the equator.

Phytoplankton are microscopic marine organisms capable of photosynthesis, just like terrestrial plants. They float in the upper layers of the oceans, provide much of the oxygen we breathe and account for about half of the total organic matter on Earth. A 40 per cent decline would represent a massive change to the global biosphere."If this holds up, something really serious is underway and has been underway for decades. I've been trying to think of a biological change that's bigger than this and I can't think of one," said marine biologist Boris Worm of Canada's Dalhousie University in Halifax, Nova Scotia. He said: "If real, it means that the marine ecosystem today looks very different to what it was a few decades ago and a lot of this change is happening way out in the open, blue ocean where we cannot see it. I'm concerned about this finding."The researchers studied phytoplankton records going back to 1899 when the measure of how much of the green chlorophyll pigment of phytoplankton was present in the upper ocean was monitored regularly. The scientists analysed about half a million measurements taken over the past century in 10 ocean regions, as well as measurements recorded by satellite.They found that phytoplankton had declined significantly in all but two of the ocean regions at an average global rate of about 1 per cent per year, most of which since the mid 20th Century. They found that this decline correlated with a corresponding rise in sea-surface temperatures – although they cannot prove that warmer oceans caused the decline.The study, published in the journal Nature, is the first analysis of its kind and deliberately used data gathered over such a long period of time to eliminate the sort of natural fluctuations in phytoplankton that are known to occur from one decade to the next due to normal oscillations in ocean temperatures, Dr Worm said. "Phytoplankton are a critical part of our planetary life support system. They produce half of the oxygen we breathe, draw down surface CO2 and ultimately support all of our fishes." he said.But some scientists have warned that the Dalhousie University study may not present a realistic picture of the true state of marine plantlife given that phytoplankton is subject to wide, natural fluctuations."Its an important observation and it's consistent with other observations, but the overall trend can be overinterpreted because of the masking effect of natural variations," said Manuel Barange of the Plymouth Marine Laboratory and a phytoplankton expert.

However, the Dalhousie scientists behind the three-year study said they have taken the natural oscillations of ocean temperatures into account and the overall conclusion of a 40 per cent decline in phytoplankton over the past century still holds true. "Phytoplankton are the basis of life in the oceans and are essential in maintaining the health of the oceans so we should be concerned about its decline."It's a very robust finding and we're very confident of it," said Daniel Boyce, the lead author of the study."Phytoplankton is the fuel on which marine ecosystems run. A decline of phytoplankton affects everything up the food chain, including humans," Dr Boyce said.

Phytoplankton is affected by the amount of nutrients the well up from the bottom of the oceans. In the North Atlantic phytoplankton "blooms" naturally in spring and autumn when ocean storms bring nutrients to the surface. One effect of rising sea temperatures has been to make the water column of some regions nearer the equator more stratified, with warmer water sitting on colder layers of water, making it more difficult for nutrients to reach the phytoplankton at the sea surface.Warmer seas in tropical regions are also known to have a direct effect on limiting the growth of phytoplankton.

While researchers are confident that the higher temperatures and resulting changes in snowpack, Colorado River flow, vegetation mortality and wildfires are human-caused, they don't know whether the drought that has plagued the West for the last 10 years – the worst since record-keeping began – is because of humans, Overpeck said.

“In Colorado, we get our wind from the west,” he explained. “Canada gets its wind from the east. Where the wind belts rub against each other – it causes friction. As friction occurs, it creates waves in the atmosphere. Waves create frontal systems. These frontal systems are most noticeable during the change of seasons, which is also when we get our biggest storms, particularly in spring and fall.” Fox concluded that climate change is tipping the balance toward a battle of heat and cold. “Storms, created when frontal systems collide, are the atmosphere’s way of dealing with differences in temperature,” he said. “The atmosphere is attempting to balance the energy and equalize the temperature with the air going from high pressure to low pressure.” Fox added that cold air is now coming further south than it used to and warm air is going further north than usual. “Wind is air trying to equalize pressure,” he said. The scientist then used the analogy of a runner eating a big bowl of pasta. “If he then downs a Red Bull, there is more energy in the system to fuel his run,” he said. This pasta analogy goes beyond the college classroom and has a practical and local effect as well. It can be applied to the recent wind and dust storms that have wreaked havoc on Durango locals and tourists alike. Bayfield motorcyclist Jeff Gilmore had his windshield sandblasted as he headed into Flagstaff recently. “Semis were lined up on the side of the road,” he said. “Foot high sand drifts progressed across I-89 from Page to Flagstaff.” Although he pulled down his full-face helmet and shut all the vents, Gilmore was still pounded. “Sand stuck to my chapstick and the fine grit got in my mouth,” he said.

Carlotta Haber and her daughter were sent 100 miles out of their way while driving from Durango to Sedona a few weeks ago. Just before Holbrook, Ariz., on I-40 West, a sign read, “Highway closed 43 miles ahead due to dust storm.” “I couldn’t see the car in front of me and big tumbleweeds were rolling at the car,” she said. These anecdotes are directly in line with scientific findings. In fact, the National Center for Atmospheric Research in Boulder has formulated global climate models forecasting that “all weather will get more extreme.” Storms are stronger than 20 years ago, according to NCAR, as the research center is predicting more precipitation per storm event, despite its forecast for fewer overall storms. Tim Foresman, former director of the United Nations Environmental program, explained, “These conditions are exactly what caused this past winter’s heavy snows in the East and the recent flooding in Tennessee. One was an extraordinary winter precipitation event and the other was a spring precipitation event.”

While these conditions may feel like an anomaly, research indicates that they are the logical result of changing conditions. National Climatic Data Center statistics reveal that in the last 30 years, the temperature has risen an average of 2 degrees in the United States. Since 1975, the average temperature in Colorado has increased by 2.28 degrees. The only two states whose temperatures have risen more are Utah, with a 2.43 degree increase, and Arizon,a with 2.79 degrees. A NASA report corroborates these findings. The report states that the last 12 months have been the warmest in at least 1,000 years. Foresman added, “The meteorological forecasts are based on prior weather patterns and may not be accurate without considering changes under way due to a warming climate. Forecasts are based on seasonal models from the immediate past and may not be a good indicator of the future due to changing climatic conditions.” His expertise has been extremely valuable to his sister-in-law, who just purchased property and is building a home in Durango. Counseling her on what to expect in the near future due to the changing patterns, she modified her construction plans.

Having recently experienced a blizzard in May in Santa Fe, Foresman stated the obvious. “The systems are all out of whack,” he said. “We’re going to be in for some interesting times. We can put our heads in the sand, or we can prepare.” In closing, Foresman remarked that the windiest days could be ahead for the Four Corners and Southwest and offered local residents a piece of advice. “If you have shutters on your windows, I suggest you make sure they’re functional and not decorative,” he said. “The winds aren’t going to go away until you turn the heat down.” •

The study also found that the two-to-one ratio across the country as a whole could be attributed more to a comparatively small number of record lows than to a large number of record highs. This indicates that much of the nation's warming is occurring at night, when temperatures are dipping less often to record lows. This finding is consistent with years of climate model research showing that higher overnight lows should be expected with climate change.

"If the climate weren't changing, you would expect the number of temperature records to diminish significantly over time," says Claudia Tebaldi, a statistician with Climate Central who is one of the paper's co-authors. "As you measure the high and low daily temperatures each year, it normally becomes more difficult to break a record after a number of years. But as the average temperatures continue to rise this century, we will keep setting more record highs."

In fact, temperature change offered a better prediction of impending conflict in the 40 countries surveyed than even changes in rainfall, despite the fact that agriculture in this region is largely dependent on such precipitation. Burke and his fellow authors argue that this could be because many staple crops in the region are vulnerable to reduced yields with temperature changes—10 to 30 percent drops per degree C of warming.

"If temperature rises, crop yields decline and rural incomes fall, and the disadvantaged rural population becomes more likely to take up arms," Burke says. "Fighting for something to eat beats starving in their fields."

Whereas 23 years in 40 countries provides a relatively large data set, it does not exclude other possible explanations, such as violent crime increasing with temperature rise, a drop in farm labor productivity or population growth. "Fast population growth could create resource shortage problems, as well," notes geographer David Zhang of the University of Hong Kong, who previously analyzed world history back to A.D. 1400 to find linkages between war and temperature change. Those results were also published in 2007 in Proceedings of the National Academy of Sciences. But "the driver for this linkage," Zhang says," is resource shortage, mainly agricultural production, which is caused by climate change." Burke and his colleagues specifically excluded records from prior to 1980, because of the conflict rampant in the wake of Africa's emerging colonial independence after World War II. "A lag of a couple of decades would leave sufficient time for post-independence turmoil to wear out," Burke argues. "We took the approach that the best analogue to the next few decades were the last few decades."

Proving the link—and providing a specific mechanism for the increase in conflict, whether agricultural productivity or otherwise—remains the next challenge. "I believe that the historical experience of human society of climate change would provide us [with] the evidence of how climate cooling and warming during the last thousand years created human crisis, and also the lessons for human adaptive choices for climate change," Zhang notes. "We feel that we have very clearly shown the strong link between temperature increases and conflict risk," Burke adds. But "what interventions will make climate-induced conflict less likely?"