Global warming is a big thing. The pine beetle is an exceedingly small thing. But when the two are combined, it means one thing for North Carolina's pine forests -- trouble.

Higher global temperatures will likely bring milder winters to North Carolina, allowing pine beetles to hatch more offspring and possibly expand their killing zones. The most recent beetle outbreak, which ended in 2001, cost the Southern lumber industry $1 billion. One U.S. study predicts up to seven times more trees dying in a warmer climate.

The beetle threat is part of a phenomenon that could affect a wide range of North Carolina staples. Rising temperatures could intensify the activity of pests, play havoc with pollination cycles and weaken the natural defenses and migratory patterns of sea life, which have developed over millennia of cooler temperatures.

There is still debate over how much of the change in temperature is due to man-made carbon dioxide and how much comes from the natural cycles of weather. But international climate scientists predict that Earth might warm between 3.5 degrees and 8 degrees by the end of this century due to heat trapped by man-made greenhouse gases.

Scientists are exploring how more heat would alter North Carolina's landscape and its bounties.

"You don't want to scare people, but you're foolhardy not to do everything you can to prepare," said Louis Daniel, director of the N.C. Division of Marine Fisheries. He counts the effect of climate change among his top long-term concerns for North Carolina's coastal waters.

Beetle attacks feared

After watching insects attack trees for 30 years, entomologist Fred Hain grew alarmed the last time drought struck North Carolina. Southern pine beetles badly damaged mountain forests in the hot, dry weather, felling trees that often resist them.

As it gets warmer, there could be more trouble. In his laboratory at N.C. State University, Hain and his team hope their findings on the beetles will help timber growers fight outbreaks.

Southern pine beetles, small as uncooked grains of rice, attack en masse, boring through a tree's bark, mating there and laying eggs. They dine on nutrient-rich phloem, tissue beneath a tree's bark that carries water and food from the crown to the roots. The beetles also carry fungus under the bark, which worsens the damage.

As the beetles eat the phloem, they dig grooves into the tissue. This can girdle a tree, blocking food from its roots and killing it.

"Even the healthiest tree can be killed if enough beetles attack it," Hain said. One irony of climate change is that it could extend the growing season of trees in the South, providing beetles with more fuel for multiple life cycles each year.

Hain wants to find out just how well the bugs do attacking white pine, a tree that appeared more vulnerable to pine beetles during North Carolina's last drought. That could help his team produce a computer model that predicts how, in warmer weather, the pest would perform in a real forest, particularly while trying to expand its terrain.

Birch McMurray is glad someone is trying to figure that out. He tends 150 acres of family timber forest in Polk County that was attacked by southern pine beetles eight years ago.

"I think it could totally wipe out the pine forest if we have enough stress from weather and the trees are planted thick and under stress," he said. Landowners cut so many trees last time that the value of lumber plummeted.

"There were acres and acres and acres," McMurray said. "People would give them to you to cut them."

More than lumber is at stake during a major outbreak of a pest such as the southern pine beetle. The killer beetle can leave millions of dead trees in its wake, scarring green forests with ugly slashes of ghostly tree skeletons. As trees die, their roots no longer hold the soil, causing erosion that muddies creeks and rivers, altering aquatic life. Their dead limbs become ready fuel for fires.

Hain and his students have reason to suspect that the southern pine beetle might try to dash higher into the mountains and to the north. They only have to look westward to see the worst of what could come. A related beetle, the mountain pine beetle, is on a rampage in the Western United States and Canada. Scientists suspect that warmer winters have fed the outbreak. The United States and Canada have invested millions of dollars to stop it, but the beetle continues its march, leaving rust-colored relics in what was once green forest.

Crops are sensitive

Temperature change doesn't affect all organisms the same way. Sometimes it alters normal development, which can spell bad news for farmers.

Last year, Ken Dawson noticed his tomato crop did poorly at Maple Spring Gardens in Cedar Grove -- a loss he blames on evening temperatures not falling as low as they normally did.

"The plants just dropped their blooms," the Orange County farmer said. "The tomatoes didn't set fruit."

Erratic weather also took a toll on a spring crop this year at Maple Spring -- the entire blueberry yield died after warm weather in late winter caused plants to bud early. A hard freeze at Easter killed the blossoms.

Dawson said he expects his organic farm, where he grows many types of fruits and vegetables rather than just one crop, can cope with climate change. Warmer weather might extend his growing season -- a benefit. But Dawson worries for farmers who specialize in single crops and, as a result, have less flexibility to make up for losses.

If temperatures in North Carolina rose modestly to levels more common in states farther south, farmers could easily adapt, said Brian Murray, a Duke University economist who studies how global warming might affect agriculture and timber forests. They could simply alter the plants they grow or the timing of their growing seasons.

But some long-term projections predict that average temperatures will rise in the last half of this century beyond anything currently common even in the Deep South. It will take a lot of money and time to figure out how to respond to that, Murray said.

Tomatoes as evidence

Research will be needed to understand the effects on different crops. Among those searching for answers is NCSU horticulturist Mary Peet, who has observed how tomato plants commonly grown in North Carolina do not pollinate well when it's hot.

Farmers have long understood the sequence that tomato plants must follow to bear fruit. Plants produce both pollen and flowers, processes exquisitely timed so that pollen can reach a flower's stigma at an ideal time for fertilization to take place.

Peet and a graduate student grew beefsteak-type tomatoes in a greenhouse and raised the mean temperature above 81 degrees for seven to 10 days -- well above the ideal 77 degrees. The plants faltered.

The heat-stressed plants produced inferior pollen and less of it. That pollen was less likely to germinate and complete basic steps required for making fruit.

"The parent plant has to provide that developing pollen grain exactly what it needs, when it needs it," Peet said. "It's a very elaborate choreography between two partners, like a dance."

Studies have since observed similar heat-related disruptions in pollen production in peanuts, corn, cotton and other crops, Peet said. Finding ways to compensate for dramatic climate change would be expensive, requiring new plants, fertilizer and farming equipment suited for the changed Southeast.

"They will be spending money to hold ground," Murray, the Duke economist, said of farmers. "If you are investing in that, you can't be investing in other things."

Oyster defenses falter

North Carolina oyster harvests -- which peaked at 1.8 million bushels in 1902 but totaled only 71,300 bushels in 2005 -- have declined as a result of overfishing; shrinking habitats from coastal development; and pollution from industry, agriculture and human waste.

Climate change could bring another serious blow. Research on oysters native to North Carolina's coastal waters shows temperature increases hurt their ability to thrive.

A few steps from her UNC-Charlotte laboratory, marine biologist Inna Sokolova and her staff tend to hundreds of oysters in temperature-controlled, 15-gallon tanks. Over millions of years, the mollusks have developed finely tuned systems to neutralize dangerous substances such as heavy metals in the seawater they filter day after day.

"These organisms can detoxify themselves," Sokolova said.

One heavy metal threat in North Carolina estuaries is cadmium, found in paints, dyes, batteries and other waste once dumped in rivers that flow toward the Atlantic coast. To defend themselves, the shellfish put molecular locks on the toxic intruder, making it unable to enter vulnerable cells and do harm.

But when Sokolova turns up the temperature in her tanks, oyster defense systems falter. Studies in her laboratory show that oysters can't produce enough energy to lock out the toxin.

Other cold-blooded marine animals have many of the same sorts of molecular defense systems as oysters. Clams, crabs and even fin fish might find those systems weakened as water temperatures rise, Sokolova suspects.

If so, the effect could be big. Pollution levels now considered less threatening to sea life could pose a greater danger in a warmer climate.

"We might have to modify what we consider safe levels of pollution," Sokolova said. "Temperature may modify its toxicity."

Water temperatures off the coast are higher. Charles "Pete" Peterson, a UNC-Chapel Hill marine scientist based in Morehead City, analyzed temperature data in waters near Pivers Island in Carteret County and found that from 1985 to 2005, average ocean surface temperatures rose 2.5 degrees. The reason is that the daily low temperatures are higher, especially in February through May.

"Winters are not as cold," Peterson said.

That is something that fishermen such as Billy Carl Tillett of Moon Tillett Fish Co. in Wanchese have observed, as well, based on fish harvests. For two or three years, black sea bass and scup, fish that normally swim south to North Carolina in winter, have stayed north. Temperatures did not drop fast enough in the fall to get them here, Tillett said. Cold-water Boston mackerel and Atlantic herring haven't made it this far south in years.

But Tillett said he isn't worrying yet -- unless the trouble continues. In 38 years of fishing, he said, he has seen countless changes in weather patterns, and he is still pulling millions of pounds of fish from the waters he is permitted to fish. Permanent change would affect him, though, because he is limited by cost and government rules that keep him in home waters.

"I can't go chase them," Tillett said of fishing in colder waters. "We've got our hands tied behind our backs."

It is not just water temperature that will change in a warmer world. Scientists have noted that coastal waters off North Carolina rose 8 inches over the past century, bringing more salt water into estuaries that are fertile breeding grounds for sea creatures.

If the process continues on pace, said Daniel of the marine fisheries division, the Pamlico Sound could become inhospitable by the second half of this century to many species that currently succeed in the massive marine nursery.

"The potential is there for it to completely change," he said. "When you start talking in the 30- to 50-year range, you're talking about pretty soon."