Climate scientists know with impressive accuracy how fast carbon dioxide is increasing in the atmosphere. A decade ago, there were about 370 parts per million of the heat-trapping gas floating around; today, the number is up to 393 or so. Much of that increase comes from the burning of fossil fuels like coal, gas and oil — but not all, and putting numbers on other sources is crucial to figuring out how to keep carbon emissions under control.

Now a team of researchers has put at least a rough number on one of those sources. According to a new paper in the journal PLOS ONE, so-called blue carbon – carbon that is pulled from the atmosphere by coastal vegetation includingmangroves, sea grasses and salt marshes and stored away in sediments at the edge of the sea -- is now being released at the prodigious rate of between 150 million and 1.02 billion tons every year.

That’s between 3 and 19 percent of the carbon released by deforestation, say the authors, and results in economic damage of between $6 billion and $42 billion annually.

The reason carbon is escaping after being stored for many tens of thousands of years, co-author Daniel Donato of the University of Wisconsin, Madison, said in an interview, is “disturbances” from human activity.

“There’s a whole range of them,” Donato said, including the conversion of coastal mangrove swamps to shrimp aquaculture, conversion of marshes to rice paddies, creation of river dams that starve downstream areas of sediments, offshore dredging, and urban development, to name just a few.

Natural forces, such as hurricanes, disturb coastal ecosystems, too. “Those have been happening for millennia, and the ecosystems have evolved to handle them,” Donato said. It's far more difficult to recover from coastal development and construction, which tend damage ecosystems far more severely, and far more permanently.

Until recently, few thought much about blue carbon. “It really started getting attention only in the past year,” said co-author Linwood Pendleton, a resource economist at Duke University’s Duke’s Nicholas Institute for Environmental Policy Solutions and the acting chief economist at NOAA as well. “At first, people didn’t know whether to take it seriously or not.”

Late last year, Pendleton organized a meeting to talk about the issue and assess the state of the science; the new paper, written jointly by participants in that meeting, is the result.

Once the scientists began looking into it, Donato said, “we realized that organic matter can accumulate into these huge, deep layers that can be as much as 25 feet thick. The plants grow and die, but once they’re buried under sediments, the lack of oxygen means they don’t decompose.”

The amount of buried carbon per acre is significantly more than the amount stored in a tropical rainforest, he said, which most people think of as a major carbon storehouse. And that's true even if you only assume the buried layer of blue carbon is only 3 feet deep, which Pendleton and his colleagues did for their calculations so they'd be sure to err on the side of being conservative.

Even so, the emissions and cost figures the authors came up with span a wide range. The reason, Pendleton said, is that while ecologists have a good idea of how fast salt marshes and sea grass habitats are being disturbed, they’re more uncertain about what’s happening to mangroves.

Nevertheless, the study is a crucial first step in understanding an important source of atmospheric carbon, and in figuring out how to limit emissions.

“We’re going to submit this to the IPCC for their next major report,” Pendleton said, “and say ‘this seems to be a substantial source of carbon. Policymakers should figure out what to do about it.”

• Posted in Impacts, Projections, Carbon Storage, Water, Oceans & Coasts, Flora & Fauna, Global, United States
  
  

Forests cover some 30 percent of Earth’s surface, and it’s hard to overestimate how crucial they are to the functioning of the planet. Forests provide shelter for uncountable numbers of species, hold soil in place that would otherwise wash away, pull excess carbon out of the atmosphere, absorb and re-emit water at such a rate that they literally control the weather, and serve as an economically vital natural resource.

All of those functions have long been endangered by human activities such as excessive logging and clear-cutting to open new agricultural land. But another factor, increasingly, is the stress of climate change — in particular, the higher temperatures and more frequent and intense droughts that human-generated greenhouse gases have begun to trigger. Now a new paper, released Sunday in Nature Climate Change, has attempted to lay out just how climate stress affects forests, and how serious the consequences of could be.

Credit: Paul Hennon/USFS

“This is the first snapshot of how these things fit together,” said lead author William Anderegg, “So we don’t have a lot of final answers yet.”

What they do know is that tree deaths go up during periods of excessive heat and drought. Some of the biggest of these die-offs have happened in the western U.S. in recent years, among pinon pines forests in the Southwest, for example, and trembling aspens in both the U.S. and Canada, and lodgepole pines and spruces in the Northwest — but they’ve also been documented on every continent except Antarctica.

“It’s a very important type of forest mortality,” Anderegg said, “And we expect it to become more common.”

Until recently, however, ecologists hadn’t really focused on drought-induced die-offs as a discrete category of forest trauma. That began to change, Anderegg said, after a meeting in Austin, Texas, last year. “Several of us decided to sit down, put our heads together and begin to look at the possible effects.”

They looked at dozens of individual studies, and found plenty. The loss of a forest’s dominant tree species has a ripple effect on all the other species that live there, by changing the amount of sunlight that reaches the forest floor; changing the mix of nutrients that enter the soil as leaves or needles decompose; allowing soil to wash away, especially on steep slopes, and — in some cases, at least — encouraging more fires.

Forest die-offs also impose an economic hit on loggers and those who depend on income from hikers, campers and others who use forests for recreation.

“One of the most interesting studies we looked at,” Anderegg said, “looked at the negative effect on real estate values in areas with forest loss.”

Forests are not only affected by climate; they also affect it. A living tree absorbs carbon from the air; kill the tree, and the carbon stays in circulation to trap heat. Not only that, as the tree decays, the carbon locked inside is gradually released back into the atmosphere. “It’s a double whammy,” Anderegg said.

On the flip side, leaves and needles are relatively dark, so they absorb solar energy. When a tree dies, they fall, exposing the ground below — and if that ground is light in color, more energy gets reflected. In a case like this, tree death can actually work to counteract global warming. “In a northerly forest where there’s snow on the ground,” said Anderegg, “this can be a big deal. In temperate forests, it’s not so much.”

The loss of trees also changes the amount of moisture in the air, which could potentially affect rainfall, although Anderegg and his co-authors write, "so far no studies have examined this.”

That’s not entirely true: a study just published in Nature argues that projected loss of tropical forests by 2050 could reduce rainfall in the Amazon basin by up to 21 percent — but Anderegg and his co-authors couldn’t have known this was coming. Broadly speaking, there are huge gaps in what scientists know. “This whole area has been fairly under-studied until now,” Anderegg said. “We need more research with a really wide net.”

To try and coordinate it, he and several colleagues have created a collaborative website to share knowledge about drought and tree mortality. The urgency of such research is only underscored by the 2012 drought, the worst to hit the U.S. in more than 50 years.

“The droughts of the early 2000’s caught us by surprise,” Anderegg said. “This one is our chance to pay attention as it unfolds.”

• Posted in Causes, Greenhouse Gases, Impacts, Climate, Extremes, Drought, Heat, Flora & Fauna, Weather, Extreme Weather,Landscapes
  
  

SEOUL, South Korea (AP) — International conservation groups have unveiled a list of the earth's most threatened 100 animals, plants and fungi and say urgent action is needed to protect them.

The groups identified the species Tuesday in a report presented to a global conservation forum on the southern South Korean island of Jeju.

The species live in 48 countries and include the Tarzan's chameleon, the spoon-billed sandpiper and the pygmy three-toed sloth.

The Zoological Society of London and the International Union for Conservation of Nature fear the 100 species will die out because they don't provide humans with obvious benefits.

Experts say that focused conservation efforts can prevent the species' extinction in almost all cases.

• by Beth Buczynski
• September 10, 2012
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BEIJING (AP) — China's imports shrank unexpectedly in August in a sign its economic slump is worsening, bad news for exporters elsewhere that count on the appetite of the world's second-largest economy for natural resources and industrial components to offset anemic Western markets.

The Chinese president warned growth could slow further, prompting expectations of possible new stimulus spending.

Imports declined 2.6 percent from a year earlier, below analysts' expectations of growth in low single digits, data showed Monday. That came on top of August's decline in factory output to a three-year low and other signs growth is still decelerating despite repeated stimulus efforts.

Analysts expect Chinese growth that fell to a three-year low of 7.6 percent in the latest quarter to rebound late this year or in early 2013. But they say it likely will be too weak to drive a global recovery without improvement in the United States, which is struggling with a sluggish recovery, and debt-crippled Europe.

President Hu Jintao cited slack exports and unbalanced domestic growth as challenges for a Chinese recovery.

"Pressure for economic growth to slow is obvious," Hu said at the Asia Pacific Economic Cooperation meeting in Vladivostok, Russia, according to a text released by the Chinese government.

Hu's speech Sunday gave no growth forecast or details of possible new stimulus but promised to continue a "proactive fiscal policy," or government spending to pump up the economy.

Beijing has cut interest rates twice since early June and is pumping money into the economy through higher spending on building subways and other public works. Still, activity has weakened steadily, spurring some analysts to cut growth forecasts and push back the timing of a possible recovery.

"The comments made by President Hu yesterday made it clear that there will be more funding support for infrastructure investments," said Goldman Sachs economists Yu Song and Yin Zhang in a report.

The slowdown hit at a politically sensitive time for the ruling Communist Party, which is trying to enforce calm as it prepares to hand power to Hu's successor and other younger leaders in a once-a-decade transition.

The slump in global demand has forced thousands of Chinese exporters out of business, raising the threat of job losses and possible unrest.

Weak Chinese imports could hurt exporters in Southeast Asia, Australia, Brazil and Africa that are counting on its appetite for oil, iron ore, industrial components and other goods to help offset low demand in the United States and Europe.

August exports rose, but by only 2.7 percent over a year ago, down from the double-digit growth of recent years as Europe's debt woes and the sluggish U.S. recovery hurt demand for Chinese goods.

Exports to the 27-nation European Union, China's biggest trading partner, fell 4.9 percent from a year earlier. Sales of Chinese goods to Italy plunged 26 percent, while exports to France andGermany were off 8.6 percent and 7.9 percent, respectively.

Exports to the United States rose 10.2 percent.

The import weakness pushed China's global trade surplus to $26.7 billion, double the level of a year ago.

Exports in August totaled $178 billion while imports were $151.3 billion.

Adding to signs of weakening Chinese demand, growth in auto sales tumbled to 3.7 percent in August. That figure reported by the China Association of Auto Manufacturers extended a decline from July's 11 percent growth and June's 15.8 percent rate.

Chinese authorities have reacted cautiously to the current slowdown after their huge spending in response to the 2008 global crisis fueled inflation. They have approved a multibillion-dollar wave of spending on public works construction and investments by state companies but are reviewing projects carefully rather than indiscriminately throwing money at the economy.

In its latest move, the government announced 25 new subway construction projects last week budgeted at tens of billions of dollars. It also has approved construction of new highways, airports, steel mills and other facilities.

Despite that mini-stimulus, August growth in factory output weakened to 8.9 percent from July's 9.2 percent — the weakest since May 2009 in the depths of the global crisis.

Analysts have trimmed their China growth forecasts for this year and in 2013, though to levels of 7.5 to 8 percent that still are robust by U.S., European or Japanese standards.

"Economic activity has remained weak as export growth slowed, policy support was not as rapid or aggressive as previously envisaged and industries continued with inventory adjustments," UBS economist Tao Wang said in a report last week.

Wang cut her growth outlook for this year from 8 to 7.5 percent and from 8.3 percent next year to 7.8 percent.

The government also could face trouble from an upturn in inflation that could make it harder to cut rates without the risk of igniting a new price spike.

Inflation in August rose to 2 percent from July's 1.8 percent, driven by a 3.4 percent gain in food prices, up from the previous month's 2.4 percent.

Despite that, China announced Monday it is raising the retail price of gasoline and diesel in the wake of rising crude prices.

The National Development and Reform Commission said gasoline will go up by 550 yuan ($87) per ton and diesel by 540 yuan ($85) per ton starting Tuesday. It said the benchmark retail price of gasoline will increase by 0.41 yuan ($.06) per liter and diesel by 0.46 yuan ($.07) per liter.