Friday, April 14, 2006

Stark warning over climate change from BBC

The really bizarre thing is that this is milder than some of the scenarios that are coming around. Check out some of the links, this is a pretty good site.

Sunday, April 09, 2006

Another ecosystem, very personal,under attack

Published on Thursday, February 9, 2006 by Reuters
Global Warming a Major Health Risk - Scientists

LONDON - Global warming is already causing death and disease across the world through flooding, environmental destruction, heatwaves and other extreme weather events, scientists said on Thursday.

And it is likely to get worse.

In a review published in The Lancet medical journal, the scientists said there was now a near-unanimous scientific consensus that rising levels of greenhouse gases would cause global warming and other climate changes.

"The advent of changes in global climate signals that we are now living beyond the Earth's capacity to absorb a major waste product," said Anthony McMichael of the Australian National University in Canberra and his colleagues, referring to greenhouse gases.

The scientists' review of dozens of scientific papers over the last five years said health risks were likely to get worse over time as climate change and other environmental and social changes deepened.

"The resultant risks to health ... are anticipated to compound over time as climate change along with other large scale environmental and social changes continues," they wrote.

The review said climate change would bring changes in temperature, sea levels, rainfall, humidity and winds.

This would lead to an increase in death rates from heatwaves, infectious diseases, allergies, cholera as well as starvation due to failing crops.

They said climate change may already have led to lower production of food in some regions due to changes in temperature, rainfall, soil moisture, pests and diseases.

"In food insecure populations this alteration may already be contributing to malnutrition," it said.

The scientists said sea levels had risen in recent decades, and people had already started moving from some low-lying Pacific islands. Such population movements often increased nutritional and physical problems and disease, they said.

"The number of people adversely affected by El Nino-related weather events over three decades, worldwide, appears to have increased greatly," it said, referring to the weather pattern caused by warming of the Pacific Ocean off South America.

The review called for research to identify groups vulnerable to climate change and said health concerns should be included in international policy debates about global warming.

"Recognition of widespread health risks should widen these debates beyond the already important considerations of economic disruption," they said.

Copyright © 2006 Reuters

Friday, April 07, 2006

The Millenium Assessment

A major presentation of info regarding the state of the world's ecosystems

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Millenium Assessment

Published on Friday, January 20, 2006 by Inter Press Service
Environment: World Stands at a Crossroads
by Stephen Leahy

BROOKLIN, Canada - With 60 percent of the Earth's ecosystems in trouble right now, according to the Millennium Ecosystem Assessment, what will the future be like in 2050?

Demand for water will increase enormously between 30 and 85 percent, especially in Africa and Asia, while an increasing number of extreme events, such as hurricanes and famine, will affect many millions, warns a Millennium Ecosystem Assessment (MA) report that looks at future world development scenarios.

Humankind is pushing up against natural thresholds and increasing the likelihood of abrupt changes -- especially when there are three billion more people in 2050.

"Two billion people currently living in drylands, including the western U.S., are especially vulnerable to climate change, which could produce intense, long-term droughts," said Stephen Carpenter, a professor of zoology at the University of Wisconsin and one of the authors of the MA report.

Demand for food is expected to grow 70-85 percent by 2050, resulting in a 10 to 20 percent decline in forest and grasslands. Rising demand for fish will likely result in major and long-lasting collapse of regional marine fisheries. Hunger will remain a major problem, most widespread in South Asia and Sub-Saharan Africa.

South Asia could reach an "environmental breaking point as deforestation spreads, industrial agriculture grows, water use goes up and sewage discharge increases".

This future is not written in stone, Carpenter points out.

Conditions could get much worse or they might get better -- it all depends on the choices and the policies put into place now and the near future, the MA report concludes.

"We will have to make changes in policies for ecosystems to get better," he said at a press conference Thursday.

The MA is a 22-million-dollar, four-year global research initiative, commissioned by the United Nations, by 1,360 experts from 95 countries. The final four volumes published Thursday by Island Press reveal why and how to slow or reverse the degradation of the Earth's ecosystems, including a look at what the future may be like in 2050.

"This is a long overdue look at the state of Earth's ecosystems that sustain all life," said Thomas Lovejoy, president of the Heinz Centre, a U.S.-based NGO dedicated to improving the scientific and economic basis for environmental policy.

"The MA reports represent a roadmap for effective sustainable human development," said Lovejoy, a former ecologist with the Smithsonian Tropical Research Institute.

"It is highly relevant to U.S. policies in agriculture, trade and the environment," he added.

All societies, industries and businesses are dependent on the goods and services provided by nature. A natural landscape -- a wood lot or marsh, for example -- generates oxygen, cleans water, prevents erosion, builds soil, captures excess carbon dioxide, provides habitat for many other species and so on.

"There is an unbreakable link between human health and wellbeing and ecosystems," said Walter Reid, director of the Millennium Ecosystem Assessment, and a professor with the Institute for the Environment at Stanford University.

Ecosystem goods and services freely available today will cease to exist or become more costly if the current decline continues. And in all future scenarios, ecosystems will be under tremendous pressure to provide significant increases in food, fibre and water, according the MA report.

Under perhaps the most optimistic scenario, where a global society takes strong steps to reduce poverty, invests in public goods such as infrastructure and education, and economic growth booms, some 4.9 billion people will still have difficulties getting water.

Much of this dark future can be avoided through policies and practices that value the goods and services that ecosystems provide, says Reid.

Destructive policies such as the agriculture subsidies by the U.S., European Union and other developed nations favour production over environmental conservation, says Prabhu Pingali, director of the Agricultural and Development Economics Division (ESA) at the U.N. Food and Agriculture Organisation.

"Those subsidies also reduce the ability of farmers in poor countries to grow food by keeping prices unrealistically low," Pingali said.

At the same time, developing countries need to change their policies that subsidise pesticides or electricity for water pumps because of their negative impact on ecosystems, he said. And farmers and others should be compensated for the environmental goods and services their lands provide society.

"By placing a monetary value on these services, we will be smarter about using them while creating alternative sources of income for people, from farmers in the United States to tribes in developing countries," he said.

"Politicians and other policymakers do not know the economic value of the goods and services provided by ecosystems," says Reid.

There have been few studies or measures of these and much more needs to be done, he acknowledges. "It's now time for us to measure the economic value of these services so we can make better decisions about our future."

But that doesn't prevent developing policies and taking actions now that reduce the pressure on species and preserve or increase biodiversity so that vital and fragile ecosystems will be more resilient, he says.

Copyright © 2006 IPS-Inter Press Service

How a northern forest can respond to warming

Here's another example of an ecosystem's inability to cope with sudden changes in a climate regime. Keep in mind that many of the global weather models assume that forest cover will act as a carbon sink, sucking CO2 from the atmosphere and mitigating its greenhouse effects. But dead trees give off CO2 as they rot, and the process of industrial logging creates lots of slash that often gets burned, yielding yet more CO2. Another problem is that living trees pump a lot of water vapor into the atmosphere, creating cloud cover which reflects sunlight (See albedo) and downwind precipitation. So fewer trees means more sunlight hitting (darker) ground, where it's absorbed, and less rainfall for ecosystem and human uses. There are some problems with assessing and modeling the balance between cooling via cloud reflection and warming by water vapor as a greenhouse gas. This conflict was a weak spot in earlier General Circulation Models (GCM) but has been one focus of recent model tweaks.

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'Rapid Warming' Spreads Havoc in Canada's Forests

Tiny Beetles Destroying Pines

By Doug Struck
Washington Post Foreign Service
Wednesday, March 1, 2006

QUESNEL, B.C. -- Millions of acres of Canada's lush green forests are
turning red in spasms of death. A voracious beetle, whose population has
exploded with the warming climate, is killing more trees than wildfires or
logging. The mountain pine beetle has infested an area three times the size of
Maryland, devastating swaths of lodgepole pines and reshaping the future of
the forest and the communities in it.

"It's pretty gut-wrenching," said Allan Carroll, a research scientist at
the Pacific Forestry Centre in Victoria, whose studies tracked a lock step
between warmer winters and the spread of the beetle. "People say climate
change is something for our kids to worry about. No. It's now."
Scientists fear the beetle will cross the Rocky Mountains and sweep across
the northern continent into areas where it used to be killed by severe cold
but where winters now are comparatively mild. Officials in neighboring
Alberta are setting fires and traps and felling thousands of trees in an
attempt to keep the beetle at bay.

"This is an all-out battle," said David Coutts, Alberta's minister of
sustainable resource development. The Canadian Forest Service calls it the
largest known insect infestation in North American history.
U.S. Forest Service officials say they are watching warily as the outbreak
has spread. The United States is less vulnerable because it lacks the
seamless forest of lodgepole pines that are a highway for the beetle in
Canada. So far, U.S. officials say, the outbreaks have been mostly in
isolated clumps of remote wilderness areas of northern Washington.
"It's a rapid warming" that is increasing the beetles' range, said Carroll.
"All the data show there are significant changes over widespread areas that
are going to cause us considerable amount of grief. Not only is it coming,
it's here."

"We are seeing this pine beetle do things that have never been recorded
before," said Michael Pelchat, a forestry officer in Quesnel, as he
followed moose tracks in the snow to examine a 100-year-old pine killed in
one season by the beetle. "They are attacking younger trees, and attacking
timber in altitudes they have never been before."

The tiny beetle has always lived in high areas from Arizona to northern
British Columbia, and occasionally populations have grown in limited
outbreaks. In Canada, where the beetle's favored lodgepole pine thrives, it
has been controlled by winters with early cold snaps or long killing spells
of 20 degrees below zero. But for more than a decade, forestry experts say,
the weather here has not been cold enough for long enough to kill the

Scientists with the Canadian Forest Service say the average temperature of
winters here has risen by more than 4 degrees in the last century. "That's
not insignificant," said Jim Snetsinger, British Columbia's chief forester.
"Global warming is happening. We have to start to account for it."
The result is a swarm of beetles that has grown exponentially in the past
six years, flying from tree to tree. The advance is marked by broad swaths
of rust-red forest, the color pines turn before they drop all their needles
to become ghostly grey skeletons.

"It's depressing to see," said Steve Dodge, a British Columbia forestry
official whose office is along the Quesnel River. This town of 10,000 sits
in the heart of the province's vast evergreen woodlands. Steam billowing
from the kilns of a half-dozen sawmills and pulp plants enshroud the town,
which proudly calls itself the "Woodsmart City" in homage to the timber
industry that sustains it.In an attack played out millions of times over, a
female beetle no bigger than a rice grain finds an older lodgepole pine,
its favored host, and drills inside the bark. There, it eats a channel
straight up the tree, laying eggs as it goes. The tree fights back. It
pumps sap toward the bug and the new larvae, enveloping them in a mass of
the sticky substance. The tree then tries to eject its captives through a
small, crusty chute in the bark.

Countering, the beetle sends out a pheromone call for reinforcements. More
beetles arrive, mounting a mass attack. A fungus on the beetle, called the
blue stain fungus, works into the living wood, strangling its water flow.
The larvae begin eating at right angles to the original up-and-down
channel, sometimes girdling the tree, crossing channels made by other

The pine is doomed. As it slowly dies, the larvae remain protected over the
winter. In spring, they burrow out of the bark and launch themselves into
the wind to their next victims. British Columbia is a buffet laid out before them. Years of successful battles against forest fires have allowed a thick concentration of old
lodgepole pines to grow -- a beetle feast that natural wildfire would have
stopped. "It was the perfect storm" of warmer weather and vulnerable old trees,
coupled with constraints that slowed logging of the infected wood, said
Douglas Routledge, who represents timber companies in the city of Prince

At the province's Ministry of Forests and Range in Quesnel, forestry
officer Pelchat saw the beetle expansion coming as "a silent forest fire."
He and his colleagues launched an offensive to try to stop or at least
delay the invasion, all the while hoping for cold temperatures. They
searched out beetle-ridden trees, cutting them and burning them. They
thinned forests. They set out traps. But the deep freeze never came.
"We lost. They built up into an army and came across," Pelchat said.
Surveys show the beetle has infested 21 million acres and killed 411
million cubic feet of trees -- double the annual take by all the loggers in
Canada. In seven years or sooner, the Forest Service predicts, that kill
will nearly triple and 80 percent of the pines in the central British
Columbia forest will be dead.

Pelchat is now spending his time trying to plan recovery through
replanting. In this area, a mature pine forest takes 70 years to grow.
Meanwhile, the beetle is moving eastward. It has breached the natural wall
of the Rocky Mountains in places, threatening the tourist treasures of
national forest near Banff, Alberta, and is within striking distance of the
vast Northern Boreal Forest that reaches to the eastern seaboard.
"If that beetle is allowed to come any further, it will absolutely
devastate our eastern slope forests," said Coutts, in Alberta. "If we're
not prepared, it's going to infest all Alberta, Saskatchewan, Manitoba, and
then northern Ontario in 20 years. This is the battlefront."

Ironically, Quesnel is booming now. The beetle has killed so many trees
that officials have more than doubled the allowable timber harvest, so
loggers can cut and haul as many dead trees as possible before they rot.
The icy roads are choked with giant trucks growling toward the mills,
loaded with logs marked with the telltale blue stain fungus.
In town, two sawmills and the plywood and pulp plants of the largest
company, West Fraser Mills, are "running flat-out," with shifts
round-the-clock, said Tom Turner, a manager there. He walked the catwalks
of a sawmill as whirling machines below grappled and twirled the offloaded
trees. Computers sized up each log, instantly figured the best cut, and
shoved it at furious speed through giant disk saws and planers to produce
lumber that rail cars would carry to home builders in the United States.
West Fraser is spending $100 million to upgrade the mill. Other companies
have added shifts and proposed new plants to make chipboard or wood-fuel
pellets. Property values in Quesnel are rising, rents are up, the local
shopping center is flourishing again and unemployment has dropped, said
Nate Bello, the mayor of Quesnel.

But the boom will end. When what people here call "beetlewood" is removed
or rots out -- and no one is sure how long that will take -- the forestry
industry "will be running at about half speed," Bello acknowledged.
He sees his chief challenge as figuring out how to convert Quesnel from a
one-industry town to something with a more diverse economic base. He and
city officials talk of attracting retirees and small, computer-based
businesses, and even of luring tourists to the area, despite the stark
industrial tableau of sawmills and pulp plants.

Some people in town say those are quixotic plans. "This town is going to
die," scoffed Pat Karey, 62, who spent 40 years at the sawmill. Other men
in the Quesnel cafe -- "Smokers Welcome" said the sign in the window --
nodded in assent.

"A mill job is $20 an hour, or $30 with benefits. The jobs they are talking
about bringing in are $8-an-hour jobs," said Del Boesem, whose runs a
business dismantling heavy logging machinery.

Thursday, April 06, 2006

Climate Science (Another Tech Blog)» Climate Models

This is an interesting site. Study the categories in the box on the right for a little more focused coverage. Their stance seems to be that global predictions are both dicey and regionally only marginally relevant. More important considerations for thinking about the impacts of climate change are regional vulnerabilities and preparation measures, for instance what is the state of water supplies and patterns of usage.

Climate Science » Climate Models

Greenland Glaciers speeding up

I just went ahead and copied this, it's probably copyrighted. The link will get you to the site, which bears lots of exploring; it's climate science written by real climate scientists. The comments are very valuable, take the time to read them if you have it.

From Real Climate

In a recent paper in Science, Eric Rignot and Pannir Kanagaratnam present new satellite observations of the speed of glaciers of Greenland, and find that they are sliding towards the sea almost twice as fast as previously thought. Additionally, between 1996 and 2005, they detected a widespread glacier acceleration and consequently an increased rate of ice discharge from the Greenland ice sheet. However, previous papers have recently noted an increase in snow accumulation in the interior (i.e. Johanessen et al., 2005), so how do these different measurements fit into the larger picture of Greenland's net mass balance?

The measurements by Rignot & Kanagartnam were made with interferometers which measure the movement of the surface horizontally, and so is complimentary to the altimeter data published previously (which measures the absolute height of the ice). Overall, they found widespread increases in glacier speeds, and increases of about 30% in ice discharge rates. (Note that the satellite image shows that the glaciers in the east tend to slide far into the sea whereas on the western coast that happens less).

The higher velocity of the ice is thought to be related to higher temperatures causing increased melt-water which can penetrate to the base of the glacier and hence reduce the ground friction. However, this accelerated movement is not necessarily tied to an increased rate of melting of the Greenland ice, although it can be related. Surges of ice streams from the ice sheet can also occur due to increased accumulation at the head of the glacier. However, when the increased ice velocity is matched to a decreasing thickness that can be sign of net mass loss. These ideas are consistent with observations of surface melting which had a record extent in 2005, and has been increasing steadily (though with significant interannual variability) since 1993. Using the analysis of Hanna et al (2005) (based on the reanalysis datasets) for the surface mass balance, Rignot & Kanagartnam estimate that Greenland is on balance losing mass, and over the period of their study the ice sheet mass deficit (the amount of ice lost to the sea) has doubled increasing from 90 to 220 km3/year (an increase of 0.23 to 0.57 mm/yr sea level equivalent - SLE).

In the earlier Science paper, Johanessen et al. found increased snow accumulation on the top of the interior Greenland ice sheet between 1992 and 2003. Above 1500m a.s.l in much of the interior Greenland they estimated an increase of 6.4 ± 0.2 cm/year and below 1500m they observed a decreasing trend of -2.0 ± 0.9 cm/year. Hence, growth in the interior parts and a thinning of the ice nearer the edges. However, Johanessen et al. were not able to measure all of the coastal ranges. Indeed, the thinning of the margins and growth in the interior Greenland is an expected response to increased temperatures and more precipitation in a warmer climate. These results present no contradiction to the accelerated sliding near the coasts, but both will affect the ice/snow (fresh water) mass estimate. Whereas the finding of Rignot & Kanagaratnam suggests a larger sink of the frozen Greenland fresh water budget (the ice is dumped into the sea), the snow deposition in Greenland interiors is a source term (increases the amount of frozen fresh water). It does not matter for the general sea level in which form the water exists (liguid or solid/frozen) when it is discharged into the sea: The same mass of liquid water and immersed ice affect the water level equally (Archimede's principle).

A third relevant study is a recent paper in the Journal of Glaciology by Zwally et al. (2005) on the ice mass changes on Greenland and Antarctica. They use the same satellite obsevations (ERS 1 & 2) as Johanessen et al. and again find that the Greenland ice sheet is thinning at the margins (-42 ± 2 Gt/year = -46 ± 2 km3/year below the equilibrium-line altitude - ELA), but growing in the inland (+53 ± 2 Gt/year = 58 ± 2 km3/year). The mass estimates have been converted to volume estimates here, assuming the density of ice is 0.917 g/cm3 at 0°C, so that the mass of one Gt of ice is roughly equivalent to 1.1km3 ice*. This means that the Greenland ice has an overall mass gain by +11 ± 3 Gt/year (=10 ± 2.7 km3/year) which they estimated implied a -0.03 mm/year SLE over the period 1992-2002.

The critical point for Greenland is whether the increased rate of glacier motion more than compensates for the greater accumulation on the surface. While the broad picture of what is happening is consistent between these papers, the bottom-line value for Greenland's mass balance is different in all three cases. Looking just at the dynamical changes observed by Rignot & Kanagaratnam, there is an increased discharge of about 0.28 mm/year SLE from 1996 to 2005, well outside the range of error bars. This is substantially more than the opposing changes in accumulation estimated by Johannessen et al and Zwally et al, and is unlikely to have been included in their assessments. Thus, the probability is that Greenland has been losing ice in the last decade. We should be careful to point out though that this is only for one decade, and doesn't prove anything about the longer term. As many of the studies make clear, there is a significant degree of interannual variability (related to the North Atlantic Oscillation, or the response to the cooling associated with Mt. Pinatubo) such that discerning longer term trends is hard.

The largest contributions to sea level rise so far are estimated to have come from thermal expansion, with the melting of mountain glaciers and icecaps being of second order. Looking forward, the current (small) imbalance (whether positive or negative) of the Greenland ice sheet is not terribly important. What matters is if the melting were to increase significantly. Ongoing observations (most promisingly from the GRACE gravity measurements, Velicogna et al, 2005) will be useful in monitoring trends, but in order to have reasonable projections into the future, we would like to be able to rely on ice sheet models. Unfortunately, the physics of basal lubrication and the importance of ice dynamics highlighted in the Rignot & Kanagaratnam results are very poorly understood and not fully accounted for in current ice sheet models. Until those models include these effects, there is a danger that we may be under-appreciating the dynamic nature of the ice sheets.


Hanna, E; Huybrechts, P; Janssens, I; Cappelen, J; Steffen, K; Stephens, A (2005) J. Geophys. Res.Vo. 110, D13108, doi:10.1029/2004JD005641

Johanessen, O.M; Khvorostovsky, K; Miles, M.W; Bobylev, L.P. (2005) ScienceVo. 310 no. 5750, pp 1013-1016

Ringnot, E; Kanagaratnam, P (2006) ScienceVo. 311 no. 5763, pp 986-990

Velicogna, I; Wahr, J; Hanna, E; Huybrechts, P. (2005) Geophys. Res. Lett.Vo. 32, L05501, doi:10.1029/2004GL021948

Zwally, H. Jay; Giovinetto, Mario B.; Li, Jun; Cornejo, Helen G.; Beckley, Matthew A.; Brenner, Anita C.; Saba, Jack L.; Yi, Donghui (2005), Journal of Glaciology, Volume 51, Number 175, December, pp. 509-527(19)

Record Coral Reef Dieoff

There's also another related article in USA today here

More on Acidification of Oceans

Source: Carnegie Institution

Posted: February 21, 2006
Oceans May Soon Be More Corrosive Than When The Dinosaurs Died

Increased carbon dioxide emissions are rapidly making the world's oceans more acidic and, if unabated, could cause a mass extinction of marine life similar to one that occurred 65 million years ago when the dinosaurs disappeared. Ken Caldeira of the Carnegie Institution's Department of Global Ecology will present this research at the AGU/ASLO Ocean Sciences meeting in Honolulu, HI on Monday, Feb 20.

Caldeira's computer models have predicted that the oceans will become far more acidic within the next century. Now, he has compared this data with ocean chemistry evidence from the fossil record, and has found some startling similarities. The new finding offers a glimpse of what the future might hold for ocean life if society does not drastically curb carbon dioxide emissions.

"The geologic record tells us the chemical effects of ocean acidification would last tens of thousands of years," Caldeira said. "But biological recovery could take millions of years. Ocean acidification has the potential to cause extinction of many marine species."

When carbon dioxide from the burning of coal, oil, and gas dissolves in the ocean, some of it becomes carbonic acid. Over time, accumulation of this carbonic acid makes ocean water more acidic. When carbonic acid input is modest, sediments from the ocean floor can buffer the increases in acidity. But at the current rate of input--nearly 50 times the natural background from volcanoes and other sources--this buffering mechanism is overwhelmed. Previous estimates suggest that in less than 100 years, the pH of the oceans could drop by as much as half a unit from its natural value of 8.2 to about 7.7. (On the pH scale, lower numbers are more acidic and higher numbers are more basic.)

This drop in ocean pH would be especially damaging to marine animals such as corals that use calcium carbonate to make their shells. Under normal conditions the ocean is supersaturated with this mineral, making it easy for such creatures to grow. However, a more acidic ocean would more easily dissolve calcium carbonate, putting these species at particular risk.

The last time the oceans endured such a drastic change in chemistry was 65 million years ago, at about the same time the dinosaurs went extinct. Though researchers do not yet know exactly what caused this ancient acidification, it was directly related to the cataclysm that wiped out the giant beasts. The pattern of extinction in the ocean is consistent with ocean acidification--the fossil record reveals a precipitous drop in the number of species with calcium carbonate shells that live in the upper ocean--especially corals and plankton. During the same period, species with shells made from resistant silicate minerals were more likely to survive.

The world's oceans came close to an acidic catastrophe one other time about 55 million years ago, when the temperature of the Earth spiked and large amounts of methane and/or carbon dioxide flooded the atmosphere. There is no evidence, however, that this caused a mass extinction event.

"Ultimately, if we are not careful, our energy system could make the oceans corrosive to coral reefs and many other marine organisms," Caldeira cautions. "These results should help motivate the search for new energy sources, such as wind and solar, that can fuel economic growth without releasing dangerous carbon dioxide into the environment."

More ocean acidification news

Here's another report on the ocean acidification aspect of increasing the amount of CO2 in the air.

Ocean demise

Pretty long, thorough, and scary. I don't have any source of comment on or criticism of the claims, and the source is an established rabble-rouser. But generally reliable. | News

Ocean Plankton response to Warming

Published on Thursday, January 19, 2006 by the Independent / UK
Warmer Seas Will Wipe Out Plankton, Source of Ocean Life
by Steve Connor

The microscopic plants that underpin all life in the oceans are likely to be destroyed by global warming, a study has found.

Any plankton haul near the surface of the sea brings in a huge variety of life forms. Plants animals larvae adults vertebrates invertebrates carnivores and herbivores are all represented in the plankton community. Scientists have discovered a way that the vital plankton of the oceans can be starved of nutrients as a result of the seas getting warmer. They believe the findings have catastrophic implications for the entire marine habitat, which ultimately relies on plankton at the base of the food chain. The study is also potentially devastating because it has thrown up a new "positive feedback" mechanism that could result in more carbon dioxide ending up in the atmosphere to cause a runaway greenhouse effect.

Scientists led by Jef Huisman of the University of Amsterdam have calculated that global warming, which is causing the temperature of the sea surface to rise, will also interfere with the vital upward movement of nutrients from the deep sea. These nutrients, containing nitrogen, phosphorus and iron, are vital food for phytoplankton. If the supply is interrupted the plants die off, which prevents them from absorbing carbon dioxide from the atmosphere. "Global warming of the surface layers of the oceans reduces the upward transport of nutrients into the surface layers. This generates chaos among the plankton," the professor said.

The sea is one of nature's "carbon sinks", which removes carbon dioxide from the atmosphere and deposits the carbon in a long-term store - dissolved in the ocean or deposited as organic waste on the seabed. The vast quantities of phytoplankton in the oceans absorb huge amounts of carbon dioxide. When the organisms die they fall to the seabed, carrying their store of carbon with them, where it stays for many thousands of years - thereby helping to counter global warming. "Plankton... forms the basis of the marine food web. Moreover, phytoplankton consumes the greenhouse gas carbon dioxide during photosynthesis," Professor Huisman said. "Uptake of carbon dioxide by phytoplankton across the vast expanses of the oceans reduces the rising carbon dioxide levels in the atmosphere."

Warmer surface water caused by global warming causes greater temperature stratification, with warm surface layers sitting on deeper, colder layers, to prevent mixing of nutrients.

Professor Huisman shows in a study published in Nature that warmer sea surfaces will deliver a potentially devastating blow to the supply of deep-sea nutrients for phytoplankton. His computer model of the impact was tested on real measurements made in the Pacific Ocean, where sea surface temperatures tend to be higher than in other parts of the world. He found that his computer predictions of how nutrient movement would be interrupted were accurate. "A larger temperature difference between two water layers implies less mixing of chemicals between these water layers," he said. "Global warming of the surface layers of the oceans, owing to climate change, strengthens the stratification and thereby reduces the upward mixing of nutrients."

Scientists had believed phytoplankton, which survives best at depths of about 100 metres, is largely stable and immune from the impact of global warming. "This model prediction was rather unexpected," Professor Huisman said. "Reduced stability of the plankton, caused by global warming of the oceans, may result in a decline of oceanic production and reduced sequestration of the greenhouse gas carbon dioxide into the oceans."

Vital link in the food chain

Microscopic plankton comes in animal and plant forms. The plants are known as phytoplankton. They lie at the base of the marine food chain because they convert sunlight and carbon dioxide into organic carbon - food for everything else.

Smaller animals such as shrimp-like krill feed on plankton and are themselves eaten by larger organisms, from small fish to the biggest whales. Without phytoplankton, the oceans would soon because marine deserts. Phytoplankton are also important because of the role they play in the carbon cycle, which determines how much carbon dioxide - the most important greenhouse gas - ends up in the atmosphere to cause global warming. Huge amounts of carbon dioxide from the atmosphere, which dissolves in the oceans, are absorbed by phytoplankton and converted to organic carbon. When the phytoplankton die, their shells and bodies sink to the seabed, carrying this carbon with them.

Phytoplankton therefore acts as a carbon "sink" which takes carbon dioxide from the atmosphere and deposits the carbon in long-term stores that can remain undisturbed for thousands of years. If the growth of phytoplankton is interrupted by global warming, this ability to act as a buffer against global warming is also affected - leading to a much-feared positive feedback.

© 2006 Independent News and Media Limited


In general a good site for numerical measures of the state of the world, with some interpretation.

Eco-Economy Indicators: TEMPERATURE and CLIMATE

Disaster Warning from UN: Death of the World's Rivers

I'm clumping some water supply info. Here's another heads-up. Certainly rings a bell for those of us in the Ozarks.

Disaster Warning from UN: Death of the World's Rivers

The Kolbert New Yorker articles

Here are links to the noted and very readable New Yorker articles by Elizabeth Kolbert that appeared about a year ago.

Part 1

Part 2

Part 3