Climate Roulette: Loss of Carbon Sinks & Positive Feedbacks

The earth dries up and withers,

the world languishes and withers;

the heavens languish together with the earth.

         The earth lies polluted under its inhabitants;

for they have transgressed laws, violated the statutes

broken the everlasting covenant.

         Therefore a curse devours the earth,

and its inhabitants suffer for their guilt.

-the prophet Isaiah (c.760-690 B.C.)

                        Isaiah 24:4-6 in the New Revised Standard Version of the Bible

Loss of Carbon Sink: Forests updated October 10, 2006
Global Warming, Forests & Bark Beetles updated February 9, 2007
Loss of Reflective Capability of Ice updated September 26, 2006
Water Vapor in the Atmosphere Increasing
Loss of Carbon Sink: Disappearing Plankton
Loss of Carbon Sink: Warming Tundra & Thawing Permafrost
Loss of Snowpack

Forests
As global warming worsens and temperatures rise, the forests become more stressed and susceptible to fire, pests and diseases. [23]  This in turn may cripple temperate forests' ability to absorb carbon dioxide.

Boreal forests, which cover 17% of the Earth's land surface area, are found in Alaska's south-central and interior regions............ Models consistently project large-scale transformation of Arctic landscapes, where the northern edge of the boreal forest advances into the tundra. Even with these projections, concerns for Alaska's boreal forests from projected climate changes include: a loss in the moisture needed for forest growth; insect-induced tree mortality; increased risk of large fires; interference with the reproduction of white spruce, a biological and economic concern; and the changes caused by permafrost thaw e.g., slumping of land and wetland development from thaw water.......... It has been suggested that the past 20 years have seen the greatest moisture stress and lowest productivity of the 20th century through much of the interior boreal forest.............. Forest fire frequency and intensity have increased markedly since 1970. The 10-year average of boreal forest burned in North America, after several decades of around 2.5 million acres, has increased steadily since 1970 to more than 7 million acres annually. Boreal forest fire reached extreme values in both Eurasia and North America in 1998, with over 27 million acres burned in total, 10 million in North America. It is suggested that substantial climate-related changes for the coastal forest could occur over several decades, including the appearance of new fungi and a significant fire risk for the first time in the observed record.

David Schindler, professor at University of Alberta says that it took 65 million years for the boreal forest to evolve, and that it is a monumental tragedy that we are seeing the decline of these majestic forests. “I can only hope,” says Schindler, “that we see the light and change our ways before the boreal is gone forever.” In its last assessment in 1996 the IPCC panel concluded that "carbon fertilization," by which elevated CO2 levels stimulate plant growth, would cause forests to absorb 290 billion tons of carbon over the next century, even without new planting. This is all unlikely now in a new report, citing the effect of respiration. Respiration occurs when plant matter breaks down the sugars they make during photosynthesis, releasing CO2 back into the air. Photosynthesis, the process that creates plant matter, absorbs CO2 from the air. Experts such as Bob Sholes of the South African government's research agency, CSIR, argue that CO2 fertilization may have already peaked, and that respiration may be about to accelerate. CO2 fertilization is an instantaneous process, but respiration increases in response to temperatures rising because of increasing levels of CO2 in the atmosphere. That warming has a built-in delay of about 50 years, caused largely by the thermal inertia of the oceans. So the extra outpouring of CO2 from the world's forests would not yet be apparent. During the period of this delay, there is an apparent carbon sink. [37]

Global Warming, Forests & Bark Beetles
Bark beetles have been pemeating forests in the last 10 years at higher latitudes (i.e. Canada, Alaska, Siberia etc.) and higher elevations (i.e Rocky Mountains). The beetles are the conveyers of positive feedback loops by killing millions of trees that result in dead forests becoming fire hazards, the trees stop absorbing CO2 and instead are a source of CO2, as they waste away or become fuel for wildfires, throwing more CO2 into the atmosphere, advancing the rise of temperatures. Warmer temperatures favor the further growth in numbers of the bark beetle.

While the lower moderate latitudes have seen temperature increases of a little over 1 degree Fahrenheit, the subarctic regions have seen about a 4 degree increase. Ed Holsten ,an entomologist with the U.S. Forest Service in Alaska says, "In Alaska, the distribution of plants and animals is controlled by climate," said Holsten. "Any subtle change in temperature will affect insects. Spruce bark beetles usually have a two-year cycle, but warmer temperatures can cause them to complete their cycle in one year. So a lot more are being bred at one time." The high temperatures have increased the survivability of bark beetles in the boreal forests. In Alaska the survival rate of beetle larvae of the spruce bark beetle during the winter months has increased, while also speeding their maturing process. As a result, there are greater populations of this beetle that have destroyed about 3 million acres of white spruce on Alaska's Kenai Peninsula. Studying the problem, University of Wisconsin entomologist, Kenneth Raffa says, "The trees have a naturally occurring insecticide in their resin, but that's ineffective against an attack this large." [52] This forest is now highly vulnerable to fire, which could, of course, spread to nearby healthy forests.

Colorado's Rocky Mountains are losing to pine bark beetles as they decimate millions of trees at altitudes where these insects had never reached before. Read more about the threat these beetles pose and listen to a report by Aspen NPR's Kurt Stiegler.

An epidemic of tree-killing beetles is spreading rapidly through the forests in Canada's largest lumber exporting province, with the deadly insects now found in a area nearly three-quarters the size of Sweden, officials said. The tiny pine beetles, which have been spreading almost unchecked through British Columbia for several years because of unusually warm winters, have seriously infested 9 million acres (3.6 million hectares) of forests and have now destroyed up 108 million cubic metres of lodgepole pine timber. Provincial officials tracking the beetle infestation warned in a report that the amount of destroyed trees could reach 150 million cubic metres next year unless the weather turns cold enough to kill larvae before they hatch. This year's winter (2002-03) in the Cariboo Region where the bugs have hit the hardest is not expected to be particularly cold. Officials said the number of trees killed in the infested area varies from area to area, but the critical infestation is considered to cover 9 million acres in the province's Interior region, up from 8 million acres last year. "This is clearly an epidemic of catastrophic proportion," said Larry Pedersen, British Columbia's chief forester. As on the Kenai Peninsula (see above), this could make the British Columbia forests more vulnerable to fire. See Planet Ark story for more detail. (Note: Sometimes referenced articles are not available)

In Canada British Columbia officials noted in an October, 2003 report, Timber Supply and the Mountain Pine Beetle Infestation in British Columbia, that beetle infestation was fast spreading through its forests. As the upward trend of temperatures continues, Canada may see even more severe beetle devastation in their forest stands, while continuing to increase the degree of exposure to forest fires.

In 2002 a report noted that in British Columbia, tree-killing pine beetles were spreading rapidly through the forests in this, Canada's largest lumber exporting province. Warmer winters have aided these beetles, and their numbers have escalated, so that 9 million acres (3.6 million hectares) of forests were infested, and have now destroyed up 108 million cubic metres of lodgepole pine timber. "This is clearly an epidemic of catastrophic proportion," said Larry Pedersen, British Columbia's chief forester.

Warmer winters in Wyoming and Yellowstone National Park are also finding healthier populations of bark beetles in whitebark pines, one of  the main food sources for grizzly bears. See NRDC Report With whitebark pines threatened by extinction, we could lose the remaining 1000 grizzly bears, now living mostly in Yellowstone and Glacier National Park..

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Loss of Reflective Capability of Ice
Ice and snow both strongly reflect the sun's rays, keeping the earth cool. But as global warming melts glaciers, as well as ice in Greenland, the Arctic and Antarctic, it exposes land and water. Land and water, being darker surfaces reflect less solar heat back out into space, allowing the atmosphere to absorb more warmth. In fact, ice absorbs less than half the sunlight that falls on it, but ocean surfaces absorb about 90%.[57]  As can be expected, more ice and snow will melt. See NASA Animation of What Happens When Ice Melts

In 1976, the average thickness was 10 feet. Scientists have since discovered that the average thickness of Arctic sea ice during the years from 1993 through 1997 was about six feet, a 40% decrease. Since the ice is already floating in water, there would be no effect on sea level rise. Researchers say that the thinning is continuing at four inches per year. One of the concerns of continuing Arctic sea ice loss, is the loss of the ability to reflect heat into space, and to dilution of the conveyor belt as mentioned above.[40] .....The melting ice could lead to even faster warming, said Ted Scambos of NSIDC [CIRES' National Snow and Ice Data Center (NSIDC)][ University of Colorado based Cooperative Institute for Research in Environmental Sciences (CIRES)]. Both sea ice and glacier ice cool Earth, reflecting about 80 percent of springtime solar radiation and 40 percent to 50 percent during summer snowmelt. This is one of the positve feedbacks, where greater loss of sea ice and albedo (the degree of reflecting ability), brings about more warming, leading to greater loss of arctic ice. CERES NASA Web Site See NASA Animation of What Happens When Sea Ice Melts

Jim Hansen, R. Ruedy, M. Sato, and K. Lo of the NASA Goddard Institute for Space Studies and Columbia University Earth Institute determined that of the warming during the 20th century, the greater warming, about .36 degrees Fahrenheit each decade, has occurred since 1975. Another study NASA scientists, released in September, 2006, finds that the world's temperature is reaching a level that has not been seen in thousands of years. The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of the rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of the melting ice and snow, and the loss of reflecting ability.

In a N.Y Times article (Nov. 17, 1999) it was reported that scientists have discovered that from 1993 through 1997 average Arctic sea ice thickness was six feet. This represents a significant reduction in Arctic sea ice from 1958 through 1976 when average thickness measured 10 feet. This means that in less than 30 years, there has been a 40% loss of arctic sea ice.  In a Washington Post  article (Dec. 3, 1999) it was noted that Arctic sea ice is shrinking at a rate of 14,000 square miles annually, an area larger than Maryland and Delaware combined.

The Antarctic Peninsula has seen an increase in average temperatures of almost 5 degrees Fahrenheit in the last 50 years. Heavy sea ice has been the norm in the Antarctic, but in the 1990's sea ice disintegration has begun, notes Robin Ross, a biological oceanographer with the University of California at Santa Barbara. During the year 1998, the Antarctic displayed a record low in winter sea ice.

Svein Tveitdal, Managing Director of GRID-Arendal which is UNEP's key polar centre said, "The loss of ice in the Arctic could lead to a sudden, acceleration, of global warming. Ice reflects radiation or heat from the sun back into space. Absorbed radiation over snow and ice is three times lower than over land. Reduced ice and snow cover might trigger an accelerated climate change." [88]

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Water Vapor in the Atmosphere Increasing
Water vapor is the most prevalent greenhouse gas on the planet, but its increasing presence is the result of evaporation caused by the warming, in turn, caused by carbon dioxide, methane and other greenhouse gases. (See NOAA's National Climate Data Center (NCDC) FAQ page) As the Earth heats up relative humidity is able to increase, allowing the planet's atmosphere to hold more water vapor, causing even more warming, thus a positive feedback scenario. Because the air is warmer, the relative humidity can be higher (in essence, the air is able to 'hold' more water when its warmer), leading to more water vapor in the atmosphere, says the NCDC. There is much scientific uncertainty as to the degree this feedback loop causes increased warming, inasmuch as the water vapor also causes increased cloud formation, which in turn reflects heat back out into space.

Disappearing Plankton
The ability of the oceans to absorb carbon dioxide may be at risk. Presently oceans are absorbing about 2 billion tons of carbon annually [3] . A report in Nature, August 1995, suggests that the oceans may be losing fixed nitrogen, an essential fertilizer that allows phytoplankton to grow. Phytoplankton absorb and fix carbon that is then transferred to the deep ocean. If in fact the oceans are losing nitrogen as they warm, they will tend to absorb less carbon, boosting the rate of carbon dioxide buildup in the atmosphere. [24]

Plankton are a major carbon sink in addition to the forests, other green plants, the permafrost, the earth's soil and atmosphere. Plankton take in about half of all the world's CO2, using the carbon for growth, while releasing oxygen during the process of photosythesis. During the past 20 years there has been a stark decline, more than 9%, in primary production of plankton, while in the same period plankton of the North Atlantic has decreased by 7%. Less plankton; less carbon uptake.Watson W. Gregg, a NASA biologist at the Goddard Space Flight Center in Greenbelt, Maryland says that the greatest loss of phytoplankton has occurred where ocean temperatures have risen most significantly between the early 1980's and the late 1990's. In the North Atlantic summertime sea surface temperatures rose about 1.3 degrees Fahrenheit during that period, Gregg said, while in the North Pacific the ocean's surface temperatures rose about 7/10ths of a degree.(San Francisco Chronicle, David Perlman, Science Editor, October 6, 2003).  See NASA Report on Ocean Plant Life Absorbing Less Carbon

In the Arctic, loss of sea ice associated with warming could result in the diminution of phytoplankton populations. This could lead to ‘knock-on effects’ throughout the Arctic food chain, including declines in the stocks of several key prey species of cetaceans, such as copepods and plankton-feeding fish, including Arctic cod, a key prey species for narwhal and beluga whales. Warming and the attendant ice melt might result in greater stratification of the water column and decreased nutrient resupply, limiting the growth of phytoplankton populations that are a critical link in the cetacean food chain in the region. See Report by William Burns, Director of Communications & Research Associate, Pacific Institute for Studies in Development, Environment and Security 

Research suggests a positive feedback scenario, where more intense storms roil oceans and cause the latter to release more carbon dioxide into the atmosphere. [36]

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See the PBS transcript of Hot Times in Alaska for more on permafrost and tundra

Permafrost
Permafrost relates to areas where the ground is frozen all year round, except for the upper layer that melts and freeze each year. Permafrost may be continuous, discontinuous, or more sporadic - and then typically in mountain areas. (84)

Rising temperatures in the Arctic are melting the permafrost, causing it to release greenhouse gases into the atmosphere. About 14 per cent of the world's carbon is stored in the permafrost of Arctic lands. Permafrost, which is a solid structure of frozen soil and on which can be used to build homes and other buildings, can, with rising temperatures, turn into a soft material causing subsidence and damage to buildings and structures. But worse yet is if, as a positive feedback, it loses its characteristic as a carbon sink and begins leaking carbon dioxide into the atmosphere.  (83) 

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Svein Tveitdal, Managing Director of the Global Resource Information Database (GRID) in Arendal, Norway, a UNEP environmental information center monitoring the melting of the permafrost, told a meeting at the 21st session of the United Nation's Governing Council in Nairobi, Kenya on February 7, 2001: "Permafrost has acted as a carbon sink, locking away carbon and other greenhouse gases like methane, for thousands of year. But there is now evidence that this is no longer the case, and the permafrost in some areas is starting to give back its carbon. This could accelerate the greenhouse effect." See UNEP Press Release

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See the PBS transcript of Hot Times in Alaska for more on permafrost and tundra

Following taken verbatim from US Global Research Program Web Site (See USGRP Site for More on Permafrost)
Permafrost underlies about 85% of Alaska, everywhere except for a narrow belt along the southern coast. It varies widely, in depth, continuity, and ice content. Permafrost has profound effects on hydrology (the land-based water cycle), erosion, vegetation, and human activities. It limits movement of ground water and the rooting depth of plants. On slopes, it allows fluid-like movement of surface soil and deposits. Seasonal thawing over continuous permafrost creates a saturated surface layer in which pools of meltwater accumulate, conducive to marsh and tundra ecosystems and peat formation. Thawing permafrost creates thermokarst terrain -- uneven surface topography that includes pits, troughs, mounds, and depressions, which can fill with water. Thermokarst damages agricultural fields and ecosystems such as forests by drying in mounded areas and flooding in low-lying zones. Further, it can contribute to erosion and increased sedimentation and siltation of rivers, which poses additional environmental concerns.

Permafrost in Alaska has been warming for more than a century. Continuous permafrost on the North Slope of Alaska has warmed 4-7°F over the last century. Because temperatures at the upper surface of continuous permafrost are still low, typically below 23°F, no significant loss of continuous permafrost is projected over the 21st century. The discontinuous permafrost to the south is warmer, usually above 28°F and increased warming at multiple sites (from 1 -- 3°F since the late 1980s) suggests that much of the discontinuous permafrost south of the Yukon River and on the south side of the Seward Peninsula must already be thawing. At some sites, the discontinuous permafrost is thawing at the top and the bottom.

With climate change, warming ranging from 3 -- 18° F over the next 100 years is possible and will be accompanied by more precipitation in the summer and winter. Thawing of Alaska's discontinuous permafrost will likely result from continued warming and predicted increases in snow depth. This thawing, resulting in warmer soils, will speed decomposition reactions and release carbon dioxide and methane, both greenhouse gases, into the atmosphere. Thawing of any permafrost increases groundwater mobility, increases susceptibility to erosion and landslides, and can affect soil storage of carbon dioxide. If the thawed soil drains and dries it could release carbon dioxide to the atmosphere, or storage of carbon dioxide in the soil could increase if the soil remains flooded.

Loss of Snowpack
Snowmelt is occuring earlier in the year in Alaska, according to a study by lead author, Terry Chapin, a professor of ecology at the University of Alaska Fairbanks' Institute of Arctic Biology. In the online journal Science Express (September, 2005) Professor Chapin found that the spring snowmelt had been occurring about 2.5 days earlier per decade, exposing dark ground to solar heat earlier in the season. By absorbing and releasing heat, instead of reflecting heat back out into space, "This heat is added to the atmosphere, so the atmosphere in the north becomes warmer and is mixed with the global atmosphere," Chapin said.

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