Human Impacts and Environmental Factors Are Changing
the Northwest Atlantic Ecosystem
According to a new ecosystem status report by the National Oceanic and Atmospheric Association (NOAA), fish in north Atlantic waters from Cape Hatteras to the Canadian border have shifted over the past 40 years from their traditional habitats because of fundamental regional ecosystem changes that include global warming.
The Northeast US Continental Shelf Large Marine Ecosystem (NES LME) spans some 100,000 square miles and supports some of the most valuable fisheries in the nation.
Michael Fogarty, who leads the Ecosystem Assessment Program at the Northeast Fisheries Science Center (NEFSC) of NOAA’s Fisheries Service in Woods Hole, Mass., says that the pressures on the ecosystem include “fishing, pollution, habitat loss from coastal development, and impacts on marine life from shipping and other uses of the ocean. In addition, changing climate conditions are warming ocean waters, changing ocean chemistry and circulation patterns, and altering atmospheric systems. These changes have, in turn, been linked to changes in the distribution and abundance of fish species in the region and their major sources of food.”
The report concludes that there is a need to manage the entire ecosystem as a whole instead of as individual separate regions.
The following are some of the highlights of the report:
Warming of coastal and shelf waters has led to northward shifts in distribution of some fish species and changes to a warmer-water fish community.
The community structure of zooplankton, a major food source for whales and many other marine species including fish, has changed, due in part to climate and physical processes acting over the North Atlantic Basin, indicating the importance of winds and atmospheric circulation patterns to the function and structure of this ecosystem.
Species-selective harvesting patterns have also contributed to shifts in the composition of the ecosystem, which is now dominated by small pelagic fishes such as herring and mackerel, shellfish species, and elasmobranchs (skates and small sharks) of relatively low economic value.
The trajectory of regional human population size suggests that human-induced pressure on the ecosystem will continue to increase.
The Northeast US Continental Shelf is classified as experiencing ecosystem overfishing, although marked improvement has occurred in the condition of a number of harvested species. Exploitation rates, or the rate at which fish are removed from the ocean, have been significantly reduced in many fish stocks during the last decade, indicating that management measures put in place to reduce overfishing are beginning to show dividends.
Links: http://www.noaa.gov
http://www.nefsc.noaa.gov/press_release/2009/SciSpot/SS0912/
Beetles and fire are destroying forests
The twin plagues of beetles and fire are destroying forests in the sub-Arctic and Arctic (Alaska, Siberia, northern Europe and northern Canada). This may be a preview of the future, as global warming continues. The land is growing drier and trees are growing weaker as pests become more active. As forests are destroyed they become a source of greenhouse gases.
Warming is occurring more rapidly in these regions. The global average increase in temperature over the past 100 years was 1.3 degrees Fahrenheit, while it was twice that rate of increase in the far north.
In eastern Russia, the average increase was more than 3.6 degrees Fahrenheit, and extreme wildfires have occurred in 8 of the last 10 summers.
Arctic boreal forests are particularly threatened by warming. These forests consist of vast expanses of spruce, pine, and other conifers that serve as a crucial carbon dioxide absorbing “sink.” As they are destroyed they become a source of greenhouse gases, providing a domino effect to global warming.
Similar problems are occurring in the northern US from Colorado to Washington State. An epidemic of mountain pine beetle has killed 6.5 million acres of forest.
In British Columbia, 35 million acres of forest (twice the are of Ireland) have been destroyed by the beetle. As much as 80 percent of lodgepole pines are expected to be destroyed by the beetle.
In the Yukon, the problem is the spruce bark beetle, which has destroyed 1 million acres of forest. In neighboring Alaska, the epidemic has been occurring for 15 years. Destruction of forest there is unprecedented in its longevity and extent. Deep freezes of minus-40-degress Fahrenheit used to kill off the larvae, but these cold snaps occur less often now. Years of summer drought have weakened the ability of the trees to protect themselves by exuding a sticky substance that traps and expels beetles.
The 2007 report by the Intergovernmental Panel on Climate Change (IPCC) cited many studies that link increasing wildfires to the global warming trend. In June of this year, Harvard scientists predicted that wildfire destruction of forests could increase50 percent by the 2050s, even under the IPCC’s best-case warming scenario.
In Siberia, the number of wildfires has increase along with the start of the fire season. A study by the US National Institute of Aerospace indicates that global warming seems to be stifling regrowth of burned-out Siberian forests, which are becoming grasslands.
In Canada, the area burned by wildfires is double what it was in the 1970s, despite greater firefighting capacity and some recent favorable weather. If the carbon-heavy peat that lies beneath much of the boreal region in Canada burns, it would pour huge amounts of carbon dioxide into the atmosphere.
In Siberia, the highly destructive Siberian moth is expected to become more active in devouring forests of pine, spruce, fir and larch. The mountain pine beetle is expected to move into the forests of the Yukon.
The dominos are falling. Even our worst-case predicted scenarios may not be pessimistic enough
Better forest management has key role to play in dealing with climate change
Climate change and forests are intrinsically linked. On the one hand, changes in global climate are already stressing forests through higher mean annual temperatures, altered precipitation patterns and more frequent and extreme weather events. At the same time, forests and the wood they produce trap and store carbon dioxide, playing a major role in mitigating climate change. And on the flip side of the coin, when destroyed or over-harvested and burned, forests can become sources of the greenhouse gas, carbon dioxide.
FAO has warned that action should be taken now to manage these complex relationships in a more holistic manner.
“We need to stop deforestation and expand the land area covered by forests, certainly,” says Wulf Killmann, who chairs FAO's interdepartmental climate change working group. "But we also need to substitute fossil fuels with biofuels,-- like wood fuels from responsibly managed forests -- in order to reduce carbon emissions, and we should use more wood in long-lasting products to keep trapped carbon out of the atmosphere for longer periods of time."
How forests trap one trillion tons of carbon
When fossil fuels are burned they release carbon dioxide into the atmosphere, contributing to an atmospheric carbon dioxide increase that, in turn, contributes to global warming and climate change.
Trees and forests help alleviate these changes by removing carbon dioxide from the atmosphere and converting it during photosynthesis to carbon, which they then "store" in the form of wood and vegetation, a process referred to as "carbon sequestration."
Trees are generally about 20 percent carbon by weight and, in addition to the trees themselves, the overall biomass of forests also acts as a "carbon sink." For instance, the organic matter in forest soils – such as the humus produced by the decomposition of dead plant material -- also acts as a carbon store.
As a result, forests store enormous amounts of carbon: in total, the world's forests and forest soils currently store more than one trillion tons of carbon -- twice the amount found floating free in the atmosphere -- according to FAO studies.
Destruction of forests, on the other hand, adds almost six billion tons of carbon dioxide into the atmosphere each year, and preventing this stored carbon from escaping is important for the carbon balance and vital in conserving the environment, the UN agency says.
Forests could be better used in combating climate change
This can be achieved not just by preventing forests from being cut down, but through afforestation (new plantings) and reforestation (replanting of deforested areas) of non-forested lands.
Particularly in the tropics, where vegetation grows rapidly and therefore removes carbon from the atmosphere more quickly, planting trees can remove large amounts of carbon from the air within a relatively short time. Here, forests can store as much as 15 tonnes of carbon per hectare per year in their biomass and wood.
FAO and other experts have estimated that global carbon retention resulting from reduced deforestation, increased forest regrowth and more agro-forestry and plantations could make up for about 15 percent of carbon emissions from fossil fuels over the next 50 years.
Harvested wood is also a carbon sink -- wood used in construction or for furniture effectively stores carbon for centuries. High-energy construction materials used in place of wood, such as plastics, aluminum or cement, typically require large amounts of fossil fuels during manufacturing. Replacing them with wood therefore has additional benefits in terms of reducing carbon emissions.
Similarly, the use of wood fuel instead of oil, coal and natural gas, can actually mitigate climate change. Although burning wood and biomass does release carbon dioxide into the air, if those fuels come from a sustainably-managed forest, those carbon releases can be offset by replanting. Indeed, if managed properly, forests can supply bioenergy virtually without contributing any greenhouse gas to the atmosphere.
Climate Change: Pushing Species To The Brink
ScienceDaily (Oct. 13, 2008) — Thirty-five percent of the world’s birds, 52 percent of amphibians and 71 percent of warm-water reef-building corals are likely to be particularly susceptible to climate change, the first results of an IUCN study have revealed.
The report identified more than 90 biological traits which are believed to make species most susceptible to climate change. It found that 3,438 of the world’s 9,856 bird species have at least one out of 11 traits that could make them susceptible to climate change.
Albatross, penguin, petrel and shearwater families are all likely to be susceptible to climate change, while heron and egret families, and osprey, kite, hawk and eagle families are among those least likely to be susceptible to climate change.
“This is the first time that a systematic assessments of species’ susceptibility to climate change has been attempted,” says Wendy Foden, of IUCN’s Species Programme. “Climate change is already happening, but conservation decision makers currently have very little guidance on which species are going to be the worst affected.”
The study found 3,217 of the 6,222 amphibians in the world are likely to be susceptible to climate change. Three salamander families are could be particularly susceptible, while 80-100 percent of Seychelles frogs and Indian Burrowing Frogs, Australian ground frogs, horned toads and glassfrog families were assessed as susceptible.
Specialized habitat requirements, such as species with water-dependant larvae, and those unable to disperse due to barriers such as large water bodies or human-transformed habitats are most at risk.
The report found that 566 of 799 warm-water reef-building coral species are likely to be susceptible to the impacts of climate change. The Acroporidae family, including staghorn corals, had particularly high numbers of susceptible species, while the Fungiidae family, including mushroom corals, and the Mussidae family, including some brain corals, possess relatively few.
Coral species qualified due to their sensitivity to increases in temperature, sedimentation and physical damage from storms and cyclones. Poor dispersal ability and colonization potential were used as a further important indicators.
According to the IUCN Red List of Threatened Species, 32 percent of amphibians are threatened with extinction. Of these, 75 percent are susceptible to climate change while 41 percent of non-threatened species are susceptible to climate change. For birds, the overall percentage of those threatened with extinction is lower – 12 percent. However, 80 percent of those are susceptible to climate change.
“There is a large overlap between threatened and climate change susceptible amphibian and bird species,” says Jean-Christophe Vié, Deputy Head of IUCN Species Programme. “Climate change may cause a sharp rise in the risk and rate of extinction of currently threatened species. But we also want to highlight species which are currently not threatened but are likely to become so as climate change impacts intensify. By doing this we hope to promote preemptive and more effective conservation action.”
