Environmental Hotspot Alert

Retreating Kangerdlugssuaq Glacier - Greenland, 2000-2005

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Kangerdlugssuaq, the largest outlet glacier on Greenland's east coast, is one of 12 fast flowing outlet glaciers that discharge ice into the surrounding oceans. Its rate of flow more than doubled between 2000 and 2005 reaching a speed of 14 km per year or 1.6 meters per hour. It has since slowed. During this same period mean summer temperature at coastal weather stations along southeastern Greenland increased 1.1¬ƒ C. While the mechanisms controlling the rate of flow are complex and not fully understood, there is a general consensus that warming temperatures are driving the increased rates of discharge.

The fronts of glaciers throughout southeast Greenland also receded rapidly during this same time period; an average retreat of 24 m/yr increasing to an average of 175 m/yr. Kangerdlugssuaq Glacier, which had been retreating 25 to 100 meters per year in the period between 1992 and 2000, retreated more than 4 km between April 2004 and April 2005.

The loss of the Greenland Ice sheet is a major factor in projecting the sea level rise which might result from global warming. Loss of the entire sheet would raise global sea level an estimated 7 meters. If melting were the only mechanism through which Greenland was losing ice mass, this could take 1000s of years. The acceleration of Greenland's glaciers raises concerns that the global sea level may rise more rapidly under global warming scenarios than had previously been estimated.

Source: http://na.unep.net/atlas/webatlas.php?id=383

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Environmental Science Alert

Likelihood of severe long-term drought in Africa

Instrumental records document persistent droughts in West Africa, attributing them to changes in Atlantic sea-surface temperatures. Until now, however, there was little information about drought prior to the 20th Century. Recent research provides evidence from the past three millennia from sediments in Lake Bosumtwi, Ghana. This ancient record shows there have been intervals of more severe and longer-term droughts than those in recent history, and that they are likely to recur. Annual sediment layers are unusually well preserved in Lake Bosumtwi. Researchers took sediment cores from the lake bottom and examined oxygen isotope concentrations in the calcium carbonate. They found a long-term record of dry and wet periods. Short-term droughts lasting 30-40 years correlated with sea-surface temperature fluctuations. But more severe droughts, lasting as long as a century, also punctuated the three-millennia record; their variability is linked to circulation changes in the Atlantic. The decades-long, severe drought that began in the late-1960s and peaked in the mid-1970s displaced millions of people in sub-Saharan Africa. Evidence from the lake sediments show that during the most recent century-long drought, which occurred some 200-300 years ago, water levels in Lake Bosumtwi fell almost four times more than they did during the 1970s drought. The researchers suggest the hydrological pattern will eventually shift to another severe, centennial-scale drought, which will be exacerbated by rising global temperatures. People in sub-Saharan Africa are heavily dependent on monsoon rains for crops, livestock, and hydropower and their populations are growing. They will be unable to adapt to a long-term, severe drought unless policymakers act immediately with contingency plans and concrete strategies.

Source: Shanahan, T. M., J. T. Overpeck, K. J. Anchukaitis, J. W. Beck, J. E. Cole, D. L. Dettman, J. A. Peck, C. A. Scholz, and J. W. King (2009) Atlantic forcing of persistent drought in West Africa. Science, 324, 377-80.

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Near Real-Time Environmental Event Alert

Extinction crisis continues as the International Year of Biodiversity approaches

Figure 1: Number of threatened mammal, bird, reptile, amphibian, fish, mollusk, invertebrate and plant species according to the IUCN Red List categories: critically-endangered, endangered, and vulnerable (IUCN 2009).

The International Union for Conservation of Nature updated its Red List of Threatened Species in November and it supports the widely accepted belief that we are in the midst of an ongoing extinction crisis. "The scientific evidence of a serious extinction crisis is mounting", says Jane Smart, director of IUCN's Biodiversity ConservationGroup.

Photo: The Micronesian Kingfisher (Todiramphus c. cinnamominus) is among the many threatened bird species on the IUCN's list. One of its subspecies, the Palau Kingfisher, has gone extinct in the wild.
Credit: Jim Frazee/Flickr.com

The update reveals that 8,500 of the 12,151 or 70 percent of plants assessed by the IUCN project are at threatened with extinction, with 114 already extinct or extinct in the wild. Similar assessments for several classes of species are given (figure 1) and they paint an alarming picture of biodiversity loss as the beginning of the International Year of Biodiversity approaches in January.

Figure 3: Number of threatened mammal, bird, reptile, amphibian, fish, mollusk, invertebrate and plant species by country according to the IUCN Red List categories: critically-endangered, endangered, and vulnerable (IUCN, 2009b).

Figure 4: The Human Influence Index is produced through overlay of a number of global data layers representing location of various factors presumed to exert an influence on ecosystems: human population distribution, urban areas, roads, navigable rivers, and various agricultural land uses. Biodiversity ’Äúhotspots’Äù are the planet's biologically richest and most endangered terrestrial ecoregions based on a defined set of criteria (Myers, et al., 2000).

Habitat destruction, overexploitation and invasive species and extinction cascades are the principal causes of extinction. The United States, Indonesia, Malaysia and Ecuador are the countries which have the most species at risk. As the human footprint grows ever larger on the planet (figure 3) these drivers of biodiversity loss become ever more pervasive. In addition human impact in "hotspots" of biodiversity such as in Southeast Asia and the South Pacific is putting these concentrated storehouses of biodiversity at risk (figure 4).

Source: IUCN (2009) Extinction crisis continues apace. IUCN-Press Release Accessed 09 November 2009 at: http://www.iucn.org/?4143/Extinction-crisis-continues-apace

Brook, B.W., Sodhi, N.S. and Bradshaw, C.J.A. (2008) Synergies among extinction drivers under global change. Trends in Ecology and Evolution 23(8):453-460.

Vié, J.-C., Hilton-Taylor, C. and Stuart, S.N. (2009). Wildlife in a Changing World. IUCN Red List, Gland, Switzerland

Mittermeier, R. A., Gil, P.R., Hoffman, M., Pilgrim, J., Brooks, T., Mittermeier, C.G., Lamoreux, J. and da Fonseca. G.A.B. (2005) Hotspots revisited: Earth's biologically richest and most endangered terrestrial ecoregions. Conservation International, Washington, DC.

Myers, N. Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B. and Kent, J. (2000) Biodiversity hotspots for conservation priorities. Nature 403:853-858.

IUCN (2009b) Wildlife in a Changing World. Eds Jean-Christophe Viˆ©, Craig Hilton-Taylor and Simon N. Stuart. IUCN, Gland, Switzerland.

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