See posted comments (0) Post a Comment Okavango Delta and Lake Ngami

Botswana

The vast stretches of grassland, wetland, and open water of the Okavango Delta are home to a variety of wildlife and vegetation as well as several native tribes. Although the Okavango ecosystem is considered one of the wonders of the world and attracts tourists from all over the globe, it faces several significant threats. Proposed upstream water projects are among these threats. The Okavango River originates in the highlands of east-central Angola and brings the flood waters and sediment necessary to maintain the dynamic flooding of the delta. Upstream dams could trap much of this sediment, causing the river View detailed information

See posted comments (0) Post a Comment Kangerdlugssuaq Glacier

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° 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. View detailed information

See posted comments (0) Post a Comment Mendenhall Glacier

Mendenhall Glacier flows 22 kilometers from an elevation of nearly 1,600 meters in the Coast Mountain Range, to just above sea level at its terminus roughly 5 kilometers northeast of Juneau, Alaska. It has been receding since the 1700s when the “Little Ice Age” ended, retreating approximately 3 kilometers in the past century. Most of this retreat occurred in the mid-1940s and the late 1990s. The majority of the global community now accepts fluctuations in glaciers, particularly changes in their volume, to be reliable indications of a global trend of warmer air temperatures. While the retreating tongues of glaciers are less directly linked to climate change than overall volume, they are much more readily observed and allow the study of glaciers which would otherwise be out of the reach of most research projects. It is believed that the current climate conditions will not be reflected in most glacier tongues for years and will eventually amount to a kilometer or more of additional retreat. If climate conditions continue to follow current trends many glaciers will disappear completely. The satellite images from 1986 and 2007 show the continuing retreat of Mendenhall Glacier. Similar changes are taking place in many of the glaciers in southeastern Alaska. A 2002 study estimated the contribution of melting Alaska glaciers to sea level rise between the 1950s and 1990s to be twice that of the melting of Greenland’s ice sheet during the same time period. View detailed information