Greenpeace is in Patagonia to document the effects of climate change on the glaciers. We are visiting two icefields: the south Patagonian ice field and the North Patagonian ice field. These areas show the fastest glacial retreat on Earth.
The icefields lost 42 cubic kilometres of ice every year for the last 7 years. That is the equivalent to the volume of ten thousand large football stadiums like for example the Wembley stadium. The melting of the ice has accelerated in recent years. Currently the Patagonian icefields contribute to nine percent of the global sea level rise from mountain glaciers.
The increased thinning is caused by climate change, as evidenced by increased air temperatures and decreased precipitation over time. Still, those factors alone are not sufficient to explain the rapid thinning, part of the answer is also to be found in the special dynamics of these glaciers. The icefields in Patagonia are dominated by so-called calving glaciers. Such glaciers spawn icebergs into the ocean or lakes and have different dynamics from glaciers that end on land and melt at their front ends. Calving glaciers are more sensitive to climate change once pushed out of equilibrium.
The icefields discharge ice and meltwater to the ocean on the west side and to lakes on the east side, via rapidly flowing glaciers. The fronts of most of these glaciers have been retreating over the past half-century or more.
Unfortunately the Patgonia Icefield’s fate is not unique. Globally, the effects of climate change are being felt in a variety of ways and scientists predict more regular, and more intense impacts. Climate change presents a threat to most natural systems. Those natural systems threatened include glaciers, coral reefs, mangroves, arctic ecosystems, alpine ecosystems, prairie wetlands, native grasslands, and biodiversity “hotspots”. Climate change will increase existing risks of species extinction and biodiversity loss in ecosystems at every latitude and in each region. This is not only impacting nature – it has devastating implications for human lives as well.
What causes climate change
Climate change is directly linked to our fossil energy consumption. Global warming of the earth is the result of increasing greenhouse gas emissions. The principal cause is carbon dioxide (CO2), which is released when fossil fuels such as coal, oil and gas are burned.
In 2001 a revised report was issued bythe Intergovernmental Panel on Climate Change (IPCC), a body under the United Nations made up of more than 2500 scientists from around the globe. The IPCC found new and stronger evidence that most of the observed warming of the past 50 years is attributable to human activities, and that about three quarters of the anthropogenic (human created) emissions of CO2 during the past 20 years are due to fossil fuel burning.
Glacial impacts globally
Throughout the entire world glaciers are disappearing through global warming, not only in the tropics but also in parts of the world with a milder climate.
The ice cap of Mount Kilimanjaro is disappearing rapidly due to melting snow and ice and is expected to disappear entirely within ten to 20 years. In February 2001 American geologist, professor Lonnie Thompson of Ohio State University’s Byrd Polar Research Centre, made public his findings based on more than 20 years research.
Thompson found that since 1912, when for the first time 12 square kilometres of snow, ice and glaciers were mapped out on the slopes of Mount Kilimanjaro, more than 80 per cent of the ice caps’ volume has disappeared. Research shows that since 1989, 33 per cent of the ice mass has vanished. According to recent estimates the remaining ice cap of approximately 2 square kilometres will have melted in 10-20 years. A unique and vital African panorama will have disappeared forever.
The Lewis glacier, the largest of Mount Kenya has shrunk 40 % since 1963.
Ice drillings in the 2km wide Dasuopu glacier near Xixabangma-peak in Tibet show that the last ten years of the 20th century have been the warmest of the past ten thousand years. Despite a severe winter, the Dokriani Barnak glacier in India shrank 20 meters in 1998, and the Gangorti Glacier retreated some 30 meters. Scientists predict that at this pace all glaciers in the central and east Himalayas will have disappeared by 2035.
Half of the glaciers that existed in 1980 have disappeared.
The Quelccaya ice cap with a diameter of 154 meters has shrunk 20% since 1963.
A mummy from the stone age (Otzi) could be found after a glacier melted in the Oetztal Alps. This attests to the fact that glacier ice is disappearing more rapidly now than in the past 5,000 years.
The Bering glacier is 5,170 square kilometres. It is the largest glacier in North America and is 800 meters thick in some places. In the last century, the estuary of this glacier has become 130 square kilometres smaller. Arial photos show that the Bering glacier has become 130 meters thinner in the last 50 years.
For further information see also:
www.greenpeace.org Further Greenpeace materials on glacial retreat, including pictures.
www.geo.unizh.ch/wgms summary of the status of world glaciers
www.earthobservatory.nasa.gov: NASA images of glaciers
www.climatehotmap.org effects of climate change
www.ipcc.ch IPCC website
