施奈德和胡克表示,研究結果與預期中全球暖化連帶產生的變化不謀而合。Earth's Largest Lakes Are Heating UpPASADENA, California, December 13, 2010 (ENS)
Earth's largest lakes have been warming during the past 25 years in response to climate change, according to the first comprehensive global survey of temperature trends in major lakes.
Researchers Philipp Schneider and Simon Hook of the NASA Jet Propulsion Laboratory in Pasadena, made the discovery using satellite data from 1985-2009 to measure the surface temperatures of 167 large lakes worldwide.
The data show far greater warming in the mid- and high latitudes of the Northern Hemisphere than in low latitudes and the southern hemisphere.
The largest and most consistent area of warming was northern Europe. The warming trend was slightly weaker in southeastern Europe, around the Black and Caspian seas and Kazakhstan. The warming trends increased slightly farther east in Siberia, Mongolia and northern China.
In North America, trends were slightly higher in the southwest United States than in the Great Lakes region. The largest alpine lake in North America, Lake Tahoe, on the California-Nevada border, was one of the primary validation sites for the global lake study.
In the Great Lakes and northern Europe, the bodies of water were found to be warming even more quickly than surrounding air temperature.
Warming was weaker in the tropics and in the mid-latitudes of the Southern Hemisphere.
Small changes in water temperature can result in algal blooms that can make a lake toxic to fish or result in the introduction of non-native species that change the lake's natural ecosystem, Schneider explained.
Beginning in 1985, surface temperatures were extracted from nighttime thermal infrared imagery of 167 large inland water bodies for the months July through September and January through March.
These months were chosen because of the difficulty in collecting data in seasons when lakes are ice-covered or often hidden by clouds.
The researchers found an average warming rate of 0.81 degrees Fahrenheit per decade, with some lakes warming as much as 1.8 degrees Fahrenheit per decade.
Schneider and Hook selected the study lakes from a global database of lakes and wetlands based on size - typically at least 193 square miles or larger - or other unique characteristics of scientific merit.
The selected lakes also had to have large surface areas located away from shorelines, so land influences did not interfere with the measurements. Satellite data were collected from the point farthest from any shoreline.
Schneider and Hook said that their results were consistent with the expected changes associated with global warming.
紅圈代表2008-2010年間興都庫什山脈及其下游地區發生的洪水(圖片來源:UNEP Grid Arendal)Melting Glaciers Cause Droughts, Floods; Norway Helps HimalayasCANCUN, Mexico, December 7, 2010 (ENS)
Climate change is causing mass loss of glaciers in high mountains worldwide. Within a few decades, melting glaciers could leave arid areas such as Central Asia and parts of the Andes even drier as the ice melts into water and flows downhill, causing disastrous floods in the lowlands, finds a new report by the UN Environment Programme presented today at the UN climate talks in Cancun.
Compiled by UNEP's Polar Research Centre GRID-Arendal and experts from research centers in Asia, Europe, Latin America and North America, the report says the larger glaciers may take centuries to disappear but many low-lying, smaller glaciers, which are often crucial water sources in dry lands, are melting much faster.
Glacial melt will change the lives of millions as over half of the world's population lives in watersheds of major rivers originating in mountains with glaciers and snow.
Glaciers in Argentina and Chile, followed by those in Alaska and its coastal mountain ranges, have been losing mass faster and for longer than glaciers in other parts of the world, finds the report, "High Mountain Glaciers and Climate Change - Challenges to Human Livelihoods and Adaptation."
The third fastest rate of loss is among glaciers in the northwest United States and southwest Canada.
Melting more slowly are glaciers in the high mountains of Asia, including the Hindu Kush region of the Himalayas, the Arctic and the Andes.
Europe's glaciers had been growing since the mid-1970s, but they began to lose mass around the year 2000, the report shows.
"These alarming findings on melting glaciers underline the importance of combating climate change globally. It sends a strong message to us as politicians and climate negotiators in Cancun," said Norway's Minister of the Environment and International Development Erik Solheim.
Solheim announced today that Norway will fully fund, with more than US$12 million, the five-year Hindu-Kush-Himalayas Climate Impact Adaptation and Assessment Programme from 2011.
"People in the Himalayas must prepare for a tough and unpredictable future. They need our committed support," said Solheim. "Therefore, Norway will fully fund the brand new five-year program. We see this program as a potent mix of solid climate science, promising intra-regional cooperation and concrete adaptation projects on the ground."
In the last 40 years, Glacial Lake Outburst Floods, often called GLOFs, have been increasing, not only in China, Nepal and Bhutan, but also more recently in Patagonia and the Andes.
Five major GLOFs took place in April, October and December 2008 and again in March and September 2009 in the Northern Patagonia Icefield in Chile. On each occasion, the Cachet 2 Lake, dammed by the Colonia Glacier, released around 200 million tonnes of water into the Colonia River. The lake has since rapidly refilled, suggesting high risk of further GLOFs.
The report recommends:Strengthening glacial research and trans-national collaboration with emphasis on mass calculation, monitoring and particularly the effects of glacial recession on water resources, biodiversity and availability downstream.
Improved modeling on precipitation patterns and effects on water availability in particular in mountain regions of Asia and Latin America.
Prioritizing support to and development of adaptation to water-related disasters.
Prioritizing programs and support to development and implementation of adaptation strategies for too much and too little water including strengthening the role of women.
Urgently supporting the implementation and improvement of both small and large-scale water capture and storage systems and improving efficiency of current irrigation systems through the use of green technology and agricultural knowledge.