NANCHANG -- International water conservation and environmental protection specialists have called on the global community to step up the fight against water shortages that have been worsened by human activity and climate change.

"It's an urgent time for the international community to take action to prevent freshwater lakes from being contaminated, as water resources has been greatly threatened by human activity and climate change," said Marion Hammerl, president of the Global Nature Fund.

Hammerl made the remarks at a seminar on lake conservancy and regional development in the city of Gongqingcheng in East China's Jiangxi province, home to Poyang Lake, the country's biggest freshwater lake.

The main threats to water conservancy, such as declining water quality and the overuse of water, are the same all over the world, Hammerl said.

More than 200 experts and officials on water conservation and environmental protection from 19 countries shared their experience concerning the exploration and use of lake resources during the four-day seminar, which ended on Tuesday.

Experts believe lakes around the world have been increasingly challenged by climate change and human exploitation, threatening global freshwater security.

Discharges of untreated industrial waste water and irrigation water containing pesticide and chemical fertilizers have contributed to the contamination of lakes, said Hammerl, who is also president of the World Living Lake Network.

A report from the China Institute of Geo-Environment Monitoring showed that more than 70 percent of global freshwater resources are used for agricultural irrigation.

Experts warned that the ever-increasing population worldwide will put a strain on irrigation water resources under current irrigation techniques.

The way water resources are managed should be transformed and existing water facilities should be upgraded so as to achieve sustainable development for the lake, said John Pinder, a British environmental protection expert.

Sayana Ayusheeva, a delegate from Russia's Baikal, the world's oldest and deepest lake, said the lake's water quality has been deteriorating because of unregulated tourism and poor public knowledge regarding lake resource conservancy.

Sho Shun Ho, a lake expert from Japan, said water quality in the Lake Biwa watershed began deteriorating in the 1960s and 1970s because of rapid urbanization and industrialization. Occasional discharges of untreated or inadequately treated industrial effluents caused large-scale fish deaths, which ultimately led to a freshwater red tide in 1977.

The Japanese government began to build a large water conservancy project in Lake Biwa in the 1980s, aiming to develop additional water resources, reduce the threat of floods in lakeshore areas, preserve the natural environment and restore water quality.

"Through about 30 years of efforts, 84 percent of local residents are now served by a large-scale sewer network," Sho said.

"But there are new problems, such as the release of phosphorus from large stores in bottom sediment have emerged over the past years, which is thought to have been caused by global warming," Sho said.

According to a National Aeronautics and Space Administration study from 2010, the surface temperatures of Earth's largest lakes have been rising over the past 25 years as a result of climate change.

Most freshwater ecosystems will be severely impacted according to current climate projections for the middle of the century, Hammerl said.

"Due to a lack of implementation for the current management system and fund shortages, it's still difficult for some developing countries to put sewage facilities to use," she said.

"We should take effective precautionary measures, which will require government efforts and adherence to laws on the part of enterprises. At the same time, NGOs should build a platform where technology can be shared," said Hammerl.