VOA常速英语:Scientists Ponder 'Epoch' of Damage to Global Water System

Scientists say a new geologic epoch has begun whereby humans are causing major damage to global water systems. They warn of a planetary transformation comparable to the retreat of the glaciers mor e than 11,000 years ago. Scientists are meeting in Bonn, Germany this week (5/21-24) to discuss what can be done about it.

While some still debate the extent to which humans have affected the environment, scientists meeting in Bonn have little doubt. In fact, there’s a name for the informal geologic epoch they say human activity has caused -- the Anthropocene. Scientists are now debating whether it should be officially included in the Geological Time Scale.

“For nearly a decade the Global Water Systems Project has been coordinating and supporting the broad research to study the complex water systems with interactions between natural and human components. And what we found is human activity plays a very central role in inducing and influencing the changes in the global water systems,” said Anik Bhaduri, executive officer of the Global Water Systems Project based in Bonn.

The project takes a global view of human effects on water systems, rather than simply studying very local environments. He called that a “game changer” in environmental research.

“Humans are impacting the global water systems by building dams, through land use changes, and it influences the global water cycle. As a consequence, the global water systems [are] vulnerable to local-scale human-induced traces. And it has wide-scale ramifications at larger, regional and continental and global scales,” he said.

For example, an International Geosphere-Biosphere Program paper says, “On average, humanity has built one large dam every day for the last 130 years.” It adds, “Tens of thousands of large dams now distort natural river flows to which ecosystems and aquatic life adapted” over thousands of years.

The paper also says groundwater and hydrocarbon pumping in low lying coastal areas have caused many river deltas to sink. That leaves coastlines more vulnerable to storms and tsunamis. It also says that humans now move more rock and sediment for various reasons than ice, wind and water combined. The drainage of wetlands for development removes a natural barrier against floods.

Bhaduri said, “The way the global water systems [are] moving we may reach a point where it is kind of irreversible. We may not go back to the equilibrium point. There it comes in the severity of human actions.”

The head of the Global Water Systems Project said that there can be a trade-off as countries try to ensure water security.

“Our global study map shows that human water security has been often achieved in the short run at the expense of the environment. It is true with the developed countries as well as developing countries. We see this kind of a trade-off between human water security and the water needs for ecosystems. And it has long-run social consequences for the socio-ecological systems as a whole. And that’s a global issue of concern.”

Bhaduri added that water security means both water quantity and water quality.

“There are nexus between energy security, water security, food security and environment. And it needs cooperation at the local level – at the policymakers’ levels – between different countries also. Otherwise, we will move at a direction where it will be very costly to come back,” he said.

Project co-chair Charles Vorosmarty said every year a half trillion dollars worth of “concrete, pipes, pumps and chemicals are thrown at our water problems.” He said that has “produced a technological curtain separating clean water…and the highly stressed natural waters that sit in the background.”

The four-day meeting in Bonn is expected to release a final communiqué outlining what steps need to be taken to mitigate the effects of the Anthropocene epoch. In the long term, the Global Water Systems Project is working on Future Earth – an international collaborative environmental research framework.