Climate change to affect water supplies: research

Staff writer, with CNA

Fri, Mar 15, 2013 - Page 5

A researcher warned on Wednesday that island nations such as Taiwan could face serious challenges in terms of water resources due to changes in global rainfall patterns, as indicated by a recent study.

Taiwan should try to make more efficient use of its water resources, said Chou Chia, a research fellow at Academia Sinica’s Research Center for Environment Changes.

Chou said that in the study, his research team found evidence of increasing differences in worldwide levels of seasonal precipitation over the past three decades, based on analysis of global rainfall data from 1979 to 2010.

The study found that wet seasons are becoming wetter, and dry seasons drier, Chou said.

This trend suggests that the volume of rainfall in southern Taiwan will increase in summer periods and decrease in winter, he said.

If that happens, the nation’s reservoirs will no longer be able to cope with water shortages, Chou said, adding that reservoirs in southern Taiwan already cannot meet demand for a whole year.

The government should start setting priorities for water usage and adopting improved methods of water distribution and control, because it is unlikely that more reservoirs can be built, Chou said.

According to a synopsis of the study, the water vapor content of the atmosphere has increased over the past few decades as a result of rising global temperatures.

“This has led to wet regions getting wetter, and dry regions drier,” the study said. “Climate model simulations suggest that a similar intensification of existing patterns may also apply to the seasonal cycle of rainfall.”

The synopsis said that even if the total amount of annual rainfall does not change significantly, the intensified seasonal precipitation cycle could affect the frequency of droughts and floods.

Chou’s team recommended that the accuracy of forecasts for rainfall patterns be improved.

“As precipitation changes are usually evaluated from annual mean changes, seasonal changes in precipitation may have been overlooked until now,” the team said.

The study, titled “Increase in the range between wet and dry season precipitation,” was published in the online edition of Nature Geoscience on March 3.