Fri, May 09, 2008 - Page 2 News List

Science council urges fast action on global warming

800-POUND GORILLAThe Hilbert-Huang Transform is an analysis method that could provide a trend curve that corresponds to the Earth’s actual climate change

By Meggie Lu  /  STAFF REPORTER

Climate change is throwing the global temperature cycles out of order and to circumvent the possibly dire consequences urgent strategies should be put into place to reduce carbon emissions, the National Science Council (NSC) said at a press conference yesterday.

The trend the council referred to was calculated by Norden Huang (黃鍔), an Academia Sinica academic who previously spent 32 years working at NASA.

Huang’s math model, the Hilbert-Huang Transform (HHT), differs from the traditional Fourier data analysis methods in that nonlinear and non-stationary data can be analyzed to an impressive degree of accuracy because variable bases are employed to “adapt” to the conditions being analyzed.

“The world is a nonlinear place, so to use set bases in data analysis would produce less than accurate results for many ‘trends,’ like climate change or the stock market,” Huang said.

“For example, a bridge may seem to oscillate at a steady speed, but, each swing may take a different amount of time, and to analyze the data using the same time base would yield a different result than if adaptive data analysis were employed,” he said.

The HHT was developed by Huang in 1998 and was inspired by the irregularity of seemingly periodic ocean waves, he said.

Since then, the method has received eight patents in the US and been honored by NASA as one of the most important applied math inventions in recent history.

Huang was also awarded NASA’s “Inventor of the Year” award in 2003 and became NASA’s 2006 Science and Environment Medal Recipient.

The list of applications of HHT is long and includes sound identification technologies using sound wave frequencies, RFID [radio frequency identification] technology, bridge safety analysis, and heart rate analysis, but the most recent application of the model is climate change analysis.

Citing late Serbian scientist Milutin Milankovitch’s (1879-1958) postulation, Huang said: “The Earth’s temperature is affected by the interaction between the planet’s orbit and the sun — stages of Earth glaciations was actually a function of the globe’s precession, obliquity and eccentricity.”

Using HHT analysis, Huang said that the Milankovitch cycle could provide a trend curve that corresponds to the Earth’s actual climate change in the past million years with an accuracy of 70 percent, adding, “If we peek into the future, the curve shows that a global cooling is coming soon.”

However, a major variable factor now throws the trend into uncertainty, Huang said.

“In the past million years, carbon dioxide concentrations had never exceeded 300 parts per million [ppm], but since current global levels are in the 370ppm to 380 ppm range, it is hard to say what will happen next,” he said.

Carbon traps heat in the atmosphere, preventing it from being released into space, Huang said, adding that the continued heating of the globe could lead to a catastrophic increase in sea level which could cause flooding in many island nations.

What is even more alarming is that “unlike what some research indicates, the global temperature is not increasing at a linear rate — it is rising at a curved, increasing speed,” he said.

“Heaven knows what will happen next [in terms of global temperature], but like the famous climate change expert, Columbia University’s Wallace Broecker said, climate change is a 800 pound gorilla with a bad temper — to avoid letting it get out of control, it’s best not to constantly poke it with sticks,” he said.

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