Take Two

Climate change: New study focuses on tropical Pacific Ocean

Romeo Gacad/AFP/Getty Images

Fish swim by a colorful variety of coral near Indonesia's Komodo island.

When you think about a bellweather for climate change, chances are you think of the Arctic: melting ice, glaciers breaking off into the ocean.

But a new study out of UCLA focuses on a less obvious target: the western tropical Pacific Ocean.

Researchers have analyzed thousands of years of data in a region of the Pacific near Indonesia that plays a big role in climate throughout the world.

For more, Aradhna Tripati, a Professor in the Departments of Earth, Planetary, and Space Sciences and Atmospheric and Oceanic Sciences at UCLA, joined Take Two on Tuesday.

INTERVIEW HIGHLIGHTS

What did you set out to do?

We looked at how climate change has affected ocean temperatures in the western tropical Pacific Ocean. I also wanted to study the impact that ocean temperatures have on glaciers that are in the tropics. Turns out that tropical glaciers have actually been called the canaries in the coal mine of climate change. They’ve been shrinking since the last ice age and have been melting even more dramatically over the last several decades so they’re perhaps even more sensitive than the arctic glaciers you mentioned previously.

Tropical glaciers are predicted to disappear altogether in places like Indonesia as well as Kilimanjaro and in parts of the Andes in just the next two decades.

On what the study found:

It’s likely to have quite dramatic consequences throughout the tropics. We found evidence for a fairly large amount of warming--about eight to 10 degrees Fahrenheit since the last ice age, which was about 20,000 years ago. This amount of ocean warming is about double what other people previously reported. So it suggests that the region might respond in a very sensitive manner. 

It got me thinking about the questions about how tropical glaciers have responded. Many scientists have puzzled over the past decades as to what sets the extent of tropical glaciers and how they relate to ocean temperatures. So it’s been a bit of a puzzle how to reconcile different types of observations from communities as wide ranging as oceanography to glaciology. So in a lot of ways we’ve solved a long-standing scientific conundrum.

How do you study temperature changes from 20,000 years ago?

We use a novel and potentially revolutionary new chemical technique actually developed here in Los Angeles. It’s a technique that uses isotopes--atoms of oxygen and carbon--that are in geological deposits. So we are measuring this in ocean sediments as well as the fossils they contain. It’s allowing us to visualize how Earth’s climate has evolved with a much higher degree of clarity than ever before. This technique has been used for a range of other questions for trying to look at the temperatures that meteorites have experienced as well as the body temperature of dinosaurs. But I specialized in developing it into a tool for studying climate change.

Why did you study that region around Indonesia, known as the sleeping dragon?

We know that temperature changes in the tropical Pacific can have a global impact and that’s why it’s called a sleeping dragon. The tropical Pacific Ocean is the warmest open ocean region on our planet and it’s a primary source of heat and water vapor to the atmosphere as a result. So even small changes in temperature in the region can influence climate, not just regionally but globally. We actually feel that in Southern California when there’s an El Nino. Temperatures in the tropical Pacific are changing by a very small amount yet as a result we see severe flooding, wildfires and droughts in Australia and the monsoon in Southeast Asia. 


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