FACTBOX-Will Australia's top wines survive climate challenges?

(Reuters) - Australia's A$5.5 billion ($4.55 billion) wine sector is sizing up the impact temperature changes brought on by drought and climate change could have on grape quality.

Here are some facts about Australia's three most popular wine varieties and changing temperatures' possible impacts on them:*

* SHIRAZ (422,600 metric tons)

-- One of the first varieties to arrive in Australia in 1832, shiraz, the same grape as France's Rhone Valley syrah, is known for its spicy, "wild" mulberry flavor.

-- Versatile shiraz is said to take on different characteristics when grown in different regions -- being peppery in cool Victoria, spicy and intense in Coonawarra and Margaret River, powerful and minty in Clare Valley, muscular in Barossa and leathery and rich in the Hunter Valley.

-- Shiraz grapes' versatility in producing this range of wine styles from a broad climate range means that this variety is not as sensitive to shifting temperature as other varieties, such as Pinot Noir. CSIRO researchers believe they will be better able to be adapt to a changing climate than some other varietals.

* CHARDONNAY (397,400 metric tons)

-- Australia's most-planted grape in the 1970s, chardonnay production peaked in the 1980s as critics and consumers tired of what some called its "oaky" and unsubtle character.

-- Still the most versatile white wine grape, it flourishes in cool regions such as Tasmania, Adelaide Hills and Mornington Peninsula, as well as warmer inland regions the Murray Darling, Riverland, and Riverina.