The wife of Victorian Greens Senator Janet Rice, renowned climate scientist and transgender woman Penny Whetton, has died suddenly, the senator has announced.

Key points: Dr Whetton died suddenly in Tasmania last Wednesday

Dr Whetton died suddenly in Tasmania last Wednesday She led climate projections for the CSIRO and was a lead author of several significant international reports on climate change

She led climate projections for the CSIRO and was a lead author of several significant international reports on climate change She was also remembered as "part of the heartbeat" of the LGBTIQ community and a role model to the trans and gender-diverse communities

In a post on Facebook, Senator Rice said her partner of almost four decades died "suddenly and apparently peacefully" at their house in Sisters Beach, Tasmania, last Wednesday. She was 61.

"She was alone, having arrived at Sisters on Tuesday to spend a week or two while I was in Canberra," Senator Rice wrote in the post, which did not specify the cause of death.

"The last anyone heard from her was early Wednesday evening, and she was found on Thursday morning, still sitting on the couch, computer on her lap.

"She was in her favourite spot in one of her favourite places in the world — a lovely place to pass away, but just 20 years too early!

"It's so unbelievable, so unexpected and so so sad.

"Penny and I had been a team for almost 38 years. She was my rock, my best friend, my biggest fan. She was proud of me and I of her."

Senator Rice said her wife was happiest in the forest. ( Facebook: Janet Rice )

Senator Rice wrote Dr Whetton was a "fabulous parent" to their children John and Leon, "always supportive, giving, and delighted in sharing her and their passions — language, music, football, cricket, politics, painting, photography...".

Dr Whetton led the CSIRO's national climate projections work from 1992 to 2014 and was a lead author of three Intergovernmental Panel on Climate Change reports, including the fourth assessment report which was awarded the Nobel Peace Prize in 2007.

"She was deeply angry about current politics that is hurtling us to avoidable climate crisis, and deeply worried about the damage being done and the future prospects for our precious natural world," Senator Rice wrote.

"She was so worried about the coming summer."

The couple married in 1986. ( ABC News: Danielle Bonica )

The couple met and married before Dr Whetton affirmed her identity as a woman.

In a 2017 interview with the ABC, she spoke of fearing that her decision to come out as a transgender woman would end their marriage.

"I was afraid for years by even admitting to this that it would lead to the end of the relationship, that's why it took me so long because the relationship was so incredibly important," Dr Whetton said at the time.

Senator Rice said she was "a role model and an inspiration for so many trans and gender diverse people".

She described her wife as "a scientist and artist, intelligent, creative and able to turn her hand and her intellect to almost anything, from the climate science that was her profession, to landscape painting and furniture making".

"She was principled and loyal, a collaborative leader, and a mentor to many," Senator Rice said.

Senator Rice said she couldn't imagine life without Dr Whetton. ( ABC News: Danielle Bonica )

"She was happiest with camera in hand in a misty day in a tall wet forest — absolute favourite being a myrtle beech forest — or striding out across mountain ranges, or in the early morning on the beach at Sisters, photographing the morning light and chatting to the Pacific Gulls and Sooty Oyster Catchers.

"It's still not real. I can't imagine life without her. I know so many of her friends and colleagues feel the same.

"We'll get through I suppose, but we will miss her so so much."

Tributes for 'heartbeat' of LGBTIQ community

The former national director of Australian Marriage Equality, Rodney Croome, posted on Facebook that he had been "overwhelmed with sadness" when he learnt of Dr Whetton's death.

"Penny and I only met recently but I found her conversation enthralling, her ideas profound and her knowledge vast," he wrote.

"I looked forward to talking with Penny again many times in the years to come.

"Now, there are no years to come."

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Change.org executive director Sally Rugg, who helped lead the campaign for same-sex marriage, described Dr Whetton as "part of the heartbeat of the LGBTIQ activist community".

"She was kind, generous and always had time for people," she posted on Twitter.

The Australian Meteorological and Oceanographic Society tweeted that Dr Whetton was a "deeply respected" member of its community, and extended its sympathies to Senator Rice and their sons.

Damien Irving of UNSW's Climate Change Research Centre said he had worked in Dr Whetton's team at the CSIRO in his first job after finishing university.

"Couldn't have asked for a better mentor starting out as a climate scientist," he posted on Twitter.

"Heartbreaking news."

Darren Koppel, a research fellow at University of Technology Sydney (UTS), tweeted that Australia had lost "a giant of the science community".

"Her strength in life served as an inspiration for many of us.

"We should know and celebrate her story."

Senator Rice said she planned to set up a memorial fund in her wife's name to fund revegetation and erosion control work at Sisters Beach.