LEAH CALLON-BUTLER gave up a career in fashion last year to become a solar panel saleswoman, joining a surge towards green jobs predicted by the Federal Government.

Modelling done by Treasury on the cost of climate change found there would be an explosion in "green-collar" work with the introduction of an emissions trading scheme, with renewable power industries like solar and wind expected to be 30 times their current size by the middle of the century.

Ms Callon-Butler, a sales executive with the Sydney solar hot-water company Endless Solar, intends to stick around for the expected boom. The company has installed 5000 rooftop solar hot water systems in five years, using technology developed at the University of NSW, and it is looking for more staff.

"Renewable energy is not something I knew a lot about before I started, but you do get really passionate about it," said Ms Callon-Butler, who will complete an undergraduate communications degree next week. "I'm not exactly sure how things will change for me when I finish the degree, but I definitely want to stay in the sustainability industry."

By 2050, Treasury predicts, renewable energy could make up as much as half the energy mix in Australia, replacing the current reliance on coal. "Renewable technologies will become increasingly competitive, and production methods will switch to less emission-intensive technologies and processes," the Treasury report said. More jobs will be created by demand for cleaner cars, and Treasury estimates one in four people will be driving a hybrid or plug-in electric car by 2050.

The Clean Energy Council said the Treasury modelling showed immediate public and private investment in renewable power would pay off.

"The smarter and more dynamic we are right now, the more options we will have in terms of deploying technologies commercially five years down the track in 2012 and 2013," said a spokesman, Matthew Warren. Unions and environment groups called on the Federal Government to pave the way for a green jobs boom.

Half a million new jobs could be created in renewable sectors of the economy by 2030, said a report yesterday by the ACTU and the Australian Conservation Foundation. The ACTU president, Sharan Burrow, said: "The report shows Australia must act swiftly to make the most of its natural advantages or our economy will be left behind. We can't afford to miss the boat."