“Originally the money was supposed to have been invested over five years – 2017-2022 – but most of it has not seen the light of day.”

Dealing with extreme weather is part of $102.1 million set aside in 2018-19 budget “to deliver outcomes that help communities and businesses adapt to a changing climate”, the budget papers show.

Even so, the amount is tiny even as Sydney and NSW emerged from their hottest autumn on record for maximum temperatures, and one of the driest starts to any year.

For instance, the plan to spend $29.2 million over five years for climate change research and adaptation – including $5.5 million in 2018-19 – is smaller on average than the $64 million to fund the eradication of invasive red fire ants over the next decade.

Fire ants

Separately, total spending on the environment appeared to have dropped significantly, particularly compared with what was budgeted for the current year.

According to the budget papers, the government will spend $1.067 billion on the Office of Environment and Heritage in the 2017-18 year, or about $165 million less than it expected to spend. In the coming year, outlays will total $1.166 billion - still shy of what was earmarked a year ago.

Penny Sharpe, Labor's environment spokeswoman, said "the Liberal and National Party war on the environment continues," with "$231 million that is not available to create national parks, tackle plastic pollution, solve the waste crisis and save threatened species”.

“The only priority of this government is building stadiums and the environment is an inconvenient afterthought,” Ms Sharpe said.

Justin Field, the Greens climate spokesman, said the shortfall was largely accounted for by the failure to develop climate-related projects.

"The money's just sitting there - for renewable energy, energy efficiency, and other climate action," he said. "Those plans are a year to 18 months behind."

Threatened species

A spokeswoman for the Office of Environment and Heritage said the drop in spending by the department was "largely as a result of the carry forward from the Climate Change Fund".

When an "important $89.3 million" for capital works programs are added, OEH's budget swells to $1.255 billion, she said.

Among key programs, the government aims to increase the numbers of threatened species and ecological communities “on track to being secure in the wild” from 240 in 2017-18 to 328 in 2018-19, the budget papers said.

There is no clear funding set aside for additional national parks, although environmental groups expect an announcement of a Sydney marine park before next March’s election.

The government has pledged to plant 380,000 trees a year until 2030 to more than double Sydney’s tree canopy to 40 per cent. Across the state, though, looser native vegetation laws mean land-clearing is highly likely to have accelerated in the past year, ecologists say.

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Mr Perrottet also cited plans to raise the height of Warragamba Dam wall by about 14 metres as part of its climate change strategy.

The government has allocated $58 million to deliver the first stage of its Flood Strategy, which includes $30 million for planning,environmental assessments and community consultation for raising the dam wall.

The project is scheduled to be built by 2024 subject to completion of environmental assessments and other planning and government approvals.

Gabrielle Upton, the environment minister, said the government would spend $196 million in the coming fiscal year on programs to improve the environment, such as reducing waste and boosting recycling.

“The NSW government is committed to providing a healthy environment for future generations,” Ms Upton said.

“Diverting waste from landfill is a key priority and the NSW government has set targets to increase the diversion of waste from landfill from 63 per cent in 2014-15 to 75 per cent by 2021.

Coal view

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The government, meanwhile, will spend $118.3 million “enabling sustainable, regulated use and access to, geological resources”, including coal.

Mining royalties, the bulk of which are from the sale of thermal coal used in power stations, added $1.8 billion to the state’s coffers in the 2017-18 year.

Royalties are forecast to bring in $7.4 billion in the four years to 2021-22, an upward revision of $813.4 million compared with the mid-year review, aided by rising commodity prices.

The Coalition government set a net-zero carbon emissions target for NSW in late 2016. This year's budget papers make only one reference to supporting low-emissions technologies, as part of the $118.3 million resources fund.

Elsewhere, it noted the state's energy efficiency programs would save 12,578 gigawatt-hours of electricity savings by the end of the 2018-19 year, up from 10,118 GW-hours at the end of 2017-18.