Health was nominated by more than one-third of people as the most critical issue for state government action in the next decade, followed by the environment (22 per cent).

Long-term water management, which had been a big issue in previous surveys, has declined in importance to 17 per cent, probably because of the easing of drought conditions.

The Who Cares About the Environment survey of more than 2000 residents has been carried out every three years since 1994 to measure changes in knowledge, attitude and behaviour of NSW residents.

The 2009 report, published last month, showed that health also ranked first among current concerns (50 per cent), followed by education (23 per cent), public transport (22 per cent), roads and traffic (15 per cent) and environment (11 per cent). (People were asked to nominate two issues).

But when the survey canvassed the most pressing issues for the future, environment shot to importance, particularly among those aged 15-24.

Bernard Carlon, executive director for the Sustainability Programs Division of the NSW Department of Environment, Climate Change and Water, said this had been the trend for some years.

''All environmental issues are generally seen as more important as future issues … [This is] because we don't want to hand on a degraded environment for future generations."

Mr Carlon, who has been examining attitudes since the first survey in 1994, said, initially, the main concerns were unemployment and dirty beaches. Water use took over as the drought set in. Now other issues, such as energy use and climate change, were coming to the fore.

The survey shows 78 per cent of people believe that climate change is happening or will happen. This was even higher for those under 35 (87 per cent).

People are also changing their behaviour to reflect concerns about the environment. The survey finds they have reduced energy and water use, cut back on the amount of food thrown out, and rejected the use of plastic bags when shopping.

The Environment Department is one of the supporters of Saturday's Earth Hour, which advocates such day-to-day changes to reduce consumption.