It is early morning on Cape York and Environment Minister Tony Burke is bouncing across the vast Aurukun wetlands in the back of a speedboat. These wetlands are one of Australia's unknown environmental wonders. Larger than their equivalent in Kakadu, they support all manner of waterbird, reptile and mammal life. It is the kind of place Burke talks about earnestly - iconic, unspoilt wilderness. The kind of place an environment minister can make a name for himself protecting.
Burke is visiting Cape York to talk to traditional owners as part of a decades-long effort to have the region protected on the United Nations' World Heritage List. The government hopes to have a nomination by February, but it will do so only with consent from the traditional owners, which is far from assured.
How he handles the competing interests on the cape is just one of many issues coming to a head for Burke in what will be a defining period.
Chief on the list is shepherding through a long-awaited plan to save the Murray-Darling Basin, which aims to quell 100-plus years of bickering between states over the management of Australia's most famous river system. Burke also faces a decision on the future of north-west Tasmania's Tarkine rainforest and is managing a still-fragile agreement between greenies and loggers to protect 500,000 hectares of native forest. And he still has to nail down what is promised to be the world's largest network of marine reserves around Australia's coastline.
''I have strategically timed things poorly enough that I have pretty much every major decision I have got to make coming up in a few weeks,'' Burke said as the boat bounces across the open water.
Don Henry, chief executive of the Australian Conservation Foundation, says Burke already has some achievements tucked under his belt - a national heritage nomination for the West Kimberley is one - but the big calls are still in front of him.
Since coming to the portfolio after the 2010 election, Burke has made much of his teenage environmental interests. In the 1980s he joined the Wilderness Society, spurred by the campaign to save the Daintree rainforest.
Soon after he was signed up to the Labor Party as a 16-year-old by Morris Iemma, joining the NSW Right. Burke is a man of ambition. It is often said one of his personal goals is to be prime minister. ''It is part of my cunning 70-year plan,'' he says with a laugh. So is that a no?
''Oh, well, I am only 43. I have seen plenty of really good careers killed by impatience. I don't intend to be one of them,'' he says. ''There is no way in the world that I would be the best person on our side to lead the show at the moment. Whether that is the case in years to come, who knows.''
After a short stint in the NSW Parliament he was elected to the federal seat of Watson and in 2007 became Labor's minister for agriculture, fisheries and forestry. He oversaw reforms of drought payments and the wheat market, and drove a plan to ban illegally logged timber imports that finally passed Parliament this week.
As forestry minister - much to the chagrin of conservationists - he also vocally backed the controversial and doomed proposal by the timber company Gunns to build a pulp mill in the Tamar Valley outside Launceston. Behind the scenes he successfully opposed mooted reforms to the agreements overseeing logging practice across the country.
Under Julia Gillard's prime ministership, he shifted from being the man responsible for primary industries to custodian of the environment. Soon after the move, he gave a speech outlining his vision for Australia's natural wilderness. The centrepiece was protection of iconic sites in the four corners of the continent: Tasmania's forests, Cape York, the Kimberley and the oceans of the south-west and Coral Sea with ''wildlife corridors'' in between.
Burke says his goal is to return to ''first principles'' - a favourite phrase. ''We have tended to have forgotten that the fact something is simply an incredibly beautiful place can be reason in itself for protecting it,'' he says.
The Burke legacy is not short of doubters. Conservationists are livid at his plans to change national environmental laws to hand decisions on new major developments such as mines and pulp mills to the states. Environmental law expert Professor Tim Bonyhady, from the Australian National University, says that under Labor, the Commonwealth proposes to disengage from environment decision-making. He says the reforms could be very damaging, particularly when states such as Queensland appear so set on resource development.
''It seems to me that Burke is much more interested in the appearance of the Commonwealth protecting Australia's environment, than actually protecting it,'' says Bonyhady.
Burke defends the reforms - which will be hammered out by the Council of Australia Governments next month - saying ways of streamlining decisions with state laws have to be found, so long as there is the same environmental outcome. But nowhere is Burke's legacy more on the line than on the Murray-Darling Basin. After five years and $10 billion of inducements, Burke has signed off on a plan to return 2750 billion litres of water to the river environment. The government has also committed another $1.8 billion to efforts to recover 450 billion litres by 2024 by improving farm irrigation.
Again, the plan has prominent critics. Peter Cosier, from the respected Wentworth Group of Concerned Scientists, says the amount of water to be recovered is insufficient to meet minimum needs. He says it is inconceivable that a government cannot fix a river with $10 billion on the table.
But Burke says he is not about to put anything off. ''In trying to get through your agenda in time you will very often have both sides of the debate agreeing delay is the option they want to take. And I think that it would be quite easy to keep the different sides of the debate marginally happy and actually achieve nothing.'' He won't, he says.
As the boat moves further into the Aurukun wetlands, he says: ''If you take everything right back to original motivations about why you want to be in politics in the first place, then you want to be in the decision-making role. You get involved in politics … to make changes real. It is the attempt to move beyond giving your political view over a cup of coffee and actually making them happen.''