''It's clear to me environmental law is inherently informed by science.''
Prof Ruhl, of Vanderbilt University, and Oxford University law professor Dr Liz Fisher were keynote speakers at the Resource Management Law Association conference at the Dunedin Centre yesterday.
About 320 environmental law and resource management specialists and Environment Court judges from around New Zealand attended the three-day conference, which ends today.
Prof Ruhl said while there were many parallels between environmental law in New Zealand and the United States, there were also major differences.
The main difference was no overarching conservation law in the US, such as New Zealand's Resource Management Act (RMA).
Those laws had not been amended since 1990, but there was room for agencies to incorporate new thinking into their work, and ecosystem management had become entrenched in work around public lands.
However, as climate change pushed ecosystem change far beyond what the US had been used to, the traditional approach on preservation might not be viable, he said.
Prof Fisher suggested New Zealand needed to look at the RMA as a constitution.
Environmental problems could be described as ''hot situations'', as they were almost always controversial, involved many people, scientific uncertainty and social and political conflict, she said.
The RMA, like similar legislation in other countries, involved relationships across local, regional and national levels.
It dealt in both decision-making and dispute resolution and relied on ''soft law''.
Looking at the RMA as a constitution meant seeing it in terms of a set of principles.
While it might suggest a common ideology, it did not mean everyone had to agree, she said.
There were no clear, simple, solutions to environmental problems, Prof Fisher said.
Other consequences of looking at the RMA as a constitution were to leave it open to interpretation, and the need for it to be debated.
''Constitutions without debate and disagreement is a dangerous thing.''
However, to ''an outsider'', New Zealand appeared to have a rich discourse around its RMA and debate around it reached the highest levels.
