Scientific truth is not established by poll results, but scientists’ consensus on scientific issues can tell us a lot. It does not tell us what optimal policy should be – that depends on costs and benefits. While scientific consensus tells us that approved vaccines are safe and wonderful, whether vaccination should be mandatory is not really in scientists’ remit. Science provides us the is; moving to the policy ought takes a different kind of work.

The scientific consensus on vaccine safety is strong enough that 86 percent of members of the American Association for the Advancement of Science (AAAS) recently said that childhood vaccination should be mandatory. That does not make the case for mandating vaccines, but it does suggest the policy debate should not start with presentations from anti-vaccination activists.

Last weekend, Te Papa hosted a conference on food safety and nutrition with an emphasis on genetically modified (GM) foods: Food Matters Aotearoa. The scientific consensus on this one is also very strong: the same survey of scientists also found 88 percent agreement that genetically modified foods are generally safe to eat.

And so a proper informative discussion would begin with that baseline scientific consensus, then address the potentially more useful aspects for policy. For instance, do our regulations around field research trials unduly hinder GM research into agriculture and forestry? Can protectionist trade action in countries with non-science-based fears about GM organisms be averted if New Zealand allows greater use of GM? Does GM has any potential for reducing agricultural methane emissions through improved pastoral systems?

Instead, the Te Papa conference keynote presentations come from the scientific fringes where genetic modification techniques are seen as scary and dangerous. SciBlogs, the blogging initiative of the Royal Society’s Science Media Centre, rounded up the evidence, with Dr Alison Campbell and Grant Jacobs demonstrating that the keynote addresses were well outside the mainstream consensus.

So what? Fringe movements should be able to have their own rallies, right? Freedom of speech is important and so too is academic freedom. But this conference was backed by Wellington Council, with a statement of support from Mayor Celia Wade-Brown. And the Greens’ Steffan Browning hosted an event in Parliament featuring many of the keynote speakers; they described it as a “broad discussion on food safety in New Zealand.”

But the scientific consensus is already well established: genetically modified foods are safe. Framing it otherwise misrepresents the underlying consensus, fuelling populist fears rather than informing policy debate.

Scientists’ consensus is not always right, and it is incredibly important that academia remain a strong and safe home for dissenting views. But officially endorsed conferences playing to populist fears do us a disservice.