Roger Pielke Senior and Roger Pielke Junior share a name, a profession and a reputation. Both are mathematics-trained history buffs. Both ski and play golf as part of their active Colorado lifestyles. And both are prominent scholars in the highly polarized field of climate science, where their name can provoke much eye-rolling.

The elder Pielke, 59, is professor of climatology at Colorado State University and the state's official climatologist. The younger Pielke, 37, is an expert in science policy at the University of Colorado, with a bumper sticker that declares ‘Question Predictions’ in his office. Father and son share a proclivity for contentious, if polite, debate, and they both antagonize their colleagues more often than their affable exteriors would suggest.

Yet there are notable differences. Pielke Sr is a true climate hound, steeped in decades of research on atmospheric science. By contrast, Pielke Jr is a self-described policy wonk, who claims he simply hasn't inherited his father's obsession with the weather.

Junior does, however, have the famous Pielke tenacity, and has put it to use in the world of science policy. He caught the bug after interning on Capitol Hill in 1991, when his adviser Rad Byerly became the chief of staff for the House Committee on Science. Pielke Jr then returned to the University of Colorado in Boulder to finish his master's degree, with a thesis that calculated the true cost of a space shuttle launch.

He concluded that each launch cost just over $1 billion, contrasting with NASA's estimate of$400 million1. Shortly after his numbers appeared in a 1993 article in The New York Times, Pielke Jr took a call from an official at NASA's Johnson Space Center, who asked him to retract his conclusions about the cost. He said he gladly would, if the official could only pinpoint what exactly was wrong. The person never called back.

The incident, says Byerly, demonstrates the younger Pielke's coolness under fire. “He knows right where the jugular is,” says Byerly.

For his doctorate work, Pielke Jr turned to the stickiest problem he could think of. “I asked myself: what's the hardest possible evaluation problem that I could do, that's messy and involves politics?” In the early 1990s, the obvious choice was climate-change policy. And so he rigorously evaluated the US Global Climate Research Program, concluding that it was not meeting its mandate of providing useful information about climate science for decision-makers2.

In science, you should come up with ways to resolve a conflict, not ignore it. Pielke Senior

From that thesis arose an idea that Pielke Jr continues to push today, much to the discomfort of some climate scientists. He argues that the traditional relationship between science and policy, in which scientists do good science and hand the results to the policy-makers, is obsolete — particularly for complex modern issues such as stem-cell research and climate change. He advocates a two-way approach, in which policy-makers point scientists at the next set of questions to which answers would be useful.

In the example of climate change, Pielke Jr says, many researchers have taken one of two sides: backing either mitigation policies to reduce greenhouse-gas emissions, or adaptation policies to deal with climate change as it occurs. “One of the most important roles science can play is to invent new options and introduce them to decision-makers,” he says. “When scientists take sides, they are giving up that role.” He persistently challenges scientists who he thinks are acting as advocates for a particular position, including members of the Intergovernmental Panel on Climate Change and scientists who run a blog called RealClimate.

Look out for the next generation: the Pielkes study different aspects of climate change with a similar intensity. Credit: K. MOLONEY

“To be frank, that irritates the hell out of me,” says Gavin Schmidt, co-founder of the RealClimate site and a climate researcher at NASA's Goddard Institute for Space Studies in New York. “What he considers to be advocacy, to me, that's just interacting in the public realm.” Schmidt and Pielke Jr have never met in person, but have had heated exchanges in the world of blogs (see ‘From the atmosphere to the blogosphere’).