The warrior who gave his life to climate change

Steve Schneider juggled with the dilemma of conveying the urgency of climate change, while conveying how we can be confident about that when the evidence is sometimes uncertain Credit: L.A. Cicero, Stanford University News.

Steve Schneider juggled with the dilemma of conveying the urgency of climate change, while conveying how we can be confident about that when the evidence is sometimes uncertain Credit: L.A. Cicero, Stanford University News.

  • This is part three of this profile. You can also read part one and two.

“Each of us has to decide what the right balance is between being effective and being honest.” Those are words – seemingly advising his colleagues to lie to shape public opinion – credited to climate scientist Stephen Schneider in a 1989 Discover magazine article. Because of that quote, Steve was told, a number of US congressional hearings chose not to invite him as an expert witness.

With extreme irony, it came from an interview where Steve was expressing frustration after having been misrepresented in the media. He later argued that he was trying to explain how to succeed faced with the “double ethical bind” of being effective and honest in conveying both uncertainty and urgency. Even in the original article he adds, “I hope that means being both” – something often overlooked in scandalised reactions to his words. But perhaps the trouble this caused Steve in fact reflects the strangeness of the idea he dedicated much of his career to getting across. How can scientific projections with an element of uncertainty lead to the conclusion that we must act on climate change urgently?

We’re instinctively uncomfortable with uncertainty, and so Steve wanted clearer ways to get it across in the UN Intergovernmental Panel on Climate Change (IPCC)’s second climate change assessment report. At a meeting in 1994 he pushed for their estimates to come as probability distributions showing the odds for each in a range of different values. This could be done, he argued, for everything from damage likely to be caused by global warming to values for numbers central to natural processes, like climate sensitivity.

With no-one backing Steve, ambiguity crept into the report. Did everyone think that saying they had “high confidence” in a statement meant the same thing? After the second report, returning to his recently-appointed post at Stanford University in California, he was determined to hammer out any doubt. Together with the IPCC’s Richard Moss, Steve found 100 examples of inconsistent use of such terms. Armed with that shocking finding they persuaded the IPCC’s working group I, which discusses the physics of climate change, to define clear scales.

The result would be a double strategy, with verbal scales both for the probability of a forecast and for the reliability of the underlying science. For probabilities, low confidence meant a less than 1-in-3 chance, medium between 1-in-3 and 2-in-3 and high 2-in-3 and above. Very high confidence meant a 19-in-20 chance, and very low confidence 1-in-20. There were four grades for the quality of science, ranging from ‘speculative’ to ‘well established’. Reading through thousands of draft pages ensuring consistency in the run-up to the IPCC’s third report, published in 2001, Richard and Steve became known as the ‘uncertainty police’. Read the rest of this entry »

Projected warming set to exceed civilisation’s experience

Oregon State University's Shaun Marcott has built a climate record reaching back 11,300 years, showing that today's temperatures are warmer than at least 70% of that period. Credit: Shaun Marcott

Oregon State University’s Shaun Marcott has built a climate record reaching back 11,300 years, showing that today’s temperatures are warmer than at least 70% of that period. Credit: Shaun Marcott

The world is headed for average surface temperatures warmer than it has seen in at least 11,300 years. That’s one conclusion US researchers have reached after bringing together 73 studies of ancient climate from across the world into a single global record. Their work supports previous records for the past 2,000 years built mainly from tree ring data, explained Shaun Marcott from Oregon State University, and gives a much broader view.

“We can put today’s global temperature into context against the entire Holocene period,” Shaun told me. “That’s when human civilisation was born, developed and progressed to today.” Modern temperatures are higher than in around three-quarters of that period, which reaches back to the end of the last ice age. And their comparison against forecasts for 2100 made in models used by the Intergovernmental Panel on Climate Change (IPCC) is even starker. “If those scenarios come to fruition, we’ll be well outside anything human civilisation has seen,” Shaun warned. “We won’t have even have been close.”

Knowing climate’s history helps understand its present, and so researchers have puzzled out temperatures on the Earth’s surface from proxy, or indirect, records for the last 2,000 years. In particular, bringing together measurements from tree rings, ice and coral has showed a sharp recent temperature rise often referred to as the ‘hockey stick’. Meanwhile, studies scattered across the world had reached back across the 11,300 years since the beginning of the Holocene. But they can be influenced by regional effects, and no one had pieced them into a global view that would overcome that. Read the rest of this entry »

Volcano cloud over tree-ring temperatures clears

Pennsylvania State University's Michael Mann thinks he has found the reason behind key outstanding disagreements between the historical temperature record based on tree rings and climate models for the same period. Credit: Pennylvania State University

Pennsylvania State University’s Michael Mann thinks he has found the reason behind key outstanding disagreements between the historical temperature record based on tree rings and climate models for the same period. Credit: Pennylvania State University

The sudden chills violent volcano eruptions cast over the world centuries ago effectively erased themselves from the historical climate record produced by examining tree-rings. So suggests a team led by Michael Mann from Pennsylvania State University, who famously used 1,000 years of tree-ring measurements in the “hockey stick” graph showing how unusual today’s temperatures are. Michael warns the skipped years could affect scientists’ estimates of how much the world warms in response to greenhouse gases in the atmosphere, known as its climate sensitivity. But other than the volcano years, the scientist notes that tree-ring data is a remarkably accurate match with the climate models they used for comparison. “Interestingly, the effect has little influence on long-term trends, including conclusions about how previous temperatures compares to modern ones,” he told me. “Instead, it appears only to have implications for how strong past short-term cooling events were.”

A tree’s age can usually be told from the rings that form across its trunk representing each year’s growth. How thick each ring is shows how much the tree grew in the year in question, which is influenced by the temperatures that tree experienced. That means examining the thickness of rings in old trees can provide a way to tell temperatures back through history. Many challenges have already been overcome in turning this simple-sounding idea into a history of the world’s temperature, but Michael was still troubled by one particular detail. Read the rest of this entry »

Inquiry clears US Climategate researcher of falsification, questions “conduct of science”

The Michael Mann 'hockey stick graph' incorporating tree rings to calculate temperatures since 1000AD in the Northern Hemisphere. Credit: IPCC

Penn State University’s inquiry into Michael Mann has dismissed widespread claims that he made up climate measurements, deleted information, or misused his position. Mann, whose emails were among those published in the University of East Anglia (UEA) leak, is however to be investigated further by a panel of Penn State researchers. Five scientists from a range of different subjects will examine whether how Mann proposed, did, or reported research differed from what is expected of an academic.

A first committee of senior university management suggests that doubts about how Mann has done his work “may be undermining public trust in science in general and climate science specifically.” Although Mann was cleared by a similar US National Academy of Sciences investigation in 2006, the University’s leaders say that the emails give a new insight into how he works that needs more attention. They have set up the second, five-strong, committee to do just this within 120 days.

Despite this, the February 3 report disagrees with those criticising the work of Mann and others on the basis of the word “trick” used in what it calls “purloined emails”.

“There exists no credible evidence that Dr. Mann had or has ever engaged in, or participated in, directly or indirectly, any actions with an intent to suppress or to falsify data. The so-called “trick” was nothing more than a statistical method used to bring two or more different kinds of data sets together in a legitimate fashion by a technique that has been reviewed by a broad array of peers in the field.”

Another key concern to come out of the Climategate emails surrounds the suggestion of the UEA’s Phil Jones that Mann and others delete emails. Henry Foley, vice president for research at Penn State therefore requested that Mann provide him with all emails related to the fourth report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). Mann duly provided a zip file containing these emails, leading the committee to conclude:

“There exists no credible evidence that Dr. Mann had ever engaged in, or participated in, directly or indirectly, any actions with intent to delete, conceal or otherwise destroy emails, information and/or data related to AR4.”

The third accusation not to be investigated further is that Mann and other climate change researchers had early access to research papers that they disagreed with, and prevented their publication. The committee asked what papers were involved, it found enormous confusion over the interpretation of the emails supposedly showing this. Some referred to papers written by the researchers themselves, but were not yet published as they were under embargo, a common situation in academic journals. Others referred to papers that were published, but that they disagreed with.

“The committee found no research misconduct in this,” the report says. “Science often involves different groups who have very different points of view, arguing for the intellectual dominance of their viewpoint.”

Mann himself responded to the report:

“This is very much the vindication I expected since I am confident I have done nothing wrong. I fully support the additional inquiry which may be the best way to remove any lingering doubts.”