Eighteen top news executives, representing some of the nation’s leading metropolitan daily newspapers and other news organizations, met all day September 5, 2007 at Stanford University with nine leading climate scientists and researchers. Their goal: to better understand the physical science underlying many scientists’ growing concerns … and to explore the energy and economic implications involved with potential “solutions.”

The morning session of the September 5 news executives roundtable on covering climate change focused principally on the physical science evidence underlying most climate scientists’ conclusions on the subject.*

Morning discussions focused on how glaciers and plants and animals around the world are reacting to a warmer world. From there, the discussion turned to mounting evidence of a human “fingerprint” in the warming.

View the Slideshow
Slideshow with scenes from
the September 5 Roundtable

Ohio State University’s highly respected glaciologist Lonnie Thompson, a 2007 winner of the National Science Foundation’s National Medal of Science, provided a series of time-scale photographs and images illustrating accelerated ice loss and showing evidence for abrupt climate change, past and present.

One of the world’s leading ice core experts, Thompson told the editors that ice cores provide unique historical insights from remote regions of the world, recording greenhouse gases and changes in Earth’s atmosphere going back 650,000 years.

He said scientific evidence shows carbon dioxide concentrations in the atmosphere “going through the charts,” with a potential for significantly changing the planet’s geography over the next century. With evidence of warming being manifested first in the north and then moving southward, Thompson said, polar regions have shown a high breakup of ice shelves. He pointed to a doubling of the speed of retreat of West Greenland’s Jakobshavn ice stream between 2000 and 2003, reaching the stage of “great urgency” since then. He said that contrasts with the period from 1953 to 2000, when the ice stream was stable (see Thompson’s “Evidence From Observations of Glaciers and Ice Sheets” – pdf).

Nature as the ‘Time Keeper’

Arctic Sea ice, according to Thompson, had rebounded somewhat in 2006 from a record low the previous year, but he said 2007 is likely to set new records for loss of sea ice. The significance of that? It’s not in sea level rise: loss of sea ice, as opposed to land ice, doesn’t markedly add to sea levels. Rather, the concern involves the albedo effect: less sea ice means less solar energy from space is reflected back to space, leading to more warming.

“History is very important for putting things into context,” Thompson told the editors. “You can actually see how glaciers have behaved …. Nature is the time keeper. It really doesn’t matter what any of us think. It only matters what’s actually happening.”

Asked by Leo Wolinsky of the Los Angeles Times the cause of the accelerated loss of glaciers, Thompson replied that most scientists point to increased greenhouse gases as the “big driver.”

Thompson responded to San Francisco Chronicle editorial page editor John Diaz’s question about the scientific community’s overall sense of all this.

“The projections are born out by what’s actually happening,” he replied. “All we have to do is look at the real world. In the end, the evidence has become stronger.”

Animals ‘Don’t Have Political Agendas’

With Thompson discussing how glaciers are reacting to a warming world, the responsibility fell to Stanford University scientist Terry Root to tell editors how another harbinger – plants and animals and, in particular, birds – are responding.

“Animals don’t have political agendas, they’re doing what they’re doing,” Root began. She cautioned against assuming we humans can accurately predict or anticipate ramifications when one or more animal communities undergoes change.

As an example, Root pointed to a time 150 years ago when there was “a pretty even relationship” among wolves, foxes, and coyotes in the Great Plains states. When humans moved against wolves, the coyote population climbed, and when they then moved against coyotes, out came more foxes.

“Surprises like these are occurring with climate change,” she said. The uncertainties arise because one species may migrate to a more ideal environment – for instance one requiring a lower expenditure of their energy – more quickly than another species. Is that a problem? It could if Species B’s migration allows a dependent species to flourish or perish. Is it a predator or a prey that is prompted to migrate elsewhere because of a warming world?

“I’m most concerned about tearing apart of communities and damaging interactions between species,” Root said. She pointed to habitat destruction and climate change as both contributing to the challenges facing established species.

Which one is more important?, The Des Moines Register‘s Carolyn Washburn wondered. Root said habitat destruction is important, but impacts of global warming are escalating. “The rate of change is the most frightening part,” she said, cautioning that some species simply cannot adapt quickly enough and may therefore face extinction.

Root pointed to a conclusion from the 2007 Intergovernmental Panel on Climate Change Fourth Assessment Report cautioning that a global increase of 4 degrees Celsius would “earmark” more than 40 percent of known species for extinction.

Why Warming? A Human Fingerprint?

So if the scientists addressing the editors have a sense of what is happening, did they have insights also on why it is happening?

Addressing that question was the responsibility of Lawrence Livermore National Laboratory physicist and atmospheric scientist Benjamin D. Santer.

Santer explained to the editors two steps in the decision process:

  • detection, the process of showing observed change is unusual in a statistical sense; and
  • attribution, doing the testing and cause-and-effect analyses to figure out why climate change is taking place.

Santer told the editors that scientific understanding of the climate has advanced to the point that there is “certainty” about a human hand in climate change. In doing so, he acknowledged three naturally occurring mechanisms influencing climate change:

  • changes in the Sun;
  • volcanic eruptions and dust; and
  • internal variability of the coupled atmosphere-ocean system.

Even without any human input, some climate change would occur as a result of those natural mechanisms, Santer said.

But in addition to those, he pointed to three human activities as also contributing to climate change:

  • changes in atmospheric concentrations of greenhouse gases as a result of the combustion of fossil fuels;
  • changes in aerosol particles resulting from the burning of fossil fuels and biomass; and
  • changes in reflectivity (the albedo effect) of the Earth’s surface.

The challenges lie in separating the effects attributable to natural factors from those occurring as a result of human activities, Santer said.

“This is not some mad scientists’ figment of the imagination,” Santer advised. “You can see this stuff …. We’ve transformed the surface of the Earth. You can see these things from space, and not all of them are natural.”

Santer said current concentrations of carbon dioxide in the atmosphere by far exceed the natural range over the past 650,000 years.

Based on the averages from a wide range of authoritative model simulations, Santer said, the rapid warming of Earth’s atmosphere cannot be explained based solely on natural influences.

He pointed to “multiple lines of evidence” supporting the conclusion of a discernible human influence on the changing climate: basic evidence of physics and physical understanding of the climate system; documented changes; paleoclimate evidence over the past century in particular; and “fingerprint” evidence from oceans and ice records.

“Natural factors alone don’t cut it,” Santer told the editors. “They can’t explain the observed climate changes we actually see in the atmosphere and the oceans.”

Santer pointed to another area of potential concern: He said water vapor in the atmosphere has been increasing substantially since the late 1980s. Water vapor is itself a potent greenhouse gas, Santer pointed out, and the increased concentrations cannot be explained based solely on natural factors.

Santer concluded his presentation by describing to the news executives what the scientific community “knows” and “what we don’t know very well.”

The “Knowns”

Human activities have changed the chemical composition of Earth’s atmosphere. Carbon dioxide concentrations have increased substantially, more than can be explained by natural variations alone.

Earth’s surface has increased by about .74 degrees Celsius (about 1.35 degrees Fahrenheit) over the past century.

The 20th Century is probably the warmest over the past two millennia.

There is a human “fingerprint” in numerous aspects of climate change.

The story being told by the climate system is “internally consistent.”

“What we don’t know very well”

How much warmer might the Earth be by 2100? How will the carbon cycle respond to and influence climate change?

How will hurricane intensity and frequency be affected?

How rapidly will the ocean’s “conveyor belt” circulation respond to climate change?

What level of temperature change will we associate with “danger”?

Forget about the status quo when it comes to the Earth’s climate, Santer advised. It’s too late for that. “We are irrevocably changing the climate.”

Most likely is a change in the range of 2 to 2.5 degrees Fahrenheit in mean temperature by 2100, Santer said, assuming “business as usual” and relative to the 1990 mean temperature baseline.

“We’re seeing these changes before our eyes,” he concluded. “It’s tremendously sad to me that my son and other children will not experience certain areas in the same ways that we have.”

Asked by Detroit Free Press Executive Editor Caesar Andrews if credible scientists might challenge his perspectives, Santer said there is “still some debate about details,” but he said there is “no debate amongst credible scientists that humans have changed the composition of Earth’s atmosphere by the burning of fossil fuels. No credible scientist is debating that.”

Schneider’s Seatbelts/Climate Change News Metaphor

It fell to charismatic Stanford scientist Stephen H. Schneider to play clean-up hitter following those opening hits from his science peers. Schneider began by referring the editors to his own extensive “Mediarology” web site specifically focusing on journalism and communications.

He asked, if the editors think, based on the presentations they had just heard, that “the science is settled.” He said environmentalists appear to generally suggest the answer is “Yes,” professional skeptics that it is “No.”

In fact, it was his rhetorical question, he teased, emphasizing that it is too broad to be answered with a yes or no response. What science? What part of the science?, he demanded.

Journalists watching a professional meeting of climate scientists would see them “carving each other up” over areas of real uncertainty, Schneider said. But not about what he considers established science.

“We can do better about public education” on how science works, Schneider urged the editors.

He pointed to an example he thinks relevant to the warming earth/human role issues:

A personal freedom advocate argues seatbelts are harmful to human life. The individual “chases ambulances” and finds 18 cases in which they contributed to the death of an occupant of a car, and, with 18 good sets of data, calls a press conference in which he seeks to “falsify” beliefs that seat belts save lives. The individual disregards some 1,800 cases in which seatbelts saved lives.

Should the media cover that press conference, report on it?, Schneider asked.

“When people go in and pluck out small bits out of thousands, why is that given equal space and time?” he asked. “Even if the time is not equal, it’s been way out of proportion.

Schneider says drug studies might be just as well challenged on the basis of findings from herbalist societies.

To Schneider, an important point for the editors to keep in mind: the science is driven by the preponderance of evidence. He pointed to the finding in the 2007 IPCC report that global warming of .75 degrees C (about 1.35 degrees F) is “unequivocal.”

“This is an unbelievable word for scientists to use,” he said. “The science is very settled.” So too is the attribution of an important part of that warming to humans, he said.
Schneider said the best scientists actually are “fans of uncertainty.” That continued warming is inevitable is certain, he said. The exact implications and the best adaptive responses leave “plenty of work to be done,” Schneider told the editors.

He repeated to the editors a point he no doubt has made often to many of their own science and environmental reporters: Beware of scientists speaking of climate change without error bars and with certainty. Those may be sure signs that there’s more behind their words than just sound science, Schneider cautions.

*This is the first of a two-part series on a September 5, 2007, news executives roundtable held at Stanford University at the start of the annual conference of the Society of Environmental Journalists, SEJ. The second part of this series is published here.

Bud Ward was editor of Yale Climate Connections from 2007-2022. He started his environmental journalism career in 1974. He later served as assistant director of the U.S. Congress's National Commission...