‘Climate shifts’

Prominent local environmentalists weigh in on IPCC’s latest climate-change report

Chico State professor Mark Stemen, who is president of the Butte Environmental Council board of directors, believes that humans “are changing the climate … and it’s going to last a long time.”

Chico State professor Mark Stemen, who is president of the Butte Environmental Council board of directors, believes that humans “are changing the climate … and it’s going to last a long time.”


Read the report:
The Intergovernmental Panel on Climate Change has posted “Climate Change 2013: The Physical Science Basis” online; go to www.tinyurl.com/mwx3p2g to find it.

Jim Pushnik and Mark Stemen are friends, as well as friends of the Earth. They share a passion for environmental issues, and along with their responsibilities as Chico State faculty members, both have assumed leadership roles in ecological organizations. Pushnik is director of the university’s Institute for Sustainable Development; Stemen is president of the Butte Environmental Council’s board of directors.

So, it’s not surprising that both are deeply interested in the latest update from the Intergovernmental Panel on Climate Change. The IPCC recently released its fifth assessment report titled “Climate Change 2013: The Physical Science Basis”—comprising research and analysis of more than 250 experts from 39 countries. It follows up on the previous assessment, which came out in 2007.

After digesting the latest findings, Stemen and Pushnik came to the same overarching conclusion: The effects of climate change are so profound that a corresponding degree of human-activity change is not only justified, but also required.

As per usual, though, the friends disagree on how exactly to move forward.

Pushnik, a biological scientist, believes in evolutionary processes. He says making incremental adjustments is the best way to ensure lasting change.

Stemen, a professor of geography and planning, tends to favor bold strokes. From his vantage point, the environment has already sustained so much damage by our own actions that we shouldn’t get bogged down by what his colleague referred to as “argumentation paralysis.”

The two have spirited debates. In the end, however, they head in the same general direction, now further emboldened by the IPCC assessment.

“All fingers point to human activity,” Stemen said, “that we are changing the climate, and it’s not going to be good, and it’s going to last a long time. They [authors of the IPCC report] talk about how ‘a large fraction of anthropogenic climate change … is irreversible on a multicentury to millennial time scale’—basically, we may have already done so much harm to the Earth that it can’t even be undone in our lifetimes or the lifetimes of future generations. Yet we’re still doing it and we’re not even talking about stopping. That hit me in the gut.”

Pushnik didn’t have such a visceral reaction: “I don’t think that there is any real major message change from the fourth assessment.” He is eager, too, to see what the IPCC has to say about the social impacts of climate change and how to mitigate the effects, which will be covered in subsequent reports released over the next year.

Nonetheless, he agrees with Stemen that change—as far as a response from humankind to the rapidly changing climate—is going to come. Indeed, he indicated, it must come, and more quickly than seems possible amid legislative gridlock.

Polar bears are already being affected by melting sea ice.

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“The only way this ultimately gets resolved is through engaged, enlightened citizens,” Pushnik said. “I think every community should take personal engagement and leadership, as this town has. …

“My concern is that the process is too slow. We’re going to run up against a catastrophe, and then we will respond, no question. But what are the consequences of action later rather than proactive prevention now?”

The new report highlights a range of environmental impacts due to carbon-dioxide emissions—many relating to the waters that cover more than two-thirds of our planet. Fresh studies of receding ice packs in the Arctic and Antarctic regions have prompted the IPCC to double its estimate of how high ocean levels will rise by the end of the century—to 1 meter. Generating less attention, but just as compelling as ice-shelf melts, is the increasing level of acidity in bodies of water around the world.

“The pH of the oceans has dropped by—what to non-chemists will seem like an insignificant amount—about .1 pH,” Pushnik said. “In reality, that is a huge shift, particularly for shell creatures and those kinds of life that depend on the condition of the ocean for existence.”

The IPCC has also examined the effects of clouds on temperature, along with the impact of aerosols and smoke. In short, clouds tend to have a warming effect, and while smoke/ aerosols have a cooling effect, they are counteracting less warmth than was thought before.

The biggest controversy from the report stems from temperature levels. Critics, including climate-change skeptics, cite readings that don’t mesh with the models used by the IPCC report. Some dissenting scientists even postulate a “global-warming pause”: A recent study done at the Scripps Institution of Oceanography in San Diego argues that what some perceive as a recent decrease in global warming is the result of variations in the El Niño/La Niña cycle, not proof that global warming has ceased.

Stemen has a blunt reaction: “To challenge the credibility is just to beg for a different conclusion.”

Pushnik cautions against bestowing equivalency to each side in the argument: The leading group of scientists refuting man-made impacts on climate has a number of around 50, he says, while more than 1,000 scientists from around the world support the IPCC’s findings.

In addition, he said, “it’s easy to point at anomalous kinds of things. We see that certain glaciers are actually growing, which sounds counter to the whole argument. But that’s really a function of shifting climate conditions: Some areas are going to see differing precipitation than they’ve seen in the past.”

Same with temperatures—not every area follows an identical pattern.

“[The term] ‘global warming’ should die an easy death,” Pushnik said. “We need to talk about the reality of the situation, and that’s ‘climate shifts.’”

Both Pushnik and Stemen are pleased with local responses, particularly the Climate Action Plan developed by the city of Chico. Stemen, an appointee to the city’s Sustainability Task Force, says specific emissions goals in the CAP may warrant re-examination in light of the IPCC update, though this process—and the role the STF might play in it—remains uncertain in light of budget cuts, layoffs and reorganization at City Hall.

“The question isn’t necessarily if it’s happening or not—it’s ‘What are we going to do in response to it?’” Stemen said.