Last week, over 20,000 Earth scientists gathered at the annual American Geophysical Union (AGU) fall conference. They shared their scientific research, ranging from identifying the causes of past climate changes, to estimating the risks of the changes we’re causing now, to how we can successfully communicate the need to mitigate those risks.
Richard Alley (the host of Earth: the Operator’s Manual) summarized the scientific community’s consensus about the threats of abrupt climate change from various potential “tipping points.” Scientists aren’t too worried about a huge methane burp from the ocean or shutdown of the thermohaline circulation (which would cause dramatic cooling in Europe) happening anytime soon. On the other hand, a collapse of the West Antarctic Ice Sheet and large associated sea level rise are becoming increasingly worrying.
This tied into paleoclimate research presented by Aaron Goldner. Atmospheric carbon dioxide levels were at similar levels to today’s (400 parts per million) 15 million years ago during the mid-Miocene period. However, the Earth’s climate was very different. Geologic records give us estimations that sea levels were 25–40 meters higher than today, global mean temperatures 3–6°C hotter, and there was very little sea ice relative to today.
As Goldner and colleagues showed in a 2013 paper, climate models couldn’t reproduce that hotter climate very well; especially the extreme heat at the poles. However, the Community Atmosphere Model his team used was recently improved, in particular to better simulate cloud properties. Goldner showed that this newer version, which is more sensitive to the increased greenhouse effect, more accurately reproduces the high global and polar temperatures during the mid-Miocene. The difference is that in the newer simulation, more clouds form at the poles, trapping heat, causing the sea ice to melt.
Today, we’re already seeing Arctic sea ice vanish at an alarming rate. The worry is that we may be approaching a tipping point that kicks us into a climate regime with significantly less ice, higher sea levels, and hotter temperatures, like the mid-Miocene or mid-Pliocene when atmospheric carbon dioxide levels were similar to today’s, but for an extended period of time. We’re on the verge of entering a hot climate state not seen in tens of millions of years.
There were many AGU talks about the climate impacts we’re already seeing. For example, human-caused global warming is amplifying many types of extreme weather like drought, heat waves, and storms. There’s uncertainty about just how bad these impacts will get, and how fast. Stephan Lewandowsky gave a talk discussing the problem that although more uncertainty translates to greater risk and urgency, people perceive the opposite. People often think we don’t need to act until uncertainty is gone, but that means letting the problem get worse in the meantime. As Andrew Dessler said in one of his AGU talks,
Uncertainty is the hammer policy advocates use to smash scientists over the head.
Climate and social scientists have struggled to communicate this urgency to the public. While most people accept that humans are changing the climate, few understand the urgency of mitigating these risks. This is particularly a problem for ideological conservatives.
Among social scientists, a consensus is forming that more climate-specific knowledge translates into greater acceptance of the science and support for mitigation. However, facts are more effective when ideological barriers are first weakened. For example, conservatives are more likely to accept the science when presented with free market solutions, as opposed to government regulation.
Scientists John McCuin, Katharine Hayhoe, John Cook, Daniel Bedford, and Scott Mandia reported success in climate education through misconception-based learning. People form mental structures of the world, and debunking a misconception can leave a gap in those structures. As it turns out, people would rather have a complete but incorrect understanding of the world than an incomplete but more correct understanding. Thus, the most effective education and communication must explain why a person’s misconceptions were formed and why they’re incorrect, replacing the mental gaps with factually correct information.
In April 2015, the University of Queensland will be hosting a free online course (MOOC) taking this approach to teaching climate science. At AGU, my colleagues and I recorded many lectures for that MOOC, and John Cook interviewed a ‘who’s who’ list of climate rock stars. In those interviews and during other talks and events, I heard about the attacks many climate scientists have faced for having the temerity to do their jobs.
Ben Santer was attacked for summarizing the evidence behind how we knew humans were driving global warming in the 1995 IPCC report. Michael Mann and Malcolm Hughes spoke of the incessant attacks they’ve faced since publishing their “hockey stick” study over 15 years ago (a result since replicated dozens of times). Katharine Hayhoe (quite possibly the nicest person on Earth, and one of the most influential) was attacked for writing a chapter about climate change for a book Newt Gingrich was writing. Naomi Oreskes, for publishing the first study in 2004 on the climate consensus.
My colleagues and I got a taste of those attacks after we published our follow-up consensus study last year. Fortunately, as Mann and Hayhoe and others noted in a terrific climate science communication session that I had the privilege of speaking in, they’ve borne the brunt of the storm. Young climate scientists today can do their research and communicate with the public with less threat of being attacked, thanks to those groundbreaking individuals and groups like the Climate Science Legal Defense Fund.
As Katharine Hayhoe pointed out in one of her AGU talks, our infrastructure and society are constructed based on the assumption of a stable climate, but we’re in the process of destabilizing it. We’re not doing enough to protect our investments, security, or future well-being.
Andrew Weaver spoke about his decision to shift from science to politics, quipping,
We need evidence-based decision-making. What we have is decision-based evidence-making.
Similarly, Aaron Goldner started working for Senator Sheldon Whitehouse after finishing his doctorate in paleoclimate research. He told me,
Posted by dana1981 on Tuesday, 23 December, 2014
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