Uncommon Ground

Climate change

Climate change and biodiversity loss in the Cape Floristic Region

Jasper Slingsby is the lead author on a recent paper in the Proceedings of the National Academy of Sciences describing some of the work he, John Silander, and others did as part of our recently concluded Dimensions of Biodiversity project. Here’s the abstract. Follow the links below to find the full paper and a story about it in UConn Today.

Prolonged periods of extreme heat or drought in the first year after fire affect the resilience and diversity of fire-dependent ecosystems by inhibiting seed germination or increasing mortality of seedlings and resprouting individuals. This interaction between weather and fire is of growing concern as climate changes, particularly in systems subject to stand-replacing crown fires, such as most Mediterranean-type ecosystems. We examined the longest running set of permanent vegetation plots in the Fynbos of South Africa (44 y), finding a significant decline in the diversity of plots driven by increasingly severe postfire summer weather events (number of consecutive days with high temperatures and no rain) and legacy effects of historical woody alien plant densities 30 y after clearing. Species that resprout after fire and/or have graminoid or herb growth forms were particularly affected by postfire weather, whereas all species were sensitive to invasive plants. Observed differences in the response of functional types to extreme postfire weather could drive major shifts in ecosystem structure and function such as altered fire behavior, hydrology, and carbon storage. An estimated 0.5 °C increase in maximum temperature tolerance of the species sets unique to each survey further suggests selection for species adapted to hotter conditions. Taken together, our results show climate change impacts on biodiversity in the hyperdiverse Cape Floristic Region and demonstrate an important interaction between extreme weather and disturbance by fire that may make flammable ecosystems particularly sensitive to climate change.

Slingsby, J.A., C. Merow, M. Aiello-Lammens, N. Allsopp, S. Hall, H.K. Mollman, R. Turner, A.M. Wilson, and J.A. Silander, Jr.  2017. Intensifying postfire weather and biological invasion drive species loss in a Mediterranean-type biodiversity hotspot. Proceedings of the National Academy of Sciences USA (early edition) doi: 10.1073/pnas.1619014114

The new game of Russian roulette for fire-prone ecosystems, UConn Today, 17 April 2017

Climate change neoskepticism

Paul Stern and colleagues1 use the term “neoskepticism” to describe the view that although climate change is real and although humans are responsible for much of it, the costs of attempting to reduce or mitigate it exceed the benefits.

[N]eoskepticism accepts the existence of [anthropogenic climate change] but advocates against urgent mitigation efforts on various grounds, such as that climate models run “too hot” or are too uncertain to justify anything other than “no-regrets” policies as having net benefits. Mainstream climate scientists are well aware of uncertainty in climate projections. But neoskeptics’ citing of it to justify policy inaction marks a shift of focus in climate debates from the existence of ACC to its import and to response options.

The problem, of course, is that uncertainty is a double-edged sword. It’s possible that the impacts of climate change won’t be as bad as current (mean) projections, but it’s also possible that they will be far worse. Worse yet, the longer we wait to mitigate impacts, the more difficult and expensive it will be to prevent them. In response, they argue both for more attention to decision sciences and to the science of science communication. Both are certainly needed. But they also focus only on part of the science communication that’s needed, the part having to do with facts about costs, benefits, and risks of action or inaction.

As scientists, we pay too little attention to the emotional aspects of persuasion involved in guiding public policy, and here I’m not talking about appeals to “your children and grandchildren” or “our fellow creatures.” I’m talking about the emotions people feel when they think about scientists in particular or experts more generally, for example. Science communication is important even when it isn’t imparting facts or knowledge. In fact, it may be even more important when it’s not imparting facts or knowledge. It may be most important when it’s sharing scientists as caring human beings who can be trusted. Only if we are trusted will anyone listen when we share our insights with them.

1Stern, P.C., J.H. Perkins, R.E. Sparks, and R.A. Knox. 2016. The challenge of climate-change neoskepticism. Science 353:653-654. doi: 10.1126/science.aaf9697