Why do Trout Unlimited scientists study climate change?

Occasionally, those of us on Trout Unlimited’s Science Team receive letters asking why we study the potential effects of climate change on trout (we also study lots of other things, by the way). Trout Unlimited has very diverse membership—that’s one of our great strengths—and while some members are very concerned about climate change; others regard it with great skepticism. We wanted to take a moment to explain why we work on this issue.

The mission of Trout Unlimited is to conserve coldwater fisheries and their watersheds. At the heart of this mission is cold water: all trout and salmon need it, though different species have different temperature requirements. In recent decades, however, air and water temperatures have been warming up, especially in the Rocky Mountain West where a lot of us live and work. There are still warm years and cold years, but if you look back at the temperature records it’s obvious that there are a lot more warm years than there used to be, and some recent years have been exceptional. This trend is bad news for trout.

Rising temperatures have many important consequences. Wildfires are increasing in the West and large storm events are more common in the East. Are these changes at least partially linked to climate change? Many scientists think they are. As temperatures rise, forests dry sooner, creating more tinder for fires while more energy is carried in storm systems. Certainly these processes are having substantial impacts on trout, as wildfires swept through major portions of the Apache, Gila and Lahontan cutthroat ranges in the past few years and major floods in the Northeast have caused local and state governments to mistakenly channelize some high quality brook trout waters.

If Trout Unlimited is to be successful at its mission, we need to plan for a future with higher temperatures, and strategize the most effective ways to help trout and salmon cope with this. On the science team we ask questions like, “how will trout distributions change as warming continues?”, and “are there places where restoration can help keep stream temperatures cool?”, as well as “how can we reconnect and restore populations to increase their resilience in the face of changes like wildfires, droughts and floods?” We hope that the answers to these questions will prove useful to our chapters and to our partners who manage trout populations.

Maybe we’ll get lucky and temperatures will stop increasing. Frankly, we think that would be great. We study trout because we like trout, just like you do; none of us wants to believe in global warming, because the implications are scary. But as scientists we need to consider the evidence, which at this point shows temperatures already have increased substantially and suggests they are likely to go even higher in the future. And we are not a minority in thinking this way: 97% of US scientists agree that climate change is occurring. Although not every climatologist believes that warming is caused by humans, over the years more and more have concluded that human activities play a substantial role (you might want to read this article written by one former scientist skeptic: The Conversion of a Climate-Change Skeptic [1]). Of course, the fish couldn’t care less about causes.

Skepticism is one of the foundations of science, and we respect people’s skepticism about the causes of climate change. As good scientists, we remain skeptical as well, and open to considering alternative ideas as to whether climate will continue to change and what is causing it. In the meantime, though, we wouldn’t be doing our jobs properly if we didn’t think about what climate change could mean for coldwater fisheries.

Finally, the management activities that help offset future climate impacts are the same things that improve trout habitat right now. We don’t know of an angler who wouldn't support protecting the most important habitats; reconnecting them to adjacent areas through improved in stream flows and eliminating barriers; and restoring areas where we'd see the highest fish return on investment. Whether we do that because it happens to be good climate change adaptation strategy or because it leads to better fishing isn’t terribly important. The important thing is that we do it.