The Force That Through the Green Fuse Drives the Flower

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I've been interested lately in how ecology and science generally can interact with art and produce some beautiful and thought-provoking images. These phenological clocks from The Environmental Health Clinic are extremely cool. They show the timing of different phenological events (like budburst or first leaves falling) in various species for lots of different cities around the world*. It conveys really well, I think, the complexity of timing of different events that determine seasonal cycles. If we could see these clocks play out over time, it would be interesting to see not only how the timing of events changes in response to climate, but how the relative timing of events can shift.

The relative seasonal timing of things like snowmelt and peak growing season, for example, can be critical to ecosystem functioning. When snow melts too early in the boreal forests of North America, the runoff is transported or evaporates before the peak of the growing season. As a result, trees are less productive because there isn't enough water to support the creation of more biomass through photosynthesis. 

The timing of annual as opposed to hourly events creates a "longer clock" and allows us to "see" things that move too slowly for us to observe directly. The idea of a long now is a helpful one, I think, in determining where our priorities should lie. Long term ecological research sites, where observations can be made continuously over decades or longer, can provide the information we need to support the long-term perspective. Long-term, continuous observation datasets, like the famous Keeling observations from Mauna Loa, are extremely important in understanding humans' impact on the environment. Long-term observations can also come from things that naturally preserve information about the environment over long periods of time, such as ice cores or tree rings.

It's an opportunity to remember our limitations in being able to observe our surroundings. The biggest aim of science, I think, is to continually broaden our vision, and collaborations with artists can evoke that sense in scientists and non-scientists alike.

*You can submit your own observations to Nature's Clock, used to create the phenological clocks, here.

Skepticism and the Creation of Knowledge

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As someone who researches high northern latitude ecosystems, the fastest-warming part of the planet, I think it's important to be clear about what we know and what we don't know about the effects and causes of climate change. It's extremely important to listen mainly to climate scientists when we're talking about climate, and I'm not one. But I'd say my work is climate-relevant*. The coupled earth-atmosphere system is so mind-bogglingly complex that I don't think anyone can claim to understand the whole of it. There are checkerboards within checkerboards within checkerboards of complexity, and how climate change itself affects climate change (or "feedback effects") is one of the most difficult questions to answer. As scientists, we chip away at these problems one research question at a time, inevitably yielding more questions in the process. It's incredibly humbling to realize how little each person can do on their own, and it points to the need to work in teams and across disciplines, to promote collaboration wherever it may be fruitful.

Studying the effects and causes of climate change can be a fairly charged environment. First there is the urgency of the problem, the sense that time is slipping away from us and we're courting serious hardship by failing to meet our climate targets (or that the targets themselves are inappropriate). Then there's the issue of uncertainties in our models and forecasts that must be explicit and understandable to people from a non-scientific background. There known unknowns, and unknown unknowns, both of which fall under the umbrella of "uncertainty". We also acknowledge that there are sometimes massive changes that we're seeing that are not solely a result of climate (e.g., glacier losses on Kilimanjaro), those that don't feedback to climate, or those whose climate feedback is unknown or even the opposite of what one might think (e.g., cutting trees and burning forests may serve to cool the climate). We've made a lot of progress towards determining what is and what is not an effect of climate change. But scientists have to be comfortable not possessing the answer to every pressing question. It's really an encouragement to us, a form of job-security.

Philosophically, scientists are (ideally) those most skeptical of their own ideas. We know that the human brain can be a pretty unreliable source (pareidolia and all that), and we have to rough up our ideas a bit to make sure they're sound. Ideally, that's how the scientific peer review process works. We acknowledge that there are always multiple explanations for a single event, and determining causality is a sticky wicket. One of the good things about a fiercely competitive research environment is that the ideas we put forward had better be defensible (sometimes we say "falsifiable", also "reproducible") so that they can withstand the scrutiny of our peers.

*Looking at fire disturbance-recovery cycles is the area of research that I'm involved in that affects and is affected by climate. This is especially true for boreal fires.

Monitoring Climate From Space MOOC

Here is quick heads up about a MOOC about Monitoring Climate From Space I participated in that was put together by the European Space Agency (ESA). There are some great presenters on the course, which lasts five weeks. They filmed my bit in Cambridge, where I got to meet them at the British Antarctic Survey, which was very cool. Then we went outside to film me talking about forests and carbon and remote sensing (oh my!). The course is geared towards policy-makers, so it's quite accessible, but it's also broad-ranging enough to likely be of interest to PhD students (or super-keen undergrads!). The next round of the course starts next Monday. If you take it, let me know what you think.

Forest Losses from Fire in Siberia

So I've been granted some funding by the UK Natural Environmental Research Council (NERC) to study Siberian forests that don't recover after a fire. Boreal wildfires have received some press attention lately, namely because of the Fort McMurray fire in Canada earlier this year. Wildfires can be fairly costly when they affect areas of human settlement, but very often they don't, and thousands of square kilometers can burn each year without much reporting in the press.

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One of the reasons we often don't worry about such big fires is that they are a natural part of boreal ecology. Boreal forests have adapted to fire disturbance and some boreal species even depend on fire for reproduction. It's true that fires emit carbon, in the form of several greenhouse gases, to the atmosphere. But when forests re-grow after a fire, they take carbon back out of the atmosphere. If the forest returns to its pre-fire conditions, there is no net increase in atmospheric carbon as a result of the fire. So if fires release carbon, and forests that grow back take it up again, why worry about fires at all? Well...

The first problem is that forests often don't return to their pre-fire conditions. Things that affect a forest's ability to grow back include fire severity (which may destroy seeds or allow them to germinate), herbivory (animals eating up recovering plants), and climate/weather conditions (that can help or hinder re-growth). Recovering forests can be different from their pre-fire condition in terms of tree density or species, and this can cause differences in the amount of carbon stored in the new forest (and of course, how much remains in the atmosphere). And it's not just differences in carbon, there's also albedo, or how much of the sun's radiation is reflected back into space without warming up the planet. Some darker trees, such a needleleaf evergreens absorb more heat, just like wearing dark colors on a sunny day. So if a conifer forest is replaced by a light-colored species, the climate effect could be a cooling one!

This NERC project I'll be working on is looking at the most dramatic type of change post-fire, where the stand doesn't come back at all. These areas are replaced with steppe, or grassland, so there's definitely less carbon being stored in the new ecosystem. We don't know yet exactly how often this occurs or why, or what the climate effect will be, but that's what we plan to study over the next few years.