Sunday, September 22, 2013

Climate Change Workshop, part 6.

The climate change workshop for teachers, sponsored by Oklahomans for Excellence in Science Education (OESE) and the Oklahoma Climatological Survey continues this morning.

The first two presentations were about phenology. Phenology is the seasonal pattern of biological processes: the time of year that trees burst their buds, that animals hibernate or migrate, etc. Phenological data are particularly valuable to a study of global warming because the organisms integrate many physical factors. How do you measure temperature? Average maximum temperature? Average minimum temperature? Threshold temperatures? But you can let the organisms themselves do the measuring. If global warming causes winter to be shorter and warmer, and spring to come earlier, perhaps the best way to measure this is to quantify the budburst date of deciduous trees or the flowering date of herbaceous plants.

I was the first presenter. I had enough time for some introductory perambulations. I told them where they could get more information about my work. And I reported what some of us had talked about over breakfast: what needs to be done to prevent global warming? My conclusion was that there was no single thing that could be done. Denialists like to consider each proposed solution--alternative energy, energy efficiency, etc.--and say that each of them are insufficient to solve the problem. They pick off each solution individually, without considering that the combined efforts on all of these things may solve the problem. But in order for us to do all of these things, we need a whole new attitude: we need to desire to be frugal with our use of resources, to recycle, to drive smaller cars. It requires a change of attitude. We can model these attitudes to people around us, many of whom may began imitating us (when they see that we are doing these things joyously) or at least no longer considering us to be quite as weird as they might have previously. But even more fundamentally, we need to think of ourselves as caretakers rather than owners not only of the Earth but of everything, even sheets of paper or plastic bottles. They are not ours to use as much as we wish; we are only the stewards of these "resources." This attitude is expressed well in the musical Nanyehi, which is based on the life of the Cherokee leader Nancy Ward (my ancestor). A white man from South Carolina tried to claim some Cherokee land, and he had the piece of paper from the colonial government of South Carolina to prove that he was the owner. When some Cherokee warriors found him, they were astonished that anyone could own land. They sang, in the musical, "This land is not our land/We're only passin' through/It don't belong to us/It don't belong to you!"

I told the group about my work with spring budburst of 22 Oklahoma deciduous tree species. Most of these species opened their buds earlier, some as much as 2 days earlier per year (compared to the typical pattern of budburst occurring 2 days earlier per decade). That is, the phenological effects of global warming are happening up to ten times faster in Oklahoma than in other parts of North America. But one species (the silver maple, Acer saccharinum) opened its buds later. The reason was not the warmer temperatures in the spring, but the heat wave and drought in the summer, which damaged the buds.

Trees cannot keep opening their buds earlier and earlier forever. How far can the trend to earlier budburst continue? If winters are too warm, some tree species will have a later budburst, not an earlier one, because cold temperatures in winter are necessary to break down inhibitors. How much winter cooling is necessary to break down those inhibitors? I have begun research to help answer these questions.

The second presenter is Dr. Lara Souza of the University of Oklahoma and the Oklahoma Biological Survey. What happens when species experience global warming? They could either stay where they are and adapt (either through natural selection or acclimatization); go extinct; or migrate to other locations with cooler temperatures.

Consider some examples. Camille Parmesan and associates showed that some British butterflies moved north during the twentieth century. They gathered their data from insect collections, in which the date and location are recorded. Another study, by Lenoir and associates, showed that most but not all species of mountain plant species shifted their distributional range to higher elevations. You can download the Lenoir data from Science (these data are open access, unlike many of the articles in Science) and have students compare the average elevation in the early vs. the late twentieth century for each species, either by making a graph or by doing a simple statistical analysis (paired-t test). The Rocky Mountain Biological Laboratory, at about 10,000 feet elevation in the Rockies, also has an excellent data set about the first day in spring at which many species of birds and mammals became active; this data set stretches back to 1974. Some, but not all species, have become active much earlier in the spring in the past forty years. Another study, by Eric Post and associates, show that the phenological patterns of arctic tundra plants have shifted dramatically, while those of caribou have not changed as much, which means that many caribou food plants are no longer available (or have older, less nutritional foliage) when the caribou need them. Therefore the caribou have fewer surviving offspring. A study by Laura Burkle and associates showed that flowering times of numerous plant species have shifted over the last 120 years, and that this has resulted in the loss of pollinator associations in many cases.

Lara then told us how students can contribute their own data to, or work with data sets made available by, the National Phenological Network. There are also some citizen-science projects being done, including common garden experiments where people in different places plant the same plants, and keep track of their phenological responses. With the example of lilacs, people all over the country have planted not just lilacs but exactly the same breed of lilacs so that they can make direct comparisons of the same breed of plant in very different geographic locations. (There are some limitations. For example, lilacs do not grow well in Oklahoma.) Students can participate in these citizen-science projects and contribute their data to a national database.

This morning the participants learned about both a whole new way of understanding and teaching about global warming.

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