Public gardens collaborate with scientists to study how global climate change impacts local plant growth, while also actively displaying the effects climate change. Public gardens have the opportunity to educate and engage the community and moderate an open, honest dialog about climate change.

What is the difference between weather and climate change?

Weather is impacted by climate and changes in local weather are the cumulative result of changes in global climate. Weather should be thought of as the daily environmental conditions for a specific area (e.g., Illinois or Chicago) whereas climate is global and measured over longer time-frames (e.g., average global air temperature in 2000 vs. 2015).

Many climate models suggest that local weather extremes (e.g., warm fall/winter temperatures, increased rainfall during typically dry months) are products of change in global climate as a result of increased anthropogenic (human caused or released) atmospheric greenhouse gas releases (e.g., carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, etc.).

Bringing the discussion of weather versus climate home, Chicago experienced one of its mildest winters on record in 2015-16. According to the National Weather Service, Chicago’s 2015-16 winter was the 14th-warmest meteorological winter since 1872 with an average temperature of only 31.3° F, which was 4.9° F higher than normal. Moreover, only 16.3 inches of snow fell in Chicago during winter 2015-16, which was 11.8 inches lower than average.

The 2015-16 winter in Chicago was so mild in fact, that as early as January and February horticulturalists and home gardeners alike were concerned that some plants may break bud early enough that a late season freeze would cause damage. The local weather extreme of a Chicago mild winter was the result of a strong El Nino – and its surprising strength was itself a result of global climate changes.

Graphical review of the 2015-16 Illinois winter courtesy of the National Weather Service, Chicago office. Figures of average and departure from normal temperatures show just how warm this past winter was in the Chicago area.

How can urban public gardens contribute to the climate change discussion?

Studying how climate change effects plant phenology

Humankind is already experiencing the effects of elevated levels of anthropogenic atmospheric carbon dioxide as shifts in temperature and precipitation patterns change local weather in both the micro- and macro-time scales.

Plant phenology is the study of how seasonal weather fluctuations effect and change plant and animal life. The impact of a warming global climate on spring plant phenology and plant adaption is beyond doubt. Seed germination, leaf emergence, flowering and fruiting, and general green-up of the northern hemisphere have all advanced in concert with regional warming trends (Parmesan & Hanley, 2015).

“(Public) Gardens pioneer and demonstrate cutting-edge strategies of landscape management and design that can be applied to the green industry or the home gardener.”
– Ben Futa, Director of Allen Centennial Garden

Anthropogenic climate change and other human activities related to land use are altering environmental conditions, driving shifts in plant species ranges, and nearing the point of outstripping a plant’s natural ability to adapt to local climate; often resulting in the creation of novel planting environments or ecosystems (Martinuzzi et al., 2015).

Even more disturbing, McKinney et al. (2012) reported that peak flowering for certain plants pollinated by hummingbirds has advanced beyond the earliest arrival date for migratory hummingbirds for northern breeding sites.

Small, urban public gardens, such as Lurie Garden and Allen Centennial Garden, can play an important role in bringing the discussion of connections among local weather extremes, global climate change, and changes in plant phenology.

Public gardens are living laboratories for people to experience these obvious changes in plant phenology that result from a warming world.

Public gardens are at the forefront of the climate change conversation—collaborating with climate scientists to study how climate change impacts plant growth and acting as active, tangible displays of the effects of climate change by discussing changes in local plant phenology.

One of the most powerful statements about climate change a public garden can make is as a living laboratory, where, as Futa sees it, “…public gardens can experiment and explore new ideas and technologies. Gardens pioneer and demonstrate cutting-edge strategies of landscape management and design that can be applied to the green industry or the home gardener.”

Public gardens are living laboratories for people to experience these obvious changes in plant phenology that result from a warming world. Through the act of seeing plants blooming or greening-up earlier-and-earlier year-after-year, the natural inquisitive nature of people asking “Why?” gives public gardens the perfect opportunity to act as a source of expert information about mitigating impacts of global climate change and changes in phenological cycles.

Linear regression best fit model of change through time until the first flowering of two plants at the Rocky Mountain Biological Laboratory (broken lines) intersects with first arrival of migratory hummingbird (solid line). Figure shows anthropogenic climate change causing early first flowering while arrival of hummingbird remains relatively constant across time. Not until nearly 2030 and 2070 will first flowering and hummingbird arrival coincide. Figure after McKinney et al. (2012).

Public Gardens as climate change education and conversation platform

Public gardens, such as Chicago’s Lurie Garden, have the opportunity to provide a sense of community in the climate change conversation by giving the opportunity to engage in honest, open dialog about climate change in objective, consistent ways that address causes and impacts as well as individual and collective actions that can make a difference.

“The 365-days of the garden are paramount, because in a world famous public garden there can be NO ‘off season’—not even for one week.”
– Guy Sternberg, of Starhill Forest Arboretum

Futa agrees and adds, “Public gardens are non-threatening; they’re safe, and comfortable places where, by virtue of their genesis, they can introduce visitors to climate change without compromising political or social capital.”

For example, public gardens allow people to see how local weather extremes can “catch” plants off-guard. In the picture below we see Muscari armeniacum ‘Superstar’ blooming at the Lurie Garden against a backdrop of an late-season snowfall. Such local weather extremes are one consequence of anthropogenic climate change.

Guy Sternberg, of Starhill Forest Arboretum, points out “At the Lurie Garden, you can see how this subject is artfully handled. The 365-days of the garden are paramount, because in a world famous public garden there can be NO ‘off-season’—not even for one week.”

Having no off-season means that people experience the connection between plant growth and climate year-round, giving a garden an opportunity to engage the public and elected officials in a discussion about climate change.

Public gardens have the opportunity to exhibit how to design, plant, and manage these emerging novel environments, highlighted by Martinuzzi et al., (2015), for both aesthetic beauty and environmental responsibility. A significant role of the Lurie Garden is to demonstrate this balance between horticultural design and environmental sustainability—showcasing the value to urban settings of mixing native and non-native plants in a garden, how garden design can reflect and reinterpret the ecological and sociological history of a site, and how sustainable management practices work in large and small garden settings.

Public Gardens are a place where every generation can learn about and experience nature.

Communities can lean on their local public gardens to learn about and contribute to the climate change conversation by visiting their garden, engage in programs and activities, and learn how to bring climate changing landscapes to their homes.

How has a public garden near you effected your experience and understanding of climate change?

You can find a public garden near you today by searching the American Public Gardens Association. Learn more about the interplay of climate change, changing plant phenology, and public gardens by reading the following:

American Public Gardens Association Climate & Sustainability Alliance

Botanic Garden Conservation International, Botanic Gardens & Climate Change

Cook, B.I., E.M. Wolkovich, C. Parmesan. 2012. Divergent responses to spring and winter warming drive community level flowering trends. Proceedings of the National Academy of Science of the USA. 109:9000-9005.

De Frenne P., B.J. Graae, J. Brunet, et al. 2012. The response of forest plant regeneration to temperature variation along a latitudinal gradient. Annals of Botany. 109:1037-1046.

Intergovernmental Panel on Climate Change, Climate Change 2014: Impacts, Adaptation, and Vulnerability

Piao, S., T. Jianguang, C. Anping, et al. 2015. Leaf onset in the northern hemisphere triggered by daytime temperature. Nature Communication. 6:6911.