RE SE A R CH
The Cold, Hard Truth About Climate Change Climate change is happening right here in Cleveland, but we can make a difference. By David J. Burke
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t’s a beautiful, sunny day in late March, and the woods at Holden Arboretum are filling with bird song. On this day, the sound of birds, and a light breeze through the treetops, mixes with the crunch of leaves beneath our feet. We are walking through Bole Woods to one of Holden’s long-term research projects. When arriving at the site, you are greeted by many multicolored flags sticking out of the ground. This project is Holden’s woodland phenology project. Phenology is the study of the timing of annual phenomena in nature, including plant emergence, growth and especially flowering, and is an important way to understand how plants may be responding to a warmer world.
“We monitor the phenology of spring ephemerals — the woodland wildflowers that grow in the spring when the forest canopy is still open. We watch trout lily, trillium, dutchman’s breeches and squirrel corn closely from late March onward to see when they’re coming up, flowering and producing seeds,” says Emma Dawson-Glass, a research specialist at Holden Forests & Gardens. “Spring ephemeral phenology is closely linked to weather, and in warmer years, flowers tend to emerge earlier. As the climate warms, these shifts in timing can have important effects for other organisms that interact with these wildflowers.” Global climate change is in the news a lot these days and often seems controversial. But there is widespread agreement among scientists and scientific organizations that the climate is changing and that this change is the direct result of human activities. In fact, at least half of the warming observed in recent decades is the result of the human activities that produce greenhouse gases such as carbon dioxide from the burning of fossil fuels. Although we may think of polar bears and melting ice floes, climate change is a global issue, and it’s impacting us right here at home. The city of Cleveland has warmed on average by 2.5 degrees Fahrenheit since the 1950s. And at current rates of greenhouse gas emission, Cleveland will warm by an additional 3 to 7 degrees Fahrenheit by 2050. Unless we take action to reduce greenhouse gas emissions, our grandchildren living in Northeast Ohio will experience average temperatures as much as 10 degrees warmer than what our parents experienced in the 1950s, with potentially serious environmental consequences.
14 FORESTS & GARDENS
The most serious impact of warming temperatures will be on patterns of rainfall and snowfall during the year. Warmer winters may be accompanied by less snowfall and more rain, changing water levels in lakes and rivers. Reduced precipitation during the growing season can reduce crop yield on our farms and in our gardens. Lack of winter snowfall can lead to increases in freezing and thawing of soil, damaging plant roots and soil organisms. The warming temperatures will also affect the timing of plant, insect and animal growth and reproduction (that is phenology). Winter warm spells can lead to early flowering and leaf out for many plants, which can be vulnerable to damage by spring frosts. Warming can also lead to plants flowering before the emergence of their insect pollinators, leading to reduced seed set and jeopardizing pollinator populations that emerge too late to take advantage of flower food sources (e.g. nectar and pollen, which are used as food).
As the climate warms, these shifts in timing can have important effects for other organisms that interact with these wildflowers. Warmer winter temperatures can also lead to pest outbreaks, especially the migration of invasive pests into our region. For example, hemlock wooly adelgid is an invasive insect attacking hemlock trees, eventually leading to tree decline and death. In the past, our cold winters have excluded this pest from northern Ohio, but as winters have warmed, the insect has begun to invade our region and is now found in many of our region’s forests, including those at the Holden Arboretum. So, what can we do as individuals or organizations to make a difference when it comes to climate change? First, we need to recognize that climate change is real and is the result of human actions. That’s both good and bad news; the bad news is that we have triggered this slew of serious changes in our climate and, subsequently, the environment. The good news is that we have the ability to change our behavior and have a positive impact.
