Spring has sprung in the Laurel Highlands of Pennsylvania. The ephemeral streams are flowing, the hillsides and valleys are blanketed with native spring wildflowers, and the neo-tropical migratory birds are making their way back to our hardwood forests, their summer breeding grounds.
To the average spectator, these signs of spring are exciting to see; we patiently wait through the last few months of winter to see these spring harbingers. Most times, we are excited to see early glimpses of spring in hopes that winter will soon be gone and sunshine is on its way.
But, when we see spring arrive early…is it a good thing?
After a recent read-through of the PA DCNR’s document “DCNR and Climate Change: Planning for the Future“, one can gather the early arrival of spring is an alarming glimpse into our future if climate change persists in its projected trend.
Since the early 1900s, Pennsylvania has recorded an average temperature increase of 1.8° F. Winter temperatures have become warmer, at a rate of 1.3 °F per decade from 1970 to 2000 in the northeast U.S.1 Even more alarming, projections show it could be as much as 5.4 °F warmer by 2050 than it was in the 1990s.2
Warmer winter temperatures may sound nice to those of us who aren’t keen on the cold, snowy winters in the Highlands. On the other hand, a warm winter brings a whole slew of problems to our forests.
You may have noticed trees blooming earlier than previous years. In fact, researchers at Carnegie Museum of Natural History have found that trees are showing leaves two weeks earlier than historic accounts have recorded. Furthermore, spring wildflowers are blooming one week earlier than their predecessors 160 years ago. Interestingly enough, this research was made possible by studying the journals of Henry David Thoreau in the mid-1800s during his time at Walden Pond.3
Early leaf-out and blooming of fruit trees is bad news for farmers with orchards. Just because the temperatures are warming sooner, doesn’t mean our last frost date won’t kill off the blooms (and future fruits) of an entire orchard that has bloomed prematurely. *Side note: I’m currently writing this blog post on April 22, 2020. Outside my window, it is snowing and the cold weather last night damaged my peach trees which had already begun to bloom.
Underneath the surface-level impacts of warmer winters, early leaf-outs, and late frosts, we need to take a look at the interconnected relationships between plants, insects, and birds. When fruit trees bloom in the spring, they await their pollinators to do the work to help them produce fruit later on in the season. But, when plants are blooming before their pollinators have emerged from dormancy, we could experience less fruit production.
On the other hand, trees can see increased damage to their bark and inner wood by insects that are emerging before the migratory birds that feed on them return to the Highlands.4 The neo-tropical migratory birds that travel from South America to the Appalachian mountains each year to breed and raise their young are leaving their warm weather wintering grounds earlier than historic record shows. Some birds are arriving more than a week earlier than previous decades. This change in migration hasn’t necessarily corresponded to the change in insect emergence so the birds have had struggles with finding enough food to fuel their very long journey to Appalachia.5
Speaking of birds, the warmer winters have also impacted the bird species that stick around for the colder months. Among 305 North American bird species, the main populations have shifted their locations more than 40 miles north between 1966 and 2013. Of the 305 bird species, 48 species have moved more than 200 miles north to experience the cold winter conditions they prefer. Black-capped chickadees are moving north at about one mile per year. As they move north, Carolina chickadees are moving up from their southern habitats, creating a hybridization of the two species where they overlap. In the southeast part of Pennsylvania the Carolina chickadee has completely replaced the black-capped chickadee.6
At this point you’re probably wondering what else could possibly be going awry due to climate change. Well, all sorts of things. But for brevity we’ll just focus on one more point: water.
In addition to the higher temperatures, Pennsylvania has also seen an increase in annual precipitation which is expected to increase by 8%, with a winter increase of 14%.2 Increased precipitation goes hand in hand with a higher frequency of large storm events, changes in peak stream flows, and decreased snow cover.
The temperature of water in our streams is an important factor in maintaining a healthy aquatic ecosystem. However, increased temperatures can lead to warmer streams. This doesn’t sit well with our coldwater fish species like brook trout. Projections show Pennsylvania could be unsuitable for coldwater fish species by the year 2100 if we don’t curb our greenhouse gas emissions.2
As precipitation changes and increased temperatures carve the path for a longer growing season, we expect to see changes in stream flows. The peak stream flows are expected to occur 10-14 days earlier and summer low-flows are expected to last about a month longer.4 This could also impact our forest ecosystems that rely on the early spring flows of ephemeral streams.
There are many ways in which climate change will impact (and is already impacting) our beloved Laurel Highlands. It’s a topic that leaves us wondering if there is hope for the future. Can we turn this ship around?
It’s crucial to continue work in conservation, environmental restoration, outdoor education, and all other environmental sectors, whether these are paid positions, volunteer opportunities, or simply hobbies we have in our own backyards.
What can you do to personally reduce your impact?
- plant a pollinator garden, participate in tree plantings, and create wildlife habitat on your property
- conserve water use, especially during dry summer months
- talk to your family, friends, and community about the impacts of climate change in our region
- become an advocate for the area you live – become aware of industrial impacts and speak out about the concerns of pollution and environmental degradation that come with industry moving through your area
- educate yourself further on the topic of climate change
There are plenty of other ways in which you can become involved. The first step is becoming aware and ready to take action!
- Climate Change in the U.S. Northeast. A Report of the Northeast Climate Impacts Assessment. October, 2006.
2. Pennsylvania Climate Impacts Assessment Update – May, 2015. Penn State University.
3. Davis, K.J. (2019, February 8). Researchers Use Thoreau’s Journals To Find Climate Change’s Impact On Wildflowers. 90.5 WESA News. https://www.wesa.fm/environment-energy/2019-02-08/researchers-use-thoreaus-journals-to-find-climate-changes-impact-on-wildflowers
4. Pennsylvania Department of Conservation and Natural Resources. DCNR and Climate Change: Planning for the Future. September 2015.
5. GrrlScientist. (2020, January 6). Climate Change Is Affecting The Timing Of Bird Migration, But Are Birds Adapting Fast Enough? Forbes. https://www.forbes.com/sites/grrlscientist/2020/01/06/climate-change-is-affecting-the-timing-of-bird-migration-but-are-birds-adapting-fast-enough/?sh=2907838d76db
6. U.S. Environmental Protection Agency. 2014. Climate Change Indicators in the United States, 2014. Third edition. EPA 430-R-14-004. www.epa.gov/climatechange/indicators